Galileo Webchat - March 6, 1998

Ron Baalke, Galileo Webmaster: . . . . Fri, Mar 6, 12:46AM PDT (-0700 GMT)
The Galileo Webchat is now in session! Enjoy!

Brian C: . . . . Fri, Mar 6, 12:46AM PDT (-0700 GMT)
Hi. How is everyone today?

David V.: . . . . Fri, Mar 6, 12:47AM PDT (-0700 GMT)
hello, is anybody there?

Brian C: . . . . Fri, Mar 6, 12:47AM PDT (-0700 GMT)
With all the new data that has come in, how has this affected our perspctive of the Jovian system...

anonymous: . . . . Fri, Mar 6, 12:47AM PDT (-0700 GMT)
Hey guys, I have a few questions for you. First of all, what do you do, exactly?

David V.: . . . . Fri, Mar 6, 12:49AM PDT (-0700 GMT)
with all the new europa images flowing in, this may seem like an odd question, but what happened to the high res images of Ganymede from G7 and G8?? They are not on the Galileo mission page. Were there camera problems? ...

Brian C: . . . . Fri, Mar 6, 12:53AM PDT (-0700 GMT)
I was just browsing one of the pages dedicated to Galileo, and was reading about the "slushy subsurface" Does this intimate that Europa may possably have an active core, or is it more like the case with IO, where tidale forces are responsable for internal heating?

Ronin: . . . . Fri, Mar 6, 12:53AM PDT (-0700 GMT)
how much data can you guys get from the new photos of europa?

Michael Strickland: . . . . Fri, Mar 6, 12:53AM PDT (-0700 GMT)
Hi Ron, thanks for your great job with the email updates!

Ronin: . . . . Fri, Mar 6, 12:53AM PDT (-0700 GMT)
in terms of physical infor like depth of ice, etc?

David V.: . . . . Fri, Mar 6, 12:54AM PDT (-0700 GMT)
i think were all on about 10 minutes early......

R Sullivan SSI: . . . . Fri, Mar 6, 12:54AM PDT (-0700 GMT)
Hi Ron: Rob Sullivan (SSI) checking in from Cornell.

anonymous: . . . . Fri, Mar 6, 12:54AM PDT (-0700 GMT)
Are there any plans for an extended mission past the current Europa Mission? If not, what happens to the spacecraft?

Ronin: . . . . Fri, Mar 6, 12:54AM PDT (-0700 GMT)
i think you got the wrong guy

anonymous: . . . . Fri, Mar 6, 12:54AM PDT (-0700 GMT)
Hello from North Dakota

anonymous: . . . . Fri, Mar 6, 12:54AM PDT (-0700 GMT)
what kind of life can exist on ewuropa

Ronin: . . . . Fri, Mar 6, 12:55AM PDT (-0700 GMT)
as far as euroa goes how many missons are planned for exploration?

Steve L: . . . . Fri, Mar 6, 12:55AM PDT (-0700 GMT)
hi---how sure are we that what we are seeing on Europa is reaaly ice/slush?

Brian C: . . . . Fri, Mar 6, 12:55AM PDT (-0700 GMT)
Is anybody from the Galileo team online?

anonymous: . . . . Fri, Mar 6, 12:55AM PDT (-0700 GMT)
Hello from North Dakota

Ronin: . . . . Fri, Mar 6, 12:55AM PDT (-0700 GMT)
if it is slush, does it indicate water nearer the surface or what?

anonymous: . . . . Fri, Mar 6, 12:56AM PDT (-0700 GMT)
could jelly fish exist there or jelly worms

gog: . . . . Fri, Mar 6, 12:56AM PDT (-0700 GMT)
I believe they turned us on before they where ready to talk.

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 12:57AM PDT (-0700 GMT)
Hello- When someone from the instruments team logs in: What instruments do you wish Galileo would have had to do direct measuremets of the thickness of Europa's crust?

Ronin: . . . . Fri, Mar 6, 12:57AM PDT (-0700 GMT)
it's still 3 mins to 1 (PST) according to my clock

Steve K./ASU: . . . . Fri, Mar 6, 12:57AM PDT (-0700 GMT)
I am an associate of the Galileo team.

AnonyMouse: . . . . Fri, Mar 6, 12:57AM PDT (-0700 GMT)
What about that movie being made about monsters living under the ice on Europa?

Ronin: . . . . Fri, Mar 6, 12:57AM PDT (-0700 GMT)
Hi Steve

R Sullivan SSI: . . . . Fri, Mar 6, 12:57AM PDT (-0700 GMT)
To Steve L.: Since at least the '70s ground-based telescopic spectral studies have identified the dominant substance on the surface of Europa to be water ice.

Ronin: . . . . Fri, Mar 6, 12:58AM PDT (-0700 GMT)
with the new photos, has anyone been able to determine say just how much ice there is?

Steve K./ASU: . . . . Fri, Mar 6, 12:58AM PDT (-0700 GMT)
REgarding the instruments to measure the crustal thickness, we are looking forward to a near future mission that will have a sounding radar system, and the ability to measure the 'tides' that rise on Europa's surface as it passes between Jupiter and the larger outer Galilean satellites.

anonymous: . . . . Fri, Mar 6, 12:58AM PDT (-0700 GMT)
what would ya do if ya did find an ocean with life

Ronin: . . . . Fri, Mar 6, 12:59AM PDT (-0700 GMT)
if not will, we be able to tell with more photos and data from galileo

David V.: . . . . Fri, Mar 6, 12:59AM PDT (-0700 GMT)
to anyone on the imaging team: what happened to the Ganymede 7 and Ganymede 8 hi-resolution images? They dont show up on your page. Were there camera problems??

JK James: . . . . Fri, Mar 6, 12:59AM PDT (-0700 GMT)
Hello to the Galileo team. A very simple question: are tidal forces a result of microgravity? I mean an orbiting satellite, whether a moon or a shuttle should experience very little pull from a planet, no?

Ron Baalke, Galileo Webmaster: . . . . Fri, Mar 6, 12:59AM PDT (-0700 GMT)
anoymous: I've the Webmaster for the Galileo home page for the past 3 years. I've been doing it part-time, I've primarly worked on telemetry systems in the Deep Space Network, including 2 years on the Galileo S-Band project, where we built a custom telemetry system to work with Galileo low gain antenna. I've only recently moved into outreach fulltime, and also work on the STARDUST and Mars '98 outreach teams.

anonymous: . . . . Fri, Mar 6, 1:00PM PDT (-0700 GMT)
Are there any plans for an extended mission past the current Europa Mission? If not, what happens to the spacecraft?

Ronin: . . . . Fri, Mar 6, 1:00PM PDT (-0700 GMT)
these "tides"? could you elaborate? Steve?

R Sullivan SSI: . . . . Fri, Mar 6, 1:00PM PDT (-0700 GMT)
To Carl Banks: Radar can sometimes be used to determine ice thickness over water (on Earth), but the thickness of Europa's ice might be too much for this method to work. Would have been interesting to try, though.

Leslie: Outreach: . . . . Fri, Mar 6, 1:00PM PDT (-0700 GMT)
Hi! This is Leslie from Galileo Outreach. Welcome, everyone!

anonymous: . . . . Fri, Mar 6, 1:01PM PDT (-0700 GMT)
steve what kind of life could exist on EUROPA ccould jelly fish or jelly worms exist when would ya send a probe to dig for life

Steve K./ASU: . . . . Fri, Mar 6, 1:01PM PDT (-0700 GMT)
The tidal forces result from a 'tug of war' that Europa experiences when large objects are on opposite sides pulling at it. Jupiter and Ganymede are the major examples.

Cathy H.: . . . . Fri, Mar 6, 1:01PM PDT (-0700 GMT)
subsurface ice on our moon, europa covered in ice, mars river impressions and icy comets; now that there is evidence of this basic molecule for life will there be further experiments like on the earlier mars landers that test for life?

PROASTRA: . . . . Fri, Mar 6, 1:01PM PDT (-0700 GMT)
Okay, I'm logged on...Could Dr. Chapman, or anyone else, confirm if the idea that Callisto may have an ocean under its frozen crust like Europa?

StarGazer: . . . . Fri, Mar 6, 1:01PM PDT (-0700 GMT)
Thank you Leslie :)

Ronin: . . . . Fri, Mar 6, 1:01PM PDT (-0700 GMT)
To R. Sullivan: so would it be accurate to say that the thickness of the ice in Europa will be at least thicker than that in say Antartic or Artic?

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 1:01PM PDT (-0700 GMT)
Steve K, thanks for the answer. Is is possible that this "sounding radar" system could make use of the communications antennas? I read that Cassini was doing something like that.

Leslie: Outreach: . . . . Fri, Mar 6, 1:02PM PDT (-0700 GMT)
anonymous: While we will no longer take images with Galileo after the GEM mission is over, there is a plan proposed to keep monitoring the radiation levels near Jupiter, and watch how Galileo and its part fail over time.

John G.: . . . . Fri, Mar 6, 1:02PM PDT (-0700 GMT)
Galileo has produced many fantastic close-up images of selected areas of Europa, Ganymede and Callisto--but in terms of over-all mapping coverage, what percentage of each moon has been imaged at a higher resolution than Voyagers 1 & 2 ?

Ronin: . . . . Fri, Mar 6, 1:02PM PDT (-0700 GMT)
so these "tides" are ice/slush right?

JK James: . . . . Fri, Mar 6, 1:02PM PDT (-0700 GMT)
Thanks Steve K., but the way they are described implies that one might actually "feel" them, if say you lived on Europa. This is false, no? Don't they result from very small gravitational fields which sum tremendously across a liquid expanse.

Brian C: . . . . Fri, Mar 6, 1:03PM PDT (-0700 GMT)
How 'bout a simple question...What's the surface temprature of Europa (approx), and have we seen any "hot spots" near or around the contravercial "Slushy" areas?

Andre: . . . . Fri, Mar 6, 1:03PM PDT (-0700 GMT)
The latest pictures of Europa are the best yet. Where on Europa would the ice be thinnest if a subsurface ocean exists?

anonymous: . . . . Fri, Mar 6, 1:03PM PDT (-0700 GMT)
leslie can ya tell me what kind of life they expect to find

Steve K./ASU: . . . . Fri, Mar 6, 1:03PM PDT (-0700 GMT)
to anonymous: Well, we still need to be sure we have liquid water. We know we have solid water ice, and a source of organic materials in the impacting meteors/comet fragments, etc. We also need a heat source, and we probably get that from the tidal forces I mentioned above. BUT, even if you have flour, eggs, milk and sugar in your kitchen, you don't necessarily have a cake, right? Nevertheless, the possibility of life, if we find we do have significant liquid water, now or in the past, is very exciting.

Ana: . . . . Fri, Mar 6, 1:03PM PDT (-0700 GMT)
Greetings from Greece everyone...nice to be here!

R Sullivan SSI: . . . . Fri, Mar 6, 1:03PM PDT (-0700 GMT)
To Cathy H.: Tests for the presence of life are inevitable, but flying a miniature biology lab somewhere in the solar system is an expensive project, so it probably won't happen soon.

Mass. Meteors: . . . . Fri, Mar 6, 1:03PM PDT (-0700 GMT)
Hi, all in the Galileo team - THANK YOU for hosting these chats...

Volcanopele: . . . . Fri, Mar 6, 1:04PM PDT (-0700 GMT)
Hi does anybody know when the new Io pix are coming out

Andre: . . . . Fri, Mar 6, 1:04PM PDT (-0700 GMT)
Does Europa have a magnetic field?

David V.: . . . . Fri, Mar 6, 1:05PM PDT (-0700 GMT)
yes, are there any new reports on Europa's (possibly) internal field??

Ronin: . . . . Fri, Mar 6, 1:05PM PDT (-0700 GMT)
To R.Sullivan: So you don't expect the first mission to Europa to find life but rather liquid water right?

Steve L: . . . . Fri, Mar 6, 1:05PM PDT (-0700 GMT)
and I might add Ron Baalke is doing an excellent job in keeping me up to date with all that is going on now. my thanks, sir

Leslie: Outreach: . . . . Fri, Mar 6, 1:05PM PDT (-0700 GMT)
Cathy H.: investigations are being made into a future mission to send a lander to Europa, then use heat to melt its way under the ice, then when it reaches an ocean, to swim there and investigate the environment. HOWEVER, we need to confirm for sure that an ocean does exist now, and then send an orbiter to determine where the thinnest place in the ice is.

herb: . . . . Fri, Mar 6, 1:05PM PDT (-0700 GMT)
how about a nuclear warhead launch to impact and detonate on europa? existing or future europa orbiters would witness the impact and(possible) outgassing--comments please..

Steve: . . . . Fri, Mar 6, 1:05PM PDT (-0700 GMT)
Hello from Potsdam

Michael Strickland: . . . . Fri, Mar 6, 1:06PM PDT (-0700 GMT)
Yes, THANKS RON!! :-)

R Sullivan SSI: . . . . Fri, Mar 6, 1:06PM PDT (-0700 GMT)
To Ronin: Certainly the ice we see in the images is thicker than the arctic (few m), and probably thicker than even the thickest Antarctic ice shelves. One must keep in mind that what we see in the images may reflect conditions of the past, and that cooling might now have thickened the ice. Large fractures running through the rubble "matrix" between plates attest to its current solidity.

Ron Baalke, Galileo Webmaster: . . . . Fri, Mar 6, 1:06PM PDT (-0700 GMT)
What kind of life can exist on Europa if it is found? Your guess is probably as good as anybody elses. If there are thermal vents at the bottom of the ocean, then it may be similar to life at the thermal vents on the bottom of Earth's oceans. However, I would definitely not rule out a few surprising exotic lifeforms.

Ronin: . . . . Fri, Mar 6, 1:06PM PDT (-0700 GMT)
to Leslie: When will this orbiter be launched?

Steve K./ASU: . . . . Fri, Mar 6, 1:06PM PDT (-0700 GMT)
Reply to andre: Right now no significant magnetic field has been measured at Europa. There are slight changes in the local magnetic field of Jupiter (very small, from what I've been able to gather) that might be some very tiny remanent field, or perhaps have to do with the circulation of salty water, if there is any liquid down there at present. Your compass sure wouldn't do any good on Europa, though!

anonymous: . . . . Fri, Mar 6, 1:06PM PDT (-0700 GMT)
what would they do if they found europa had life and an ocean

Volcanopele: . . . . Fri, Mar 6, 1:06PM PDT (-0700 GMT)
I have seen landscape on earth before that looked exactly like the landscape in the Highest rresolution pic. Can anybody jog my memory as to whre that would be

Steve: . . . . Fri, Mar 6, 1:07PM PDT (-0700 GMT)
How do we determine the thickness of the ice?

Ronin: . . . . Fri, Mar 6, 1:07PM PDT (-0700 GMT)
Thanks Ron, that helped a lot.

David V.: . . . . Fri, Mar 6, 1:08PM PDT (-0700 GMT)
to herb: uh, a nuclear warhead wouldny be the best thing for those of us interested in life on Europa....

Ronin: . . . . Fri, Mar 6, 1:08PM PDT (-0700 GMT)
is there sophisticated equipment that will allow us to determine the thickness of Europa's ice if it is so thick?

peter o.: . . . . Fri, Mar 6, 1:08PM PDT (-0700 GMT)
Do you know how deep the ocean is?

El Matao (from Spain): . . . . Fri, Mar 6, 1:08PM PDT (-0700 GMT)
Hi from Spain

Mass. Meteors: . . . . Fri, Mar 6, 1:08PM PDT (-0700 GMT)
R Sullivan: If tidal forces are the putative energy source for a liquid (or formerly liquid) subsurface ocean, then what might have changed? I'd always understood the Galilean satellites' orbits to have been rock-solid over pretty long periods...

Ronin: . . . . Fri, Mar 6, 1:09PM PDT (-0700 GMT)
to herb: someone joked that the mission would be called "in pieces we come" if we decided to sent a warhead :)

Michael Strickland: . . . . Fri, Mar 6, 1:09PM PDT (-0700 GMT)
Peter, they don't even know *if* there is an ocean.

Steve K./ASU: . . . . Fri, Mar 6, 1:09PM PDT (-0700 GMT)
reply to Steve: Well, it's tough with just pictures like we currently have, especially since you're seeing evidence of features that formed sometime in the past (near or distant?). But one can get some handle on the thickness of the ice by seeing how a radar signal is reflected and absorbed by an ice layer that may have water beneath it.

anonymous: . . . . Fri, Mar 6, 1:09PM PDT (-0700 GMT)
what program did you use to map the trajectory from earth to europa? did your team use NAVIGATOR?

R Sullivan SSI: . . . . Fri, Mar 6, 1:09PM PDT (-0700 GMT)
To Ronin: The order of your objectives sounds reasonable. Both will be expensive projects, probably easier to fund and fly separately. Hard to predict, though.

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 1:09PM PDT (-0700 GMT)
I have some specific questions for the participants of the last web chat. Will James Granahan or Duane Bindschadler be joining us today?

Steve L: . . . . Fri, Mar 6, 1:09PM PDT (-0700 GMT)
Why not keep taking pictures as long as the spacecraft can? Can DSN handle the load?

Leslie: Outreach: . . . . Fri, Mar 6, 1:09PM PDT (-0700 GMT)
anonymous: We don't really EXPECT to find any kind of life on Europa with what we know now. However, scientists suspect that the necessary conditions for life exist on Europa. With what we have learned on Earth in the last 10 years or so about microbial life near heat vents on Earth's ocean floor, the possibility for life in a similar environment on Europa becomes more real.

Brian C: . . . . Fri, Mar 6, 1:09PM PDT (-0700 GMT)
Is there any plans to send a mission to Titan to see how it compares with Europa??

anonymous: . . . . Fri, Mar 6, 1:09PM PDT (-0700 GMT)
what next after the probe

Doug Inwood: . . . . Fri, Mar 6, 1:09PM PDT (-0700 GMT)
Hello all

Steve: . . . . Fri, Mar 6, 1:10PM PDT (-0700 GMT)
The visual data suggests strongly that there is some liquid below the surface

Webslingr: . . . . Fri, Mar 6, 1:10PM PDT (-0700 GMT)
Is there a way to determine the depth of the water beyond the ice with radar technology?

anonymous: . . . . Fri, Mar 6, 1:10PM PDT (-0700 GMT)
To R. Sullivan, If radar fails to measure the ice thickness are there any plans to send a lander to look for natural or induced(with a small explosion) sceismic activity to determine the internal structure. Dennis D.

Ronin: . . . . Fri, Mar 6, 1:10PM PDT (-0700 GMT)
To Ron: how expensive. doable in 2 discovery class missions?

anonymous: . . . . Fri, Mar 6, 1:10PM PDT (-0700 GMT)
what program did you use to map the trajectory from earth to europa? did your team use NAVIGATOR?

Leslie: Outreach: . . . . Fri, Mar 6, 1:10PM PDT (-0700 GMT)
Ronin: An orbiter for Europa may be launched in 2003. Plans are underway for that now.

Andre: . . . . Fri, Mar 6, 1:10PM PDT (-0700 GMT)
Will the malfunctioning gyroscope be a problem for the next encounter or can the other gyroscope take over?

Steve K./ASU: . . . . Fri, Mar 6, 1:10PM PDT (-0700 GMT)
to peter o.: Ditto what Michael STrickland just said. We see good evidence that the ice layer was at least very ductile or slushy in the past. We don't know for sure how long ago, and probably won't for some time, as we don't know the age of the surface of Europa. The presence of liquid water, now or in the past, remains a distinct POSSIBILITY, and one we are all interested very much in investigating.

Laura, SPOT: . . . . Fri, Mar 6, 1:11PM PDT (-0700 GMT)
Perry, Duane Bindschadler is out sick today. James is hopefully going to join us later today if he gets a chance.

David V.: . . . . Fri, Mar 6, 1:11PM PDT (-0700 GMT)
based on galileo/voyager imags, what is the HIGHEST relief yet seen on Europa, and what does that imply about ice thickness (based on isostasy)?

PROASTRA: . . . . Fri, Mar 6, 1:11PM PDT (-0700 GMT)
My question to R. Sullivan. I understand there are some mountains on Europa, called massiffs. How high are they? And what are the slopes like, compared to say a steep ski hill on Earth?

Leslie: Outreach: . . . . Fri, Mar 6, 1:11PM PDT (-0700 GMT)
Brian C: The Cassini mission that was launched late last year will drop a parachuted probe into Titan when it arrives (2004???)

Steve: . . . . Fri, Mar 6, 1:11PM PDT (-0700 GMT)
Will the orbiter contain a probe?

Laura, SPOT: . . . . Fri, Mar 6, 1:11PM PDT (-0700 GMT)
Hi there. I'm Laura Barnard and I work on the Science Planning Operation Team (SPOT).

Doug Inwood: . . . . Fri, Mar 6, 1:11PM PDT (-0700 GMT)
How is the Galilro probe performing today ?

Webslingr, GaTech: . . . . Fri, Mar 6, 1:11PM PDT (-0700 GMT)
Is there any data on the rate at which the surface recovers from a crack or layer damage?

anonymous: . . . . Fri, Mar 6, 1:12PM PDT (-0700 GMT)
IM CURIOUS WOULD WE SEARCH FOR INTELEGENT LIFE EVEN FURTHER AFTER WE FOUND LIFE ON EUROPA

John G.: . . . . Fri, Mar 6, 1:12PM PDT (-0700 GMT)
TO: Volcanopele - the highest res picture looks like desert sand dunes with vegetation around the bases, like near an oasis.

Jeshua: . . . . Fri, Mar 6, 1:12PM PDT (-0700 GMT)
If the next probe launches in 2003, what year will the probe get there?

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 1:12PM PDT (-0700 GMT)
Laura: Thank you! I'll lurk for now. :)

Steve K./ASU: . . . . Fri, Mar 6, 1:12PM PDT (-0700 GMT)
to david v.: The highest relief yet seen on Europa is about 1.5 to 2 km, but we have error bars on the order of 0.5 km, so greater than or equal to 1 km would be a safe bet. We will be imaging one of the two very high features within the next couple of months.

Brian C: . . . . Fri, Mar 6, 1:13PM PDT (-0700 GMT)
What does Arthur C. Clark have to say about this...After all he wrote about liquid water and life on Europa in his 2001 series of books...

El Matao (from Spain): . . . . Fri, Mar 6, 1:13PM PDT (-0700 GMT)
I have a question, in a previous web chat somebody said something about a probe that would penetrate the ice by "melting", How this probe communicate with a relay to send the information back to Earth? doesn't the water absorb the radio signal?

Michael Strickland: . . . . Fri, Mar 6, 1:13PM PDT (-0700 GMT)
Ditto Jeshua, when would a probe get there if launched in 2003?

volcanopele: . . . . Fri, Mar 6, 1:13PM PDT (-0700 GMT)
Hi Laura I don't know if your the person to ask but what area will be mapped on Io during flybys I24 andI25

Leslie: Outreach: . . . . Fri, Mar 6, 1:13PM PDT (-0700 GMT)
anonymous: Looking for life within our own solar system is just one aspect of what NASA wants to pursue. There are missions planned to look for planets orbiting other stars.

Michael Strickland: . . . . Fri, Mar 6, 1:13PM PDT (-0700 GMT)
And ditto El Matao's question too, please answer....

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 1:14PM PDT (-0700 GMT)
To Andre: The gyro problem will not be a problem for the next encounter, E14. We have taken steps in the development of the science plan to minimize the gyro problem. In addition, we are making a patch to the flight software to further minimize it's affect.

David V.: . . . . Fri, Mar 6, 1:14PM PDT (-0700 GMT)
thanks, steve K!

Jeshua: . . . . Fri, Mar 6, 1:14PM PDT (-0700 GMT)
I can't wait!!!

Ron Baalke, Galileo Webmaster: . . . . Fri, Mar 6, 1:14PM PDT (-0700 GMT)
To herb: there is some kind of international space treaty banning the denotation of nuclear weapons in space. Ignoring the treaty for the moment, a nuclear explosion is so destructive that it would easily obscure any science data you are trying to obtain. Also, the costs involved with thetransport, housing and security of nuclear material is very high and prohibitive in our current environment of building smaller and cheaper missions.

R Sullivan SSI: . . . . Fri, Mar 6, 1:14PM PDT (-0700 GMT)
To Mass. Meteors: I don't know much about periodic variations in Europa's orbit, or any other effects that might produce thermal cycling. Could be something simpler: that "chaos" breakouts are rare, temporary events that nonetheless leave clear signatures on the surface. Looking at the pictures, one can see that conditions at any one "chaos" place have changed with time. That's the geologist in me talking - I'm afraid I don't know the explanation why.

Bryan S.: . . . . Fri, Mar 6, 1:15PM PDT (-0700 GMT)
This is wonderful, first time to enter

Brian C: . . . . Fri, Mar 6, 1:15PM PDT (-0700 GMT)
To Leslie: thanks...the software IS Y2K compliant i hope! (Grin)

Phoenix: . . . . Fri, Mar 6, 1:15PM PDT (-0700 GMT)
hi. the images suggest the idea of glacial movements

: . . . . Fri, Mar 6, 1:15PM PDT (-0700 GMT)
Will or has Galileo taken images of the tiny outer moons beyond Callisto?

Leslie: Outreach: . . . . Fri, Mar 6, 1:15PM PDT (-0700 GMT)
Brian C: Arthur C. Clarke has been in contact with us and is very excited about what we are learning at Europa. He was very astute in his speculations, wasn't he?

Steve K./ASU: . . . . Fri, Mar 6, 1:15PM PDT (-0700 GMT)
to el matao: Good question. One way to try and overcome this problem would be to have a 'reel' of cable that would be secured to the surface and would reel out as the probe descended. However, the reel might need to be real (no pun intended) long. We'd like to know the thickness of the ice first!

Laura, SPOT: . . . . Fri, Mar 6, 1:15PM PDT (-0700 GMT)
volcanopele - The plan for mapping Io in I24 and 125 has not been clearly planned as yet. We will be allocating resources in June of 1999.

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 1:15PM PDT (-0700 GMT)
Is there any substance to the rumour that the GEM is unfunded beyond 1999 because the hardware is Y2K incompatible?

anonymous: . . . . Fri, Mar 6, 1:15PM PDT (-0700 GMT)
Im Jorge, Im a meteorologist in Uruguay. I want send congratulations to JPL and NASA. All is beautifull. More success. Thanks.

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 1:16PM PDT (-0700 GMT)
Is there any probability of extending the mission for further visits to Europa to conduct further 'life' tests ?

anonymous: . . . . Fri, Mar 6, 1:16PM PDT (-0700 GMT)
WHAT EVIDENCE DO WE HAVE FOR A LIQUID OCEAN EXISTING TODAY

Fabien: . . . . Fri, Mar 6, 1:16PM PDT (-0700 GMT)
I would like to known if the Europa Ice Clipper and/or the Europa Orbiter are going to be build...?

Pete Goldie: . . . . Fri, Mar 6, 1:16PM PDT (-0700 GMT)
I am trying to help San Francisco Community TV raise $10,000 for a new satellite dish, so we can get NASA-TV back on the cable system. TCI and the City will not be helping, so I would be delighted if Bay Area People reach out to me to help get this rolling. Please write me at pg@lbin.com (sorry for the intrusion, but NASA-TV has covered Galileo, and we miss it!)

Renato: . . . . Fri, Mar 6, 1:16PM PDT (-0700 GMT)
Hello guys ! Thanks for this great opportunity. Now, I would like to ask about how, by looking at the pictures sent by Galileo, you can be sure of the existence of liquid water under the ice cap...I mean there are may satelites in Jupiter or Saturn that are covered by an ice cap, so what's so different about Europa.

Iceman from Newfoundland: . . . . Fri, Mar 6, 1:17PM PDT (-0700 GMT)
Greetings from the far east of the western world! I have been involved in iceberg and sea ice studies for 20 years here in the Canadian Arctic,offshore Labrador and the Grand Banks of Newfoundland. The scale of the ice features on Europa is huge. There are many similiarities to Iceberg and Pack ice imagery; however. Congratulations to the entire Galileo team for a splendid job!,

PROASTRA: . . . . Fri, Mar 6, 1:17PM PDT (-0700 GMT)
A question for Laura. I read that the moon Ganymede has a strong magnetic field. Is that magnetic field powerful enough to protect an astronaut on the surface from cosmic rays and other radiation?

Ronin: . . . . Fri, Mar 6, 1:17PM PDT (-0700 GMT)
to Steve K: more on the communication between probe and earth. wouldn't placing random radio transimitter as it descend create a continuous communication link? will radio signals pass through ice and water? i believe so right?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 1:17PM PDT (-0700 GMT)
I think there is strong evidence from the images received so far ....

anonymous: . . . . Fri, Mar 6, 1:17PM PDT (-0700 GMT)
Ed:... Could you comment on the shape of the landforms. Why are these long spagetti shapes?

Laura, SPOT: . . . . Fri, Mar 6, 1:17PM PDT (-0700 GMT)
Jorge in Uruguay - Thank you for your support!

Pioneer 10: . . . . Fri, Mar 6, 1:17PM PDT (-0700 GMT)
Has Galileo taken images of the tiny outer moons beyond Callisto?

Webslingr, GaTech: . . . . Fri, Mar 6, 1:17PM PDT (-0700 GMT)
What program was used to calculate the path for which Galileo would perform it's flyby of Europa? Morespecifically what type of machine?

Andre: . . . . Fri, Mar 6, 1:18PM PDT (-0700 GMT)
Brian P: Thanks, that sure is a relief!

Steve L: . . . . Fri, Mar 6, 1:18PM PDT (-0700 GMT)
What can be done to speed up time it takes to get to Jupiter? Must we always use gravity assist or could be get a lighter spacecraft with the biggest rocket we now have and get there faster, I am an old retired guy and would like my answers to come faster.

anonymous: . . . . Fri, Mar 6, 1:18PM PDT (-0700 GMT)
DO YOU THINK EUROPA STILL HAS A LIQUID OCEAN

HAL: . . . . Fri, Mar 6, 1:18PM PDT (-0700 GMT)
Hi! Is there any place on the visible surface that is _solid rock_? I mean, is there any place that looks solid enough for a conventional landing? Or is it *all* ice?

Brent Turcotte: . . . . Fri, Mar 6, 1:18PM PDT (-0700 GMT)
Have you guys ever considered photographing Europa while Europa was in eclipse with the Sun and Jupiter to Galileo's back? If you did you could see an interesting phenomena. From Earth it is impossible to see Earthshine on the Moon during a solar eclipse. But in Jupiter's region of space, it is possible to see Jupiter-shine on a moon while the moon is eclipse. This is possible because of Jupiter's very large diameter as seen from the four Galilean sattelites reflects a large portion of the sun's light. I believe it ranges from a five to ten magnitude dip in light. In addition, as long as you were not too close to the moon in eclipse, you could see for example, the corona complement Europa bathed in an orangish/ yellow light from Jupiter

Brian C: . . . . Fri, Mar 6, 1:18PM PDT (-0700 GMT)
To Leslie: Yes he was...Science fiction authers sometimes seem to have some startling clarity of vision... What is your role in this mission?

anonymous: . . . . Fri, Mar 6, 1:18PM PDT (-0700 GMT)
Is there any evidence to suggest that there may have been liquid water on Europa. I think this would be interesting to know when considering the possiablity of Mars once having water flowing on its surface and what it could indicate about our solar systems past.

Ken Arromdee: . . . . Fri, Mar 6, 1:18PM PDT (-0700 GMT)
Something I'm wondering: I noticed that there is an Amalthea observation tucked in among all the other GEM observations. How good a picture will this get? (I assume the resolution will be higher than non-GEM Amalthea images for it to be worth doing).

Ron Baalke, Galileo Webmaster: . . . . Fri, Mar 6, 1:18PM PDT (-0700 GMT)
To Mass.Meteors: Some scientists have suggested that orbits of the Galilean moon may have been different in the past than what they are today.

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 1:18PM PDT (-0700 GMT)
tp perry: Nope. One of the primary reason GEM ends in '99 is our estimate of radiation dose expected on spacecraft. We are not completely sure we will survive beyond the FIRST Io flyby.

Leslie: Outreach: . . . . Fri, Mar 6, 1:18PM PDT (-0700 GMT)
Regarding Europa orbiter mission, I think it would arrive in 2006, but don't quote me on that! Have a look at button

Sheffield Steve (UK): . . . . Fri, Mar 6, 1:18PM PDT (-0700 GMT)
What is the dark material in the troughs of the grooves?

SteveB: . . . . Fri, Mar 6, 1:19PM PDT (-0700 GMT)
It's amazing how we can get all those images of Europa right at our desktops...thanks

Brent Turcotte: . . . . Fri, Mar 6, 1:19PM PDT (-0700 GMT)
Have you guys ever considered photographing Europa while Europa was in eclipse with the Sun and Jupiter to Galileo's back? If you did you could see an interesting phenomena. From Earth it is impossible to see Earthshine on the Moon during a solar eclipse. But in Jupiter's region of space, it is possible to see Jupiter-shine on a moon while the moon is eclipse. This is possible because of Jupiter's very large diameter as seen from the four Galilean sattelites reflects a large portion of the sun's light. I believe it ranges from a five to ten magnitude dip in light. In addition, as long as you were not too close to the moon in eclipse, you could see for example, the corona complement Europa bathed in an orangish/ yellow light from Jupiter

Michael Strickland: . . . . Fri, Mar 6, 1:20PM PDT (-0700 GMT)
Yes, What is the dark material in the troughs of the grooves?

Steve K./ASU: . . . . Fri, Mar 6, 1:20PM PDT (-0700 GMT)
To ronin: Wow, it's hard to keep up! Yes, one could place transmitters at various depths, and the signals can penetrate a certain amount of ice. I'm afraid I am no expert on radio signals, however, so I can't tell you much about how far they could be spaced, etc. Sorry!

Mass. Meteors: . . . . Fri, Mar 6, 1:20PM PDT (-0700 GMT)
Nukes on Europa: scary thought for sure. But observing the effect of a cataclysmic(-enough) impact WOULD solve many technical problems in the research on Europa, wouldn't it? If SL-9 had impacted Europa, we would have an impact spot to examine, as well as debris to take spectra from in search of organic compounds... Any thoughts on the practicality of "engineering an impact", from the Galileo team?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 1:20PM PDT (-0700 GMT)
thanx to the web SteveB .. greatest thing in astronomy yet .. apart from the probe itself of course !!

Jeshua: . . . . Fri, Mar 6, 1:20PM PDT (-0700 GMT)
I truly beleive once we get to Europa, we WILL find life of some sort. How could you have an Ocean WITHOUT life??

Ronin: . . . . Fri, Mar 6, 1:20PM PDT (-0700 GMT)
thanks Steve K. Just needed to know if the idea was feasible or not.

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 1:20PM PDT (-0700 GMT)
Hi Everyone, Sorry I'm a bit late. Any NIMS questions as of yet?

Bryan S.: . . . . Fri, Mar 6, 1:21PM PDT (-0700 GMT)
Europa has had ice and activity in the coronal region for millions of years. The question, here I should think would be "is there possible life formations that have "evolved" and how long have they been there////also other than the inner mooms of Jupiter...the same possiblity holds true for other planets as well

Mike: . . . . Fri, Mar 6, 1:21PM PDT (-0700 GMT)
Greetings from Seattle, Washington, online and watching, Great Job,KUDO's to the whole team.

Sheffield Steve (UK): . . . . Fri, Mar 6, 1:21PM PDT (-0700 GMT)
What is the dark material in the troughs of the grooves?

Ronin: . . . . Fri, Mar 6, 1:21PM PDT (-0700 GMT)
to Jeshua: the problem is we don't know if there is an ocean of liquid water or not, right?

Leslie: Outreach: . . . . Fri, Mar 6, 1:21PM PDT (-0700 GMT)
Brian C: I am responsible for coordination of the effects to get the word about what we're learning with Galileo out to the public. One of our programs is this web chat. We also maintain the Galileo home page. Our web master, Ron, is joining us for this chat, too.

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 1:21PM PDT (-0700 GMT)
Could the communications antennas on Galileo or a future orbiter double as sounding radar for crust measurements? Or would you need extra equipment?

Jeshua: . . . . Fri, Mar 6, 1:21PM PDT (-0700 GMT)
I think Europa needs more publicity! Everyone I tell that it may have an Ocean has not even heard about Europa!

Laura, SPOT: . . . . Fri, Mar 6, 1:21PM PDT (-0700 GMT)
PROASTRA - I don't know the answer to your question. I hope that someone out there can! I deal in daily operations support and planning.

John G.: . . . . Fri, Mar 6, 1:21PM PDT (-0700 GMT)
Galileo has produced many fantastic close-up images of selected areas of Europa, Ganymede and Callisto--but in terms of over-all mapping coverage, what percentage of each moon has been imaged at a higher resolution than Voyagers 1 & 2?

anonymous: . . . . Fri, Mar 6, 1:21PM PDT (-0700 GMT)
When you do send a mission to Europa, how will you determine the landing site? What information from Galileo will help you with that determination?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 1:22PM PDT (-0700 GMT)
If SL-9 hit Europa ... would there be much left ?

R Sullivan SSI: . . . . Fri, Mar 6, 1:22PM PDT (-0700 GMT)
To SteveB: The dark smooth units in troughs and on the lower slopes are probably debris that disaggregated from the steeper slopes above. Some markings on this "talus" indicate that these materials start out bright then darken with increasing exposure age. Sublimation of an unknown volatile ice may be involved, leaving behind darker materials.

Laura, SPOT: . . . . Fri, Mar 6, 1:22PM PDT (-0700 GMT)
Marcia - Why don't you explain what NIMS does and all the great data you have been getting?

anonymous: . . . . Fri, Mar 6, 1:22PM PDT (-0700 GMT)
WHAT WOULD YA DO WITH THE LIFE

Michael Strickland: . . . . Fri, Mar 6, 1:22PM PDT (-0700 GMT)
RON and/or LESLIE: I can't stay for the whole chat, and it's hard to keep up anyway. Do you post transcripts on the website?

Steve K./ASU: . . . . Fri, Mar 6, 1:22PM PDT (-0700 GMT)
to Brent Turcotte: INteresting you should suggest that. Yes, we plan on looking at Europa during 'eclipse' about 5 orbits from now. One possibility in such an observation would be to see a 'plume' of water vapor (actually, ice crystals) that might have been vented from Europa. That would be a great new piece of information. However, it would have to be very large for us to detect it, and we don't even know if there is liquid beneath the crust, but we're going to take a look!

Webslingr, GaTech: . . . . Fri, Mar 6, 1:22PM PDT (-0700 GMT)
Do you think the proposed Europa Ice Clipper would be a wise idea considering it will be impacting very old ice and collecting fragments from orbit with an aerogel on the orbiter?

Ronin: . . . . Fri, Mar 6, 1:22PM PDT (-0700 GMT)
to R SUllivan: you said the missions to find water and life respectively would be expensive, just how expensive woudl they have to be? what class of mission would they fall under?

anonymous: . . . . Fri, Mar 6, 1:22PM PDT (-0700 GMT)
to: Brian P, SPO Team Chief: Same question I asked earlier. Could we use a lander to look for sciesmic activity on Europa to determine the internal structure just like oil companies sometimes do to find oil. dennis d.

Ed: . . . . Fri, Mar 6, 1:22PM PDT (-0700 GMT)
What type of force would create the long spagetti forms often running in pairs on top of several other layers of similar strands? Why are these strands running for what appears to be up to perhaps a hundred miles or so. Is t similar to a lava flow?

Jeshua: . . . . Fri, Mar 6, 1:22PM PDT (-0700 GMT)
Ronin: From all of the evidence I have seen, i KNOW there is liquid. Most evident are the "Icebergs" that have broken and shifted orientation...

Fabien: . . . . Fri, Mar 6, 1:23PM PDT (-0700 GMT)
to Jeshua: yes, without sunlight I wonder from where the life can have its energy.

Leslie: Outreach: . . . . Fri, Mar 6, 1:23PM PDT (-0700 GMT)
Thanks, Mike! We're excited, too. What can we answer for you?

PROASTRA: . . . . Fri, Mar 6, 1:23PM PDT (-0700 GMT)
Question to Ron B...Has anybody at JPL ever made a working laboratory model, using salt water, a freezer, and a vacuum pump to simulate the Europan icy surface?

SteveB: . . . . Fri, Mar 6, 1:23PM PDT (-0700 GMT)
A great time for astronomers..even when you live in a bright city

David V.: . . . . Fri, Mar 6, 1:23PM PDT (-0700 GMT)
jeshua: mars steals the publicity....we need a "europa surveyor program" in order to compete!!

Ron Baalke, Galileo Webmaster: . . . . Fri, Mar 6, 1:23PM PDT (-0700 GMT)
To Fabian: The Europa Ice Clipper was a Discovery proposal that did not make the final cut in the selection process. The Europa Orbiter is part of the Ice & Fire program which consists of 3 missions, the Europa orbiter, a Pluto flyby, and a solar probe. At this point, it the odds look very good for the Ice & Fire program to get fully funded.

El Matao (from Spain): . . . . Fri, Mar 6, 1:23PM PDT (-0700 GMT)
there are any signals of differential heat coming from the core of Europa? (at infrared light)

Bryan S.: . . . . Fri, Mar 6, 1:23PM PDT (-0700 GMT)
but there would be sunlight on Europa's surface right????

Brian C: . . . . Fri, Mar 6, 1:24PM PDT (-0700 GMT)
The idea of a liquid ocean on Europa, is it fairly certan that it's a water based oean? or could it possibly be methane or another substance. Do we know what elements can exist in its surface in a triple state?

John C: . . . . Fri, Mar 6, 1:24PM PDT (-0700 GMT)
Hi! Have any global maps been drawn up from the combination of Voyager and Galileo data for the Galilean moons?

Leslie: Outreach: . . . . Fri, Mar 6, 1:24PM PDT (-0700 GMT)
Jeshua, Funny you should say that Europa needs more exposure. We do have a public event planned in May. Please see my next message!

Jeshua: . . . . Fri, Mar 6, 1:24PM PDT (-0700 GMT)
Fabien: There is life on earth with absoulutely ZERO sun light...

Phill,,Newcastle,Staffs: . . . . Fri, Mar 6, 1:24PM PDT (-0700 GMT)
Hi from UK Sorry late but didn't see announcement of 'live chat' till late Has anyone any 'ideas' as to what caused the many,many overlain 'furrows/ridges' on Europa. Is there anything equivalent,geologically,on Earth and where? Phill Parker,UK

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 1:24PM PDT (-0700 GMT)
What would be the probably of putting a submarine onto Europa ....then send it under the ice ?

Steve K./ASU: . . . . Fri, Mar 6, 1:25PM PDT (-0700 GMT)
reply to ed: Ah, the origin of the ridges (some of which do indeed look a bit like spaghetti!) is a hot topic among the team. We aren't sure yet how they form. Some possibilities are from warm ice rising from below and pushing up the surface, ice or slush oozing out of cracks, icy volcano deposits, crunching up of the crust under compression, etc.

Ronin: . . . . Fri, Mar 6, 1:25PM PDT (-0700 GMT)
To Ron:what would be the main purpose of the Europa Orbiter?

Sheffield Steve (UK): . . . . Fri, Mar 6, 1:25PM PDT (-0700 GMT)
What is the dark material in the troughs of the grooves?

SteveB: . . . . Fri, Mar 6, 1:25PM PDT (-0700 GMT)
How much radiation is reflected off Jupiter onto Europa?

anonymous: . . . . Fri, Mar 6, 1:25PM PDT (-0700 GMT)
Hi everyone, i have two simple questions: 1: what happens with images of inner moons? it seems their imaging was in almost every orbit program for SSI, yet it was only one image of thebe on the net. Have you succed to get any more since then? 2. One of the proposal on last Discovery selection was Europa sample return (they call it ICe clipper, i believe) and it was rejected. In light of new data, would you consider it again in next selection?

Ed: . . . . Fri, Mar 6, 1:25PM PDT (-0700 GMT)
What type of force would create the long spagetti forms often running in pairs on top of several other layers of similar strands? Why are these strands running for what appears to be up to perhaps a hundred miles or so. Is t similar to a lava flow?

Artemis: . . . . Fri, Mar 6, 1:25PM PDT (-0700 GMT)
if you were to send something underneath the ice, how would it transmit data back to the surface?

Steve L: . . . . Fri, Mar 6, 1:26PM PDT (-0700 GMT)
Leslie Don your best to makes the date known ASAP. Takes a lot of talk to get a project off the ground

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 1:26PM PDT (-0700 GMT)
What exactly is the composition of the water on Europa ? Do we know ?

R Sullivan SSI: . . . . Fri, Mar 6, 1:26PM PDT (-0700 GMT)
To Ronin: The answer to those questions lies in food groups far above me in the NASA chain. The current "Discovery" class missions (Pathfinder, Lunar Prospector, NEAR) are probably too limited in budget to do the job, but others working on proposals to NASA right now may disagree.

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 1:26PM PDT (-0700 GMT)
What do you use the probe relay antenna for now?

Steve K./ASU: . . . . Fri, Mar 6, 1:26PM PDT (-0700 GMT)
reply to phil, newscastle, staffs: Well, we don't have anything on the scale of the Europa ridges, nor do we have icy volcanism (cryovolcanism) on Earth. We do get small ridges in compressing ice packs, but that's probably not what forms the ridges on Europa.

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 1:26PM PDT (-0700 GMT)
to dennis d: Yes. This whould be feasible, once we send a lander to Europa, to measure the seismic activity. Infact, I believe we did this a number of times with our early lander mission to the moon.

anonymous: . . . . Fri, Mar 6, 1:26PM PDT (-0700 GMT)
WHAT IF LIFE THERE DERIVED SLIGHTLY DIFFERENT THERE THAN HERE ON EARTH

Webslingr, GaTech: . . . . Fri, Mar 6, 1:26PM PDT (-0700 GMT)
What type of shielding was used on Galileo to protect it from the jovian electromagnetic fields, and what type of power output is needed to send the images back here to earth?

Ronin: . . . . Fri, Mar 6, 1:27PM PDT (-0700 GMT)
thanks R. Sullivan.

PROASTRA: . . . . Fri, Mar 6, 1:27PM PDT (-0700 GMT)
Since Dr. Chapman is not online, could Steve K. reply? Is there a possible water ocean under the surface of Callisto?

Andre: . . . . Fri, Mar 6, 1:27PM PDT (-0700 GMT)
When will Galileo image the polar regions of Europa? How do you think that terrain will differ?

Leslie: Outreach: . . . . Fri, Mar 6, 1:28PM PDT (-0700 GMT)
TO ALL: I'd like to let you know that we are having a celebration of the exploration of Europa on May 20-21, 1998. Its called "A Day on Europa". On May 20, we'll be participating in a nationwide electronic field trip that the Challenger Center is coordinating (button On May 21, we will have a series of public talks in the evening across the USA where experts on Europa research and fiction (our panel includes Arthur C. Clarke) will discuss this intriguing moon of Jupiter! The details are still being worked out, but please watch our web page for further announcements, locations, and details.

John C: . . . . Fri, Mar 6, 1:28PM PDT (-0700 GMT)
What will Galileo's orbit be like when GEM is finished?

Ron Baalke, Galileo Webmaster: . . . . Fri, Mar 6, 1:28PM PDT (-0700 GMT)
To Jeshua: I agree with you, Europa needs more publicity. In fact, we are planning a Europa Day event on May 20-21.

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 1:28PM PDT (-0700 GMT)
Laura, NIMS - the Near Infrared Mapping Spectrometer covers the near-infrared region of the spectrum. We have wavelength overlap with the Solid State Imaging System to provide continuity in the data set. NIMS primary objective is to determine the composition of the icy satellite surfaces as well as Jupiter's atmosphere.

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 1:28PM PDT (-0700 GMT)
to Carl Banks. Nothing. It's been stowed for the rest of the mission.

Brian C: . . . . Fri, Mar 6, 1:29PM PDT (-0700 GMT)
To Leslie: I for one would like to applaud both you and Ron the webmaster!!..Yours is probably one of the toughest jobs on the team!! Thanks for the wonderfull job so far. As a layman I feel exilerated when I hear of some new discovery, or see Pictures of our solar couzens for the first time. I'd love to see these chat sessions be a perminant thing, 7-24.

anonymous: . . . . Fri, Mar 6, 1:29PM PDT (-0700 GMT)
Hi Marcia I know you are asked this every chat, but, How many hotspot have there been detected by NIMS? I have a web site on Io and could use the info(somebody asked me).

David V.: . . . . Fri, Mar 6, 1:29PM PDT (-0700 GMT)
the ice clipper mission was rejected inpart because it only carried one instrument (camera) and would bot even enter orbit around JUPITER, much less europa. Thus, it would be near europa for only a couple of hours, and if the sample collection failed for some reason, we would have NOTHING to show for it. Europa orbiter sounds like a much more promising mission

Ronin: . . . . Fri, Mar 6, 1:29PM PDT (-0700 GMT)
to leslie: try fixing the link, remove the ) from the URL :)

Phill,,Newcastle,Staffs: . . . . Fri, Mar 6, 1:29PM PDT (-0700 GMT)
Further to 'ridges' - anyone any thoughts/ideas as to why they may be in 'long'finger-straight' lines Has anyone done any 'modelling' of trying to reproduce ridges using warm ice/cold ice,slush soil etc anywhere? Any ridges like this seen in Antartica or around KAmtchatka where there may be ice and volcanoes?

anonymous: . . . . Fri, Mar 6, 1:29PM PDT (-0700 GMT)
WHAT HAPPENS IF THE MOON DID HAVE LIFE WOULD IT BECOME A PLANET

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 1:29PM PDT (-0700 GMT)
Marcia, is the NIMS an imager, or will it observe only a single point at a time?

Tayfun: . . . . Fri, Mar 6, 1:29PM PDT (-0700 GMT)
Hi Marcia, are there any new material that Voyager spectrometers could not see but Galileo have proved to exist in the Jovian system?

Jeshua: . . . . Fri, Mar 6, 1:29PM PDT (-0700 GMT)
The implications of an ocean are by far the most exciting thing in astronomy/sciences, I still can't beleive it doesn't get more attention...

PROASTRA: . . . . Fri, Mar 6, 1:30PM PDT (-0700 GMT)
Thanks, Laura...I'll try finding someone on the Fields & Particles experiment.

anonymous: . . . . Fri, Mar 6, 1:30PM PDT (-0700 GMT)
WHAT HAPPENS IF THE MOON DID HAVE LIFE WOULD IT BECOME A PLANET

Rene' Ortman: . . . . Fri, Mar 6, 1:30PM PDT (-0700 GMT)
Hi...can anyone answer my question about the depth the supposed ocean is underneath Europa's surface??

Mark: . . . . Fri, Mar 6, 1:30PM PDT (-0700 GMT)
Ron, I have been reading your E-mails about galileo and enjoy them very much. I am looking forward to reading more about the Cassini mission as the mission progresses. I am starting to study astronomy officially in school, and I find all of this very interesting, as does my Astronomy teacher. I hope everything goes according to plan with the missions following Galileo and Cassini.

Webslingr, GaTech: . . . . Fri, Mar 6, 1:30PM PDT (-0700 GMT)
Actually I think Laura meant this A HREF="button

R Sullivan SSI: . . . . Fri, Mar 6, 1:30PM PDT (-0700 GMT)
To anonymous on (1): Very limited amount of data on the small satellites (inside the orbit of Io) has been obtained. Resolution has not been nearly as high as with the Europa pictures, because getting close enough for better resolution would expose the Galileo spacecraft to too much radiation. Resolution is good enough to determine their shapes better, however.

Brent Turcotte: . . . . Fri, Mar 6, 1:30PM PDT (-0700 GMT)
Steve K./ASU: It would be interesting to see a plume of water vapor. In that picture, if the exposure was long enough, you could see Jupiter shine, assuming Jupiter is to Galileo's back. I would imagine that getting a view of the sun corona's is out of the question because it would obtruct the view of the water plume and risk Galileo's imaging system.

Laura, SPOT: . . . . Fri, Mar 6, 1:30PM PDT (-0700 GMT)
John C. - There should be a couple of our navigation team members on today. Mike or Tim are you on yet?

Ole P. Dybvik: . . . . Fri, Mar 6, 1:30PM PDT (-0700 GMT)
When do you think the first human will visit Jupiter?

Ronin: . . . . Fri, Mar 6, 1:30PM PDT (-0700 GMT)
to m. strickland: i believe so, all the past webchat transcripts have been available on galileo's website

volcanopele: . . . . Fri, Mar 6, 1:30PM PDT (-0700 GMT)
Hi Marcia You can address the answer to me(forgot to type handle in)

Jeshua: . . . . Fri, Mar 6, 1:30PM PDT (-0700 GMT)
Micheal Strickland:Yes you can find the transcripts at: button

Steve K./ASU: . . . . Fri, Mar 6, 1:31PM PDT (-0700 GMT)
reply to proastra: Hmm. Callisto is certainly not my area, but my understanding is that IF there is liquid water on Callisto, it would have to be very deep. Callisto doesn't appear to be differentiated/ separated in to ice vs. rock layers, like Europa is. It also is pretty cold, because there is no good source of tidal energy - it's the outermost big satellite. I would suspect that if there is liquid water it certainly isn't near the surface.

John C: . . . . Fri, Mar 6, 1:31PM PDT (-0700 GMT)
Could someone tell me whether the polar regions of Io are less volcanic or not? They seem to be, and they are under less stress from tidal friction.

Phill,,Newcastle,Staffs: . . . . Fri, Mar 6, 1:31PM PDT (-0700 GMT)
Just a humurous item for all UK dwellers. Can we borrow Galileo's umbrella tonite - its raining non stop all day over 1 inch or more in less than 8 hours! Are the techies leaving the umbrella antenna e problem alone now we are into long extended duration mission?

Ken Arromdee: . . . . Fri, Mar 6, 1:31PM PDT (-0700 GMT)
I asked this question before but since it's brought up again... I noticed an Amalthea image among the tour descriptions for GEM. How good a resolutiion will this have?

Artemis: . . . . Fri, Mar 6, 1:31PM PDT (-0700 GMT)
if there is liquid water below the surface of europa, would there be currents or tides, or would it be still?

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 1:32PM PDT (-0700 GMT)
To M. Srickland: Yes! Expect it up in a couple of days.

volcanopele: . . . . Fri, Mar 6, 1:32PM PDT (-0700 GMT)
To michael-They did for the old ones

Leslie: Outreach: . . . . Fri, Mar 6, 1:32PM PDT (-0700 GMT)
Michael: The transcripts are posted on the same page that you joined us on button

Kane: . . . . Fri, Mar 6, 1:32PM PDT (-0700 GMT)
Hello

moondweller: . . . . Fri, Mar 6, 1:32PM PDT (-0700 GMT)
What is the best way to determin how far under the ice is the terrestrial surface?

Laura, SPOT: . . . . Fri, Mar 6, 1:32PM PDT (-0700 GMT)
MIchael - Past webchats are located at the bottom of the front chat page button They only have up to April 1997 I think on-line.

Orion: . . . . Fri, Mar 6, 1:32PM PDT (-0700 GMT)
Ive noticed in the image of the large chasm on Europa, there seems to be some "sparkling" coming from the shadowed area of the canyon. Would this be due to the many reflections of sunlight off the walls of the sunlit side into the shadow area?

Ken Arromdee: . . . . Fri, Mar 6, 1:32PM PDT (-0700 GMT)
Oh, also, this is too late to fix now but maybe next time. The help says that new messages have a red arrow pointing to them; I don't get one.

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 1:32PM PDT (-0700 GMT)
to john c.: Assuming we do not do any maneuvers after GEM, we will continue to orbit jupiter with a periapsis range between Io and Europa. There is some very small probabilities of impacting one of the Galilean satellites.

Kane: . . . . Fri, Mar 6, 1:32PM PDT (-0700 GMT)
so what about the water A

PROASTRA: . . . . Fri, Mar 6, 1:33PM PDT (-0700 GMT)
Thanks for the reply Steve.

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 1:33PM PDT (-0700 GMT)
PROASTRA, The Radio Science data taken of Callisto during the prime mission pretty much ruled out the possibility of a liquid ocean under the surface of Callisto.

Ronin: . . . . Fri, Mar 6, 1:33PM PDT (-0700 GMT)
is there a mailing list for latest updates on Galileo?

anonymous: . . . . Fri, Mar 6, 1:33PM PDT (-0700 GMT)
DO YA THINK EUROPA HAS AN OCEAN TODAY STILL SPEWING

Ken Arromdee: . . . . Fri, Mar 6, 1:33PM PDT (-0700 GMT)
Oh, also, this is too late to fix now but maybe next time. The help says that new messages have a red arrow pointing to them; I don't get one.

peter o.: . . . . Fri, Mar 6, 1:33PM PDT (-0700 GMT)
How do you know that it is water and ice that we see?

Steve K./ASU: . . . . Fri, Mar 6, 1:33PM PDT (-0700 GMT)
to moondweller: With our current mission, the best information we have is based on gravity data. These suggest that the outer icy shell of Europa is about 150 km thick. Doesn't tell us anything about the relative thicknesses of ice and liquid water (if any) that are present, though.

Andre: . . . . Fri, Mar 6, 1:33PM PDT (-0700 GMT)
What instruments would be on a Europa orbiter?

Mark: . . . . Fri, Mar 6, 1:33PM PDT (-0700 GMT)
A few questions for the scientists. First, what (if anything) do you expect to find under the ice on europa? Second, are you planning to send another probe to just explore europa after Galileo ceaces to exist?

Laura, SPOT: . . . . Fri, Mar 6, 1:34PM PDT (-0700 GMT)
So - Brian P. SPO Team Chief - What do you do on GEM ;-)

eduardo: . . . . Fri, Mar 6, 1:34PM PDT (-0700 GMT)
Which are the instruments used to detect surface composition of Jupiter satellites

Phoenix: . . . . Fri, Mar 6, 1:34PM PDT (-0700 GMT)
To Galileo Team. The program will continue if Galileo survive after the two Io flyby?

Jeshua: . . . . Fri, Mar 6, 1:34PM PDT (-0700 GMT)
At the end of GEM, are you going to crash Galileo into Europa, to get even more high-res data??

Ed: . . . . Fri, Mar 6, 1:34PM PDT (-0700 GMT)
Why is everyone saying that this is ice? As in H20? Why not form liquid methane or some other liquid. I dont see why this is necessaraly ice. Is it the albedo of this surface? I fly often over the Arctic ice pack and I have never seen shapes like this.

R Sullivan SSI: . . . . Fri, Mar 6, 1:34PM PDT (-0700 GMT)
To Andre: We will have polar passes on orbits 17 (south pole) and 18 (north pole). We saw some of the south pole at low resolution on orbit 1. In the area we could see, there appeared to be fewer dark regions and dark bands, either because Europa is less tectonically active at the poles, or because everything was covered with frost.

volcanopele: . . . . Fri, Mar 6, 1:34PM PDT (-0700 GMT)
To John C. The polar region is less volcanic for the reason you mentioned but it does outgas Hydrogen.

Brian C: . . . . Fri, Mar 6, 1:34PM PDT (-0700 GMT)
What is the approximite surface temprature of Europa?

Artemis: . . . . Fri, Mar 6, 1:35PM PDT (-0700 GMT)
How do you determine the depth of the ice on Europa? Are there areas were it is significantly thinner than others?

David V.: . . . . Fri, Mar 6, 1:35PM PDT (-0700 GMT)
is anyone here involved with the europa orbiter/ice and fire preprojects??

Sheffield Steve (UK): . . . . Fri, Mar 6, 1:35PM PDT (-0700 GMT)
The long triple bands snaking across the surface look very much like the tracks of a moving object, cutting through the terrain regardless of existing structures. What do you think? Would a new crack follow lines of weakness, which is definitely NOT seen in these cases?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 1:35PM PDT (-0700 GMT)
where is the probe today ?

Leslie: Outreach: . . . . Fri, Mar 6, 1:35PM PDT (-0700 GMT)
proastra: Also, we think that the reason Europa's water is liquid, when its so far away from the warming rays of the sun, is from internal heating due to friction. Jupiter and the other moons pull on Europa, causing tides, which can heat the interior. Callisto is much farther out from Jupiter and doesn't experience the strong pull. Io, being the closest large moon to Jupiter, relieves the intense stress of its tides through its erupting volcanoes!

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 1:35PM PDT (-0700 GMT)
Anonymous, I believe the last count was 39 hot spots detected by NIMS. We have been referring to them as the "Ring of Fire"! Most seem to be within 30 degrees of the equator.

Steve K./ASU: . . . . Fri, Mar 6, 1:36PM PDT (-0700 GMT)
reply to jeshua: No, there are not any plans to crash into Europa after the mission ends. In fact, I believe that the project had to insure that the spacecraft would NOT hit Europa for at least 200 years after the end of the mission.

Mike: . . . . Fri, Mar 6, 1:36PM PDT (-0700 GMT)
I read that the Huygens probe was to touch down some 20km "off shore". Was the site selected with idea that the probe would land in liquid methane? Won't this end the transmisions from the probe?

anonymous: . . . . Fri, Mar 6, 1:36PM PDT (-0700 GMT)
IF YOU FOUND AN OCEAN IT WOULD BE THE BIGGEST THING SINCE THE DISCOVERY OF THE PACIFIC

El Matao (from Spain): . . . . Fri, Mar 6, 1:36PM PDT (-0700 GMT)
What would be the final for the Galileo after it ends the mission? it would be directed aginst Jupiter or it will be left at the gravity forces?

Mass. Meteors: . . . . Fri, Mar 6, 1:36PM PDT (-0700 GMT)
I'm an amateur meteor observer: on the subject of (slightly less cataclysmic) impacts, I'd imagine the Jovian system passes through many meteoroid streams in its 12 year orbit. Some of these must be composed of fairly dense meteroids: any way to collect enough information to actually arrange a "Europa-meteoroid stream" rendezvous? Observing the impact of even a 1-10kg particle might give us significant seismic as well as visual data. And if lucky, a 100-1000kg impact would also give an orbiter or lander a gorgeous plume to analyze... Just curious! :)

Laura, SPOT: . . . . Fri, Mar 6, 1:36PM PDT (-0700 GMT)
Phoenix - Leslie Lowes answered a similar question earlier. At the end of GEM after the Io encounters we will hopefully continue to do radiation studies as the hardware deteriorates.

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 1:36PM PDT (-0700 GMT)
Hey, anonymous has a point there... I realize this is pure speculation, but do any of the geology staff expect to observe a 'plume' event or are the odds just too low? I do remember from some research that there was one anomalous IR spike from Europa, that at the time was suspected to be vaporous water...

Jeshua: . . . . Fri, Mar 6, 1:36PM PDT (-0700 GMT)
Doesn't the NIMS gather temperture data? Can we see if there are any "Hotspots"?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 1:36PM PDT (-0700 GMT)
Could that ring of fire be caused by tidal effects ?

Brent Turcotte: . . . . Fri, Mar 6, 1:36PM PDT (-0700 GMT)
When are the fact sheets for Metis, Adrastea and Thebe going to be posted?

Mark: . . . . Fri, Mar 6, 1:37PM PDT (-0700 GMT)
Scientists, are you planning any missions in later years to any more of the Jovian satellites, such as Io maybe?

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 1:37PM PDT (-0700 GMT)
oops. I meant to include from Voyager in 1979.

anonymous: . . . . Fri, Mar 6, 1:37PM PDT (-0700 GMT)
Hello, I'm a math teacher in kansas and I have some questions from students. First, why should federal taxes continue to pay for the Galileo Project.

Jeshua: . . . . Fri, Mar 6, 1:37PM PDT (-0700 GMT)
Steve: Thanks, so what will be the grand finally??

PROASTRA: . . . . Fri, Mar 6, 1:37PM PDT (-0700 GMT)
This is for Ron B....The reason I brought up the working model of Europa question is because I have seen corrugated and buckled ice on frozen ponds in Winnipeg, Canada that look like Europa's surface.

Renato: . . . . Fri, Mar 6, 1:37PM PDT (-0700 GMT)
To R Sullivan: Hello, greetings from Sao Paulo, Brazil... I know how busy yhis can be so I will ask my question again. I am puzzled by the fact that by studying the pictures sent from Europa it is possible to conclude it has liquid water underneath the ice cap while on other moons that also have an ice cap, no evidence of liquid water have been found. I am aware, of course, that there are other science instruments that have aided to this conclusion, but what I really would like to know is how we can be so sure about the presence of liquid water on Europa based on the features shown on the pictures. Thank you.

Phoenix: . . . . Fri, Mar 6, 1:37PM PDT (-0700 GMT)
where are more images on MAdrastea Amaltea, Thebe and Metis?

Ed: . . . . Fri, Mar 6, 1:38PM PDT (-0700 GMT)
Why is everyone saying that this is ice? As in H20? Why not form liquid methane or some other liquid. I dont see why this is necessaraly ice. Is it the albedo of this surface? I fly often over the Arctic ice pack and I have never seen shapes like this.

Tyc: . . . . Fri, Mar 6, 1:38PM PDT (-0700 GMT)
What surface minerals NIMS found on Europe so far?

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 1:38PM PDT (-0700 GMT)
Ken A. Yes we have an amalthea observation in C22. The resolution of these observations are 8.5km/pixel and 9.2 km/pixel. I'm not sure off-hand how much better this is than the prime mission

Venci: . . . . Fri, Mar 6, 1:38PM PDT (-0700 GMT)
Hi Steve K. From what department ( asu ) are you?

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 1:38PM PDT (-0700 GMT)
Hi Peter O., Each chemical compound, mineral, gas, etc... has a different spectral signature much like a human fingerprint. We compare those signatures to libraries of spectra that we have.

Steve K./ASU: . . . . Fri, Mar 6, 1:39PM PDT (-0700 GMT)
to Jeshua: The 'grand finale' is to look at Io at high res. I don't know of anything beyond the end of 1999 right now. The instruments will likely be pretty fried by radiation at that point.

Jim Galasyn: . . . . Fri, Mar 6, 1:39PM PDT (-0700 GMT)
Europa's surface seems to be an almost textbook fractal, i.e., each line, on magnification, becomes a pair of lines, down to small scales. Such structures are often the fingerprint of iterative processes -- could this be interpreted to mean that the lines (ridges) are formed by a process of repeated freeze/thaw, or perhaps repeated flex/relax from tidal stresses?

Steve K./ASU: . . . . Fri, Mar 6, 1:39PM PDT (-0700 GMT)
to venci: Geology department.

John-O: . . . . Fri, Mar 6, 1:39PM PDT (-0700 GMT)
There seems to be allot of talk about how a future probe might use the brute force, undoubtedly expensive, and technologically daunting method of boring through miles of ice into an ocean, if it exists. If there are geysers on the surface, it seems that signs of life could be dredged up out of warmer depths. Assuming this, wouldn't it be worth it to spend allot of effort looking closely for geysers then, having found some, land a probe in close proximity to one of these then sampling the ejected material for telltale signs of life ?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 1:39PM PDT (-0700 GMT)
that is what i was thinking before Ed .....what is the 'water' made up of ..is it mostly H2O and can we tell what other chemicals/elements are in it ?

John Cody: . . . . Fri, Mar 6, 1:39PM PDT (-0700 GMT)
What would happen to liquid water if it was released onto the surface of Europa. Would it freeze and boil simultaneously in the near vacuum? What sort of topography would form- similar to the features that have been seen in recent images?

Ed: . . . . Fri, Mar 6, 1:40PM PDT (-0700 GMT)
Why is everyone saying that this is ice? As in H20? Why not form liquid methane or some other liquid. I dont see why this is necessaraly ice. Is it the albedo of this surface? I fly often over the Arctic ice pack and I have never seen shapes like this.

peter o.: . . . . Fri, Mar 6, 1:40PM PDT (-0700 GMT)
Thanks, Marcia!

R Sullivan SSI: . . . . Fri, Mar 6, 1:40PM PDT (-0700 GMT)
To Phoenix: The Galileo spacecraft will be over its designed maximum radiation exposure at the end of the last (25th) orbit, an Io encounter. There is real risk that radiation damage will end the mission sooner than this. Personally, I'm not optimistic about extending the mission beyond I25. NASA would probably have to spend its money on other things.

Laura, SPOT: . . . . Fri, Mar 6, 1:40PM PDT (-0700 GMT)
Math Teacher and Students in Kansas - As a taxpayer, not an employee, I'm proud of the fact that the United States is willing and able to pay for an engineering and science feat like Galileo.

David V.: . . . . Fri, Mar 6, 1:40PM PDT (-0700 GMT)
to ron baalke (or SSI people) What happened to the Ganymede orbit 7 and genymede orbit 8 high resolution images. They haven't been put online....were there more wierd contrast-related problems, like during Ganymede 1 and 2??

Kansas: . . . . Fri, Mar 6, 1:40PM PDT (-0700 GMT)
Will you ever have a Galileo II?

Phill,,Newcastle,Staffs: . . . . Fri, Mar 6, 1:40PM PDT (-0700 GMT)
Just because its raining here - do you guys and guyesses have to put a lovely sunny picture from your window of JPL just to upset us here in UK :-)) Other than that - thanks for yet another brilliant JPL mission nd thanks for time to chat with you Great!

Mark: . . . . Fri, Mar 6, 1:41PM PDT (-0700 GMT)
Ron: Is there any evidence that there is a tectonic plate structure under the ine, and maybe this could be the cause of the cracks?

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 1:41PM PDT (-0700 GMT)
To Steve: Can you put extra points on my grad. application for asking good questions? ;)

Steve K./ASU: . . . . Fri, Mar 6, 1:41PM PDT (-0700 GMT)
reply to doug inwood: Mostly just h2o, but the NIMS instrument has been looking into what the smaller percentage 'contaminant' components might be. Sulfate salts have been suggested.

Rene' Ortman: . . . . Fri, Mar 6, 1:41PM PDT (-0700 GMT)
Again I ask, how deep is the supposed ocean underkneath Europa's surface?

Lars Eriksson: . . . . Fri, Mar 6, 1:41PM PDT (-0700 GMT)
Hej. What temperature is it on Europa?

PROASTRA: . . . . Fri, Mar 6, 1:41PM PDT (-0700 GMT)
Okay. Thanks to all the team that managed to answer some of the questions I asked.

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 1:41PM PDT (-0700 GMT)
I would go with Tidal stresses that cause a freeze of exposed water

Brian: . . . . Fri, Mar 6, 1:41PM PDT (-0700 GMT)
Hello from Dubuque, IA. Two questions. Will you try to download the pre probe entry pictures off of the tape recorder, and how did you alter the telemetry system on galileo to get a clearer signal on earth?

Phoenix: . . . . Fri, Mar 6, 1:41PM PDT (-0700 GMT)
My dream (like many)is to participate in some manner to JPL and NASA interplanetary projects. It is possible?

Steve K./ASU: . . . . Fri, Mar 6, 1:42PM PDT (-0700 GMT)
to Perry Frix: Sorry. Not in my power! :-)

Antonio de Morais: . . . . Fri, Mar 6, 1:42PM PDT (-0700 GMT)
I'm extremely interested on the research of Europa. I'll present an article (A posible internal structure of Europa) in the XXIII General Assembly of the European Geophysical Society, in NIce, FRance, on April 22. And some scientists know me weel by email (Dr. Adriana Ocampo, Dr. Chris McKay (Ames) , Dr. and Dr. Luke Dones (Ames) knows me personally (in the Rio de Janeiro International Workshop in Planetary Sciences - I presented a model about Europa). I'd like very much to work officially (at distance - I'm in Brasil) in some Galileo Team; here we don't have the study of the Solar System yet - I recently gave a suggestion of creation of a study group of diferent Profesors Drs.(physics, chemistry, geology, oceanography, engineering, etc) .) in the Institute of Advanced Studies of the University of Sao Paulo). I hope I can come to be useful to NASA and the exploration of Europa. Thank you for your attention. Sincerely, Antonio de Morais

Leslie: Outreach: . . . . Fri, Mar 6, 1:42PM PDT (-0700 GMT)
Brian C: Europa's daytime temperature is about -225 degrees Fahrenheit

Michael Strickland: . . . . Fri, Mar 6, 1:42PM PDT (-0700 GMT)
Lars: surface Temp. on Europa -260 degrees Fahrenheit

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 1:42PM PDT (-0700 GMT)
To L. Eriksson: I just saw a number today for average surface temp: 100 K.

Laura, SPOT: . . . . Fri, Mar 6, 1:42PM PDT (-0700 GMT)
Ed - Marcia of the NIMS team will be able to help you with your questions regarding ice. Marcia?

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 1:43PM PDT (-0700 GMT)
Jeshua, Yes, NIMS collects thermal data as well. We do have temperatures for hot spots, the hightest reported temperature is 1300 degrees Kelvin. We are still analyzing data with some indication of higher temperatures still.

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 1:43PM PDT (-0700 GMT)
Is there any thoughts to how these Sulfate salts compare the the hot water plumers we get here on earth ?

Orion: . . . . Fri, Mar 6, 1:43PM PDT (-0700 GMT)
I have noticed that some shadows seem to indicate very slender spikes on the surface. Kind of like the "superman fortress" from the movie. Any comments on what it would look like to stand on the surface of Europa?

volcanopele: . . . . Fri, Mar 6, 1:43PM PDT (-0700 GMT)
On my website I have my sheet from my project on making a plan to send an orbiter to IO. Check it out at button and click on Io Volcanic Observer.

Jeshua: . . . . Fri, Mar 6, 1:45PM PDT (-0700 GMT)
Marcia: Thanks, when will the temperture map be released? What is the eq. of 1300K in Fahernheit?

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 1:45PM PDT (-0700 GMT)
To Dubuque, IA: The only pre-probe entry picture we took before the tape recorder went flaky was a global image of jupiter. We have talked about trying to get this picture back after I25. Unfortunately, because of the major modifications to the flight software that we made, we would have to disable some of those changes to get hack to that part of the tape that the jupiter image is on. This is probably out of scope for us post Io.

Tomas W (Stockholm, Sweden): . . . . Fri, Mar 6, 1:45PM PDT (-0700 GMT)
Could DS2-type penetrators be used on the 2003 Europa Orbiter mission to monitor seismic activity? Maybe fitted with retro rockets to slow them down before impact?

Kenneth: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Hey there Ppl. Congrats tu u all on the fine work. I would like to know whats the temperature in the surface of Callisto and Ganymede

Steve K./ASU: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
to Phoenix: There are many cooperative efforts being implemented between universities, NASA programs and secondary schools. If you are in college and are majoring in geology or astronomy, there are also internships available through the Lunar and PLlanetary institute in Houston, among others.

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
At the end of the GEM, might you try to retrieve the image of Jupiter that is stored on the "unsafe" part of the tape? Assuming, of course, the tape still works.

Mark: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Leslie: Outreach - If the surface temperature of Europa is -225 F, then do you expect the awter temperature to be same, or warmer?

Tomas W (Stockholm, Sweden): . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Could DS2-type penetrators be used on the 2003 Europa Orbiter mission to monitor seismic activity? Maybe fitted with retro rockets to slow them down before impact?

El Matao (from Spain): . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Marcia, 1300 degrees Kelvin? its'n a lot?

R Sullivan SSI: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
To ED, RENATO: Spectral studies from telescopes in the '70s showed that the dominant surface constituent of Europa was water ice. We just couldn't see the details that we can now. What they show is that the water ice (no doubt with other "contaminants" mixed in) is part of a relatively young (geologically speaking) surface with surprizing tectonic activity. The presence of water ice is well established, too, by the Galileo NIMS instrument, which confirmed the ground-based telescope work at very high resolution (and more...Marcia, wish to add more?)

anonymous: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
IF THEY FOUND LIFE ON EUROPA IT WOULD PROVE WERE NOT ALONE IN THE UNIVERSE

Pat Beyer/DeepSpace Network/telecommunications support: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Pat Beyer signing in

Ed: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Have any of the pictures shown a possable sourse of the extruded strands? Why do they appear to be in pairs?

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Ed, Please repeat the question? I'm typing as fast as I can....

Jeshua: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Marcia: Thanks, when will the temperture map be released? What is the eq. of 1300K in Fahernheit?

moondweller: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
It's likly that if life exists on Europa, the energy would have to derive from geothermal sources like the deep earth ocean life at the black smokers. Is there anything about Europa to suggest that tectonic forces will allow deep ocean fissures that may release geothermal energy?

Tayfun: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Yes????

El Matao (from Spain): . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Marcia, 1300 degrees Kelvin? its'n a lot?

Mark: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Leslie: Outreach - If the surface temperature of Europa is -225 F, then do you expect the awter temperature to be same, or warmer?

El Matao (from Spain): . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Marcia, 1300 degrees Kelvin? its'n a lot?

John Cody: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Are any of the Galileo team members here involved with Cassini?

Ed: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Have any of the pictures shown a possable sourse of the extruded strands? Why do they appear to be in pairs?

Laura, SPOT: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Phoenix - Of course it is possible! There are a lot of different career paths available at JPL and NASA.

John Cody: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Are any of the Galileo team members here involved with Cassini?

Laura, SPOT: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Phoenix - Of course it is possible! There are a lot of different career paths available at JPL and NASA.

Tayfun: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Sinan?????

John Cody: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
Are any of the Galileo team members here involved with Cassini?

Artemis: . . . . Fri, Mar 6, 1:46PM PDT (-0700 GMT)
How are you determining from Galileo's pictures the depth of Europa's ice?

Jeshua: . . . . Fri, Mar 6, 1:47PM PDT (-0700 GMT)
volcanopele: IO is tired, Europa is WIRED! Personally, I would like ALL of nasas funding to go into developing a submarine vessel...

volcanopele: . . . . Fri, Mar 6, 1:47PM PDT (-0700 GMT)
make that "Space craft to go to Io."

Brian C: . . . . Fri, Mar 6, 1:47PM PDT (-0700 GMT)
To Laura, SPOT: Kudos!! also as a taxpayer, I agree, I personally think that NASA is grossly underbudgeted every year, and I continually pester my congressman, Sander Leven to vote for more... I remember the days of Apollo, when I was young, and what kind of benifits that were derived from that project, and wonder what wonders we could discover, and learn to understand and use with that kind of budget today.

John Cody: . . . . Fri, Mar 6, 1:47PM PDT (-0700 GMT)
Sorry about repetition.....

David V.: . . . . Fri, Mar 6, 1:47PM PDT (-0700 GMT)
to rene ortman: we dont know that there IS an ocean yet....so how can they post DEPTHS yet?

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 1:47PM PDT (-0700 GMT)
Jeshua, The temperature in F is 1850 degrees

steve k/asu: . . . . Fri, Mar 6, 1:48PM PDT (-0700 GMT)
to Rene' Ortman: We don't know yet whether there is still liquid water beneath the ice crust. If so, it could be anywhere from less than a kilometer to many tens of kilometers. We would like to know the answer to this very question!

jw: . . . . Fri, Mar 6, 1:48PM PDT (-0700 GMT)
what is the biggest setback you have encountered whilst working on the project?

steve k/asu: . . . . Fri, Mar 6, 1:48PM PDT (-0700 GMT)
To John Cody: Yes, some are.

Artemis: . . . . Fri, Mar 6, 1:48PM PDT (-0700 GMT)
what is a DS2 type penetrator?

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 1:48PM PDT (-0700 GMT)
Marcia, you are talking about hotspots on Io?

Laura, SPOT: . . . . Fri, Mar 6, 1:49PM PDT (-0700 GMT)
Pat Beyer - Thanks for joining us! Why don't you tell everyone what you do on Galileo.

anonymous: . . . . Fri, Mar 6, 1:49PM PDT (-0700 GMT)
HOW MANY WORLDS DO YA THINK COULD HAVE LIFE

Mark: . . . . Fri, Mar 6, 1:49PM PDT (-0700 GMT)
I hate to rush you guys, but I need to go. Can anyone possible answer my question with in the nex minute or two?

R Sullivan SSI: . . . . Fri, Mar 6, 1:49PM PDT (-0700 GMT)
To jw: the failure of the main antenna to open, which restricts the number of images we can return to Earth (through the low-gain antenna).

steve k/asu: . . . . Fri, Mar 6, 1:49PM PDT (-0700 GMT)
to jw: Well, Galileo has overcome many 'set-backs', in fine fashion, due to some very clever engineers/programmers, etc. The failure of the high-gain antenna to open comes to mind.

Brent Turcotte: . . . . Fri, Mar 6, 1:49PM PDT (-0700 GMT)
Which is a greater contributer to Io's tides: the slight eccentricity in Io orbit making the tidal bulge shift from side to side, or Europa and Ganymede making close passes to Io?

: . . . . Fri, Mar 6, 1:49PM PDT (-0700 GMT)
yes Sinan !! well is here correct place to chat about elastic tickness variations of crusts of different planets ???? by the way could you look at mail tayfun ???

Pete Goldie: . . . . Fri, Mar 6, 1:49PM PDT (-0700 GMT)
Ms. Segura: Is the high temperature on the surface of Europa? (This is news to ne, and very exciting!)

David V.: . . . . Fri, Mar 6, 1:50PM PDT (-0700 GMT)
to SSI TEAM MEMBERS: what happened to the Ganymede 7 and 8 high res images from last summer??

Leslie: Outreach: . . . . Fri, Mar 6, 1:50PM PDT (-0700 GMT)
Math teacher in Kansas: Great question! We have many reasons for wanting to understand what is going on at Europa, and asking the US taxpayers to foot the bill. I'll just mention a couple here for you. First, since Galileo is already at Jupiter, many, many costs are saved by extending the mission (rather than trying to launch a new one). I should mention that we are running Galileo now for $15 million per year, less than it costs to make most movies. Also, imagine how much we can learn about what the possibilities are for life in extreme environments on Earth, and help answer the "what-if" questions if we learn about similar areas elsewhere. By studying other environments, we can learn how our own home would react to man- or nature- imposed changes.

R Sullivan SSI: . . . . Fri, Mar 6, 1:50PM PDT (-0700 GMT)
To all: Sorry I can't keep up with all the questions I've been asked. Please repeat if I haven't responded.

Pete Goldie: . . . . Fri, Mar 6, 1:50PM PDT (-0700 GMT)
Ms. Segura: Is the high temperature on the surface of Europa? (This is news to ne, and very exciting!)

Ken: . . . . Fri, Mar 6, 1:51PM PDT (-0700 GMT)
Hello.

Donald G. Strachan, Geologist, Gardnerville, NV: . . . . Fri, Mar 6, 1:51PM PDT (-0700 GMT)
What process might explain the uniquely large volume of uncombined or "free" water-ice on Europa's surface? Similarly, why the large volume of sulphur concentrated on Io? What are your theories on both of these questions? Why the partitioning?

Pete Goldie: . . . . Fri, Mar 6, 1:51PM PDT (-0700 GMT)
Ms. Segura: Is the high temperature on the surface of Europa? (This is news to ne, and very exciting!)

volcanopele: . . . . Fri, Mar 6, 1:51PM PDT (-0700 GMT)
Jeshua-Europa is not weird. It(going on present data)has an ocean with the top of it frozen solid. Some time a meteor rattles this tranquil world and shatters the surface. Io, on the other hand, thats weird!

Rene' Ortman: . . . . Fri, Mar 6, 1:51PM PDT (-0700 GMT)
Thank u Steve k/asu...wanted to know depth because I'm planning a mission to Europa right now with some fellow students and would like to know how far we would have to drill/melt through the ice....do u have any suggestions for me ??

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 1:51PM PDT (-0700 GMT)
Ed,Renato, and Rob, NIMS has determined that along with water ice, there appears to be hydrated minerals including sulfates, carbonates, and possibly clays. These seem to be very abundant in the visibly darker regions and are concentrated towards the equator.

Ed: . . . . Fri, Mar 6, 1:51PM PDT (-0700 GMT)
Have any of the pictures shown a possable sourse of the extruded strands? Why do they appear to be in pairs?

anonymous: . . . . Fri, Mar 6, 1:52PM PDT (-0700 GMT)
WHAT WILL THE FUTURE BRING FOR LIFE SEARCHING

Jim/Proj.Mgt: . . . . Fri, Mar 6, 1:52PM PDT (-0700 GMT)
Checking in.

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 1:52PM PDT (-0700 GMT)
To Artemis: unprofessional answer I believe the DS2 penetrator is under development as a ballistic subsurface probe for the Mars Surveyor 2003 mission.

R Sullivan SSI: . . . . Fri, Mar 6, 1:52PM PDT (-0700 GMT)
To Brent: Am not an expert, but I believe it is a resonance with the other satellites that forces Europa into an orbital configuration that makes it vulnerable to stresses from Jupiter. Both items you mentioned are important.

Laura, SPOT: . . . . Fri, Mar 6, 1:52PM PDT (-0700 GMT)
jw -My most recent setback and challenge was losing the staff and inheriting all of the work. We originally had ~200+ people and we have scaled back to less than 70.

Ken: . . . . Fri, Mar 6, 1:52PM PDT (-0700 GMT)
Could you summarize any new discoveries that our exploration of Europa has caused. (i.e. planet formations, behaviors, etc.)

Frank: . . . . Fri, Mar 6, 1:52PM PDT (-0700 GMT)
Marcia Segura: I want to know what minerals NIMS found so far on Europas surface

Tim McElrath, Navigation Team: . . . . Fri, Mar 6, 1:52PM PDT (-0700 GMT)
To Webslingr, GaTech: Please repeat your navigation/trajectory questions -- I was busy catching up the first time they came by.

steve k/asu: . . . . Fri, Mar 6, 1:52PM PDT (-0700 GMT)
to math teacher in Kansas: Also, I have seen nothing that inspires young children in school to want to learn science and math like learning about the information brought back from space missions.

Pete Goldie: . . . . Fri, Mar 6, 1:52PM PDT (-0700 GMT)
Ms. Segura: Is the high temperature on the surface of Europa? (This is news to ne, and very exciting!)

jw: . . . . Fri, Mar 6, 1:53PM PDT (-0700 GMT)
Because of the recent speculation about inhabiting the moon, do you think that every one will expect a colony on uropa next.

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 1:53PM PDT (-0700 GMT)
Have any navigation people arrived yet? The server seems to be on daylight savings time....

Gerry P: . . . . Fri, Mar 6, 1:53PM PDT (-0700 GMT)
Regarding observing the effects of an impact on the surface of Europa: Would it be possible to send galileo crashing to the surface at the end of its mission? If so, later probes can view the impact site and perhaps gleen some useful information.

Artemis: . . . . Fri, Mar 6, 1:53PM PDT (-0700 GMT)
How are you determining from the images Galileo is returning how deep the ice on Europa is? How do you identify areas with thinner ice?

Antonio de Morais: . . . . Fri, Mar 6, 1:53PM PDT (-0700 GMT)
To Laura,SPOT: Thank you very much. What kind of career paths could I take at JPL nd NASA ? What are the procedures please (where could I take the info. ?) Best regards, Antonio de Morais

Renato: . . . . Fri, Mar 6, 1:53PM PDT (-0700 GMT)
TO MARCIA: Could you give me a brief explanation on how the NIMS can help proving that there is liquid water under the ice cap of Europa ?

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 1:53PM PDT (-0700 GMT)
The high temperatures that I previously discussed were HOTSPOTS on IO. Not Europa. We have determined we would need more than longjohns to hike on Europa.

steve k/asu: . . . . Fri, Mar 6, 1:54PM PDT (-0700 GMT)
to rene ortman: Couldn't tell you the right thickness, but I'd suggest you plan for 10 km or more.

Leslie: Outreach: . . . . Fri, Mar 6, 1:54PM PDT (-0700 GMT)
Brent: I believe that the eccentricity in Io's orbit is actually due in part to the tug from the other moons. The eccentricity is the main reason for the tides.

Ed: . . . . Fri, Mar 6, 1:54PM PDT (-0700 GMT)
Have any of the pictures shown a possable sourse of the extruded strands? Why do they appear to be in pairs?

Jeshua: . . . . Fri, Mar 6, 1:54PM PDT (-0700 GMT)
volcanopele: I meant Wired, not Weird. eg. Exciting...

anonymous: . . . . Fri, Mar 6, 1:54PM PDT (-0700 GMT)
WOULD THE LIFE CHANGE HISTORY LIKE THE BIBLE

brendan: . . . . Fri, Mar 6, 1:54PM PDT (-0700 GMT)
Hello, I am wondering where does Europa get heat to cause the slush?

Pat Beyer/DeepSpace Network/telecommunications support: . . . . Fri, Mar 6, 1:54PM PDT (-0700 GMT)
Laura, you asked what I do. I am the manager responsible for the development and commitment of DSN resources to support Galileo. I have been doing this for 7 years. Just recently I was given the additional duty of the development and commitment of AMMOS (advanced multimission operations systems) support to Galileo as well. This involves more data processing at JPL before sending certain data to the Project. AMMOS also formats commands for the Project and passes them to the DSN for transmission to the spacecraft.

Rene' Ortman: . . . . Fri, Mar 6, 1:55PM PDT (-0700 GMT)
thanks steve k/asu....would u suggest drilling or melting??

R Sullivan SSI: . . . . Fri, Mar 6, 1:55PM PDT (-0700 GMT)
To David V.: You've asked a reasonable question I hoped someone would be qualified to answer..but you're stuck with me. I don't know much about the Ganymede plans (try Brown University) but many of the images I have seen from G7 and G8 were some of the best ever, better in many respects than G2 (where some of the images were overcompressed). There were no camera anomalies during these encounters that I know of.

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 1:55PM PDT (-0700 GMT)
Tim, how can you make such close flybys to Europa without significantly changing the orbit? Won't the close flybys always change Galileo's energy?

DB: . . . . Fri, Mar 6, 1:55PM PDT (-0700 GMT)
Are the pictures we are seeing from Galileo the equivalent of time-exposures? Given the distance from the sun, would the moonscape of Europa, for example, appear dimmer to an observer orbiting the moon than the pictures portray? Thanks.

Jeshua: . . . . Fri, Mar 6, 1:55PM PDT (-0700 GMT)
Laura: I am confused. Is there a temperture map of Europa? If not, why? If so, when will it be released?

Rene' Ortman: . . . . Fri, Mar 6, 1:55PM PDT (-0700 GMT)
to brendan....plate tetonics cause heat

Webslingr, GaTech: . . . . Fri, Mar 6, 1:55PM PDT (-0700 GMT)
To brendan: it comes from the gravitational tiding energy from Jupiter. Combined with the energy of Europa's core and insulation from the Ice on the surface.

Kansas: . . . . Fri, Mar 6, 1:55PM PDT (-0700 GMT)
Another question from a student, what is the top speed any galileo craft could go, know or in the future??

John G.: . . . . Fri, Mar 6, 1:55PM PDT (-0700 GMT)
For: R. Sullivan - In terms of over-all mapping coverage, what percentage of Europa, Ganymede and Callisto's surfaces have been imaged at a higher resolution than Voyagers 1&2?

Phoenix: . . . . Fri, Mar 6, 1:56PM PDT (-0700 GMT)
Thanks

steve k/asu: . . . . Fri, Mar 6, 1:56PM PDT (-0700 GMT)
to Ed: It appears that many of the ridges (if not nearly all) are associated with fractures that form in the icy crust as it is pulled on by tidal and rotational forces. If some material gets pushed up around or out of one of the cracks, and further fracturing occurs, the ridges can be split down the middle. We don't really know how this process works yet, though.

Beau B/SwRI: . . . . Fri, Mar 6, 1:56PM PDT (-0700 GMT)
Hello everyone! This is Beau Bierhaus, a Galileo SSI Affiliate at Southwest Research Institute in Boulder, CO.

Brenda: . . . . Fri, Mar 6, 1:56PM PDT (-0700 GMT)
To Steve K. - This is very interesting and informative! Thanks for all the info! :o)

Maltair: . . . . Fri, Mar 6, 1:56PM PDT (-0700 GMT)
If there is an ocean below the ice, would it be water or could it be something else like mythene?

roman navarrete: . . . . Fri, Mar 6, 1:56PM PDT (-0700 GMT)
there are any posibylities of life in europ

Donald G. Strachan, Geologist, Gardnerville, NV: . . . . Fri, Mar 6, 1:57PM PDT (-0700 GMT)
What process might explain the uniquely large volume of uncombined or "free" water-ice on Europa's surface? Similarly, why the large volume of sulphur concentrated on Io? What are your theories on both of these questions? Why the partitioning?

Tim McElrath, Navigation Team: . . . . Fri, Mar 6, 1:57PM PDT (-0700 GMT)
To Gerry P: We could crash Galileo on Europa, but that would be prohibited due to not wanting to contaminate the Europa environment with either life from Earth that may still be on the spacecraft or accidentally killing off anything that might be alive on Europa. I'm not sure we'd learn anything unless another spacecraft was watching anyway.

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 1:57PM PDT (-0700 GMT)
to carl banks:

volcanopele: . . . . Fri, Mar 6, 1:57PM PDT (-0700 GMT)
To Mr. Strachan(Im 14 okay)- I can answer your question about Io. Jupiter was very hot in the beginning and blew off the volatles near Jupiter. Water being extreamly volatle(or at least the Hydrogen in it)was wiped off the map. Does that answer your question?

David V.: . . . . Fri, Mar 6, 1:57PM PDT (-0700 GMT)
to R SULLIVAN (SSI) THanks! thats a relief! However, the G7 and G8 images of GANYMEDE have never been put on the web. We all have access to G7 and G8 images of io, europa, jupiter, amalthea, etc, but no ganymede. It seems like Ganymede is getting shortchanged

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 1:57PM PDT (-0700 GMT)
Frank, NIMS has seen evidence of hydrated sulfates, carbonates, and possibly clays.

anonymous: . . . . Fri, Mar 6, 1:57PM PDT (-0700 GMT)
HOW DO COMETS HAVE THE NESSESITIES TO CREATE LIFE

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 1:57PM PDT (-0700 GMT)
To Jeshua: (non staff answer) As I understand it thermal mapping (as in IR) has a depth range of about six inches from orbit. Galileo is limited to flybys only.

brendan: . . . . Fri, Mar 6, 1:58PM PDT (-0700 GMT)
Will Galileo survive travelling through the radiation belts later in the mission to get to Io?

Ed: . . . . Fri, Mar 6, 1:58PM PDT (-0700 GMT)
Have any of the pictures shown a possable sourse of the extruded strands? Why do they appear to be in pairs?

Jim Galasyn: . . . . Fri, Mar 6, 1:58PM PDT (-0700 GMT)
Is there an effort to "reassemble" the Europa surface to see how it appeared some time ago? For example, is somebody trying to assemble the "puzzle pieces" is the chaos regions?

Beau B/SwRI: . . . . Fri, Mar 6, 1:58PM PDT (-0700 GMT)
Maltair: The ocean on Europa would most likely

Jeshua: . . . . Fri, Mar 6, 1:58PM PDT (-0700 GMT)
Is the data from Dec 5 the highest-res we will get out of GEM?

Rafael. Malaga Spain.: . . . . Fri, Mar 6, 1:58PM PDT (-0700 GMT)
A simple question. What colour has EUROPA?: White, Brown, Blue? Photos are B&W and it is difficult to imagine...

Kansas: . . . . Fri, Mar 6, 1:58PM PDT (-0700 GMT)
How long does it take for galileo to get to Jupiter??

Beau B/SwRI: . . . . Fri, Mar 6, 1:59PM PDT (-0700 GMT)
Maltair: SOrry about that, got cut off -- the ocean would most likely be liquid water, as in H20.

Brian: . . . . Fri, Mar 6, 1:59PM PDT (-0700 GMT)
Thanks Brian for answering my tape recorder question. Now a transmitter question. Did I hear that the way the spacecraft signal is transmitted was changed in some fundamental way, like less power in the carrier signal but more in the modulation or some such unfathomable (for me) thing?

R Sullivan SSI: . . . . Fri, Mar 6, 1:59PM PDT (-0700 GMT)
To D.B. Right you are. The SSI camera was designed for these lower light levels, so taking images so far from the sun is not a problem.

steve k/asu: . . . . Fri, Mar 6, 1:59PM PDT (-0700 GMT)
to anonymous: some carbon-containing compounds have been found in meteorites and should also be present in the icy bodies of comets. As far as we know, we need carbon to get life (as we know it :-).

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 1:59PM PDT (-0700 GMT)
Brian P: you began to answer me, but it never appeared....

Chiron: . . . . Fri, Mar 6, 1:59PM PDT (-0700 GMT)
Will we know for sure if there is any sort of ocean on Europa after the mission results are in ?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 1:59PM PDT (-0700 GMT)
Would there be any point in that Jim Galasyn?

Rene' Ortman: . . . . Fri, Mar 6, 2:00PM PDT (-0700 GMT)
to Beau....could u tell me where on Europa is the most likely place where the supposed ocean underneath the surface would be the most shallo???

steve k/asu: . . . . Fri, Mar 6, 2:00PM PDT (-0700 GMT)
to jeshua: Yes. 6 m/pixel is the best we'll do. Not bad, though, considering a semi-truck would be several pixels across!

anonymous: . . . . Fri, Mar 6, 2:00PM PDT (-0700 GMT)
I WANT TO KNOW ALL THE THEORIES FOR LIFE THERE

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 2:00PM PDT (-0700 GMT)
to carl b.: sorry. someone stopped by my office and i forget your original question.

Leslie: Outreach: . . . . Fri, Mar 6, 2:00PM PDT (-0700 GMT)
Hi Michael: In the Outreach Office, went through our own changes when we transitioned from the Galileo Prime Mission to the Galileo Europa Mission, and lost our competent student who put the questions and answers together in the chat transcripts. We are still looking for a replacement, so the chats remain "unmatched". We'll get them up much more quickly when the position is filled.

Jim/Proj.Mgt: . . . . Fri, Mar 6, 2:00PM PDT (-0700 GMT)
brendan: We're pretty confident that we should be able to survive at least the first encounter and playback with Io. I'm personally confident we'll get both of the encounters.

Brian C: . . . . Fri, Mar 6, 2:00PM PDT (-0700 GMT)
I have to go and be with my kids now....Thanks for the wonderfull opertunity to chat like this...

Jim Galasyn: . . . . Fri, Mar 6, 2:01PM PDT (-0700 GMT)
To Doug: I don't know, but "reassembling" the surface seems like it might reveal some underlying dynamics...

roman navarrete: . . . . Fri, Mar 6, 2:01PM PDT (-0700 GMT)
there ara any posibylities of life in that moon?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:01PM PDT (-0700 GMT)
all the theories .......there's a biggie

Joel: . . . . Fri, Mar 6, 2:01PM PDT (-0700 GMT)
What is Europa's atmosphere like?

anonymous: . . . . Fri, Mar 6, 2:01PM PDT (-0700 GMT)
Other than red tape, are there any reasons that one the already-scheduled Mars landers can't be refitted and retasked to become a Europa lander, complete with radar, et al...??

Tim McElrath, Navigation Team: . . . . Fri, Mar 6, 2:01PM PDT (-0700 GMT)
To Carl Banks: Each Europa flyby is the equivalent of 100 to 500 meters/second of delta-V (velocity change), and this is by design to get to the next flyby. By comparison, we don't have enough propellent left to do even 100 m/s. The Europa orbit doesn't change noticeably (in case that's what you meant) since the spacecraft has only 1.D-20 the mass of Europa (approximately).

Jeshua: . . . . Fri, Mar 6, 2:01PM PDT (-0700 GMT)
steve k/asu: Thanks, it's brillant! I was just hoping for even more brillance!

Webslingr, GaTech: . . . . Fri, Mar 6, 2:01PM PDT (-0700 GMT)
to anonymous: We still don't know about the true exact theories of life here on earth, that's why we're going to Europa.

moondweller: . . . . Fri, Mar 6, 2:01PM PDT (-0700 GMT)
Please explain again what is next for the galileo probe? How long do you intend to operate it? Are any further missions over and above the initial missions planned for Galileo?

Icewolf: . . . . Fri, Mar 6, 2:02PM PDT (-0700 GMT)
Other than red tape, are there any reasons that one the already-scheduled Mars landers can't be refitted and retasked to become a Europa lander, complete with radar, et al...??

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 2:02PM PDT (-0700 GMT)
Renato, For Jupiter's satellites, NIMS can only "see" the surface. If there is water below the ice, NIMS could not see it directly but NIMS could detect minerals left behind after the water has evaporated.

anonymous: . . . . Fri, Mar 6, 2:02PM PDT (-0700 GMT)
DO THINK AN OCEAN IS STILL SPEWING TODAY

volcanopele: . . . . Fri, Mar 6, 2:02PM PDT (-0700 GMT)
Jeshua- Well I think they are both interesting in their own ways

Donald G. Strachan, Geologist, Gardnerville, NV: . . . . Fri, Mar 6, 2:02PM PDT (-0700 GMT)
Donald G. Strachan, Geologist, Gardnerville, NV. If you Galileo people have to leave before answers are given, please feel free to email me at "dgstrachan@nanosecond.com". Thank you.

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 2:02PM PDT (-0700 GMT)
Brian P: no problem. I was wondering how you manage to fly by so close to the moons without drastically changing Galileo's orbit?

Steve & Charlotte Gist: . . . . Fri, Mar 6, 2:02PM PDT (-0700 GMT)
Cardiff UK (Phill from Newcastle, Staffs is right, it hasn't stopped raining anywhere in the UK today). Congratulations and commiserations to all the team, it must be really hard to keep track of this, but please keep doing it - it's got to be good. To the question - Why does Europa seem to be unique? Is it a capture? If it isn't, shouldn't there be other similar satellites around Jupiter and indeed Saturn? Best Wishes.

steve k/asu: . . . . Fri, Mar 6, 2:02PM PDT (-0700 GMT)
reply to joel: Europa's atmosphere is almost non-existent. It's just scattered molecules of oxygen, etc., that have been ejected from the surface ice by radiation bombardment. You'd never know there was one if you were on the surface without very sensitive instruments.

Jake: . . . . Fri, Mar 6, 2:02PM PDT (-0700 GMT)
Hi. I just logged on. This is for R. Sullivan...I'm confused! Scientists say Europa is flat. But I've seen pictures of mountains and cliffs on Europa. How high are they? How steep?

Beau B/SwRI: . . . . Fri, Mar 6, 2:02PM PDT (-0700 GMT)
Rene: since we aren't definite yet whether or not there is an ocean, it is hard to say where it will be deep or shallow -- one idea though is that perhaps there might not be a global ocean, but "pockets" of liquid water underneath the ice shell.

Webslingr, GaTech: . . . . Fri, Mar 6, 2:03PM PDT (-0700 GMT)
to anonymous: (non-staff answer) yes

R Sullivan SSI: . . . . Fri, Mar 6, 2:03PM PDT (-0700 GMT)
To John G.: I can answer for Europa better than the others...Voyager only imaged about 20% of the surface at about 2 km/pxl. The rest of the surface was at 10-20 km/pixel. Galileo coverage will increase the "2 km/pixel or better" baseline to around 50% of the surface, with large swaths covered at better than 250 m/pixel. The leading hemisphere cannot be easily seen during Galileo's mission until I25, when a distant flyby of Europa occurs on Galileo's inbound journey to Io. Unless we last that long, we won't get much better coverage of this part of Europa.

Star: . . . . Fri, Mar 6, 2:03PM PDT (-0700 GMT)
Just wanted to tell the team they have done a great job with this project. Keep up the good work everybody:)

Ken Arromdee: . . . . Fri, Mar 6, 2:03PM PDT (-0700 GMT)
If there were mats of seaweed or similar life on Europa, could they eventually make it to the surface frozen in the ice somehow and be detectable by Galileo (or the Europa Orbiter)?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:03PM PDT (-0700 GMT)
Jm/Proj.Mgt could it be possible to put Gelileo into a faster approach to Io near the end of the mission to expose it to the radiation for shorter bursts and give it 'clearer' space to transmit the data back to earth .. and possibly loose any radiation effects it acquired on the way past ?

Laura, SPOT: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
Hi Tim McElrath! We had a few Navigation questions in the beginning. Glad you could join us!

Srdjan (from Yug, Europe): . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
Hello and congratulation for the great picture of Europa. I would like to ask why Galilieo didn�t take picture of Europe when he was at 200 km from surface?

Maltair: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
How long does it take radio transmissions to reach back and forth from Io? I think an underwater rover would be something to see! What are the chances?

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
to moondweller. The galileo ORBITER will have 6 more close flybys of europa, 4 orbits that traverse the inner jupiter magnetosphere, and 1-2 close flybys of Io. GEM will end in Dec '99.

Gerry P: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
O.K., so crashing galileo into the surface might not be such a hot idea. How about "threading the needle" by having galileo pass the surface REALLY close (a dozen or so miles)to get a few very-high resolution shots. I realise that this manuver might alter the trajectory of galileo so that no further enounters would be possible, but would this be a problem if this very close flyby occured at the end of the Europa mission?

Jim/Proj.Mgt: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
moondweller: At the moment, we don't have any committment past the two Io encounters in late 99. Summer of 99 we will take a look at the spacecraft's health and decide what the appropriate next step is. We already have some ideas that we might want to do.

Xman: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
What temperatures might be expected for an ocean on Europa?

anonymous: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
How likely is it to find a moon orbiting a moon? I imagine it might be possible to see a tiny moon orbiting Europa, say 10 meter in diameter. What are the contraints on moons around moons?

Webslingr, GaTech: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
What is the best m/pixel resolution Galileo has obtained from Europa?

David V.: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
can anyone verify any of this? i have found bits abd pieces of plans for the europa orbiter all over the net Is any of the following true: 1: may be able to launch on an Atlas IIAR insted of a Delta rocket 2: must perform a mini tour of the Jupiter system (in jupiter orbit) before entering europa orbit 3: may possibly use solar panels 4: may possibly use solar electric propulsion to shorten travel time 5: might use optical communications link instead of a large dish radio antenna also, is the Europa orbiter concept going to be on the level of the Discovery missions in terms of funding, or will it be somewhat better funded (more/more complex instruments payload, longer lifetime, etc) (all of this info is floating around NASA/JPL pages, please verify/correct anything I misunderstood

steve k/asu: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
reply to Carl Banks: The close fly-bys are used to do exactly that - to change the orbits in preparation for future flybys. I'm no rocket scientist, but it sure works well.

Leslie: Outreach: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
Jim G.: This is exactly what scientists are busy working on - piecing the history of Europa's surface together. We've even made an activity out of it. The URL is http:// www.jpl.nasa.gov/galileo/sepo/education/europa/europaedu.html

Webslingr, GaTech: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
What is the best m/pixel resolution Galileo has obtained from Europa?

Rene' Ortman: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
Thanks Beau....but do u have any idea what so ever where those pockets would be...like maybe near that big crater or something???

R Sullivan SSI: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
To Rafael: Europa is a very pale yellow, with browinish lineaments.

Star: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
Is there any way to tell if the water/ice is salty or not?

Brent Turcotte: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
How likely is it to find a moon orbiting a moon? I imagine it might be possible to see a tiny moon orbiting Europa, say 10 meter in diameter. What are the contraints on moons around moons?

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
To Steve: So we can assume the atmosphere does jack squat for radiation relief?

roman navarrete: . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
are there any posibylities of life in europa?

Sheffield Steve (UK): . . . . Fri, Mar 6, 2:05PM PDT (-0700 GMT)
This is moving a bit too fast!!! Before it disappears can I congratulate Ron Baalke and all involved in the project for the phenominally interesting coverage of the mission. A job very well done.

Webslingr, GaTech: . . . . Fri, Mar 6, 2:06PM PDT (-0700 GMT)
What is the best m/pixel resolution Galileo has obtained from Europa?

Tayfun: . . . . Fri, Mar 6, 2:06PM PDT (-0700 GMT)
Marcia can you give us a volcano report for Io. Which ones were active when you last checked?

Joel: . . . . Fri, Mar 6, 2:06PM PDT (-0700 GMT)
Are the subterrarnian volcanos still active on Europa?

brendan: . . . . Fri, Mar 6, 2:06PM PDT (-0700 GMT)
I have read reports of missions to Europa but when will a probe go to land there?

Eliz. SSI outreach: . . . . Fri, Mar 6, 2:06PM PDT (-0700 GMT)
Ganymede images: We haven't forgotten Ganymede releases from the later orbits and hope to get a set of images on the web soon. We would like to share them with you, but keep getting bogged down in other requirements. Please join the Galileo mailing list so you'll hear as soon as we can get some posted.

Donald G. Strachan, Geologist, Gardnerville, NV: . . . . Fri, Mar 6, 2:06PM PDT (-0700 GMT)
DG Strachan to Mr. Volcanopele: What would concentrate your "blow-off" water on the surface of just one moon, when there are several such candidates?

Renato: . . . . Fri, Mar 6, 2:06PM PDT (-0700 GMT)
Thanks R. Sullivan, Marcia. Leslie: I wasn't expecting to hear from you guys so soon (I participated on the web chat last year... was it in December ?) and I would like to send my best wishes to the whole staff who are presenting us these terrific opportunities to broaden our view on what's out there in the outer limits of our intriguing Solar System.

steve k/asu: . . . . Fri, Mar 6, 2:06PM PDT (-0700 GMT)
to perry frix: Right you are!

Charles Leon: . . . . Fri, Mar 6, 2:06PM PDT (-0700 GMT)
Hello, everyone. Could someone answer this one for me: Why are no studies being done on the small outer moons? I know they are very remote, but any observations would obtain better information than ground-based. At the very least, we could refine their positions more presisely and see how they evolve over time. Albedo information would help indicate compositions and perhaps indicate where in the Asteroid Belt the parent bodies may have originated.

Tim McElrath, Navigation Team: . . . . Fri, Mar 6, 2:07PM PDT (-0700 GMT)
To Doug Inwood: the limiting factor in getting to Io quickly is needing to use gravity assists to get there. If we had 1 km/sec or so of delta-V left, and wanted to use it for that, radiation wouldn't be a problem, since we could drop the closest point of the orbit to Io in 1 orbit.

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:07PM PDT (-0700 GMT)
good point Jim ......that could tell us something of what was happening beneathe the surface indeed

R Sullivan SSI: . . . . Fri, Mar 6, 2:07PM PDT (-0700 GMT)
Am late...gotta go. Thanks all.

Tomas W (Stockholm, Sweden): . . . . Fri, Mar 6, 2:07PM PDT (-0700 GMT)
Question for navigation team: I understand that entering into Europa orbit requires lots of fuel (delta-V). What are the options for the 2003 mission? Propulsion, gravity assists etc.

Star: . . . . Fri, Mar 6, 2:07PM PDT (-0700 GMT)
I like Maltair's idea too. An underwater rover would really be something

Jim Galasyn: . . . . Fri, Mar 6, 2:07PM PDT (-0700 GMT)
Leslie: really cool! Thanks for the URL.

anonymous: . . . . Fri, Mar 6, 2:07PM PDT (-0700 GMT)
EXPLAIN

Jeshua: . . . . Fri, Mar 6, 2:07PM PDT (-0700 GMT)
What is your rough estimate for a submarine probe to be on the surface? 2010? I can't wait!! Send one tomorrow!

Pat Beyer/DeepSpace Network/telecommunications support: . . . . Fri, Mar 6, 2:08PM PDT (-0700 GMT)
To Brian: Both the Galileo always had the ability to "fully suppress the carrier" which means to put all the power into the telemetry. However there were no plans to use it or need it with the High Gain Antenna. Fortuneately, the DSN was already developing our next generation receiver called a BVR - Block "five" receiver, which can successfully track a suppressed carrier and still demodulate telemetry. The BVRs became operational in July of 1995.

steve k/asu: . . . . Fri, Mar 6, 2:08PM PDT (-0700 GMT)
Well, I have to hand off to another SSI associate here at ASU. Thanks for all the GREAT questions. See you in a future web-chat. Steve

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 2:08PM PDT (-0700 GMT)
to webslinger. 6m/pixel on europa

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:08PM PDT (-0700 GMT)
could that not be planned for now Tim McElrath ?

Webslingr, GaTech: . . . . Fri, Mar 6, 2:08PM PDT (-0700 GMT)
What is the best m/pixel resolution Galileo has obtained of Jupiter?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:09PM PDT (-0700 GMT)
Brent -- At least one moon around an asteroid has been found. Probably there could be moons around moons, as well. But the gravitational field is much more complex, with Jupiter and other big satellites nearby. Our imaging sequences are focussed on the Galilean satellites themselves and we're not hunting for moons of moons.

Jim/Proj.Mgt: . . . . Fri, Mar 6, 2:09PM PDT (-0700 GMT)
Doug Inwood Observatory Director New Zealand: We really don't have many options to change our trajectory when we approach Io, and no options that would significally shorten the amount of time we would spend in the high radiation environment.

Webslingr, GaTech: . . . . Fri, Mar 6, 2:09PM PDT (-0700 GMT)
Sorry, Thank you Brian. By the way is there a specific page I can find such images?

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 2:09PM PDT (-0700 GMT)
Tim, I am curious, why use Callisto for perijove reduction? It seems that Ganymede is A) more massive, B) faster moving, and C) more interesting than Callisto, making a better GA candidate?

Icewolf: . . . . Fri, Mar 6, 2:09PM PDT (-0700 GMT)
Other than red tape, are there any reasons that one the already-scheduled Mars landers can't be refitted and retasked to become a Europa lander, complete with radar, et al...??

: . . . . Fri, Mar 6, 2:09PM PDT (-0700 GMT)
Are you SSI people planing and taking stereo pair 3D images

kim h/asu: . . . . Fri, Mar 6, 2:09PM PDT (-0700 GMT)
Hello again from ASU (Arizona State University)

Beau B/SwRI: . . . . Fri, Mar 6, 2:09PM PDT (-0700 GMT)
Rene: It is true that potential "melt pockets" exist underneath craters, epsecially big craters, for some time after their formation. However, even though we strongly suspect that Pwyll is a young crater -- geologically speaking -- it probably doesn't have any liquid water beneath it now.

Jake: . . . . Fri, Mar 6, 2:09PM PDT (-0700 GMT)
Could anyone from the SSI team answer my question about, how steep? and how high? are the mountains and cliffs on Europa?

enif: . . . . Fri, Mar 6, 2:09PM PDT (-0700 GMT)
What will happen with spacecraft after the mision, will it just wander in space?

Webslingr, GaTech: . . . . Fri, Mar 6, 2:10PM PDT (-0700 GMT)
Is there a specific page I can find 6m/pixel resolution?

Tim Z: . . . . Fri, Mar 6, 2:10PM PDT (-0700 GMT)
when the sun changes to a red giant, could the extra solar radiation melt the ice on europa? Or is Europa too far away?

John G.: . . . . Fri, Mar 6, 2:11PM PDT (-0700 GMT)
To jump ahead 10 years--will the planned Europa Orbiter be using gravity assists from other Jovian moons to assist entry into Europa orbit? And would the Europa Orbiter's instruments return data from such encounters?

John D: . . . . Fri, Mar 6, 2:11PM PDT (-0700 GMT)
The Europa pictures just released are awesome. But when you look closely there are fewer than ten images, some of which are 1/2 frames (300x700 pixels, when the image size for Galileo shots are 800x800). What happened to the rest of the data? Did any of the color shots planned for this flyby get back to Earth? And will we see any more color in the future?

kim h/asu: . . . . Fri, Mar 6, 2:11PM PDT (-0700 GMT)
to Jake: we've seen slopes up to 50 degress (almost certainly some are higher), and the relief is mostly less than 300 meters. Isolated tilted 'bergs' have heights up to half a km or so, though!

Eliz. SSI outreach: . . . . Fri, Mar 6, 2:11PM PDT (-0700 GMT)
Thanks to project participants: I see that it's as hectic as always on these chats and commend our GLL project volunteers for their efforts. Our second shift of SSI people should be on now, so THANKS to our first shift for working so hard to answer as many questions as you could. (I'll be gone for a while, but back again later ...)

brendan (IRL): . . . . Fri, Mar 6, 2:11PM PDT (-0700 GMT)
If Galileo survives the dives into the radiation belts, what will happen at the end of the GEM mission in December 1999

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 2:11PM PDT (-0700 GMT)
To Icewolf: (non-staff answer) Here are some problems: First, power requirements are different. Second, Radiation requirements are different. Third, science objectives are different. Etc...

roman navarrete: . . . . Fri, Mar 6, 2:12PM PDT (-0700 GMT)
can answer my question? are there any posibylities of life in europa?

Laura, SPOT: . . . . Fri, Mar 6, 2:12PM PDT (-0700 GMT)
Webslingr - button has the newset images at 6m/pixel

Webslingr, GaTech: . . . . Fri, Mar 6, 2:12PM PDT (-0700 GMT)
What kind of radiation shielding was used on Galileo to endure the electromagnetic fields of Jupiter?

Srdjan (from Yug, Europe): . . . . Fri, Mar 6, 2:12PM PDT (-0700 GMT)
Is the picture of Europa (from 560 km ; 6m/pixel), that is posted on the WWW, part of the bigger picture or you receive just that part?

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 2:12PM PDT (-0700 GMT)
to webslingr: check out the galileo home page, it has the latest E12 images, which includes the highest res picture.

Jeshua: . . . . Fri, Mar 6, 2:12PM PDT (-0700 GMT)
I like Icewolfs question. Can someone please answer it?

Jake: . . . . Fri, Mar 6, 2:12PM PDT (-0700 GMT)
A question for Leslie from Outreach. Could you please provide me with an e-mail address for anyone of the scientists involved in Galileo's "Fields & Particles Experiment"?

Rene' Ortman: . . . . Fri, Mar 6, 2:12PM PDT (-0700 GMT)
Beau...just on ur opinion only, do u think the "ice" on Europa is filled with crap (dirt, rock, etc.) which would make melting through the "ice" with a probe almost impossible??

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:12PM PDT (-0700 GMT)
I read that Galileo will continue to orbit Jupiter well after it has been killed by the radiation ....true ?

Pat Beyer/DeepSpace Network/telecommunications support: . . . . Fri, Mar 6, 2:12PM PDT (-0700 GMT)
Kansas: I never saw Tim McElrath answer your question about the journey to Jupiter. Galileo was launched on October 18, 1989 and arrived at Jupiter on December 7, 1995. This is how long it took. Depending on many variables, the time can be much shorter.

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:12PM PDT (-0700 GMT)
Charles Leon -- We wanted to study the small outer moons, but the fact is that they are far away from Jupiter and Galileo's trajectory, which is optimized for passing close to the Galilean moons on successive encounters, comes nowhere near those small moons. Because of all the limitations (permitting other instruments to get their data, the limited antenna capability, etc.) it was decided that we couldn't learn enough about the small moons to make that a priority.

Steve & Charlotte Gist: . . . . Fri, Mar 6, 2:13PM PDT (-0700 GMT)
Cardiff UK (Phill from Newcastle, Staffs is right, it hasn't stopped raining anywhere in the UK today). Congratulations and commiserations to all the team, it must be really hard to keep track of this, but please keep doing it - it's got to be good. To the question - Why does Europa seem to be unique? Is it a capture? If it isn't, shouldn't there be other similar satellites around Jupiter and indeed Saturn? Best Wishes.

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 2:13PM PDT (-0700 GMT)
Hi Kim! I bet you can't put points on my grad. application for asking good questions either. ;)

moondweller: . . . . Fri, Mar 6, 2:13PM PDT (-0700 GMT)
What other instraments are on the galileo than cameras?

volcanopele: . . . . Fri, Mar 6, 2:13PM PDT (-0700 GMT)
Mr. Strachan-Could you please explain

Spaceman: . . . . Fri, Mar 6, 2:13PM PDT (-0700 GMT)
Hi, I'm from England and I would like to congratulate the team on a great mission. I was lucky enough to be at the launch of Galileo way back in Oct 89 and had to avoid the anti nuclear protestors

Gonzalo Rico: . . . . Fri, Mar 6, 2:14PM PDT (-0700 GMT)
Hi everybody. Now we now the presence of water at the Moon, Ganymedes, Europa and Calisto, mayby many other bodys in our solar system. Did you espect that abundace of water in the solar system?

Jim Galasyn: . . . . Fri, Mar 6, 2:14PM PDT (-0700 GMT)
Could a Europa penetrator use a chunk of plutonium to melt its way though the ice crust?

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 2:14PM PDT (-0700 GMT)
to brendan: we will continue to orbit jupiter. There is a proposal to do an engineering mission using galileo. no pictures. just evaluating the radiation effect on the spacecraft hardware.

anonymous: . . . . Fri, Mar 6, 2:14PM PDT (-0700 GMT)
DO YA THINK THERES AN OCEAN ON EUROPA POSSIBLY CONTAINING LIFE

Tim McElrath, Navigation Team: . . . . Fri, Mar 6, 2:14PM PDT (-0700 GMT)
To Gerry P (sp?): As I understand it, really low altitude is not ideal for pictures since they end up smeared, since the scan platform can't slew fast enough, even at exposures of a few milliseconds. We could do a 50 km flyby for fields and particles, but that wasn't as important as getting to Io.

MClary: . . . . Fri, Mar 6, 2:14PM PDT (-0700 GMT)
Hi. This is Maurice Clary old retired Instrument Mgr. How's SSI performing?

kim h/asu: . . . . Fri, Mar 6, 2:14PM PDT (-0700 GMT)
to Perry Frix: Just like Steve, I don't have the power either. Sorry

Jake: . . . . Fri, Mar 6, 2:15PM PDT (-0700 GMT)
A question or two for Dr. Chapman. Sir, is it ice or mostly snow that covers Europa? If it's snow, what kind of snow?

Beau B/SwRI: . . . . Fri, Mar 6, 2:15PM PDT (-0700 GMT)
Rene: We do see other materials on the surface of Europa, but the vast majority of the surface is water ice. Take a look at the new pictures, all the bright terrain you see is essentially water ice! The other material on the surface shouldn't be a big obstacle for something (a probe) trying to get beneath the ice sheet.

Jim/Proj.Mgt: . . . . Fri, Mar 6, 2:15PM PDT (-0700 GMT)
Webslingr, GaTech: Most of the "radiation shielding" is the aluminum structures that hold our electronics. We tried to ensure that all of the main parts achieved at least 2 grams per square centimeter of effective shielding.

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:15PM PDT (-0700 GMT)
so Galileo won't be entirely dead ? how long can it's power supplies hold out?

brendan (IRL): . . . . Fri, Mar 6, 2:15PM PDT (-0700 GMT)
Hi spaceman

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 2:15PM PDT (-0700 GMT)
to moondweller. there are 11 science instruments on galileo. there are 4 recmote sensing instruments and 6 fields and particle instrument and the radio science instrument (i.e., the antenna).

Webslingr, GaTech: . . . . Fri, Mar 6, 2:15PM PDT (-0700 GMT)
What kind of shielding did Galileo use to protect itself from Jupiter's magnetic field? Morespecifically what method and material did it use?

Spaceman: . . . . Fri, Mar 6, 2:15PM PDT (-0700 GMT)
Has anyone spotted a face on Europa yet?? HAHA!! Just kidding !!

Ed: . . . . Fri, Mar 6, 2:16PM PDT (-0700 GMT)
R Sullivan SSI: I'm a little rusty on my chemistry but isn't this true? Without an atmosphere like ours wouldn't the water literaty boil away into the atmosphere? Wouldn't ice on Europa SUBLIMATE into the atmosphere of which there is for all practicle purposes none on Europa?

Rene' Ortman: . . . . Fri, Mar 6, 2:16PM PDT (-0700 GMT)
Beau...thanks, u've been a big help :-)

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 2:16PM PDT (-0700 GMT)
Star, We have indication of "salts" but they are not the "Morton" table salts which is more or less in our oceans. Rather they are more like salts of Mono Lake or Baker dry lake.

Spaceman: . . . . Fri, Mar 6, 2:16PM PDT (-0700 GMT)
Hi Brendan (IRL)

Webslingr, GaTech: . . . . Fri, Mar 6, 2:16PM PDT (-0700 GMT)
Sorry Jim thought that my question was forgotten, thank you.

Brent Turcotte: . . . . Fri, Mar 6, 2:16PM PDT (-0700 GMT)
Has the Galileo team made fact sheets for the tiny inner moons of Jupiter besides Amalthea. I was hoping that when you photographed Metis, Adreastea and Thebe, you would post statistics on these small moons. I am a collector of planet stats.

David V.: . . . . Fri, Mar 6, 2:16PM PDT (-0700 GMT)
has anyone spotted any BLACK MONOLITHS on Europa?? (huh-huhuh)

Maltair: . . . . Fri, Mar 6, 2:16PM PDT (-0700 GMT)
So what do you think about the submarine rover?

Tim Z: . . . . Fri, Mar 6, 2:16PM PDT (-0700 GMT)
When the sun changes into a red giant, could the ice on europa's surface melt? Or is europa too far away?

Jim/Proj.Mgt: . . . . Fri, Mar 6, 2:17PM PDT (-0700 GMT)
MClary: Hi! Glad to hear from you.

Brian P, SPO Team Chief: . . . . Fri, Mar 6, 2:17PM PDT (-0700 GMT)
to spaceman. no, but have you checked out ganymede. :) just kidding!!

anonymous: . . . . Fri, Mar 6, 2:17PM PDT (-0700 GMT)
MY FAMILY AND I SUPPORT THE POSSIBILITIES OF LIFE THERE AND ELSEWHERE IN UNIVERSE

Steve & Charlotte Gist: . . . . Fri, Mar 6, 2:17PM PDT (-0700 GMT)
Cardiff UK (Phill from Newcastle, Staffs is right, it hasn't stopped raining anywhere in the UK today). Congratulations and commiserations to all the team, it must be really hard to keep track of this, but please keep doing it - it's got to be good. To the question - Why does Europa seem to be unique? Is it a capture? If it isn't, shouldn't there be other similar satellites around Jupiter and indeed Saturn? Best Wishes.

Laura, SPOT: . . . . Fri, Mar 6, 2:17PM PDT (-0700 GMT)
moondweller - There are several other instruments - all receiving great data on Galileo. Dust Detector (DDS) Energetic Particles (EPD) Heavy Ion Counter (HIC) Magnetometer Team (MAG) Near Infrared Mapping Spectrometer (NIMS) Radio Science (RSG) Plasma Particle Investigation (PLS) Photopolarimeter/Radiometer (PPR) Plasma Wave Investigation (PWS) Solid State Imaging (SSI) Ultra Violet Spectrometer/Extreme Ultra Violet spectrometer (UVS/EUV)

Star: . . . . Fri, Mar 6, 2:17PM PDT (-0700 GMT)
Simple question: is there a difference between what we call 'snow' and what we call 'ice'?

brendan (IRL): . . . . Fri, Mar 6, 2:17PM PDT (-0700 GMT)
to Spaceman: do you think will galileo survive the rediation

Gonzalo Rico: . . . . Fri, Mar 6, 2:17PM PDT (-0700 GMT)
Hi everybody. Now we now the presence of water at the Moon, Ganymedes, Europa and Calisto, mayby many other bodys in our solar system. Do you espect that abundance of water in the solar system?

Maltair: . . . . Fri, Mar 6, 2:18PM PDT (-0700 GMT)
Whats the differance in the salts you were talking about?

Jeshua: . . . . Fri, Mar 6, 2:18PM PDT (-0700 GMT)
Marcia: I live near Mono lake! Is there any science that I can contribute?

volcanopele: . . . . Fri, Mar 6, 2:18PM PDT (-0700 GMT)
does anybody here know when the Io pictures from E11 and E12 will come out

Joel: . . . . Fri, Mar 6, 2:18PM PDT (-0700 GMT)
How does the size of Europa compare with Earth?

Spaceman: . . . . Fri, Mar 6, 2:18PM PDT (-0700 GMT)
Brian P, I was going to ask you about that..maybe we should go into the Project XX room (please note not the XXX room)!!!!

Rene' Ortman: . . . . Fri, Mar 6, 2:18PM PDT (-0700 GMT)
Beau...sorry, thought I was done, but could u tell me if u think dropping something really heavy (ie. cannon ball) out of the orbiter and onto Europa's surfacewould be a good idea...this way, the probe wouldn't need so much energy to melt so fa.

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:18PM PDT (-0700 GMT)
Maurice -- it's doing just great! As for the question about why Europa is unique: many bodies in the solar system have unique "personalities". In Europa's case, it is probably because of the amount of tidal heating it is receiving, due to its gravitational tug-of-war with Jupiter, Io, and Ganymede. Io gets much more hear, and has continuous active volcanism. Europa has enough to keep it much warmer and more active than Ganymede.

Antonio de Morais: . . . . Fri, Mar 6, 2:18PM PDT (-0700 GMT)
I'm extremely interested on the research of Europa. I'll present an article (A posible internal structure of Europa) in the XXIII General Assembly of the European Geophysical Society, in NIce, FRance, on April 22. And some scientists know me weel by email (Dr. Adriana Ocampo, Dr. Chris McKay (Ames) , Dr. and Dr. Luke Dones (Ames) knows me personally (in the Rio de Janeiro International Workshop in Planetary Sciences - I presented a model about Europa). I'd like very much to work officially (at distance - I'm in Brasil) in some Galileo Team; here we don't have the study of the Solar System yet - I recently gave a suggestion of creation of a study group of diferent Profesors Drs.(physics, chemistry, geology, oceanography, engineering, etc) .) in the Institute of Advanced Studies of the University of Sao Paulo). I hope I can come to be useful to NASA and the exploration of Europa. Thank you for your attention. Sincerely, Best regards, Antonio de Morais (I'm finishing my undergraduate course in physics at the University of Sao Paulo, Brasil) Email: macca@cbpfsu1.cat.cbpf.br

Tim McElrath, Navigation Team: . . . . Fri, Mar 6, 2:19PM PDT (-0700 GMT)
About Europa orbiter strategies: At this time, I believe that the plan is for a combination of delta-Vs and gravity assists to get into Europa orbit. The last delta-V has to be at least 520 m/sec (Europa parabolic to circular at 100 km), and there needs to be a Jupiter arrival maneuver. Current plans seem to be for about 2-3 km/sec of delta-V in the Jupiter system, which is difficult but possible. SEP is a possibility, but only before getting to Jupiter.

Webslingr, GaTech: . . . . Fri, Mar 6, 2:19PM PDT (-0700 GMT)
Good question Spaceman, how much more time is given for Galileo to survive the radiation of Jupiter?

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 2:19PM PDT (-0700 GMT)
Hi Maurice, You still wearing those red suspenders?

Jim Galasyn: . . . . Fri, Mar 6, 2:19PM PDT (-0700 GMT)
Can we infer anything (life-related) from the presence of salts? A salty sea sounds very inviting to life...

Xman: . . . . Fri, Mar 6, 2:19PM PDT (-0700 GMT)
What temperatures might be expected for an ocean on Europa?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:19PM PDT (-0700 GMT)
i don't know David V but a friend and i found discovery when we were analsying images taken with our scope during the SL-9 events (artifact on the data tape tho)

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 2:19PM PDT (-0700 GMT)
To M. Segura: So the salts we're talking about are K, Mg, etc? Mr. Granahan mentioned radio isotope dating of these compounds last time, and i was rather curious about specific decay regimes that could be used. (i.e. K40 => Ca40)

Srdjan: . . . . Fri, Mar 6, 2:19PM PDT (-0700 GMT)
I would like to ask why Galilieo didn�t take picture of Europe when he was at 200 km from surface?

Spaceman: . . . . Fri, Mar 6, 2:19PM PDT (-0700 GMT)
brendan (IRL) sorry i'm not that technical ask the REAL A TEAM or should that be G team!

Jim/Proj.Mgt: . . . . Fri, Mar 6, 2:20PM PDT (-0700 GMT)
MClary: SSI's doing great. If you want all the details, e-mail us. I'd like to hear from you anyway.

Ronin: . . . . Fri, Mar 6, 2:20PM PDT (-0700 GMT)
to Joel: i believe europa is the size of our moon

Renato: . . . . Fri, Mar 6, 2:20PM PDT (-0700 GMT)
TO MARCIA: Now I think I got the point about the NIMS... thanks. Bye! TO LESLIE: I'll have to go now, I hope the next chat will come even sooner.Thanks again. Bye !

Icewolf: . . . . Fri, Mar 6, 2:20PM PDT (-0700 GMT)
How does the surface temperature at the warmest area of Europa compare with the surface temperature of the areas of the moon where ice has been found? I've heard that a major obstacle to using the moon's ice will be getting machinery to work at such cold temperatures. Might it be cheaper/easier to use the ice on Europa to make fuel?

David V.: . . . . Fri, Mar 6, 2:20PM PDT (-0700 GMT)
to steve from UK (i am NOT a scientist on the mission): but all lines of evidence point to Europa being a natural member of Jupiter's family. I.E. it has a very circular orbit that is in the plane of Jupiter's equator, and rotates in the same direction as the other large moons. (a prograde orbit)

Webslingr, GaTech: . . . . Fri, Mar 6, 2:20PM PDT (-0700 GMT)
What kind of computer processor is on-board Galileo and is it made to endure the high radiation of Jupiter? What is the error rate?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:20PM PDT (-0700 GMT)
Joel, Europa is smaller than Earth, about the size of our Moon.

volcanopele: . . . . Fri, Mar 6, 2:21PM PDT (-0700 GMT)
Star- You can punch snow with your feet and make a tiny crater. Ice you have to hit much harder and then it will only make cracks

Antonio de Morais: . . . . Fri, Mar 6, 2:21PM PDT (-0700 GMT)
To: Rene' Ortman: Could I be useful to your project ? Antonio Email: macca@cbpfsu1.cat.cbpf.br

Star: . . . . Fri, Mar 6, 2:21PM PDT (-0700 GMT)
Thanx Marcia, but..uh.. what is the difference in salts? If we tasted the stuff on Europa would it taste like what we consider 'salty'?

Joel: . . . . Fri, Mar 6, 2:21PM PDT (-0700 GMT)
Do we know of any minerals on Europa?

brendan (IRL): . . . . Fri, Mar 6, 2:21PM PDT (-0700 GMT)
I have made the Galileo model and I am wondering - what will the radiation do to the craft?

Ed: . . . . Fri, Mar 6, 2:21PM PDT (-0700 GMT)
What happened to sublimation? I don't see how these structures could be made of ICE? With such low atmospheric pressures and cold temps.

moondweller: . . . . Fri, Mar 6, 2:22PM PDT (-0700 GMT)
Does the ultra violet spectrometer enable you to determin what the composition of the surface ice is made of? Are their any signs of organic molicules, like found in the atmosphere of titan?

Webslingr, GaTech: . . . . Fri, Mar 6, 2:22PM PDT (-0700 GMT)
What kind of computer processor is on-board Galileo and is it made to endure the high radiation of Jupiter? What is the error rate? How much more time is given for Galileo to survive the radiation of Jupiter?

Jim Galasyn: . . . . Fri, Mar 6, 2:22PM PDT (-0700 GMT)
Europa's surface seems to be an almost textbook fractal, i.e., each line, on magnification, becomes a pair of lines, down to small scales. Such structures are often the fingerprint of iterative processes -- could this be interpreted to mean that the lines (ridges) are formed by a process of repeated freeze/thaw, or perhaps repeated flex/relax from tidal stresses? Would this kind of analysis be helpful for inferring dynamics?

Beau B/SwRI: . . . . Fri, Mar 6, 2:22PM PDT (-0700 GMT)
Rene: An interesting idea that would be very hard to execute. First, we are pretty sure that the ice shell is at least 1 kilometer (just over 1/2 a mile) thick, so it would take something much bigger than a cannonball to help penetrate any significat distance through the ice. The second problem would be trying to land the probe in exactly the same spot where you punched a partial hole in the ice -- that's a very hard thing to do!

Icewolf: . . . . Fri, Mar 6, 2:22PM PDT (-0700 GMT)
In regards to my temperature question a minute ago - by 'the moon' I was refering to Earth's satellite. Sorry.

Spaceman: . . . . Fri, Mar 6, 2:22PM PDT (-0700 GMT)
Are there any publically available CD Roms with the best Galileo pictures on??

Gonzalo Rico: . . . . Fri, Mar 6, 2:22PM PDT (-0700 GMT)
Hi everybody. Now we now the presence of water at the Moon, Ganymedes, Europa and Calisto, mayby many other bodys in our solar system. Do you espect that abundance of water in the solar system?

Jake: . . . . Fri, Mar 6, 2:23PM PDT (-0700 GMT)
Is Leslie from Outreach still logged on??

Tim McElrath, Navigation Team: . . . . Fri, Mar 6, 2:23PM PDT (-0700 GMT)
To Carl Banks: The reason for not using Ganymede to lower the periapsis (closest point to Jupiter in the orbit) is that it's in the wrong place! The best place to lower periapsis is at apoapsis (the highest point of the orbit), and Callisto is a lot higher than Ganymede, and at 73% as massive is not that much smaller.

Rene' Ortman: . . . . Fri, Mar 6, 2:23PM PDT (-0700 GMT)
to Antonio...y would u be useful?...r u a scientist who knows a lot about Europa and can answer my questions?

Star: . . . . Fri, Mar 6, 2:23PM PDT (-0700 GMT)
Thanx volcanopele, now I know

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 2:24PM PDT (-0700 GMT)
Beau, crashing a well-damped cannonball spacecraft into Europa would solve the Delta V problem....

Maltair: . . . . Fri, Mar 6, 2:24PM PDT (-0700 GMT)
Was the question about estimated water temp ever answered?

anonymous: . . . . Fri, Mar 6, 2:24PM PDT (-0700 GMT)
WOULD WE FIX EUROPA IF IT DID HAVE LIFE

Jim/Proj.Mgt: . . . . Fri, Mar 6, 2:24PM PDT (-0700 GMT)
Webslingr, GaTech: We have many processor's on board, mostly 1802's and a pair of ATAC processors. If you don't remember these, it's because they are circa 1980. They are rad hard parts, and we believe we haven't seen any radiation induced errors in the processors yet. Some errors in the memory chips (TCC244's mainly).

John D: . . . . Fri, Mar 6, 2:24PM PDT (-0700 GMT)
I realize that the GEM mission sends back lots of different data from different instruments. But most of us are simple folk who identify with pictures. That being said, about how many SSI images do you get back on a given Europa fly-by? This last time you only released about seven images.

Eduardo Pulver: . . . . Fri, Mar 6, 2:24PM PDT (-0700 GMT)
Which instruments are used by Galileo to detect surface composition of Jupiter satellites

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:25PM PDT (-0700 GMT)
Beau B/SwRI what about landing it in one of the slush areas ? and having it find a hole?

Ryan A. Boas: . . . . Fri, Mar 6, 2:25PM PDT (-0700 GMT)
How old do you think the ice on Europa is? I've read that you would try to determine its age by counting the number of craters on its surface. Are there any other ways?

Ronin: . . . . Fri, Mar 6, 2:25PM PDT (-0700 GMT)
Beau: regarding the "cannonball" idea, aren't they going to try that on the moon or mars. i think i read something about that. and what if the cannonball is the probe itself, how feasible is that?

Jake: . . . . Fri, Mar 6, 2:25PM PDT (-0700 GMT)
Dr. Chapman...Europa has an oxygen atmosphere. Could you say it's comparable in density to the martian atmosphere?

Joel: . . . . Fri, Mar 6, 2:25PM PDT (-0700 GMT)
What's an average temp of Europa?

Tim Z: . . . . Fri, Mar 6, 2:25PM PDT (-0700 GMT)
Does anyone know if Europa's ice will melt when the sun becomes a red giant? Or is Europa too far away for that?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:25PM PDT (-0700 GMT)
To Icewold -- Europa's surface is extremely cold (the sun is only a few percent as bright as on Earth). But it's not as cold as permanently shadowed parts of the Moon! The temperature of the ocean, by the way, is roughly near freezing...just as the water temperature in one of the Great Lakes under the ice. (Actually, it has been so warm this winter that there is less ice, but you get the idea. If it is very salty or dirty from infalling comets, the freezing temperature would be suppressed somewhat, of course.

Oliver Schulze: . . . . Fri, Mar 6, 2:25PM PDT (-0700 GMT)
Could it be posible to send Microprobes(Depth Space 2) to Europa to know if there is liquid ocean there?

anonymous: . . . . Fri, Mar 6, 2:25PM PDT (-0700 GMT)
I have noticed what appear to be frozen "pillars" on the latest hi rez pictures of Europa. Any confirmations on this? Also, I have seen what look like reflections coming from the shadowed regions of a hi-rez "canyon". I thank you for any comments.

Rene' Ortman: . . . . Fri, Mar 6, 2:25PM PDT (-0700 GMT)
Beau...ya we realize that...but just a thought...also, another problem we're not sure about is the ice freezing back over after the probe melts through it, trapping it inside the ice and therefore severing communication with the lander...is this feesiable??

Leslie: Outreach: . . . . Fri, Mar 6, 2:25PM PDT (-0700 GMT)
Hi Jake.

anonymous: . . . . Fri, Mar 6, 2:26PM PDT (-0700 GMT)
IM INTERESTED

Spaceman: . . . . Fri, Mar 6, 2:26PM PDT (-0700 GMT)
Jim/Proj.Mgt Did these processors come with a money back guarantee !!

Webslingr, GaTech: . . . . Fri, Mar 6, 2:26PM PDT (-0700 GMT)
Thank you very much Jim regarding the computing power of Galileo.

Leslie: Outreach: . . . . Fri, Mar 6, 2:26PM PDT (-0700 GMT)
Joel, the daytime temperature of Europa at its equator is -225F.

Srdjan: . . . . Fri, Mar 6, 2:26PM PDT (-0700 GMT)
to Maltair: water temp is about 0 - 100 C

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 2:26PM PDT (-0700 GMT)
Hi Maurice, You still wearing those red suspenders?

David V.: . . . . Fri, Mar 6, 2:27PM PDT (-0700 GMT)
i just hop that the proposed europa orbiter is not so limited in scope that it will be unable to make observations of other objects in the jupiter system. While in europa orbit, spectacular science could also be done on Jupiter, Io, and amalthea......expecially io monitoring and jupiter atmospheric dynamics. with such a dynamic system, it's difficult to choose.

Jim/Proj.Mgt: . . . . Fri, Mar 6, 2:27PM PDT (-0700 GMT)
Spaceman: The processors have lasted past their guarantee period, and are still going great!

Brian P, SPOT Chief: . . . . Fri, Mar 6, 2:27PM PDT (-0700 GMT)
to eduardo pulver: there are 4 remote sensing instrument on galileo that can, at their specific wavelengths, determine the surface composition of the jovian satellite.

Jake: . . . . Fri, Mar 6, 2:27PM PDT (-0700 GMT)
Leslie, is it possible for you to provide me with an e-mail address for the scientists working on Galileo's fields and particles experiment?

Brent Turcotte: . . . . Fri, Mar 6, 2:27PM PDT (-0700 GMT)
Has the Galileo ever been in sight of an occulation event where one moon wholly or partially covers another moon?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:28PM PDT (-0700 GMT)
Jake -- Mars has a *real* atmosphere, even if it is just 1% of Earth's. None of the Galilean satellites have an atmosphere that is more than what we would call a very good vaccum on Earth. But our instruments are very sensitive, so we can detect oxygen, sulphur dioxide, and other gaseous species near the surfaces of these Moons, even if very little of it is present.

Icewolf: . . . . Fri, Mar 6, 2:28PM PDT (-0700 GMT)
Ince the surface temperature of Europa is warmer than the surface temperature of the permanently shadowed parts of the moon, might it make more since to build a processing plant for fuel on Europa instead of Earth's satellite?

Maltair: . . . . Fri, Mar 6, 2:28PM PDT (-0700 GMT)
When the sun goes red I think the surface will reach out to Mars. I don't know what the radiating temp will be.

Sparkles K.: . . . . Fri, Mar 6, 2:28PM PDT (-0700 GMT)
Will there be robots on the craft. If so, please include a sassy one.

Leslie: Outreach: . . . . Fri, Mar 6, 2:28PM PDT (-0700 GMT)
To All: I'd like to say "Thank You" very appreciatively to our participating scientists and engineeres from the Galileo Project. Thanks for taking the time to chat with our guests online!

Joel: . . . . Fri, Mar 6, 2:28PM PDT (-0700 GMT)
are there any other probes that will be heading towards Europa?

Tayfun: . . . . Fri, Mar 6, 2:28PM PDT (-0700 GMT)
Does anybody know which volcanoes on Io were active the last time they were checked by Galileo?

Jake: . . . . Fri, Mar 6, 2:28PM PDT (-0700 GMT)
Thanks, Dr. Chapman.

Laura, SPOT: . . . . Fri, Mar 6, 2:29PM PDT (-0700 GMT)
Eduardo Pulver and moondweller - UVS is used to help determine surface properties, and NIMS can help determine surface and internal composition. Marcia can give you a more detailed answer when she gets back to her desk!

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 2:29PM PDT (-0700 GMT)
To O. Schulze: (non-staff answer) Since the numbers given so far on ice depth optimistically predice 10 km, I don't think the DS2 probes can penetrate far enough to be of use on Europa. Also, trying to incorporate a 'drill' structure for such a depth onto a DS2 probe seems rather difficult. I (non-staff opinion) feel the design is incompatible with a Europan environment.

Gonzalo Rico: . . . . Fri, Mar 6, 2:29PM PDT (-0700 GMT)
Hi everybody. Now we now the presence of water at the Moon, Ganymedes, Europa and Calisto, mayby many other bodys in our solar system. Do you espect that abundance of water in the solar system?

Beau B/SwRI: . . . . Fri, Mar 6, 2:29PM PDT (-0700 GMT)
Doug/Ronan: Landing a probe in one of the slush areas wouldn't bypass the ice issue -- we know those areas are now frozen ice as well. However, they *may* represent places where the ice shell is thinner, so the probe wouldn't have to penetrate as far. NASA is planning a "penetrator" mission to the Martian ice caps, where they will send the probes straight into the surface without slowing down at all, letting their impact veolicty carry them some distance (a few meters) into the ground.

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 2:29PM PDT (-0700 GMT)
Jeshua, Actually, if you would like to send a small Clean sample in a vial, we will be happy to use it in our studies. You can send in to me at 4800 Oak Grove Drive Pasadena, Ca 91109 Mail Stop 264/580

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 2:29PM PDT (-0700 GMT)
Mr Chapman- you mentioned that Galileo has detected the Europa atmosphere? Which instruments did it use?

Spaceman: . . . . Fri, Mar 6, 2:29PM PDT (-0700 GMT)
Hmm, Excuse me if i am stupid but shouldn't PDT be -0800 GMT it's 22:26 approx here in the UK. Can you confirm anyone in JPL???

Ed: . . . . Fri, Mar 6, 2:29PM PDT (-0700 GMT)
To Ron SSI: Yes they found water on the moon but isn't it literally in rock? It is not in it's free state.

Michael Wilson, Navigation Team: . . . . Fri, Mar 6, 2:30PM PDT (-0700 GMT)
Hello. I'm signing in.

Webslingr, GaTech: . . . . Fri, Mar 6, 2:30PM PDT (-0700 GMT)
What was the proposed cost of the Galileo mission?

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 2:30PM PDT (-0700 GMT)
Jeshua, We mean a sample of the dry salt crust not liquid.

Tony: . . . . Fri, Mar 6, 2:30PM PDT (-0700 GMT)
Hi Guys: Does Europa have an atmosphere ? Is there any oxygen dissolved in this ice, or water ? Would this oxygen be essential for the possible life on europa ?

Maltair: . . . . Fri, Mar 6, 2:30PM PDT (-0700 GMT)
Thanks Srdjan... I think.

Leslie: Outreach: . . . . Fri, Mar 6, 2:30PM PDT (-0700 GMT)
Jake, if you send me your email, I'll make sure someone from the project gets back to you. If you have specific questions, it'd\ be best to ask them in the email. The address is askgalileo@galileo.jpl.nasa.gov

bufi(egon): . . . . Fri, Mar 6, 2:30PM PDT (-0700 GMT)
how much power is left on you craft you mission greaaattttttttt.

Laura, SPOT: . . . . Fri, Mar 6, 2:30PM PDT (-0700 GMT)
Hi Mike! We have been getting a lot of navigation questions that you can help Tim answer!

Icewolf: . . . . Fri, Mar 6, 2:30PM PDT (-0700 GMT)
Spaceman: You're forgetting daylight savings time...

Ronin: . . . . Fri, Mar 6, 2:30PM PDT (-0700 GMT)
to Beau: I am aware of that Martian mission. My question is how feasible will it be to replicate in Europa?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:31PM PDT (-0700 GMT)
Eduardo -- The instrument designed to measure the composition of the satellite surfaces is NIMS (Near Infrared Mapping Spectrometer). The camera has color filters, which provide some clues about composi- tion which are useful for tiny regions on the satellites too small to be resolved by NIMS.

John Cody: . . . . Fri, Mar 6, 2:31PM PDT (-0700 GMT)
This may be a stupid question, but why was the best resolution picture of Europa taken from 560km when Galileo passed at around 200km on Dec. 16?

Oliver Schulze: . . . . Fri, Mar 6, 2:31PM PDT (-0700 GMT)
to Perry Frix: Thanks for your comment.

Brian P, SPOT Chief: . . . . Fri, Mar 6, 2:31PM PDT (-0700 GMT)
to carl banks. the ultraviolet spectrometer was used to determine the atmosphere of europa.

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 2:31PM PDT (-0700 GMT)
To Marcia: Can any of these salts be used for radioisotope dating?

moondweller: . . . . Fri, Mar 6, 2:31PM PDT (-0700 GMT)
The atmosphere of Jupiter is fascinating!!! When can we expect another atmospheric probe? And will it be more ambitious, since the last one only sampled a tiny, and possibly atypical portion of the Jovian atmosphere?

Tim McElrath, Navigation Team: . . . . Fri, Mar 6, 2:31PM PDT (-0700 GMT)
To David V: The Europa orbiter planning is struggling to have a spacecraft that will stay alive for even 30 days, so the priorities have to be pretty focused on Europa. However, it will take probably 2 years in the Jupiter system to get to Europa, so hopefully some other science can be done then, assuming someone's willing to pay for it.

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:31PM PDT (-0700 GMT)
interesting Beau ......that data/performance will on doubt be used to compare it to europa ...

Spaceman: . . . . Fri, Mar 6, 2:32PM PDT (-0700 GMT)
ICEWOLF: Is the US already in Daylight savings time??

Douglas Sinclair, Surrey Space Center: . . . . Fri, Mar 6, 2:32PM PDT (-0700 GMT)
Good evening all. Has any work been done on a Jovian aerocapture, similar to the aerocapture for the Mars 2001 orbiter? It might be a good way to save mass on the future Europa missions

Star: . . . . Fri, Mar 6, 2:32PM PDT (-0700 GMT)
Anybody got an answer to my 'salt' question yet????

Jim Galasyn: . . . . Fri, Mar 6, 2:32PM PDT (-0700 GMT)
Could a Europa penetrator slowly melt its way through the ice with a chunk of plutonium?

Pat Beyer/DeepSpace Network/telecommunications support: . . . . Fri, Mar 6, 2:32PM PDT (-0700 GMT)
Spaceman: Your are correct. We are still on PST.

Steve & Charlotte UK: . . . . Fri, Mar 6, 2:32PM PDT (-0700 GMT)
To David V. Thanks. Understood. The process that makes something so unique will be wonderful to find out. Cheers!

Leslie: Outreach: . . . . Fri, Mar 6, 2:33PM PDT (-0700 GMT)
Hi Michael (Nav). Glad you made it. Some folks have been asking about what Galileo's orbit will be after the Galileo Europa Mission is completed. Can you elaborate?

Webslingr, GaTech: . . . . Fri, Mar 6, 2:33PM PDT (-0700 GMT)
Michael Wilson, what program and what computer were used to calculate the trajectories of Galileo's flyby of Europa, how powerful is the equipment and software?

Maltair: . . . . Fri, Mar 6, 2:33PM PDT (-0700 GMT)
What about using one of the missle types used to hit Saddams underground bunkers as a penetrator?

MClary: . . . . Fri, Mar 6, 2:33PM PDT (-0700 GMT)
Maurice Clary (retired) I look in at the Galileo HomePage frequently and am proud of all you Galileo troops.

Jake: . . . . Fri, Mar 6, 2:33PM PDT (-0700 GMT)
Thanks, Leslie... My e-mail address is: cerma5@vcn.bc.ca

Oliver Schulze(Asuncion/Paraguay): . . . . Fri, Mar 6, 2:33PM PDT (-0700 GMT)
How depth is the liquid ocean that you are especting?

Brian P, SPOT Chief: . . . . Fri, Mar 6, 2:33PM PDT (-0700 GMT)
to moondweller. as of this time, i know of no future missions planned to send another probe or probes into the atmosphere of jupiter.

David V.: . . . . Fri, Mar 6, 2:33PM PDT (-0700 GMT)
Tim McElrath: 30 days?? Is that from radiation damage? Wow! I would expect that from orbiting Io or something......of course, 2003 is still 5 years off, hopefully they'll figure out a radiation shield by then.

volcanopele: . . . . Fri, Mar 6, 2:33PM PDT (-0700 GMT)
What would be the goals of a sub if it has to be held by a string.

A.C., GA Tech: . . . . Fri, Mar 6, 2:33PM PDT (-0700 GMT)
How would a lander on the surface of Europa communicate with earth in terms of aligning its antenna to Earth's position and how would the position of Jupiter affect comunication links with the spacecraft and DSN.

Srdjan: . . . . Fri, Mar 6, 2:33PM PDT (-0700 GMT)
Are you hiding picture from 200 km? Is there something special?

Ed: . . . . Fri, Mar 6, 2:34PM PDT (-0700 GMT)
To Ron SSI: Yes they found water on the moon but isn't it literally in rock? It is not in it's free state.

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:34PM PDT (-0700 GMT)
there's a thought jim ....just have to get it past the enviromentalists .....and the radiation ...

Joel: . . . . Fri, Mar 6, 2:34PM PDT (-0700 GMT)
plutonium, wouldn't that raise some major environment issues on a plantet not even fully explored yet, why ruin it so soon?

Beau B/SwRI: . . . . Fri, Mar 6, 2:34PM PDT (-0700 GMT)
Ronin: The Martian polar caps and the ice shell on Europa are two completely different dynamical considerations in terms of a penetrator. Even if the ice is as thin as 1 km (it may be thicker than 20 km!), getting something to punch through 1 km of ice is no small task! It would require an enormous amount of energy, and therefore a VERY FAST impact velocity. Even if we could get something moving fast enough, we'd have a tough time designing something that could withstand the impact!

Brian P, SPOT Chief: . . . . Fri, Mar 6, 2:34PM PDT (-0700 GMT)
hi maurice... how's retirement going. Hope your having fun.

Jake: . . . . Fri, Mar 6, 2:35PM PDT (-0700 GMT)
Well, I have to log off. I thank all the scientists and engineers for participating, and all the JPL staff, and for their time as well.

David V.: . . . . Fri, Mar 6, 2:35PM PDT (-0700 GMT)
joel:why ruin it at all?

Leslie: Outreach: . . . . Fri, Mar 6, 2:35PM PDT (-0700 GMT)
Ronin and others: Landers on Europa that are being considered by scientists and engineers are looking to use heat to bore through Europa's ice, rather than a "drill".

vq1@earthlink.net: . . . . Fri, Mar 6, 2:35PM PDT (-0700 GMT)
Other than possible protests about the destructive nature, would it be possible to send an explosive rocket (certainly not nuclear, of course)onto the surface to break a hole in the ice and follow it quickly with a probe to get the probe into the water?

Mass. Meteors: . . . . Fri, Mar 6, 2:35PM PDT (-0700 GMT)
The *surface* resolution of images from Galileo is unprecedented: many kudos to the incredibly talented teams that made this possible! But can any of the imaging systems be used to estimate GLOBAL

Bios: . . . . Fri, Mar 6, 2:35PM PDT (-0700 GMT)
Hello everyone. What are the future plans for missions to Jupiter ?

Gonzalo Rico: . . . . Fri, Mar 6, 2:35PM PDT (-0700 GMT)
TO MARCIA. Now we now the presence of water at the Moon, Ganymedes, Europa and Calisto, mayby many other bodys in our solar system. Do you espect that abundance of water in the solar system?

Ronin: . . . . Fri, Mar 6, 2:35PM PDT (-0700 GMT)
thanks Beau!

Webslingr, GaTech: . . . . Fri, Mar 6, 2:35PM PDT (-0700 GMT)
Michael Wilson, what program and what computer were used to calculate the trajectories of Galileo's flyby of Europa, how powerful is the equipment and software?

Ed: . . . . Fri, Mar 6, 2:35PM PDT (-0700 GMT)
To Ron,SSI: Why are the strands often seen in pairs?

John Cody: . . . . Fri, Mar 6, 2:36PM PDT (-0700 GMT)
Why is the very high res. image of Europa from 560km, and not from 200km?

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 2:36PM PDT (-0700 GMT)
Marcia Segura, I am curious about how the NIMS works--I am guessing it detects the IR emission spectra of the target, employing some sort of diffaction technique?

Maltair: . . . . Fri, Mar 6, 2:36PM PDT (-0700 GMT)
John Cody... They said earlier that the delta v was to great and made for blurry pics. Correct?

Antonio de Morais: . . . . Fri, Mar 6, 2:36PM PDT (-0700 GMT)
To: Rene' Ortman: I'm not a scientist, just a student, but I have my model on Europa (based on my scientific independent reserch), and other several ideas. If you have a project, I'd like to be useful as a student since I'm extremely interested about planetary reserch, and I intend to try to do my PhD in that field. Antonio

anonymous: . . . . Fri, Mar 6, 2:36PM PDT (-0700 GMT)
hello

Ryan A. Boas: . . . . Fri, Mar 6, 2:36PM PDT (-0700 GMT)
How old do you think the ice on Europa is? I've read that you would try to determine its age by counting the number of craters on its surface. Are there any other ways?

Star: . . . . Fri, Mar 6, 2:36PM PDT (-0700 GMT)
I know this is off topic, but my bro here wants to know who here thinks Pluto is a moon and who calls it a planet.

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:36PM PDT (-0700 GMT)
and Beau it might destroy what is under the ice that you hope to look at

Tayfun: . . . . Fri, Mar 6, 2:36PM PDT (-0700 GMT)
Are there any plans for searching new small satellites during the Galileo Europa mission?

Jim Galasyn: . . . . Fri, Mar 6, 2:36PM PDT (-0700 GMT)
Of course I agree that indiscriminately

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 2:36PM PDT (-0700 GMT)
Perry, I am not all that familiar with radioisotopic dating techniques. But I think you have to have potassium in the salts.

Ronin: . . . . Fri, Mar 6, 2:37PM PDT (-0700 GMT)
Leslie: could you elaborate on thie "boring"instead of drilling?

Joel: . . . . Fri, Mar 6, 2:37PM PDT (-0700 GMT)
David: Because eventually we probally will anyway, just like earth...

Spaceman: . . . . Fri, Mar 6, 2:37PM PDT (-0700 GMT)
Are there any shops that sell models of JPL craft, I particulary wanted Galileo and Mars Pathfinder models the Sojourner was really cute :-)

Eduardo Pulver: . . . . Fri, Mar 6, 2:37PM PDT (-0700 GMT)
After Galileo Proyect, is there any other probe to be sent to Jupiter in the next future?

Tim McElrath, Navigation Team: . . . . Fri, Mar 6, 2:37PM PDT (-0700 GMT)
To Douglas Sinclair: Jovian aerocapture has been considered (by myself among many others). It turns out that after a aerocapture the spacecraft has to raise periapsis to about Europa's altitude, and that maneuver is bigger than what you save, considering the mass of the aeroshell, etc. Seems a pity to waste all the nice thick atmosphere, tho...

Ed: . . . . Fri, Mar 6, 2:37PM PDT (-0700 GMT)
To Ron,SSI: Why are the strands often seen in pairs?

Brent Turcotte: . . . . Fri, Mar 6, 2:37PM PDT (-0700 GMT)
Star: Pluto is a kuiperoid

Beau B/SwRI: . . . . Fri, Mar 6, 2:37PM PDT (-0700 GMT)
Doug: Right you are.

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:38PM PDT (-0700 GMT)
The picture was a slant-range picture, which is part of the explanation. As for the depth of the ocean, there is already evidence from Galileo's radio experiment (tracking the spacecraft motion through Europa's gravity field) that the ocean is about 100 km deep -- very deep indeed! Whereas the ice on top may average around 10 km in thickness, there must be places that are thinner than usual -- perhaps much thinner, following a recent rupture. Obviously any probe mission would seek to find the thinnest possible ice.

Spaceman: . . . . Fri, Mar 6, 2:38PM PDT (-0700 GMT)
STAR; Pluto is a cartoon character from Disney ;-)

Webslingr, GaTech: . . . . Fri, Mar 6, 2:38PM PDT (-0700 GMT)
Ryan: Problem is Europa's surface is dynamic and is constantly regenerating, so craters can't be used and also the ice sinks to the bottom so we can't know how old ice is until we get to the bottom layer.

Rene' Ortman: . . . . Fri, Mar 6, 2:38PM PDT (-0700 GMT)
Beau...another problem my team has is the possibility of the water created by the melting probe refreezing on top of the probe therefore sealing it inside the ice and elliminating communication back to the lander..is this feezable??

Brian P, SPOT Chief: . . . . Fri, Mar 6, 2:38PM PDT (-0700 GMT)
to tayfun. Nope. the galileo europa mission goals are extremely focused. We do not have enough resources (i.e., bits-to-ground) to further search for small satellites.

David V.: . . . . Fri, Mar 6, 2:38PM PDT (-0700 GMT)
joel:not if i can help it.......thats a lousy attitude to embark on space exploration with!!

Gonzalo Rico: . . . . Fri, Mar 6, 2:38PM PDT (-0700 GMT)
We are so close and so far!

Tomas W (Stockholm, Sweden): . . . . Fri, Mar 6, 2:38PM PDT (-0700 GMT)
Could DS2-type penetrators be used on the 2003 Europa Orbiter mission for seismic studies etc? Maybe fitted with retro rockets to slow them down before impact?

Webslingr, GaTech: . . . . Fri, Mar 6, 2:38PM PDT (-0700 GMT)
Michael Wilson, what program and what computer were used to calculate the trajectories of Galileo's flyby of Europa, how powerful is the equipment and software?

Star: . . . . Fri, Mar 6, 2:38PM PDT (-0700 GMT)
Bro says "Thanx for the answer Brent"

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:38PM PDT (-0700 GMT)
there might be a lot of fuel in that thick atmosphere ?

Jim Galasyn: . . . . Fri, Mar 6, 2:39PM PDT (-0700 GMT)
Uh, meant to say that indiscriminately irradiating a new world would definitely be bad form. But Pu is not terribly radioactive, and with proper packaging its chemically poisonous nature could be contained. Maybe.

Ed: . . . . Fri, Mar 6, 2:39PM PDT (-0700 GMT)
To Ron,SSI: Why are the strands often seen in pairs?

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 2:39PM PDT (-0700 GMT)
To M. Segura: Thanks! I'll check with Mr. Granahan when he gets in later! (He mentioned it earlier)

John D: . . . . Fri, Mar 6, 2:39PM PDT (-0700 GMT)
If I understand how we estimate age of solar system bodies it is a combination of two things, the cratere density and the data we got from studying samples from the Moon. If that is correct (and I may be making this overly simple) can we really use that method in the outer solar system? We don't have any actual samples from the outer solar system and our guesses about impact rates would seem to be just that, only guesses. So what are we basing our estimates on the age of surfaces of Ganymede, Europa, etc?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:39PM PDT (-0700 GMT)
Star, Pluto is Pluto, and a very interesting double world at that. Getting caught up in nomenclature often gets us away from science.

Maltair: . . . . Fri, Mar 6, 2:39PM PDT (-0700 GMT)
Whats a kuiperoid? I say its a planet. Small but a planet. Maybe a moon of the sun.

Brian P, SPOT Chief: . . . . Fri, Mar 6, 2:39PM PDT (-0700 GMT)
to eduardo pulver. there are several mission planned to be sent to Europa.

Joel: . . . . Fri, Mar 6, 2:39PM PDT (-0700 GMT)
David:glad to hear you will make an attempt to preserve...

Leslie: Outreach: . . . . Fri, Mar 6, 2:40PM PDT (-0700 GMT)
Star: Thanks for your interest in space in general! However, please keep your topics to Europa now, ok? We have so much traffic right now, we'd like to keep it clear to make sure we can answer everyone's questions. Thanks! :)

Emilio: . . . . Fri, Mar 6, 2:40PM PDT (-0700 GMT)
Hi my name is Emilio and I just got on to the chat site right now so I don't know what we've discussed, but I was wondering about the predictions of the ice thickness on Europa. Also which moon has the better prospects of harboring life, Titan or Europa? Both are under the influence of large gravity fields, so both have a reasonable source of energy.

Webslingr, GaTech: . . . . Fri, Mar 6, 2:40PM PDT (-0700 GMT)

volcanopele: . . . . Fri, Mar 6, 2:41PM PDT (-0700 GMT)
Star- Pluto is the largest of the known kuiperoids. But until everybody agrees with this, it, technically is a planet.

Webslingr, GaTech: . . . . Fri, Mar 6, 2:41PM PDT (-0700 GMT)
Michael Wilson, what program and what computer were used to calculate the trajectories of Galileo's flyby of Europa, how powerful is the equipment and software?

anonymous: . . . . Fri, Mar 6, 2:41PM PDT (-0700 GMT)
I can't understand why there are tidal forces effecting Europa if it keeps the same face pointed at Jupiter.

Joel: . . . . Fri, Mar 6, 2:41PM PDT (-0700 GMT)
Do we know of any minerals on Europa? Or is too early to tell?

Michael Wilson, Navigation Team: . . . . Fri, Mar 6, 2:41PM PDT (-0700 GMT)
Leslie: A perfect flyby of Io at the end of GEM would bring us right back to Io for a 100,000 km flyby. If we do not control the spacecraft beyond the end of GEM then reasonable predictions cannot be made for more than a couple of orbits.

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:41PM PDT (-0700 GMT)
idea for penerating the ice .....laser ...from orbit entry beside a lander already down ....then it drops thru the hole before it freezs over .. ??

BritishAirwaysdelayedflight: . . . . Fri, Mar 6, 2:41PM PDT (-0700 GMT)
Hello all,

Beau B/SwRI: . . . . Fri, Mar 6, 2:41PM PDT (-0700 GMT)
Rene': The water is indeed freezable, and it would definitely freeze behind the probe! The idea for the probe, as mentioned just a little bit earlier, is that it would have a small "ground station" that would reel out a communications wire to the probe as the probe descends. The wire would allow the probe to communicate with the surface even as the water froze behind the probe.

Tim Z: . . . . Fri, Mar 6, 2:42PM PDT (-0700 GMT)
Could the extra solar energy from our future red giant sun melt the surface ice on Europa? Could the resulting water vapor become an atmoshere?

Brent Turcotte: . . . . Fri, Mar 6, 2:42PM PDT (-0700 GMT)
Maltair: A kuiperoid is a member from the Kuiper belt. The Kuiper belt is like a new asteroid belt out around Pluto's orbit. Pluto is the largest member of the belt. About 60 kuiperoids are known at the moment.

David V.: . . . . Fri, Mar 6, 2:42PM PDT (-0700 GMT)
to the SSI dudes: do crater counts tell us anything about surface ages of europa relative to one another (ie are the poles older than the equator, are some chaos areas older than other chaos areas.....) I realize that absolute dating via crater counts is impossible, we dont know what the Jovian impact history has been......but does Europa seem to have a uniform age surface or heterogeneous one?

Tim McElrath, Navigation Team: . . . . Fri, Mar 6, 2:42PM PDT (-0700 GMT)
To Doug Inwood: If we flew a nuclear thermal rocket, for instance, then scooping Jovian atmosphere for reaction mass would be great. Actually, Titan works better in the Saturn system, but no such option for Jupiter. Don't know any way to effectively use hydrogen chemically that would be worth the bother of scooping (ie. LOX is heavy and doesn't last well)

BritishAirwaysdelayedflight: . . . . Fri, Mar 6, 2:42PM PDT (-0700 GMT)
When does the Galileo mission finally end and what will happen to the spacecraft?

Tayfun: . . . . Fri, Mar 6, 2:42PM PDT (-0700 GMT)
To Brian P, SPOT. Then we must hope them to get into view while you shoot the small ones.

Brian: . . . . Fri, Mar 6, 2:42PM PDT (-0700 GMT)
To the imaging people. Are there any stereo pair images being taken so that we could use those funny colored glasses or a split screen to see a 3D effect? Thanks for this wonderfull opportunity to talk to the experts. What a world we live in!

volcanopele: . . . . Fri, Mar 6, 2:43PM PDT (-0700 GMT)
A Kuiperoid is a member of sun's outer small body belt. Its where short period comets come from.

Douglas Sinclair, Surrey Space Center: . . . . Fri, Mar 6, 2:43PM PDT (-0700 GMT)
To Tim McElrath: I see. It's too bad that it wouldn't work for a Europa mission. I'm currently considering it as a mechanism for injecting nanosatellites (<10 Kg) into a Jovian orbit as part of my MSc research. These spacecraft would be too small to carry a liquid fuel engine, but would have a solid motor for a perijove raise burn.

Maltair: . . . . Fri, Mar 6, 2:43PM PDT (-0700 GMT)
Couldn't you use sonar to control the rover.

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 2:43PM PDT (-0700 GMT)
Gonzalo, Water is abundant in the universe, roughly 50%. The issue is the distribution, very little in the inner solar system while most of the 50% is retained in the outer solar system, outside of Jupiter.

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 2:44PM PDT (-0700 GMT)
Beau, isn't a communications wire risky? Supposing there are tides on Europa, the wire would be at the mercy of moving plates of ice-- wouldn't acoustics or low freq. radio be better (and lighter)?

Maltair: . . . . Fri, Mar 6, 2:45PM PDT (-0700 GMT)
Thanks Brent Turcotte

Webslingr, GaTech: . . . . Fri, Mar 6, 2:45PM PDT (-0700 GMT)
To: Michael Wilson, what program and what computer were used to calculate the trajectories of Galileo's flyby of Europa, how powerful is the equipment and software?

volcanopele: . . . . Fri, Mar 6, 2:45PM PDT (-0700 GMT)
Marcia-Is Pillan still active?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:45PM PDT (-0700 GMT)
John D -- very perceptive question! We do *not* have any samples from the Jovian system, so we can't measure rock ages in the laboratory. We are forced to a much less precise method: astronomers like the late Gene Shoemaker use telescopes to try to discover how many asteroids and comets are in the outer solar system, in a position to run into Jupiter. Then we count the craters on the satellites. From the numbers of discovered projectiles, we can tell how often they should hit, and so how many should accumulate in the cratering record over a certain amount of time. The problem is that comets and asteroids are very small, and extremely faint at Jupiter's distance from the Sun and Earth. So Shoemaker could find only those bodies capabale ofmaking craters larger than 10 or 20 km diameter. And there are hardly any craters that size on Europa. So, because of all the uncertainties, the calculated ages (say between 1 and 100 million years for parts of Europa) are very uncertain. But it's the best we can do

Joel: . . . . Fri, Mar 6, 2:45PM PDT (-0700 GMT)
How long did galileo take to reach the Jovian system?

BritishAirwaysdelayedflight: . . . . Fri, Mar 6, 2:45PM PDT (-0700 GMT)
Where is everbody located?? Me in the UK

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 2:45PM PDT (-0700 GMT)
Carl, You're right but most of the time we look at reflected light except for Jupiter and Io volcanoes we use emitted light.

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 2:45PM PDT (-0700 GMT)
To Carl Banks: I challenge the Jovian tidal force to rip apart a half-inch fiberoptic cable! ;)

Rene' Ortman: . . . . Fri, Mar 6, 2:45PM PDT (-0700 GMT)
Beau....that's the idea we had, would the wire be in the probe itself...it'd have to , right, but if it has to go over 10km..that's a lot of wire in one small probe!!!

Oliver Schulze(Asuncion/Paraguay): . . . . Fri, Mar 6, 2:45PM PDT (-0700 GMT)
How much is the capacity (in bytes) of the tape recorders onboard Galileo?

David V.: . . . . Fri, Mar 6, 2:45PM PDT (-0700 GMT)
to Marcia Segura: Surely you don't mean water composes 50% of the Universe!?!?!? since over 70% of the universe is (probably) taken up by H2 molecules, and most of the remainder is helium......that s a LOT of water!

Star: . . . . Fri, Mar 6, 2:46PM PDT (-0700 GMT)
Well, thanx for all the answers everyone, sorry my Bro got us off topic:{

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:46PM PDT (-0700 GMT)
has anyonr tried to extend the high gain antenna ? now that the probe has been flung around a bit and had it's speed changed a lot .....could it have freed up ?

Brent Turcotte: . . . . Fri, Mar 6, 2:46PM PDT (-0700 GMT)
Maltair: sonar would be no good on any of Jupiter's moons. The atmospheres of these worlds too thin. You need atmosphere to carry the sound waves sonar would travel on. You could use sonar but the power requirements would be tremendous.

Srdjan: . . . . Fri, Mar 6, 2:46PM PDT (-0700 GMT)
Is here anyone from Galileo Imaging Team ? It was a lot of question about picture of Europa from 200 km.

Ryan A. Boas: . . . . Fri, Mar 6, 2:47PM PDT (-0700 GMT)
Have you found any ice volcanoes or any other direct evidence of churning water below Europa's surface?

Maltair: . . . . Fri, Mar 6, 2:47PM PDT (-0700 GMT)
Washington State

Brian P, SPOT Chief: . . . . Fri, Mar 6, 2:47PM PDT (-0700 GMT)
to oliver. The galileo tape recorder capacity is 9x10^8 bits.

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:47PM PDT (-0700 GMT)
David V -- we don't have great coverage of all parts of Europa. But there are no giant differences in relative age for the parts we have studied so far.

Gonzalo Rico: . . . . Fri, Mar 6, 2:47PM PDT (-0700 GMT)
Thanks Marcia. And why the earth have so many water? Europa has more water than the Earth?

Maltair: . . . . Fri, Mar 6, 2:48PM PDT (-0700 GMT)
I was talking about using sonar for an underwater rover.

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 2:48PM PDT (-0700 GMT)
Perry and Beau: won't a 1/2 inch fiber optic cable be quite heavy? Exactly how far are you planning to decend into the ice?

Steve & Charlotte UK: . . . . Fri, Mar 6, 2:48PM PDT (-0700 GMT)
Thanks all. Signing off. This is the first time but not the last. Enjoyed it. Cardiff, UK. Out.

: . . . . Fri, Mar 6, 2:48PM PDT (-0700 GMT)
This question is to all team members who might like to answer- if another craft was built today to do the same job as Galileo, how would it differ from the current space-craft, which was, I think, conceptualized in 1977 as JOP. Would there be vast improvements? Would it still have the same design for the HGA? Not that one would be built, of course, considering the great work Galileo and the people involved are doing.

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 2:48PM PDT (-0700 GMT)
Volcano-Pele, Pillan has been active over the prime mission of Galileo. Check out the SSI images for E6, G7, and C10 (if my memory serves me)on the Galileo web site. There is a beautiful image of a black bullseye. That I believe to be Pillan.

Tim McElrath, Navigation Team: . . . . Fri, Mar 6, 2:48PM PDT (-0700 GMT)
To Douglas Sinclair: Jovian aerocapture and solid rocket perijove raise should work well for orbits within about 1 Rj altitude, I would guess.

Webslingr, GaTech: . . . . Fri, Mar 6, 2:48PM PDT (-0700 GMT)
Anyone, what program and what computer were used to calculate the trajectories of Galileo's flyby of Europa, how powerful is the equipment and software?

Seagull: . . . . Fri, Mar 6, 2:48PM PDT (-0700 GMT)
Brian P: What's the equivalent in hard disk space??

Michael Wilson, Navigation Team: . . . . Fri, Mar 6, 2:48PM PDT (-0700 GMT)
Webslingr, GaTech: We use a suite of trajectory programs depending on the analysis task. For high precision integrations, searches or optimization we use the DPTRAJ (double precision trajectory program) and CATO programs, low precision linear analysis of maneuvers we use the LAMBIC software. There are a number of other tools as well.

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:48PM PDT (-0700 GMT)
I'm on the Galileo Imaging Team..what do you want to know about the closest picture?

anonymous: . . . . Fri, Mar 6, 2:48PM PDT (-0700 GMT)
Hi everybody. I would like to ask to a navigation member if the trajectory Cassini is now taking could be done by a Jupiter orbiter such as Galileo. I suppose this a much faster trajectory than the one Galileo took (6 years).

Pat Beyer/DeepSpace Network/telecommunications support: . . . . Fri, Mar 6, 2:48PM PDT (-0700 GMT)
A.C., GA Tech: I am not sure about your question about aligning a lander's antenna to earth. It should be simple software to have the lander know where the earth is. And it would have a small antenna, so that it really only has to be close. By the time the beam gets to earth, it probably will cover the whole planet. If Jupiter occults the earth (comes between Europa and the earth) communications will be blocked for the duration. Radio scientists are intrigued by those times when the signal is just on the edges of the occulting body. The radio waves change and allow the radio scientists to determine composition and other things. For most of the time, Jupiter does not affect the communications link.

anonymous: . . . . Fri, Mar 6, 2:49PM PDT (-0700 GMT)
Hi everybody. I would like to ask to a navigation member if the trajectory Cassini is now taking could be done by a Jupiter orbiter such as Galileo. I suppose this a much faster trajectory than the one Galileo took (6 years).

Jim/Proj.Mgt: . . . . Fri, Mar 6, 2:49PM PDT (-0700 GMT)
Doug Inwood Observatory Director New Zealand: All of the speed changes that Galileo's undergone have been very gentle. We haven't seen any changes in the spacecraft that would indicate there is any reason to try opening the high gain antenna again.

Jim Galasyn: . . . . Fri, Mar 6, 2:49PM PDT (-0700 GMT)
Speculation is that Europan "tectonic plates" are floating on slush, or soft ice, or water. From the latest pictures it looks like the medium might resemble mud more than anything. Could the "ocean" actually be more like a thick mud puddle?

vq1@earthlink.net: . . . . Fri, Mar 6, 2:49PM PDT (-0700 GMT)
Instead of a fiber optic cable, why not use low frequency radio to communicate between the probe and the lander?

Webslingr, GaTech: . . . . Fri, Mar 6, 2:49PM PDT (-0700 GMT)
Thank you very much Mr. Wilson

Beau B/SwRI: . . . . Fri, Mar 6, 2:50PM PDT (-0700 GMT)
Carl Banks:The question of tides is a good one. Right now we don't know if the tides act over a Europa day (about 3.5 Earth days) or if they happen much more slowly. Certainly anything that is within the ice sheets is subject to whatever stresses and strains they undergo. I'm not part of the Europa Orbiter/Penetrator design team, so I can't speak as to why they aren't using radio.

John C.: . . . . Fri, Mar 6, 2:50PM PDT (-0700 GMT)
In the future, is planned other missions to land in other Jupiter's moons (expect Europa)?

Maltair: . . . . Fri, Mar 6, 2:50PM PDT (-0700 GMT)
9 gig harddrive. I think.

anonymous: . . . . Fri, Mar 6, 2:50PM PDT (-0700 GMT)
Isn't water/ice unstable in space? If so, then Europa must have at least a minimal atmosphere?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:50PM PDT (-0700 GMT)
worth a shot tho ?

Michael Wilson, Navigation Team: . . . . Fri, Mar 6, 2:51PM PDT (-0700 GMT)
The computers we rely on for most of our trajectory work are Hewlett Packard work stations (HP 755's and 720's).

Ryan A. Boas: . . . . Fri, Mar 6, 2:51PM PDT (-0700 GMT)
Have you found any ice volcanoes or any other direct evidence of churning water below Europa's surface?

Oliver Schulze(Asuncion/Paraguay): . . . . Fri, Mar 6, 2:51PM PDT (-0700 GMT)
to Brian P: are we talking about 11GB ? Wow, thats really great!

John Cody: . . . . Fri, Mar 6, 2:51PM PDT (-0700 GMT)
This question is to all team members who might like to answer- if another craft was built today to do the same job as Galileo, how would it differ from the current space-craft, which was, I think, conceptualized in 1977 as JOP. Would there be vast improvements? Would it still have the same design for the HGA? Not that one would be built, of course, considering the great work Galileo and the people involved are doing.

Brian P, SPOT Chief: . . . . Fri, Mar 6, 2:51PM PDT (-0700 GMT)
to seagull: that would be a 112 Mbyte hard disk.

Tim Z: . . . . Fri, Mar 6, 2:51PM PDT (-0700 GMT)
Could the extra energy from our future red giant sun melt the surface ice on Europa? If so could Europa's gravity field hold an H2O atmosphere?

anonymous: . . . . Fri, Mar 6, 2:51PM PDT (-0700 GMT)
Isn't water/ice unstable in space? If so, then Europa must have at least a minimal atmosphere?

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 2:51PM PDT (-0700 GMT)
David V, If you condensed the universe, there is still a lot of H2 and He left. It ends up in stars. The dust and ice is approx 50% water. It's actually the oxygen that controls the ice abundance.

Joe: . . . . Fri, Mar 6, 2:52PM PDT (-0700 GMT)
What is planned after the end of GEM?

anonymous: . . . . Fri, Mar 6, 2:52PM PDT (-0700 GMT)
Isn't water/ice unstable in space? If so, then Europa must have at least a minimal atmosphere?

David V.: . . . . Fri, Mar 6, 2:52PM PDT (-0700 GMT)
Is there any chance that the Europa Orbiter will have a steerable scan platform? This seems to be an increasingly undesirable option for low-cost missions, but doesn't it allow for more pointing flexability and less fuel consumption (than turning the entire craft around to image different regions)?

Douglas Sinclair, Surrey Space Center: . . . . Fri, Mar 6, 2:52PM PDT (-0700 GMT)
To Tim McElrath: Thanks for the vote of confidence. Now I just have to withstand the radiation at 1Rj... If you know of any papers or other resources on Jovian trajectories, I'd really appreciate an email at eem2ds@ee.surrey.ac.uk. Thanks.

Jim/Proj.Mgt: . . . . Fri, Mar 6, 2:52PM PDT (-0700 GMT)
Doug Inwood Observatory Director New Zealand: Not with what we know now. We keep watching though. If anything gave any sign of changing, we'd eagerly consider it.

Srdjan: . . . . Fri, Mar 6, 2:53PM PDT (-0700 GMT)
To Clark Chapman: The closest encounter with Europa was 200 km. And the best picture (6m/pix) was taken from 560 km. Why Galileo didn�t take picture from 200 km? Thanx.

Chuck Wood, ND: . . . . Fri, Mar 6, 2:53PM PDT (-0700 GMT)
Hi Clark - I am doing a TV interview now and the interviewer wants to know: The elements necessaary for life are water, hear and organic matter. Does Europa have organic matter, and if so what is the implication for life. Thanks! Chuck

John Cody: . . . . Fri, Mar 6, 2:53PM PDT (-0700 GMT)
This question is to all team members who might like to answer- if another craft was built today to do the same job as Galileo, how would it differ from the current space-craft, which was, I think, conceptualized in 1977 as JOP. Would there be vast improvements? Would it still have the same design for the HGA? Not that one would be built, of course, considering the great work Galileo and the people involved are doing.

David V.: . . . . Fri, Mar 6, 2:53PM PDT (-0700 GMT)
to Marcia Sims: Thanks, i guess I misread your answer. At any rate, I missed the question you were answering...

anonymous: . . . . Fri, Mar 6, 2:53PM PDT (-0700 GMT)
Isn't water/ice unstable in space? If so, then Europa must have at least a minimal atmosphere?

Maltair: . . . . Fri, Mar 6, 2:53PM PDT (-0700 GMT)
I like Tim Z's question! and we were both off by a decimal place.

Brian P, SPOT Chief: . . . . Fri, Mar 6, 2:53PM PDT (-0700 GMT)
to oliver: i think we're getting bits and bytes mixed up. the galileo tape recorder is equivalent to a 112 mbyte hard disk.

volcanopele: . . . . Fri, Mar 6, 2:53PM PDT (-0700 GMT)
To the SSi member on this chat-when will the Io pictures from orbit E11 and E12 come out? Or have you even recieved them? If you have reieved them, can you tell us anything about them?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:53PM PDT (-0700 GMT)
the probe would i guess have a great advance in computer power .. and maybe a spring loaded HGA ... ? :-)

Ryan A. Boas: . . . . Fri, Mar 6, 2:54PM PDT (-0700 GMT)
Have you found any ice volcanoes or any other direct evidence of churning water below Europa's surface?

A.C., GA Tech: . . . . Fri, Mar 6, 2:54PM PDT (-0700 GMT)
Pat Beyer, A Europa mission might be a Discovery class misssion, how does telecommunication support from DSN for these types of missions differ from others (Galileo, Cassini, etc.) and does that entail using the 30m antennas over the 70+m ones?

Mass. Meteors: . . . . Fri, Mar 6, 2:54PM PDT (-0700 GMT)
Re: Beau B's comment "getting something to punch through 1 km of ice is no small task!" I heartily agree. And all the comments re: nukes disturbing Europa's "environment" seem warranted. That's the reason I was curious about the frequency of "large" (1-1000kg) impacts on Europa's surface... Surely, with the knowledge of particle stream dynamics which meteoricists are developing these days, we might have a stab at actually predicting "high impact" periods during Jupiter's orbit around the sun? Maybe a far-out question: but such a project sure would pour some much needed funds into meteoroid stream research. ;>

Tiago : . . . . Fri, Mar 6, 2:54PM PDT (-0700 GMT)

Tim McElrath, Navigation Team: . . . . Fri, Mar 6, 2:55PM PDT (-0700 GMT)
to anonymous: The Cassini trajectory actually takes longer to reach Saturn (7 years), although it has a Jupiter flyby in 4-5 years (as I recall). However, it is going too fast at Jupiter to efficiently be a Jupiter orbiter. The shortest efficient trajectories from Earth to Jupiter are 2.5 years, with no gravity assists. However, I suppose a Venus-Venus-Earth trajectory could be used to get to Jupiter if everything was lined up right.

bufi: . . . . Fri, Mar 6, 2:55PM PDT (-0700 GMT)
how much power is left on you craft? how long can you power last on the craft

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:55PM PDT (-0700 GMT)
What is "direct evidence of water churning"? An actual ice volcano erupting into space would be proof. A dead volcano might or might be: how can one be sure that a feature is actually a volcano? A seismometer on the surface of Europa would provide definitive proof, and sonar devices in orbit. For now, geologists must toil with trying to learn about the inside of something from studying pictures of its outside. Think about that! Would *you* be able to infer what the inside of a banana would be like from studying its peel? There *are* parts of Europa that are surprisingly flat and look as though water once were at or near the surface, but EVERYTHING is frozen on Europa's immediate surface right now... otherwise we would see the vapors.

anonymous: . . . . Fri, Mar 6, 2:55PM PDT (-0700 GMT)
Someone mentioned earlier that the cracks and ridges did not appear to be following the paths of least resistance. I agree. They look similar to the paths left behind by earthworms in mud after a rain. Any speculation on this. Could it be a combination of temperature, lack of atmosphere/pressure, low gravity, etc..?

Rene' Ortman: . . . . Fri, Mar 6, 2:56PM PDT (-0700 GMT)
to Beau...or anyone else...would it be feasible to put an RTG on the probe into Europa's ice...or is it too big??

Ed: . . . . Fri, Mar 6, 2:56PM PDT (-0700 GMT)
Could someone answer the question about sublimation in a low atmosphere? And why the strands appear in pairs? Or have all the scientists gone home?

Oliver Schulze(Asuncion/Paraguay): . . . . Fri, Mar 6, 2:57PM PDT (-0700 GMT)
to Brian P: thanks, now I know why it take to long (with the giroscope fixed) to transfer the pictures to the earth.

Seagull: . . . . Fri, Mar 6, 2:57PM PDT (-0700 GMT)
How long does it take for a return signal from Galileo right now? ThanX !

Leslie: Outreach: . . . . Fri, Mar 6, 2:57PM PDT (-0700 GMT)
anonymous: At the cold temperatures and vacuum in space, water cannot remain in liquid form. However, in solid form (ice) it does fine. The ice layer on top of Europa provides the pressure "shield" that keeps liquid underneath from immediately vaporizing.

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 2:57PM PDT (-0700 GMT)
Rico, A group of people in my office are debating this issue. It's making for great conversation. When we come up with a consensus, we'll get back to you.

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 2:57PM PDT (-0700 GMT)
To Clark Chapman: Any comments on the 1979 anomalous IR spike on the last Voyager image of Europa? I don't think debate amongst the team ever determined whether it was an artifact of the instrument or a vapor plume.

volcanopele: . . . . Fri, Mar 6, 2:58PM PDT (-0700 GMT)
Does anybody know why some of the places on the high res from E12 look like potato chips?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:58PM PDT (-0700 GMT)
About Io -- I don't know if these are on the ground are not...I haven't seen them myself and don't know when they will be released. Most of the imaging was concentrated on Europa during E12.

monty, new milford,ct : . . . . Fri, Mar 6, 2:58PM PDT (-0700 GMT)
Dr Chapman, could you explain how there are tidal forces effecting Europa, if it keeps the same side facing Jupiter. Thank you.

Jack Pappalardo: . . . . Fri, Mar 6, 2:58PM PDT (-0700 GMT)
Is NASA optimistic that it will receive the funding from Congress necessary to properly follow up on the recent extraordinary findings in the Jovian area? For example, do you think you will be able to launch a probe that can bore into the ice of Europa to verify the existence of slushy water just beneath the surface?

Ryan A. Boas: . . . . Fri, Mar 6, 2:59PM PDT (-0700 GMT)
Both of my previous questions came from information out of an issue of the Planetary Report. So I used the same phrases they did.

John Cody: . . . . Fri, Mar 6, 2:59PM PDT (-0700 GMT)
When will the next bunch of images be released? (Question for SSI people)

Jim/Proj.Mgt: . . . . Fri, Mar 6, 2:59PM PDT (-0700 GMT)
Seagull: One way transmission from Galileo to the Earth takes 50 minutes and 8 seconds today. This is about it's maximum, and gets as low as about 34 minutes

Seagull: . . . . Fri, Mar 6, 2:59PM PDT (-0700 GMT)
volcanopele, because Macdonalds have opened a new store there???

Brian P, SPOT Chief: . . . . Fri, Mar 6, 2:59PM PDT (-0700 GMT)
to seagull. the one-way light time to jupiter is about 50 minutes.

Beau B/SwRI: . . . . Fri, Mar 6, 2:59PM PDT (-0700 GMT)
One of the best ways to power a spacecraft in the outer Solar System is by RTG since the sunlight is so weak -- solar panels that could collect enough power to operate a spacecraft at the orbit of Jupiter would have to be HUGE! Thus any Europa orbiter mission would probably have some RTG. Whether or not the RTG is used to penetrate throught the ice is a different story -- there are all sorts of environmental questions that would need to be addressed.

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 2:59PM PDT (-0700 GMT)
Jack .....with the huge success of this mission i think funding would be easier ...

Ed: . . . . Fri, Mar 6, 2:59PM PDT (-0700 GMT)
Could someone answer the question about sublimation in a low atmosphere? And why the strands appear in pairs? Or have all the scientists gone home?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 2:59PM PDT (-0700 GMT)
Perry, the observation has been mentioned but, as your question implies, it was not definitive. We're hoping to see something much more definitive, but have seen no plume so far.

Michael Wilson, Navigation Team: . . . . Fri, Mar 6, 3:00PM PDT (-0700 GMT)
If the spacecraft could survive the different thermal environment at Saturn distances then I would see no reason why a Galileo spacecraft would have any trouble navigating the Cassini trajectory (Galileo also flew by Venus on its way to Jupiter, so I don't think the inner solar system would be a problem).

steve k/asu: . . . . Fri, Mar 6, 3:00PM PDT (-0700 GMT)
Hi, Ed. What was the question regarding sublimation?

volcanopele: . . . . Fri, Mar 6, 3:01PM PDT (-0700 GMT)
I know they did plume shots during E11 but nothing has been said about them. I was wondering what was seen on these observations?

Seagull: . . . . Fri, Mar 6, 3:01PM PDT (-0700 GMT)
Jim/Proj Mgt. What speed is the signal travelling at? in mph thanX

TheHealer: . . . . Fri, Mar 6, 3:01PM PDT (-0700 GMT)
Is the interest in Europa purely scientific and oriented towards looking for extra-terrestrail life, or is there also the thought of colonizing on or near Europa considering the abundant water source?

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 3:02PM PDT (-0700 GMT)
To volcanopele: Plume shots on E11??!!! Wait a second! Is this an X-File?

Ed: . . . . Fri, Mar 6, 3:02PM PDT (-0700 GMT)
To: Leslie, Outreach: Are you saying that ice does not sublimate in space?

Tayfun: . . . . Fri, Mar 6, 3:02PM PDT (-0700 GMT)
Because of the low budget we get less pictures on the WEB, do you also get less data from Galileo?

Oliver Schulze(Asuncion/Paraguay): . . . . Fri, Mar 6, 3:02PM PDT (-0700 GMT)
to Seagull: at speed of light

Pat Beyer/DeepSpace Network/telecommunications support: . . . . Fri, Mar 6, 3:02PM PDT (-0700 GMT)
A.C., GA Tech: Telecommunications design is fundamental to mission design. Factors are wavelength (frequency), available power, maximum range, antenna size, etc. And power and antenna size on the spacecraft are limited by allowable mass. One thing all these factors determine is the maximum allowable bit rate. As for the second part of your question, Galieo is S-band and 70m support. Most future missios are designing to higher frequencies (X-band and Ka-band) and try to be compatible with our 34M antennas. It sounds like you know we have many more 34M antennas available. And that is the largest we build anymore.

Rene' Ortman: . . . . Fri, Mar 6, 3:02PM PDT (-0700 GMT)
Beau: I have many more questions...but this chat thing is a little rediclious...thank u so much for ur time all of u...especially Beau...and keep up the good work. I hope to be working on the next Europa project with NASA

Gonzalo Rico: . . . . Fri, Mar 6, 3:02PM PDT (-0700 GMT)
Marcia Segura I'll be very (VERY) glad to receive your comments. Here is My e-mail: trico@edg.net.mx

Judy T.Texas: . . . . Fri, Mar 6, 3:02PM PDT (-0700 GMT)
Congratulations on your fine work! The images are incredible...

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 3:02PM PDT (-0700 GMT)
seagull - sped of light 6.7x10^8 mph

Jim/Proj.Mgt: . . . . Fri, Mar 6, 3:02PM PDT (-0700 GMT)
Seagull: The radio signal (just another form of electromagnetic radiation like visible light) travels at roughly 186,000 miles per second.

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:02PM PDT (-0700 GMT)
Ed, I wish I could tell you why the strands occur in pairs. There are some ideasw, based on analogs with ice sheets in the arctic. When cracks develop, the separate ice blocks bump into each other buckling up material on both sides of the cracks. On the Earth the ice motions are driven by winds and underwater currents. On Europa it may be tides. I don't think we *really* understand the picturesque double rideges, however. Do *you* have any ideas? By the way, an earlier question asked about tides if Europa keeps one face always towards Jupiter. The fact is, it doesn't quite keep the same face toward Jupiter because of a slight ellipticity in its orbit forced by the gravitational tug of war with Io and Ganymede.

Brent Turcotte.: . . . . Fri, Mar 6, 3:03PM PDT (-0700 GMT)
Would the tidal bulge of Io be? I bet about 10 meters. Unfortunately, it would be nearly impossible to detect because the bulge is stationary.

steve k/asu: . . . . Fri, Mar 6, 3:03PM PDT (-0700 GMT)
to volcanopele: the plume observations that have been performed so far have been focusing on Io. Europa gets its chance on orbit E-19.

Brent Turcotte.: . . . . Fri, Mar 6, 3:03PM PDT (-0700 GMT)
(fixed grammar)How big would the tidal bulge of Io be? I bet about 10 meters. Unfortunately, it would be nearly impossible to detect because the bulge is stationary.

Jim Galasyn: . . . . Fri, Mar 6, 3:04PM PDT (-0700 GMT)
To Clark and Ed: Europa's surface seems to be an almost textbook fractal, i.e., each line, on magnification, becomes a pair of lines, down to small scales. Such structures are often the fingerprint of iterative processes -- could this be interpreted to mean that the lines (ridges) are formed by a process of repeated freeze/thaw, or perhaps repeated flex/relax from tidal stresses?

Klem/ASU: . . . . Fri, Mar 6, 3:04PM PDT (-0700 GMT)
Hello everyone, this is Jim Klemaszewski signing on, an SSI affiliate from ASU.

Seagull: . . . . Fri, Mar 6, 3:04PM PDT (-0700 GMT)
Doug..thanX but can you speak in English please what is 6.7x10~8mph thanx ;-)

Sara G.: . . . . Fri, Mar 6, 3:04PM PDT (-0700 GMT)
What newspaper published the articles on Europa as possibly having liquid water? My science teacher is not aware of these new photos.

Webslingr, GaTech: . . . . Fri, Mar 6, 3:04PM PDT (-0700 GMT)
How long a window is open for DSN to recieve data from Galileo? And at what bit rate?

Tiago : . . . . Fri, Mar 6, 3:04PM PDT (-0700 GMT)
Has there been any prospect in finding the right trajectory to get the proper delta-V, in order to enter Europa orbit by the end of the GEM mission?

Tim Z: . . . . Fri, Mar 6, 3:04PM PDT (-0700 GMT)
Could the extra heat from our future red giant sun melt the surface ice on Europa? If so, could Europa hlod an H2O atmosphere? Would radiation from the sun then break down the H2O leaving a thick oxygen atmosphere?

Brian P, SPOT Chief: . . . . Fri, Mar 6, 3:04PM PDT (-0700 GMT)
to tayfun. nope. the galileo europa mission will send back about the same amount of data from the galileo prime mission. our current estimate is about 1.8 gigabits.

volcanopele: . . . . Fri, Mar 6, 3:04PM PDT (-0700 GMT)
Perry-I read somewhere that during the 11th orbit, Galileo would take pictures of the posible plume at Culann and other volcanoes. I was wondering what are the results?

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 3:05PM PDT (-0700 GMT)
Rico, The experts of debate have determined that the amount of water on Europa and the amount of water on Earth are about the same. While Europa is a smaller body, the water layer is much thicker than the Earth's 4 km deep oceans.

steve k/asu: . . . . Fri, Mar 6, 3:05PM PDT (-0700 GMT)
to ed: Yes, ice sublimates in a vacuum, but at the cold temperatures on Europa, it would do so VERY slowly.

Ed: . . . . Fri, Mar 6, 3:05PM PDT (-0700 GMT)
To: Leslie, Outreach: Are you saying that ice does not sublimate in space?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 3:05PM PDT (-0700 GMT)
sorry seagull .. different symbols on the keyboards i guess speed is 670,320,000 miles per hour

Brent Turcotte.: . . . . Fri, Mar 6, 3:06PM PDT (-0700 GMT)
Has the Galileo spacecraft ever seen, could have seen or will see any eclipses involving two of Jupiter's moons?

volcanopele: . . . . Fri, Mar 6, 3:06PM PDT (-0700 GMT)
steve-I am talking about Io

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 3:06PM PDT (-0700 GMT)
To volcanopele: If there were plumeshots on E11, I think it would have hit the mass media. Maybe Pillan Patera on Io on another flyby?

Ronin: . . . . Fri, Mar 6, 3:06PM PDT (-0700 GMT)
to steve k and leslie: so what will happen to the ice when we try to melt it? and back to the other question. what's the difference between boring nad drilling

Seagull: . . . . Fri, Mar 6, 3:06PM PDT (-0700 GMT)
thanX Doug ;-)

Klem/ASU: . . . . Fri, Mar 6, 3:06PM PDT (-0700 GMT)
Sara G - Europa articles were published in many newspapers around the country -- USA Today carried the article on Tue the 3rd.

Rene' Ortman: . . . . Fri, Mar 6, 3:06PM PDT (-0700 GMT)
KLEM...don't u think that putting enough wire not to mention enough power into a probe to melt through possibly hundreds of Kilometers is a little unrealistic..not to mention how heavy an big it will be??

Maltair: . . . . Fri, Mar 6, 3:06PM PDT (-0700 GMT)
Hey Tim, I think IO is to small to hold on to a thick atmosphere if the ice melted.

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:07PM PDT (-0700 GMT)
Sara -- There have been newspaper articles during the last 10 months about a possible ocean underneath Europa's ice. A Galileo press conference on Monday generated a bunch of additional articles (in papers like USA Today, the Boston Globe, etc.) Check out papers on Tuesday and Wednesday.

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 3:07PM PDT (-0700 GMT)
SSI people, how do you decide where to photograph and how much to photograph? I am interested also in what percentage of bandwidth do images get.

Leslie: Outreach: . . . . Fri, Mar 6, 3:07PM PDT (-0700 GMT)
hey, Klem. You made it home safe!

Oliver Schulze(Asuncion/Paraguay): . . . . Fri, Mar 6, 3:07PM PDT (-0700 GMT)
to Brian P: in what type of format store Galileo the Images? I mean, JPEG, GIF, TARGA, etc. Thanks

Tayfun: . . . . Fri, Mar 6, 3:07PM PDT (-0700 GMT)
To Brian P, SPOT. I'm glad to hear that. As long as you get the same amount of data I wouldn't mind waiting to see them.

David V.: . . . . Fri, Mar 6, 3:08PM PDT (-0700 GMT)
to SSI people: can you infer thickness of pre-chaos ice in the chaos regions based on how wide the upended slabs appear, or how high they protrude above the present matrix? They seem to indicate an ice layer less than 2 km thick at the time of disruption. (i am not a planetary geologist by any means......just need input)

Tim Z: . . . . Fri, Mar 6, 3:08PM PDT (-0700 GMT)
Maltair, maybe, that is what I have been asking for the past hour now.

LookN4Life: . . . . Fri, Mar 6, 3:08PM PDT (-0700 GMT)
I understand that there is no direct evidence yet, but in a personal opinion do any of the Europa folk here think that there is even a remote chance of finding complex animals and plant life (Seaweed and fish) in these oceans?

Ed: . . . . Fri, Mar 6, 3:08PM PDT (-0700 GMT)
If Europa rotates very slowly would the tidal forces be very small?

dogeared: . . . . Fri, Mar 6, 3:08PM PDT (-0700 GMT)
Just a bit of light relief. What is everbodys favourite space film? mine is 20011 (superb epic) sorry im off topic but I thought it was worth taking a coffee break team?? public??

Tim McElrath, Navigation Team: . . . . Fri, Mar 6, 3:09PM PDT (-0700 GMT)
To Brent Turcotte: Actually the equatorial radius is about 6km larger than the polar radius, so the tidal bulge would be 3km or so. This is easy to detect in the gravity field, which we measure by the spacecraft Doppler tracking data. Unfortunately, the first Io flyby data was inconclusive for various reasons, so the number above is based on images.

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:09PM PDT (-0700 GMT)
Brent -- eclipses involving Jupiter's moons only happen at special times when the plane of their orbit very nearly exactly includes the sun -- twice during a Jovian year of about a dozen Earth years. I don't have a schedule, but I'm unaware that these happened during Galileo's orbital tour.

James C.: . . . . Fri, Mar 6, 3:09PM PDT (-0700 GMT)
If this slush found on the surface of Europa is an indication that there is water on the surface, which in turn could possibly prove the existence of life on other worlds, do you think that would add any validity to the theory of Panspermia and the origin of life here on earth?

steve k/asu: . . . . Fri, Mar 6, 3:09PM PDT (-0700 GMT)
to Ronin: If ice is melted to a liquid on the surface, it will boil and freeze over pretty rapidly. The boiling occurs until an ice sheet of about 0.5 m thickness forms over the top. Boring is about the same as drilling, except it suggests the object doing it is moving down into the hole (boring) vs. having a stationary drill rig on the surface.

anonymous: . . . . Fri, Mar 6, 3:09PM PDT (-0700 GMT)
Hello :) I was wondering whether the capacity of the tape recorder or the limited time between encounters is more limiting?

: . . . . Fri, Mar 6, 3:09PM PDT (-0700 GMT)
Does Europa have a core, and if so what is it likly to be made of?

steve k/asu: . . . . Fri, Mar 6, 3:09PM PDT (-0700 GMT)
Gotta sign of now that Jim K is here! Thanks again for the great questions! Steve

Mass. Meteors: . . . . Fri, Mar 6, 3:10PM PDT (-0700 GMT)
To follow up on some questions I was wondering about: does the Galileo imaging system allow global topographic measurements of e.g. Europa's surface? This seems like it might allow us to measure tidal effects, and guess at the structure & extent of the ice sheet over Europa. Second question, have any of the planning teams for the Europa Orbiter (or potential future missions) considered attempting to catch a medium size (1-1000kg) impact event during a future mission? Thanks again for allowing the world at large to chat with you all, by the way! :)

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 3:10PM PDT (-0700 GMT)
To LookN4Life: (non-staff answer) plant life is out of the question (no photosynthesis). Archaeophytes and chemosynthetic organisms are a different matter, however. (crosses fingers)

Oliver Schulze(Asuncion/Paraguay): . . . . Fri, Mar 6, 3:10PM PDT (-0700 GMT)
to anonymous: the capacity of the tape recorder is 112MB.

volcanopele: . . . . Fri, Mar 6, 3:10PM PDT (-0700 GMT)
It wouldn't because Io throws up all the time. I just want to know as of the latest data(Orbit 11) which volcano was erupting. It also wouldn't hit the media because Europa is the star now

Brent Turcotte: . . . . Fri, Mar 6, 3:11PM PDT (-0700 GMT)
Tim and Maltair: Io is not too small to hold a thick atmosphere. Titan of Saturn is about the same size as Io, and is 20% thicker than Earth's atmosphere. I guess it would depend on the amount of ice on Io.

Beau B/SwRI: . . . . Fri, Mar 6, 3:11PM PDT (-0700 GMT)
Thanks everyone for your questions! Signing off until the next chat, Beau

Leslie: Outreach: . . . . Fri, Mar 6, 3:11PM PDT (-0700 GMT)
thanks, steve asu!

Klem/ASU: . . . . Fri, Mar 6, 3:11PM PDT (-0700 GMT)
Rene' - the amount of wire/heat needed to melt through an ice crust depends on how thick the ice is. If you think about the distance of fiber optic wires and telephone lines around the world, including under the ocean, it is theoretically possible to have that much. Deploying it is going to be the interesting part.

Ronin: . . . . Fri, Mar 6, 3:11PM PDT (-0700 GMT)
thanks steve k

Gonzalo Rico: . . . . Fri, Mar 6, 3:11PM PDT (-0700 GMT)
Marcia. I made a mistake because I were thinking that this issue was a discussion at your laboratory time ago. Anyware i'm very ineterested.

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:11PM PDT (-0700 GMT)
LookN4Life -- Seaweed sounds very Earthlike -- the result of long evolution on Earth. I surely wouldn't rule out the possibility of something complex and fascinating (Nature has a way of doing that), but I wouldn't look for anything familiar.

Brian P, SPOT Chief: . . . . Fri, Mar 6, 3:12PM PDT (-0700 GMT)
to oliver: the galileo images are stored on the tape recorder in their raw format. That is, each pixel of the camera is stored as 1 byte (8-bits) of information. for every full frame image (800x800 pixels), 5120000 bits are stored on the recorder.

Michael Wilson, Navigation Team: . . . . Fri, Mar 6, 3:12PM PDT (-0700 GMT)
Tiago: We have only about 50 kg of propellant (about 100 m/sec) remaining in the tanks and that is not enough to get into to orbit about Europa. Our flyby speed at the upcoming encounter with Europa on March 29 is approximately 6.5 km/second.

Terry: . . . . Fri, Mar 6, 3:12PM PDT (-0700 GMT)
how long is the mission? i.e., what is the expected life of the probe?

volcanopele: . . . . Fri, Mar 6, 3:12PM PDT (-0700 GMT)
Clark-The pheomenon You were discribing happened last year. I think it stopped in November.

Ed: . . . . Fri, Mar 6, 3:12PM PDT (-0700 GMT)
If Europa rotates very slowly would the tidal forces be very small?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 3:12PM PDT (-0700 GMT)
if nyone is interested there is a very good overview of the mission available from nasa. It's in 11 pdf format files and is well worth reading. Has all sorts of information about the probe and it's construction and equipment on board

Klem/ASU: . . . . Fri, Mar 6, 3:13PM PDT (-0700 GMT)
Hi Leslie - I made it home safely after dropping off Steve.

dogeared: . . . . Fri, Mar 6, 3:13PM PDT (-0700 GMT)
Doug: got the WWW info on that??

anonymous: . . . . Fri, Mar 6, 3:13PM PDT (-0700 GMT)
ohh.....Are the data rates posted on the web analagos to computer modem DCE or DTE rates?

Tim McElrath, Navigation Team: . . . . Fri, Mar 6, 3:13PM PDT (-0700 GMT)
To Brent Turcotte: I don't think there is any significant water (or ice) on Io, since all the heating would have driven it off. There's no spectroscopic evidence for ice or water on the surface that I've ever heard of. Of course, if you did transport an atmosphere there, it would probably stay, which would be interesting.

Rene' Ortman: . . . . Fri, Mar 6, 3:13PM PDT (-0700 GMT)
signing off all...thanks so much for ur input...it's greatly appreciated and will be used! ;-)

Tim Z: . . . . Fri, Mar 6, 3:14PM PDT (-0700 GMT)
Brent Turcotte: My original question was: will our future red giant sun have enough heat to sublime the surface ice on Europa into an H2O atmosphere? Then, would the H2O break down from solar radiation, release the hydrogen, and leave an oxygen atmosphere?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 3:14PM PDT (-0700 GMT)
i can look it up

A.C., GA Tech: . . . . Fri, Mar 6, 3:14PM PDT (-0700 GMT)
Since all ice is not the same, what are the various types of ice that are hypothesized to exist at various depths at Europa?

Maltair: . . . . Fri, Mar 6, 3:14PM PDT (-0700 GMT)
Thanxs for the answers. Bye

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 3:14PM PDT (-0700 GMT)
Hm-transition time. Perhaps some of the SSI team who are just joining us could help me out: what percent of bandwidth do images get?

dogeared: . . . . Fri, Mar 6, 3:14PM PDT (-0700 GMT)
Doug: I would be obliged thankyou

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 3:15PM PDT (-0700 GMT)
looooooong time to wait tim z ...

anonymous: . . . . Fri, Mar 6, 3:15PM PDT (-0700 GMT)
I am interested in the dark substances seen at the bottom of the double trenches. Is this material that has been expelled out of the oceans and then has fallen back to the surface as "snow"? This substance seems to have slid on the ice and collected in the low areas.

Tiago : . . . . Fri, Mar 6, 3:15PM PDT (-0700 GMT)
Michael Wilson: I know, but some time ago therer was some talk about the possibility of making some sort of gravoty assist within Jupiter orbit to get to Europa orbit. Or is this only possible at Jupiter Orbit arrival?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:16PM PDT (-0700 GMT)
The best concept of Europa's interior is that it has a metal-rich core. We know that Europa is heated and that warm planets "differentiate" -- that is, the heaviest materials sink and the lightest ones float. For the usual proportions of materials of which cosmic material is made (and we have no reason to suspect that Europa is anything else), the heavy stuff would be iron or iron-sulphide and the light stuff would be water (waqter-ice). This theoretical picture of Europa's interior is entirely consistent with the latest measurements of Europa's gravity field from radio-tracking of Galileo's trajectory.

Ljubo: . . . . Fri, Mar 6, 3:16PM PDT (-0700 GMT)
Hello everyone! I would like to know how healthy is the Galileo spacecraft. Has the radiation already caused some serious damage?

volcanopele: . . . . Fri, Mar 6, 3:16PM PDT (-0700 GMT)
A month ago I read about Io's poles and about something was found about it, what was it?

James C.: . . . . Fri, Mar 6, 3:16PM PDT (-0700 GMT)
Mr. Clark Champman, my name is James Colraine. I'm doing a report for my Biology class on the origin of life. Do you think that if water is found on the surface and if bacterial life is found on Europa then it will lead to a greater acceptance of the Panspermia theory of life here on earth?

Doug Inwood Observatory Director New Zealand: . . . . Fri, Mar 6, 3:16PM PDT (-0700 GMT)
sorry to distract ppl ... it's on the web page dogeared icarus@es.co.nz for details

dogeared: . . . . Fri, Mar 6, 3:17PM PDT (-0700 GMT)
why we are talking about ice a colleague told me that hot water placed in an icebox will freeze quicker than cold water..would any of you Xperts kmow that this is true??

Brent Turcotte: . . . . Fri, Mar 6, 3:17PM PDT (-0700 GMT)
Clark Chapman: I am referring to eclipses that involve only the sattelites not the sun. From say Amalthea, you could probably see an eclipse of moons about once a day on average because the moons are in there own plain, and nearly every time one moon passes another moon there is an eclipse. But I guess Galileo is only rarely situationed in Jupiter's plane.

LookN4Life: . . . . Fri, Mar 6, 3:17PM PDT (-0700 GMT)
Perry Frix: I suppose what I'm asking is if anybody is of the personal opion that anything beyond archeophytic or photosynthetic life could stand a remote chance of being discovered. Macroscopic animals swimming through the dark waters.

Oliver Schulze(Asuncion/Paraguay): . . . . Fri, Mar 6, 3:17PM PDT (-0700 GMT)
to anonymous: I think that this material is part of the meteoryt.

Klem/ASU: . . . . Fri, Mar 6, 3:17PM PDT (-0700 GMT)
A.C. - Pure water crystals reorganize based on pressure and temperature, producing Ice I, Ice II, Ice III...etc. The addition of "impurities" (e.g. ammonia) will also change its physical and chemical properties.

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 3:18PM PDT (-0700 GMT)
Carl Banks, The bandwidth that SSI gets is about 50% over the mission. Herb of SSI says it's not enough. Marcia of NIMS says it's too much. So now you get an idea of the day to day dilemma. But we both agree that fields and particles gets too much. :)

: . . . . Fri, Mar 6, 3:18PM PDT (-0700 GMT)
yes true ....it makes the thermostat turn on earlier as the temp goes up

Ed: . . . . Fri, Mar 6, 3:18PM PDT (-0700 GMT)
If Europa rotates very slowly would the tidal forces be very small?

Brian P, SPOT Chief: . . . . Fri, Mar 6, 3:18PM PDT (-0700 GMT)
Ljubo: the spacecraft is still in good health. we have had a recent problem with the gyros on the scan platform that we believe may be associated with radiation effects.

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:18PM PDT (-0700 GMT)
The dark stuff has surely accumulated in the bottoms of depressions. My guess (as a scientist on the imaging team) is that Europa's ice has always gotten "dirty" by infalling comets, perhaps including eruptions of dirty ocean-water from below. When subjected to sublimation and other preferential losses of the water ice, the dark stuff is liberated and gradually migrates downhill. We see the very same thing on Ganymede.

WOU student: . . . . Fri, Mar 6, 3:18PM PDT (-0700 GMT)
Are any of you cognizant of current Europa exploritory missions that might elaborate on some of Galileo's recent findings?

Stefano Riva: . . . . Fri, Mar 6, 3:18PM PDT (-0700 GMT)
To all experts, a question for the future: I would like to know if it would be possible to design a general-purpose, small and cheap interplanetary probe, in order to build and send many very-low-cost probes all around the Solar System. I mean, what about a tenth or so small cheap probes, each one with four or five standard instruments aboard and a small rocket stage, launched for example from a single Shuttle mission to many planets and moons (fly-bys only, of course)? Would it technically feasible and convenient, from the monetary and scientific points of view?

: . . . . Fri, Mar 6, 3:19PM PDT (-0700 GMT)
Marcaia - what do fields and particles say to that ?

Leslie: Outreach: . . . . Fri, Mar 6, 3:19PM PDT (-0700 GMT)
Hello Europa fans! I wanted to remind everyone that Project Galileo is sponsoring a 2-day celebration on the exploration of Europa on May 20 and 21, 1998. On May 20, we'll have a nationwide "Electronic Field Trip" aimed at middle school classes, that talks about space exploration and highlights Galileo's exploration of Europa, among other things. On May 21, we are having a nationwide series of panel talks on the Europa and our exploration of it, which includes a message from Arthur C. Clarke. Please watch our web site for information and details on locations and times.

Oliver Schulze(Asuncion/Paraguay): . . . . Fri, Mar 6, 3:19PM PDT (-0700 GMT)
If the Ice in Europa is clear, could the light of the sun get thru the 10Km of solid Ice?

Gonzalo Rico: . . . . Fri, Mar 6, 3:19PM PDT (-0700 GMT)
Marcia: In the last weeks you have focused on Europa. How about Jupiter? Is there still working on?

Tiago : . . . . Fri, Mar 6, 3:19PM PDT (-0700 GMT)
To Michael Wilson, Navigation Team: I know, but some time ago therer was some talk about the possibility of making some sort of gravoty assist within Jupiter orbit to get to Europa orbit. Or is this only possible at Jupiter Orbit arrival?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:20PM PDT (-0700 GMT)
Brian, that's ture. It happens rarely. We have seen the satellites pass in front of the much larger Jupiter. I wouldn't rule out that (by accident) we have seen mutual interactions of the sort you describe, but I don't remember seeing any.

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 3:20PM PDT (-0700 GMT)
To LookN4Life: Well, if you like convergent evolution theory... Entire ecosystems _have_ developed on earth with archaeophytes at the base.

Mass. Meteors: . . . . Fri, Mar 6, 3:20PM PDT (-0700 GMT)
Oh, well - tough to keep up with such dynamic, interesting discussions from my little Web browser here at work... I'll try sending my question re: meteoroid impacts to the askgalileo email address. Thanks again to all the scientists and engineers who participated - these chats are a WONDERFUL (if overwhelming) forum for us out in the populace. Keep up the good work - you're a credit to our species. :) Clear skies, Lew Gramer Medford, MA lewkaren@tiac.net

Laura, SPOT: . . . . Fri, Mar 6, 3:20PM PDT (-0700 GMT)
.... I'm positive that they ALL say "we want more", especially when it comes to timelines and resources;-)

Jim Galasyn: . . . . Fri, Mar 6, 3:21PM PDT (-0700 GMT)
Stefano: I'm no expert, but I too have often wondered if it would be possible to make hundreds or thousands of tiny penetrator probes that would be launched by mass driver, much like a machine gun. We could Instrument the entire solar system on the cheap and monitor all these signals with the DSN.

Pat Beyer/DeepSpace Network/telecommunications support: . . . . Fri, Mar 6, 3:21PM PDT (-0700 GMT)
Gotta go. It's been fun.

Jim/Proj.Mgt: . . . . Fri, Mar 6, 3:21PM PDT (-0700 GMT)
Ljubo: The spacecraft is surprisingly healthy. We've seen some transient faults probably due to radiation, and some damage to our gyro's. We may also have lost part of our ability to sense plasma waves.

Brent Turcotte: . . . . Fri, Mar 6, 3:21PM PDT (-0700 GMT)
Tim: Thanks and sorry about misintrepreting the question. I didn't see the orginal, as this site is so fast. By the time Europa melts or sublimes by the Sun being a red giant it will so hot that the atmosphere will have much less holding power. Perhaps a Mars thick atmosphere is possible, with the water slowly leaking out into space.

Dopler: . . . . Fri, Mar 6, 3:22PM PDT (-0700 GMT)
If Galileo was taken picture of Europa from 200 km, what resolution would be?

Tiago : . . . . Fri, Mar 6, 3:22PM PDT (-0700 GMT)
To Michael Wilson, Navigation Team: I know, but some time ago therer was some talk about the possibility of making some sort of gravoty assist within Jupiter orbit to get to Europa orbit. Or is this only possible at Jupiter Orbit arrival?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:22PM PDT (-0700 GMT)
Oliver -- that is a very important question. It would take remarkably clear ice (impossibly remarkable) for sunlight to penetrate 10 km. But I wouldn't rule out that there are isolated places, e.g. where the ice cracks and water is able to rise close to the surface, where the ice is much thinner and sunlight could penetrate to support photosynthesis. But don't forget that there is an enormous amount of energy to support life (in all probability) at the base of Europa's oceans. We now know (from explorations by the Alvin, etc.) that there is abundant life around hot vents at the bottom of the Earth's oceans.

Doug Inwood CAS Obs Director: . . . . Fri, Mar 6, 3:22PM PDT (-0700 GMT)
that plasma loss permanent ?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:23PM PDT (-0700 GMT)
Dopler -- a few meters. We could see a truck, or a whale, on Europa with that kind of resolution.

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 3:23PM PDT (-0700 GMT)
Maybe telemetry has too much bandwidth?

Sheffield Steve (UK): . . . . Fri, Mar 6, 3:23PM PDT (-0700 GMT)
Still no reply about the possibility of an object moving across the surface producing the triple bands. I feel sure these features cannot be easily explained by upwelling of water in cracks - they are far too symmetrical, they are continuous for hundreds of kilometers and they cut all terrain types like they were not there. Anyone else with any thoughts on the subject?

WOU student: . . . . Fri, Mar 6, 3:24PM PDT (-0700 GMT)
Does Arthur Clarke have a relationship with JPL at this time?

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 3:24PM PDT (-0700 GMT)
Oliver, No. That's why we don't expect photosynthetic life.

Ronin: . . . . Fri, Mar 6, 3:24PM PDT (-0700 GMT)
again i ask, are there mailing list out there for galileo and europa?

Tim Z: . . . . Fri, Mar 6, 3:24PM PDT (-0700 GMT)
TO ANYONE: When our sun becomes a red giant will it radiate enough energy to sublime the surface ice on Europa into an H2O atmosphere? Would the H2O then get broken down from solar radiation, release the hydrogen, and hold on to the oxygen?

dogeared: . . . . Fri, Mar 6, 3:24PM PDT (-0700 GMT)
clark chapman, have you seen a truck, you will start the conspirators off again :-)

Oliver Schulze(Asuncion/Paraguay): . . . . Fri, Mar 6, 3:25PM PDT (-0700 GMT)
to Clark: thanks Clark.BR

Klem/ASU: . . . . Fri, Mar 6, 3:25PM PDT (-0700 GMT)
Dopler - the image resolution from 200 km would range from 2-4 m/pixel, depending on camera mode and the target (whether or not it is directly under the spacecraft).

Jim/Proj.Mgt: . . . . Fri, Mar 6, 3:25PM PDT (-0700 GMT)
Doug Inwood CAS Obs Director: Still in analysis. Doesn't look very good. But it's only in the low frequency end of one sensor. Any PWS types on-line?

bufi(egon): . . . . Fri, Mar 6, 3:25PM PDT (-0700 GMT)
how much power is left on you craft you mission greaaattttttttt.

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 3:26PM PDT (-0700 GMT)
Carl, One thing we can all agree upon is there certainly isn't enough bandwidth.

Jim Galasyn: . . . . Fri, Mar 6, 3:26PM PDT (-0700 GMT)
To Ronin: Ron Baalke maintains an email list for Galileo.

Tim Z: . . . . Fri, Mar 6, 3:26PM PDT (-0700 GMT)
Brent, thank you!

Ed: . . . . Fri, Mar 6, 3:26PM PDT (-0700 GMT)
If Europa rotates very slowly would the tidal forces be very small?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:26PM PDT (-0700 GMT)
About triple bands, Sheffield Steve -- I'm a believer that they are caused by a geological process, even if we don't completely know what that process is -- yet! Studied in detail, they are not entirely symmetrical. Faults on the Earth (like the San Andreas) go for hundreds of km. And, whatever "terrain types" you are talking about, they are all made of ice.

Dopler: . . . . Fri, Mar 6, 3:26PM PDT (-0700 GMT)
to Clark: why didn't you take pic from 200 km when you had a chance??

Brent Turcotte: . . . . Fri, Mar 6, 3:26PM PDT (-0700 GMT)
Ronin: on the front page of the Galileo web site, there is a mailing list. Click on the link that says: "Subscribe to Galileo Mailing List"

Rodrigo (Caracas-Venezuela): . . . . Fri, Mar 6, 3:26PM PDT (-0700 GMT)
Can we find similar features in satellite images from Antartica like the ones from Europa? Can you identify how old is the surface ice?

Oliver Schulze(Asuncion/Paraguay): . . . . Fri, Mar 6, 3:27PM PDT (-0700 GMT)
Marcia and Clark: so we are especting live only near the base of the oceans?

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 3:27PM PDT (-0700 GMT)
Rico, There are still Jupiter observations occurring in each orbit but our primary focus is Europa.

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:27PM PDT (-0700 GMT)
Sorry, Ed, ask a longer question about tidal forces. Europa as a body doesn't rotate, although its ice cap could be decoupled from the rest of the body. The tides are due to Jupiter pulling on Europa from slightly different distances and slightly different directions.

Leslie: Outreach: . . . . Fri, Mar 6, 3:27PM PDT (-0700 GMT)
WOU student: Arthur C. Clarke doesn't have an "official" relationship with JPL, but he does help us out from time to time by appearing (remotely via phone or video link) in some of our events.

David V.: . . . . Fri, Mar 6, 3:27PM PDT (-0700 GMT)
Sheffield Steve (UK): why would they have to be formed by moving objects. I have seen ponds and lakes with ice ~1 cm thick, which have very straight, slightly curved, or jumbled arrays of short straight ridges in them, apparently having to do only with the crystallization of the ice. There isn't anything inherantly unnatural about straight lines in nature,and many Earthly geologic faults cut through completely unrelated terrains and rock types.

Tiago : . . . . Fri, Mar 6, 3:28PM PDT (-0700 GMT)
To anyone on the Navigation Team: Some time ago there was some talk about the possibility of making some sort of gravity assist within Jupiter orbit to get to Europa orbit. Is this only possible at Jupiter Orbit arrival?

WOU student: . . . . Fri, Mar 6, 3:28PM PDT (-0700 GMT)
Is it thought likely that Europa possesses a nickel/iron core sufficient in that it might produce a detectable magnetosphere?

Inquisitor: . . . . Fri, Mar 6, 3:28PM PDT (-0700 GMT)
In one of the recent hi rez pics of a gorge on Europa, I noticed that a few pixels seemed to indicate reflections in the shadowy region of the canyon. Does this indicate that light has reflected off the other side of the canyon and is in turn "double reflected" towards the probe?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:29PM PDT (-0700 GMT)
Oliver, I wouldn't expect life only at the base. Perhaps that's where life might have originated on Europa. But, just as on Earth, where life has migrated deep into the rocks and flies high in the atmosphere, I would expect life to move throughout the oceans. The big question is how it ever formed and evolved into sufficient complexity. Thereafter, nature seems to be very ingenious about evolving adaptations to the most extreme adjacent environments.

Leslie: Outreach: . . . . Fri, Mar 6, 3:29PM PDT (-0700 GMT)
Ronin: To sign up for the Galileo email list, go to http:// www.jpl.nasa.gov/galileo/mail.html, or Send email to majordomo@sender.jpl.nasa.gov and include the following text in the body of the message: subscribe galileo

Stefano Riva: . . . . Fri, Mar 6, 3:30PM PDT (-0700 GMT)
Jim Galasyn: I know that the high cost of interplanetary missions is a major problem and Pathfinder is an example of a new generation, relatively cheap probe. I wonder, instead of going from huge probes with custom technical solutions to smaller ones with a lot of commercial technical solutions, why not going to lots of very small, standardized probes. Maybe hundreds or thousands of penetrators would be possible in a not-so-near future, but what about an intermediate solution?

Ronin: . . . . Fri, Mar 6, 3:30PM PDT (-0700 GMT)
Thanks Jim & Brent

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 3:30PM PDT (-0700 GMT)
Next question: does Galileo use waste heat from the RTGs to maintain thermal balance? And if so, how? I don't see any thermal experts here.

monty, new milford,ct : . . . . Fri, Mar 6, 3:30PM PDT (-0700 GMT)
How did all the water get on Europa to form the ice.

Brent Turcotte: . . . . Fri, Mar 6, 3:30PM PDT (-0700 GMT)
Ed: Europa rotates synchronistly with Jupiter. The time it takes to circle Jupiter is equal to the time Europa takes to make one complete turn. This is true for most moons. Europa's tides come mainly from close passes from Io and Ganymede and some from Callisto.

dogeared: . . . . Fri, Mar 6, 3:31PM PDT (-0700 GMT)
thanks team and public for being here. Leslie..can you arrange these chats for similar time frames in the future its been fun

Klem/ASU: . . . . Fri, Mar 6, 3:31PM PDT (-0700 GMT)
Ed - I'm not an expert on this but let me take shot at it. Because the tidal forces are a result of the masses of Jupiter and other moons nearby Europa, and their respective distances from Europa, Europa's rate of rotation would not directly contribute to the tidal forces. However, the rotation rate WOULD affect the strain rate on the surface. For example, if you pull silly putty slowly it will stretch (the total stress is spread out over time) but if you pull the silly putty quickly it will break (a high strain rate). If Europa rotates very slowly, the resulting strain rates would be small as well.

WOU student: . . . . Fri, Mar 6, 3:31PM PDT (-0700 GMT)
Would the presence of a Europan magnetosphere increase the viability of life with Europa's ocean?

Mike V: . . . . Fri, Mar 6, 3:31PM PDT (-0700 GMT)
Leslie, A great job today, a tough task also, Again Thanks to Everyone, I'll be watching the Main Site. Seattle, Washington

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:31PM PDT (-0700 GMT)
Inquisitor -- I don't know what picture you are talking about. The Galileo camera is very good and, on Ganymede at least, has taken pictures that help us look into shadows by reflected light. But we have to process the pictures specially to see into the shadows. What you are probably seeing on the released Europa views are simply little projections that peak out of the shadows into sunli9ght.

Tiago : . . . . Fri, Mar 6, 3:31PM PDT (-0700 GMT)
Is there anyone from the navigation team?

Michael Wilson, Navigation Team: . . . . Fri, Mar 6, 3:32PM PDT (-0700 GMT)
Tiago: Sorry, I'm getting distracted by the phone here. There was some early consideration of using gravity assists to rendezvous with Europa, but it was quickly dropped. The Europa Orbiter mission will use all of the Galileans at various points in the mission, in addition to delta-v, to get into orbit about Europa.

Shawn B/SwRI: . . . . Fri, Mar 6, 3:32PM PDT (-0700 GMT)
Tim Z. In order to melt any ice on Europa, the Sun would have increase its luminosity by a factor of about 20. I'm not a stellar theorist, so I don't know how likely that is to happen, but it doesn't seem beyond the realm of possibility to me

Steve L.: . . . . Fri, Mar 6, 3:32PM PDT (-0700 GMT)
With a good spacecraft why not keep taking pictures beyond 1999.

dogeared: . . . . Fri, Mar 6, 3:32PM PDT (-0700 GMT)
Tiago, no they got lost on the way here :-))))))

John Cody: . . . . Fri, Mar 6, 3:32PM PDT (-0700 GMT)
I'm getting tired...it's about 11:30 here in Farnborough (England) One more question- has Galileo filled all the gaps in the Voyager coverage?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:32PM PDT (-0700 GMT)
WOU -- A magnetic interaction with Europa has been detected by the Galileo magnetometer, but it's not very strong and is probably not from the core.

Gonzalo Rico: . . . . Fri, Mar 6, 3:33PM PDT (-0700 GMT)
How is the health of Galileo now?

Jim/Proj.Mgt: . . . . Fri, Mar 6, 3:33PM PDT (-0700 GMT)
Carl Banks, Project Asterius: We don't use the waste heat from the RTGs. We actually have them on long booms away from the spacecraft so that the fields and particles instruments havve less interference from them.

Tim Z: . . . . Fri, Mar 6, 3:33PM PDT (-0700 GMT)
Shawn B, Thank you!

Herb,Science Coordinator: . . . . Fri, Mar 6, 3:33PM PDT (-0700 GMT)
Monty - Outer solar system is where volitile materials like water condense when the solar system formed.

David V.: . . . . Fri, Mar 6, 3:33PM PDT (-0700 GMT)
Michael Wilson and the nav team: thanks a million for your info on the Europa Orbiter planning process!!

Ronin: . . . . Fri, Mar 6, 3:34PM PDT (-0700 GMT)
Thanks to everyone, you people have been doing a great job

Tiago : . . . . Fri, Mar 6, 3:34PM PDT (-0700 GMT)
I heard about (on this chat, early on) an Europa Orbit insertion within 1 Jupiter orbit after JOI.

Ed: . . . . Fri, Mar 6, 3:34PM PDT (-0700 GMT)
If Europa rotates very slowly would the tidal forces be very small?

Shawn B/SwRI: . . . . Fri, Mar 6, 3:34PM PDT (-0700 GMT)
Tim Z. Sorry, I'm not used to this mode of communication. I wanted to add that some theorists believe that it is posible that Europa, Ganymede and Callisto all began their existences with atmospheres of water vapor. Being so far from the Sun, however, any such atmosphere would quickly have frozen out onto their surfaces.

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 3:34PM PDT (-0700 GMT)
To Clark Chapman: No magnetometer people here? Would the scale of the measured interaction be consistent with electrolytic solutes in motion in the liquid water layer?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:34PM PDT (-0700 GMT)
Steve L, we'd love to keep taking pictures so long as the spacecraft still works. But it takes money to pay the people to keep up the good work. In the past, NASA sometimes keeps spacecraft and instruments operating until they "die" but more often it doesn't...

Herb,Science Coordinator: . . . . Fri, Mar 6, 3:34PM PDT (-0700 GMT)
Steve L - We would love to take more pictures, but we need a healthy spacecraft and money!

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:35PM PDT (-0700 GMT)
Perry, beyond my scope of knowledge!

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 3:35PM PDT (-0700 GMT)
John Cody, Galileo has done a great job but alas there will always be gaps.

Tim Z: . . . . Fri, Mar 6, 3:35PM PDT (-0700 GMT)
Shawn B, thank you again, I appriciate the input!

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 3:36PM PDT (-0700 GMT)
To Clark Chapman: :) ok! I'll try to get in touch with Mr. Bindschadler on that one.

dogeared: . . . . Fri, Mar 6, 3:36PM PDT (-0700 GMT)
MONEY?? surely with Eileen Collins and water on the moon the public must be bursting with eagerness to give cach to NASA

Ronin: . . . . Fri, Mar 6, 3:36PM PDT (-0700 GMT)
someone said that due to Jupiter's strong magnetic field, it is a viable source of power generation for spacecrafts there. comments?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:36PM PDT (-0700 GMT)
Ed, I tried to comment on your oft-repeated question earlier. But I wish you'd rephrase it and make it clearer what you want to know

Jim/Proj.Mgt: . . . . Fri, Mar 6, 3:36PM PDT (-0700 GMT)
Steve L.: Taking pictures significantly beyond 1999 would mean that we survived two high radiation passes. Each couple of months would mean additional major radiation doses. We will take a look at the s/c in summer of 99 and see where we are, and then make better plans.

Oliver Schulze(Asuncion/Paraguay): . . . . Fri, Mar 6, 3:36PM PDT (-0700 GMT)
to all: I would like to thanks all the Galileo Team and all the people that make this web chat posible. Thanks Brian P, Clark Chapman and Marcia Segura. Great Job! Galileo Rulez! ;-)

Daisuke: . . . . Fri, Mar 6, 3:36PM PDT (-0700 GMT)
I wish to adress the theory proposed by that russian astronomer that states that there is an advanced civilization under the crust of europa, is there any evidence to support such a theory?

Terry: . . . . Fri, Mar 6, 3:36PM PDT (-0700 GMT)
When is the next probe scheduled to enter the Jovian system?

Klem/ASU: . . . . Fri, Mar 6, 3:37PM PDT (-0700 GMT)
John Cody - there are still (and will be) gap (no data coverage) and the north and south poles after GEM. In addition, there are still low resolution (>10 km resolution) regions that will be mostly filled by data ranging from 200-1.5 km/pixel if everything goes according to plan.

WOU student: . . . . Fri, Mar 6, 3:37PM PDT (-0700 GMT)
Can anyone explain the etymology of the name, "Europa"?

Klem/ASU: . . . . Fri, Mar 6, 3:37PM PDT (-0700 GMT)
John Cody - there are still (and will be) gap (no data coverage) and the north and south poles after GEM. In addition, there are still low resolution (>10 km resolution) regions that will be mostly filled by data ranging from 200 m/pixel -1.5 km/pixel if everything goes according to plan.

Doug Inwood CAS Obs Director: . . . . Fri, Mar 6, 3:38PM PDT (-0700 GMT)
is there anyway of measuring 'ocean currents' on Europa ?

dogeared: . . . . Fri, Mar 6, 3:38PM PDT (-0700 GMT)
Daisuke try alt.conspirator.europa or take less of the funny weed :0(

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:38PM PDT (-0700 GMT)
No evidence that I know of for civilization, whether advanced or not, nor even any evidence for life. What we have are conditions possibly better for life toi form and evolve in than anywhere else in the solar system...

Inquisitor: . . . . Fri, Mar 6, 3:38PM PDT (-0700 GMT)
pia01182 is the image with the light specks in the shadow. Also, any comments on the ridge in image pia01179. I detect some lines in it's border indicating repeated outflows of water/slush at this location.

David V.: . . . . Fri, Mar 6, 3:38PM PDT (-0700 GMT)
dogeared: that was cruel.....but very amusing :)

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 3:39PM PDT (-0700 GMT)
To WOU Student: (non-staff answer) In Greek mythology, Europa was one of the many women Zeus frolicked with. He supposedly appeared to her in the form of a white bull.

Klem/ASU: . . . . Fri, Mar 6, 3:39PM PDT (-0700 GMT)
Diasuke - there is no evidence to support the theory that any life currently or has existed on (or in Europa)...advanced or otherwise.

avmich: . . . . Fri, Mar 6, 3:39PM PDT (-0700 GMT)
if Galileo would remain in good health, does it mean that there's no need to send additional missions to Jupiter - at least, with similar scientific devices?

Shawn B/SwRI: . . . . Fri, Mar 6, 3:39PM PDT (-0700 GMT)
Doug, I believe that gravity data could, in theory, tell us something about any ocean currents that might exist on Europa. We would, however, have to know a LOT more about Europa before we could extract such information.

Gonzalo Rico: . . . . Fri, Mar 6, 3:40PM PDT (-0700 GMT)
ONE MORE. If Galileo Could open its main antena, in percent, how more data would be send?

Ronin: . . . . Fri, Mar 6, 3:40PM PDT (-0700 GMT)
To: WOU Student: to add on more greek mythology, she was brought to Europe by Zeus and thus the continent got its name. Also i believe she was the only mistress that escaped the wrath of Hera, who IMO is the Goddess of Housewives

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:40PM PDT (-0700 GMT)
Inquisitor -- I'll look at these images later...for now, the questions are coming so fast I don't have time to go off-line and find these images...

Daisuke: . . . . Fri, Mar 6, 3:40PM PDT (-0700 GMT)
a simpler question I guess... is there any evidence to suggest an "ocean" as such? because all I've gathered that europa is just a big slushy

WOU student: . . . . Fri, Mar 6, 3:40PM PDT (-0700 GMT)
Fascinating..what that episode refered to as, "the rape of Europa?", in Bulfinch's Mythology?

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 3:40PM PDT (-0700 GMT)
WOU Student - "Europa" is from mythology -- I believe she was Jupiter's lover -- Jupiter courted her in the form of a white bull.

MJ from RI: . . . . Fri, Mar 6, 3:41PM PDT (-0700 GMT)
I was wondering how the imaging team *tweaks* the photos from Galileo. Are the images posted on the web sight adjusted to bring out the contrast of the features, or is this how they would appear to the naked eye if one was hitching a ride on Galileo?

Klem/ASU: . . . . Fri, Mar 6, 3:42PM PDT (-0700 GMT)
WOU student - yes, that is the same Europa.

Doug Inwood CAS Obs Director: . . . . Fri, Mar 6, 3:42PM PDT (-0700 GMT)
correct Carl

anonymous: . . . . Fri, Mar 6, 3:42PM PDT (-0700 GMT)
hi

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:42PM PDT (-0700 GMT)
Gonzalo -- if the antenna opened *now*, we could send little more because the mission is adapted to the current situation. If we had always been able to open the antenna, we could have sent vastly more data (e.g. 100,000 pictures). But we've been carefully selecting the "cream of the crop", so for the satellites (if not for Jupiter, which we once hoped to take movies of), we've got a good fraction of what we ever really needed...

Tim Z: . . . . Fri, Mar 6, 3:42PM PDT (-0700 GMT)
I have to go. Thank you Shawn B and Brent Turcotte for the input! And thank you Clark Chapman for answering my questions last April and on discovery online. keep up the good work JPL, I'm enjoying it! Bye.

Rostik Rusev: . . . . Fri, Mar 6, 3:43PM PDT (-0700 GMT)
I got question to everyone

Klem/ASU: . . . . Fri, Mar 6, 3:43PM PDT (-0700 GMT)
MJ from RI - as someone involved in the image processing, yes, the images are contrast enhanced to bring out detail. If you here hitching a ride on Galileo, wear some really good sunglasses. The darkest spot on Europa is still brighter than our moon.

WOU student: . . . . Fri, Mar 6, 3:44PM PDT (-0700 GMT)
What additional resistance do modern areospace electronics possess beyond what Galileo was outfitted with? How much longer could a Galileo type craft survive in Jovian orbit it was produced today?

Rostik Rusev: . . . . Fri, Mar 6, 3:44PM PDT (-0700 GMT)
Is it true that hey found frozen water on moon?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:44PM PDT (-0700 GMT)
MJ -- The pictures are generally contrast-enhanced somewhat, but not radically so. Most of the pictures aren't too different from what you would see hitching a ride on Galileo.

Herb,Science Coordinator: . . . . Fri, Mar 6, 3:44PM PDT (-0700 GMT)
Marius, Simon 1573-1624 (Aka Mayr) a German astronomer named Europa. In 1614, Marius did provide the names of the Jupiter's moons that we are familiar with today, based on a suggestion from Johannes Kepler: "Jupiter is much blamed by the poets on account of his irregular loves. Three maidens are especially mentioned as having been clandestinely courted by Jupiter with success. Io, daughter of the River, Inachus, Callisto of Lycao, Europa of Agenor. Then there was Ganymede, the handsome son of King Tros, whom Jupiter, having taken the form of an eagle, transported to heaven on his back, as poets fabulously tell . . . . I think, therefore, that I shall not have done amiss if the First is called by me Io, the Second Europa, the Third, on account of its majesty of light, Ganymede, the Fourth Callisto . . . ."

Doug Inwood CAS Obs Director: . . . . Fri, Mar 6, 3:44PM PDT (-0700 GMT)
you've got about 84% of what you wanted .. correct ?

Rostik Rusev: . . . . Fri, Mar 6, 3:45PM PDT (-0700 GMT)
Is it true that they found frozen water on moon?

Crasher: . . . . Fri, Mar 6, 3:45PM PDT (-0700 GMT)
Since the possibility exists of running out of funding before the probe dies, would there be any value at all in ending the mission by crashing onto Europa so that future missions could see how the crash site is affected by Europa's environment?

Gonzalo Rico: . . . . Fri, Mar 6, 3:45PM PDT (-0700 GMT)
Clark: Is that because the compresion of the data?

WOU student: . . . . Fri, Mar 6, 3:45PM PDT (-0700 GMT)
I was refering to radiation,...sorry.

Rostik Rusev: . . . . Fri, Mar 6, 3:45PM PDT (-0700 GMT)
Is it true that they found frozen water on moon?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:45PM PDT (-0700 GMT)
There's a little bit of frozen water at the poles of the Moon, mixed in with the soils (according to Lunar Prospector scientists). But the Jupiter moon we've been discussing is *covered* with water ice...everywhere!

Rostik Rusev: . . . . Fri, Mar 6, 3:45PM PDT (-0700 GMT)
Is it true that they found frozen water on moon?

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 3:45PM PDT (-0700 GMT)
Galileo team, thank you so much for taking the time to mingle with the public, such as I. Especially thank you to Marcia, Tim, and Beau. Keep up the good work, and I will do everything I can to try to get you all the money currently allocated to National Endowment for the Humanities. :-)

Michael Wilson, Navigation Team: . . . . Fri, Mar 6, 3:46PM PDT (-0700 GMT)
Tiago: I haven't heard of that possibility. However unlikely, I would guess it would have include multiple gravity assists on the orbit insertion leg, and include a very large orbit insertion burn (I don't think aerocapture would be entertained given the uncertainty/variability of the Jovian atmosphere).

Eduardo Pulver: . . . . Fri, Mar 6, 3:46PM PDT (-0700 GMT)
Have you already published some book or printed material about Galileo Prime Mission results? and if so how can I have it? (I'm chatting from Argentina)

Rostik Rusev: . . . . Fri, Mar 6, 3:47PM PDT (-0700 GMT)
so there is water on jupiter too

Jim/Proj.Mgmt: . . . . Fri, Mar 6, 3:47PM PDT (-0700 GMT)
WOU student: Modern electronics really haven't advanced significantly in their radiation hardness. What they have done is increase their capabilities (speed, size). The length of time a "modern Galileo" would survive in orbit would still be dependent on how long it spent in the high radiation environment inside of 14 Rj (Jupiter radii).

volcanopele: . . . . Fri, Mar 6, 3:47PM PDT (-0700 GMT)
well I got to go. This has certainly been fun. I have a web site dealing with the moon Io. Maybe some of you can come to it(okay so I am doing a little advertising). It is at the button . You will find info and LOTS of pictures. If some of you don't find an answer, ask me either through the guestbook, my email at the bottom of the index page, or by going to button If some of the Galileo staff have a possible addition for me like info(trust me no need for pictures) I would aprreciate that and I will put it on my page. Thank so much and Bye. Congrats and good luck to all the staff of the GEM!!!

Ronin: . . . . Fri, Mar 6, 3:47PM PDT (-0700 GMT)
Again, before I sign off, I would like to extend my sincerest appreciation and gratitude to the people who volunteered to help out. Thanks for everything and keep up the good work.

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:47PM PDT (-0700 GMT)
Crasher -- if there were a seismometer on Europa to study the Europa-quake generated by the crash, we might learn something from it. But there isn't.

Rostik Rusev: . . . . Fri, Mar 6, 3:48PM PDT (-0700 GMT)
ok thank you very much. i apricciated talking to ya. bye

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 3:48PM PDT (-0700 GMT)
Carl, It's been a pleasure. I'd like to acknowledge some help I've had this afternoon. Gathered in my office were, Gary Hansen of U of Hawaii, Brad Dalton of UC Boulder, and Herb Brenemen of SSI fame. Thanks guys...

Eduardo Pulver: . . . . Fri, Mar 6, 3:48PM PDT (-0700 GMT)
Have you already published some book or printed material about Galileo Prime Mission results? and if so how can I have it? (I'm chatting from Argentina)

Carl Banks, Project Asterius: . . . . Fri, Mar 6, 3:48PM PDT (-0700 GMT)
I also thank you on behalf of Project Asterius (which is my spacecraft design team at Penn State), your information will certainly help us. Bye

Doug Inwood CAS Obs Director: . . . . Fri, Mar 6, 3:49PM PDT (-0700 GMT)
just got an interesting mail from Ron Baalke about Clues To Possible Life On Europa May Lie Buried In Antarctic Ice very interesting

WOU student: . . . . Fri, Mar 6, 3:49PM PDT (-0700 GMT)
Do you know the specific effects radiation has on electronics and what measures are taken to,"radiation harden" them?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:49PM PDT (-0700 GMT)
Eduardo -- the prime mission is barely over. The imaging team is working on a book that might be ready by autumn. Contact the Project (thru the web site) at that time.

Daisuke: . . . . Fri, Mar 6, 3:49PM PDT (-0700 GMT)
from the data that has been gathered, is there actually an "ocean" under the surface? or is it just slush?

volcanopele: . . . . Fri, Mar 6, 3:49PM PDT (-0700 GMT)
sorry Typo. my FAQ page is at button Sorry once again.

Crasher: . . . . Fri, Mar 6, 3:50PM PDT (-0700 GMT)
Clark-- Actually, I understand that nothing would be learned at the time of the crash- but if a few years later we go back and find the crash site mightn't it put forth some more clues from it's state after enduring a few years of the environment?

michaelk: . . . . Fri, Mar 6, 3:50PM PDT (-0700 GMT)
What kinds of discoveries are you hoping to find in future flybys over Io?

Tomas W (Stockholm, Sweden): . . . . Fri, Mar 6, 3:50PM PDT (-0700 GMT)
David V wrote: Michael Wilson and the nav team: thanks a million for your info on the Europa Orbiter planning process!! I agree! Now I'm waiting for the Europa Orbiter home page to take up speed!

Steve L.: . . . . Fri, Mar 6, 3:50PM PDT (-0700 GMT)
Clark Chapman/ SwRI I understand your point with earth orbit satellites but it is going to be a long time before we have anything at Jupiter again. Isn't this a good point to make to extend the mission again

WOU student: . . . . Fri, Mar 6, 3:51PM PDT (-0700 GMT)
What is the Europan core probably composed of? Silicates, or perhaps a hint of Ni/Fe?

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:51PM PDT (-0700 GMT)
Crasher -- I suppose that might be possible. But with the Project management participating in this chat, I don't really want to talk about destroying this remarkable spacecraft we've lived with all these years (actually, decades).

Brent Turcotte.: . . . . Fri, Mar 6, 3:51PM PDT (-0700 GMT)
Trivia bit: from the anti-Jupiter point of Thebe look towards Io. When it totally eclipses the Sun, Io will suddenly blink on. This is at five magnitudes less than full-Io. The corona and Io will likely shine at similiar brightnesses (I will need to calculate this later). This effect is best on Thebe because it is closest to Io, making Io cover about one degree of arc. It is best with Io because Io is very close to Jupiter and Jupiter is quite bright from Io.

Manuel Castillo: . . . . Fri, Mar 6, 3:51PM PDT (-0700 GMT)
Can someone explain something about the Pwyll crater and the consequences that can be extracted?

Inquisitor: . . . . Fri, Mar 6, 3:51PM PDT (-0700 GMT)
Thanks a million to all of you who have put in the long hours at the lab. I live for new information from our space program. Everybody remember to keep your senators and representatives informed as to how important this is to all of us.

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:52PM PDT (-0700 GMT)
Steve -- I think it would be great to extend the mission further, if the spacecraft survives the hazardous environment deep in the radiation belts while studying Io. Write your Congressman!

brent: . . . . Fri, Mar 6, 3:52PM PDT (-0700 GMT)
what exactly is europa?from a 12 year old

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 3:52PM PDT (-0700 GMT)
WOU, NIMS has suffered some radiation effects over the course of the mission. Effectively, one of the symptoms was for our software to stop processing. This caused a loss of NIMS data in the first orbit. But we now "reload" the instrument software many times during an orbit to protect the science. The instrument recovers nicely with no know side effects.

Jim/Proj.Mgmt: . . . . Fri, Mar 6, 3:52PM PDT (-0700 GMT)
Crasher --/Clark Chapman/SwRI: As for crashing Galileo on Europa - I'd really rather do more Io flybys.

Doug Inwood CAS Obs Director: . . . . Fri, Mar 6, 3:52PM PDT (-0700 GMT)
i think it would be much better to park Galileo after the GEM and try monitior it for radiation effects etc ...as was said some time ago

Jim Galasyn: . . . . Fri, Mar 6, 3:53PM PDT (-0700 GMT)
This was a cool forum. Thanks for sponsoring it and thank you for all the amazing work.

Gonzalo Rico: . . . . Fri, Mar 6, 3:53PM PDT (-0700 GMT)
Thanks For the oportunity of chating with you guys, and don't forget to send more probes to space. By

Bill: . . . . Fri, Mar 6, 3:53PM PDT (-0700 GMT)
Thanks for the information. Maybe next time I'll even have a question.

Brent Turcotte.: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
brent: Europa is a moon of Jupiter. It has captured the public's attention because it is believed to have an underground ocean.

Crasher: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
Clark -- Point well taken; I certainly don't look forward to the demise of this stately ship! But if it's a choice between sending it careening off into space never to be seen again, making it an addition to Jupiter's atmosphere, or gaining even one more piece of information from Europa, then wouldn't the extra info be nice? Since one of these things must happen eventually, I'd love to get that last usage before we fare the intrepid Galileo farewell!

David V.: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
why is everyone so obsessed with "crashing" things into Europa??? This isn't the Dukes of Hazzard, or stock-car racing.......Orbiters and landers are way better tools for scientists than "crashers"

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
Any last minute or long unanswered questions?

Steve L.: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
Jim Proj mgmt the longer we can get data the happier i will be

Brent Turcotte.: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
brent: Europa is a moon of Jupiter. It has captured the public's attention because it is believed to have an underground ocean.

Clark Chapman/SwRI: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
Manuel -- The Pwyll crater is about 25 kilometers across and appears to be one of the most recent events to have happened on Europa. It is not a normal bowl-shaped crater. Some people think that it crashed through the ice into the water (the projectile that made it, that is ... probably a comet about a mile across), but we're beginning to think that the ice it struck was at least 10 km thick. Things big enough to make a crater like Pwyll strike Europa every couple of million years, so that is most likely to be its approximate age.

Klem/ASU: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
Hi Brent, Europa is a moon that orbits Jupiter. It has an outer layer of water-ice, which might have a liquid-water "ocean" underneath its ice shell.

WOU student: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
Thank you for this opportunity...excelsior!

Brent Turcotte: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
brent: Europa is a moon of Jupiter. It has captured the public's attention because it is believed to have an underground ocean.

Michael Wilson, Navigation Team: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
Crasher: Any consideration of deliberately crashing the probe into a moon of Jupiter would likely not have Europa as a target option (given all of the discussion of the possibility of a liquid ocean and life below the surface).

volcanopele: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
Bye keep up the good work!!!

Scotty: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
Great info coming in, thanks fellas.

Steve L.: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
Jim Proj mgmt the longer we can get data the happier i will be

T Ferdinand: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
Just curious about the general topology of the surface. Earlier images ("the dark shadow knows") display these extremely strange tubular cracks or ridges that in places seem to be disassociated to the surface, overlapping in the same manner that tangle of rope might. Any ideas on how these were formed?

brent: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
what exactly is europa?from a 12 year old

Doug Inwood CAS Obs Director: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
on behalf of everyonr in NZ well done and may the amazing science and images continue

Jim/Proj.Mgmt: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
brent: Europa is one of the four large moons orbiting Jupiter. It's been recently discovered to probably have a surface of ice over either slush or water.

Tiago : . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
To Michael Wilson. Got it. I misunderstood some of what your colleague Tim McElrath had said before.

anonymous: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
Guess I found out about this thing to late, eh?

Brent Turcotte.: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
brent: Europa is a moon of Jupiter. It has captured the public's attention because it is believed to have an underground ocean of water. And because it has an underground ocean it may also have life

Manuel Castillo: . . . . Fri, Mar 6, 3:56PM PDT (-0700 GMT)
Hello?

michaelk: . . . . Fri, Mar 6, 3:57PM PDT (-0700 GMT)
From Galileo's observations, what conclusions have JPL been able to come to about how Europa and Ganymede have evolved? Are there any interesting similarities or differences?

Michael Wilson, Navigation Team: . . . . Fri, Mar 6, 3:57PM PDT (-0700 GMT)
Crasher: Any consideration of deliberately crashing the probe into a moon of Jupiter would likely not have Europa as a target option (given all of the discussion of the possibility of a liquid ocean and life below the surface).

volcanopele: . . . . Fri, Mar 6, 3:58PM PDT (-0700 GMT)
Bye keep up the good work!!!

Klem/ASU: . . . . Fri, Mar 6, 3:58PM PDT (-0700 GMT)
anonymous - do you have any quick questions?

David V.: . . . . Fri, Mar 6, 3:59PM PDT (-0700 GMT)
To all on the team, and to everyone else as well, thanks for the chat!!! The mission has been spectacular success against all odds......we all look forward to the Io flybys and the distant Europa Orbiter!

Laura, SPOT: . . . . Fri, Mar 6, 3:59PM PDT (-0700 GMT)
The webchat is coming to an end. Thank you to all of the Galileo volunteers, and to all of the public that participated! It's been fun.

Shawn B/SwRI: . . . . Fri, Mar 6, 3:59PM PDT (-0700 GMT)
Crasher, there's also the issue of smashing the Galileo RTGs onto the surface of another body. IF there are Europans, imagine the ensuing political scandal.

Ronin: . . . . Fri, Mar 6, 3:59PM PDT (-0700 GMT)
THANKS

Doug Inwood CAS Obs Director: . . . . Fri, Mar 6, 4:00PM PDT (-0700 GMT)
thank you to all the personal who took the time to host this chat ...it has been great

brent: . . . . Fri, Mar 6, 4:00PM PDT (-0700 GMT)
How did you come about finding the under-ground ocean?

Klem/ASU: . . . . Fri, Mar 6, 4:00PM PDT (-0700 GMT)
good night gracie

Clark Chapman/SwRI: . . . . Fri, Mar 6, 4:00PM PDT (-0700 GMT)
Gotta go folks...thanks for the great questions and commentaries! Clark Chapman, member Galileo Imaging Team

Steve L.: . . . . Fri, Mar 6, 4:00PM PDT (-0700 GMT)
thank you for the good mission galileo team members. I hope you can chat again soon

Crasher: . . . . Fri, Mar 6, 4:00PM PDT (-0700 GMT)
David V: They certainly are better tools than crater makers, but once they die, they are nothing more than exquisite piles of metal. If crashing a really nice piece of metal gives us some information, isn't that better than flinging it off into the universe?

Perry Frix, Georgia Institute of Technology: . . . . Fri, Mar 6, 4:00PM PDT (-0700 GMT)
Thank you for the opportunity to ask our questions! This has been very informative!

Bill Higgins-- Beam Jockey: . . . . Fri, Mar 6, 4:01PM PDT (-0700 GMT)
Hi, Bill Higgins looking in from Fermilab...

Marcia Segura, Near Infrared Mapping Spectrometer: . . . . Fri, Mar 6, 4:01PM PDT (-0700 GMT)
I am now signing off. Thanks for the kind words and support. It truly means a lot to those of us in the trenches.

Manuel Castillo: . . . . Fri, Mar 6, 4:01PM PDT (-0700 GMT)
Clark. I was working with your images of Pwyll crater in order to extract the topography using shape-from-shading, and the results was qualitative very similar to the released DEM perspective obtained by photogrammetry. The unusual shape was evident by shape-from-shading too.

Steve L.: . . . . Fri, Mar 6, 4:01PM PDT (-0700 GMT)
thanks Marcia

David V.: . . . . Fri, Mar 6, 4:02PM PDT (-0700 GMT)
crasher: i mean, you're right in principle, but there isnt anything near jupiter to observe the impact, and, believe me, the impact will shred Galileo beyond recognition, so that the effects of radiation exposure will be lost...besides, there isnt enough propellant left to do it.......Anyhoo...

Brian P. SPOT Chief: . . . . Fri, Mar 6, 4:02PM PDT (-0700 GMT)
By all. Thanks for all the public interest. Brian Paczkowski, Science Planning and Operations Team Chief.

Mak E: . . . . Fri, Mar 6, 4:02PM PDT (-0700 GMT)
Is the chat still open

Sheffield Steve (UK): . . . . Fri, Mar 6, 4:02PM PDT (-0700 GMT)
Great stuff!! See you all again.....

Jim/Proj.Mgmt: . . . . Fri, Mar 6, 4:02PM PDT (-0700 GMT)
Bill Higgins-- Beam Jockey: Welcome. A voice from SSP.

Brent Turcotte.: . . . . Fri, Mar 6, 4:03PM PDT (-0700 GMT)
Sorry about the repeating messages, I not sure what happened. Thank to everybody for answering my questions. I also feel privilaged to have answered some questions for this forum, even though I am not an expert, just a knowledgable armchair amateur astronomer. I recommend to anybody, if they want to keep a copy of this forum to save a copy directly to hard drive using the Save as command. Just remember to reload all the messages.

Tiago : . . . . Fri, Mar 6, 4:03PM PDT (-0700 GMT)
To Michael Wilson: I'm not much into astronautics because I study aerospace engineering, but I plan to do some sort of study on it when I end the course. Could you please explain why one mentions a 2-3km/s delta-V from JOI to Europa orbit for Europa Orbiter? Does it have something to do with the energy change from an orbit to another? How does this energy vary in general terms?

Frog: . . . . Fri, Mar 6, 4:03PM PDT (-0700 GMT)
To WOU student:In Greek mythology -Europa was daughter of Agenor, king of Tyre.Jupiter fell in love with her and appeared to her as a white bull when she was playing by the seashore. She climbed on its back and he carried her off. The most frequent portrayal of the scene in paintings shows Europa holding on as the bull plunges through the waves! the bull plunging through the waves with Europa holding a horn.

Penultimate word: . . . . Fri, Mar 6, 4:04PM PDT (-0700 GMT)
am i the last thus fouling my handle?

Turbo51: . . . . Fri, Mar 6, 4:04PM PDT (-0700 GMT)
hi, does anyone of you know anything about the lunar prospector web site?

Doug Inwood CAS Obs Director: . . . . Fri, Mar 6, 4:04PM PDT (-0700 GMT)
here's a flyer ........would it be possible to synch the orbit of Europa and Galileo ..and 'land' it ??

Turbo51: . . . . Fri, Mar 6, 4:04PM PDT (-0700 GMT)
hi, does anyone of you know anything about the lunar prospector web site?

David V.: . . . . Fri, Mar 6, 4:04PM PDT (-0700 GMT)
sorry for all the repeated questions.....this chat program takes double clicks too literally :)

Mak E: . . . . Fri, Mar 6, 4:05PM PDT (-0700 GMT)
What is the point of all the extra orbits that won't be as close as earlier ones. Will you be imaging more area or just looking for changes?

Doug Inwood CAS Obs Director: . . . . Fri, Mar 6, 4:05PM PDT (-0700 GMT)
hmm forget that ....nothing of Galileo to sit on

D Dixon: . . . . Fri, Mar 6, 4:05PM PDT (-0700 GMT)
D Dixon, Geologist....My ?? On Earth there is literally no where that parallel lines exist that extend over long distances. What hypotheses do you have to explain these features?

Turbo51: . . . . Fri, Mar 6, 4:05PM PDT (-0700 GMT)
i mean, it's a cool page, but it's realvideo is in 500bps... poor americans like me can never watch that.

Tiago: . . . . Fri, Mar 6, 4:05PM PDT (-0700 GMT)
Turbo51: button

David V.: . . . . Fri, Mar 6, 4:06PM PDT (-0700 GMT)
D Dixon: ever looked at the Appalacian Valley & Ridge??

Steve L.: . . . . Fri, Mar 6, 4:06PM PDT (-0700 GMT)
bye

Gonzalo Rico: . . . . Fri, Mar 6, 4:06PM PDT (-0700 GMT)
button

Tiago: . . . . Fri, Mar 6, 4:07PM PDT (-0700 GMT)
Is everyone from the Galileo Team gone now?

Jim/Proj.Mgmt: . . . . Fri, Mar 6, 4:07PM PDT (-0700 GMT)
Jim E signing off. Thanks for all the questions.

Doug Inwood CAS Obs Director: . . . . Fri, Mar 6, 4:07PM PDT (-0700 GMT)
is it ?

Gonzalo Rico: . . . . Fri, Mar 6, 4:07PM PDT (-0700 GMT)
The last Button Is for Lunar Prospector

Brent Turcotte.: . . . . Fri, Mar 6, 4:07PM PDT (-0700 GMT)
Wow, this forum has been fun. Hope to be around for the next one. Perhaps I will come up with even more ununsual questions 8-)

Doug Inwood CAS Obs Director: . . . . Fri, Mar 6, 4:07PM PDT (-0700 GMT)
thank you Jim for your valuable time

Mark E: . . . . Fri, Mar 6, 4:08PM PDT (-0700 GMT)
Is anybody from Galileo still out there? Pleas be patient I have a 14k modem.

Doug Inwood CAS Obs Director: . . . . Fri, Mar 6, 4:10PM PDT (-0700 GMT)
well i have work to do ...so thank you to any of the ppl left .......next time

Ice wolf: . . . . Fri, Mar 6, 4:11PM PDT (-0700 GMT)
Thanks doug!

Turbo51: . . . . Fri, Mar 6, 4:12PM PDT (-0700 GMT)
br

Bill Higgins-- Beam Jockey: . . . . Fri, Mar 6, 4:12PM PDT (-0700 GMT)
Uh-oh, looks like I missed most of the chat session. I was excited to see the new images of Europa this week, but sorry the press conference wasn't broadcast on NASA TV.

Mark E: . . . . Fri, Mar 6, 4:12PM PDT (-0700 GMT)
Is any one from Galileo still here?

Klem/ASU: . . . . Fri, Mar 6, 4:13PM PDT (-0700 GMT)
Mark - yes.

Klem/ASU: . . . . Fri, Mar 6, 4:14PM PDT (-0700 GMT)
sleep well.

Brent Turcotte: . . . . Fri, Mar 6, 4:14PM PDT (-0700 GMT)
Mark E: Probably not, but I might be able to answer your question. Small probablity.

Doug Inwood CAS Obs Director: . . . . Fri, Mar 6, 4:14PM PDT (-0700 GMT)
What do you do Klem ?

Klem/ASU: . . . . Fri, Mar 6, 4:14PM PDT (-0700 GMT)
Mark - did you have a question?

Mark E: . . . . Fri, Mar 6, 4:14PM PDT (-0700 GMT)
Bill: since your the only one talking interestingly, do you have any idea what can be gained by more orbits at a greater distance?

Michael Wilson, Navigation Team: . . . . Fri, Mar 6, 4:15PM PDT (-0700 GMT)
Tiago: It takes a significant amount of energy change to transfer from an interplanetary trajectory, hyperbolic with respect to Jupiter, to an orbit about Jupiter. Typically that initial orbit about Jupiter will have a very long period and will be highly eccentric. To circularize that orbit to be able to rendezvous with Europa would take another significant energy change. The 2-3 km/s you mentioned is a measure of that energy change required to do the necessary maneuvers.

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