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 intere