Galileo WebChat - July 18, 1996
7PM - 8PM PDT

Seattle: . . . . Thu, Jul 18, 7:00PM PDT (-0700 GMT)
Thanks again to everyone involved with Galileo, especially for your efforts in public outreach. Keep up the good work, and best of luck with the remainder of the mission!

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 7:01PM PDT (-0700 GMT)
Thanks for you interest, Seattle!

scorpion: . . . . Thu, Jul 18, 7:01PM PDT (-0700 GMT)
could there be a similiar type of mission to saturn and it's moons..especially titan?

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 7:02PM PDT (-0700 GMT)
Scorpion: The Cassini mission to Saturn is in the planning stages, and I believe involves an atmospheric probe into Titan. I'm sure there's a web page at JPL with more info.

Jim Kaufman, Galileo Imaging Team, JPL: . . . . Thu, Jul 18, 7:03PM PDT (-0700 GMT)
scorpion: Yes. It's called Cassini. It will launch in Oct. 1997. See button for more info.

Bill Arnett: . . . . Thu, Jul 18, 7:01PM PDT (-0700 GMT)
I guess I misstated my earlier question. I know that there are lots more details visible on the Galileo images. What I'm wondering is if any new bfeatures/b have been seen that weren't there at the time of Voyager.

Geoff Collins, Brown University/Galileo Imaging Team: . . . . Thu, Jul 18, 7:06PM PDT (-0700 GMT)
Bill Arnett: We haven't found any features on Ganymede yet that have been formed since Voyager, but check out the picture of Io that's been released compared to a Voyager picture! New stuff there!

Steve Collins Galileo Backroom (Attitude Control): . . . . Thu, Jul 18, 7:02PM PDT (-0700 GMT)
Cynthia Phillips: Are there portions of the images that fully saturated the detector? In some of the pictures there seem to be rectangular artifacts in the highlights that all trend the same direction. Is this a saturation/compression artifact of some kind?

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 7:05PM PDT (-0700 GMT)
Steve Collins: There were small regions of some of the images that saturated the detector (I think in some of the Ganymede hi-res, and some of the Jupiter atmospheric images). If you examine the images closely, you can see some compression artifacts (mostly in 8x8 pixel squares, I believe).

Gene: . . . . Thu, Jul 18, 7:04PM PDT (-0700 GMT)
Probably been asked before, but, where can I find MORE pictures from Galileo? The web site has only 5 or 6. Thanks!

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 7:06PM PDT (-0700 GMT)
Gene, we are trying to release an image a day, it takes time to get them on the ground and then process them (a week or two lag). PIO will release some images and the rest can be found on the imaging team web page button

Elizabeth Alvarez, GLL Imaging, NOAO: . . . . Thu, Jul 18, 7:06PM PDT (-0700 GMT)
Gene: The imaging team has released 8 images to date. Another one will arrive tomorrow morning. We are aiming to continue releasing one image a day. Watch the pages! button

Matthew Fishburn, Imaging Team, NOAO: . . . . Thu, Jul 18, 7:06PM PDT (-0700 GMT)
Gene: The webpages contain all the images that have been released. More images will be added to the pages as they are released at a rate of about one per business day.

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 7:06PM PDT (-0700 GMT)
Gene: the images are trickling back from Galileo, and we'll be releasing them as fast as we can assemble and process them! I think the plan is for approx. 4-5 images per week. Watch the web sites for the latest.

Don B: . . . . Thu, Jul 18, 7:05PM PDT (-0700 GMT)
Why do the "craters" on Ganymede have such strange rims, bottoms and no rays or ejecta blanckets? Are the small ones really impact craters. If so, why do they difer so much from small craters on other bodies? Thanks

Geoff Collins, Brown University/Galileo Imaging Team: . . . . Thu, Jul 18, 7:08PM PDT (-0700 GMT)
Don B.: You hit the nail on the head! Good question, and there's a lot of us who wish we had an answer. I know I'm still scratching my head about the craters.

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 7:09PM PDT (-0700 GMT)
Don, we're still looking at the Ganymede images trying to answer the very questions you have posed (the lack of ejecta is VERY puzzling).

Eileen Ryan, Imaging Team, NOAO/PSI: . . . . Thu, Jul 18, 7:09PM PDT (-0700 GMT)
Don B. : We're just starting to ponder the physics behind the craters on Ganymede. One reason they look different than normal, bowl-shaped craters is that the surface of Ganymede is mostly ice and not simply rock. The tricky part is that at Ganymede surface temperatures, ice SHOULD be acting like rock. Another morphology difference is the "flat-floors''--- this is due to viscous relaxation of the ice over time. We'll be working on it...

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 7:10PM PDT (-0700 GMT)
Don B: Craters on Ganymede are different from what we're used to from other planets / satellites, because the surface of Ganymede is largely ice instead of rock. Ice has different physical and chemical properties - it acts like rock out in the cold temps. there, but can also flow / relax a lot more easily than rock. So craters on the earth's moon tend to be preserved in a pristine state, while we think those on Ganymede flow and deform.

John Krikawa (JK) jkrikawa@ccit.arizona.edu: . . . . Thu, Jul 18, 7:12PM PDT (-0700 GMT)
On the lack of ejecta: If Ganymede was mostly ice or rock ice, perhaps the heat generated by impact would cause evaporation of the ejecta, to later settled over a very large area. Tangentially, what is the apparent surface gravity of Ganymede?

Gene: . . . . Thu, Jul 18, 7:08PM PDT (-0700 GMT)
Will there be a NASA special publications book published for the Galileo mission the way there was for the Voyager at Jupiter and Saturn? Also, was there ever a NASA book like those for Voyager at Uranus and Neptune?

Steve Collins Galileo Backroom (Attitude Control): . . . . Thu, Jul 18, 7:09PM PDT (-0700 GMT)
Geoff: there is a larger crater in one of the Uruk Sulkus pics that has a dark region right next to it. It looks almost like some of the aeolian (sp?) deposition features you see in Mars pics. Any idea what that might be? I'm guessing its not an atmospheric artifact...

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 7:12PM PDT (-0700 GMT)
Steve Collins: the dark splotch next to the Uruk Sulcus crater could be where the alien spacecraft crashed and burned... :)

Andrew: . . . . Thu, Jul 18, 7:13PM PDT (-0700 GMT)
Steve/Geoff: Regarding the image of the large crater in Uruk Sulkus, it does seem like the image 'punched' through to a viscous liquid underneath the crust and it poured out into the nearby terrain. Seems to be similar to the dark floor of the 'flooded' crater GLL is expected to image on G2. Is this dirty water-ice?

Geoff Collins, Brown University/Galileo Imaging Team: . . . . Thu, Jul 18, 7:14PM PDT (-0700 GMT)
Steve: It's probably ejecta. Either the crater "punched through" the bright ice to a darker layer, or this is a lag deposit of mud that was mixed with the icy ejecta, and the ice has now evaporated. It's strange though, because in Voyager images there are both craters with bright ejecta and dark ejecta. Are they excavating different materials? It's a question some people I know are working hard to answer.

John Krikawa (JK) jkrikawa@ccit.arizona.edu: . . . . Thu, Jul 18, 7:16PM PDT (-0700 GMT)
Steve/Geoff: I see that one, it's P47065.full.jpeg. Beyond the dark spot is the intersection of several fractures/rifts....interesting coincidence? Dinner's cold, gotta go!

Geoff Collins, Brown University/Galileo Imaging Team: . . . . Thu, Jul 18, 7:18PM PDT (-0700 GMT)
A very instructive thing to do in order to get some perspective on the strange appearance of the high-sun Ganymede craters is to look at lunar high-sun pictures. Otherwise normal-looking lunar craters start losing their ejecta and looking like cheerios when the sun is overhead.

Geoff Collins, Brown University/Galileo Imaging Team: . . . . Thu, Jul 18, 7:22PM PDT (-0700 GMT)
Andrew: That's a big question: are the craters flooded by dark material? I haven't really seen any evidence yet that it's not just some impact melting/vaporization phenomenon, but flooding of the craters by dark material (ice-mud slush?) is a possibility and that G2 observation you mentioned of a dark floor crater should help.

Stephen Licata GLL Mission Control Team: . . . . Thu, Jul 18, 7:23PM PDT (-0700 GMT)
Status Report from Galileo Mission Control: As of today at 19:00 PDT, there have been NO, I repeat NO sightings of the Black Monolith, the "Face" or Elvis yet from Jupiter or Ganymede. That is all for now.

Geoff Collins, Brown University/Galileo Imaging Team: . . . . Thu, Jul 18, 7:26PM PDT (-0700 GMT)
Steve Licata: But the Weekly World News this week said Elvis's grave is empty! He has to have gone somewhere! :-)

scorpion: . . . . Thu, Jul 18, 7:23PM PDT (-0700 GMT)
to kelly bender> do to the recent photos of pyramids and the face on mars..do you believe life exists on mars or existed on mars??..

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 7:26PM PDT (-0700 GMT)
scorpion - as there was once liquid water on the surface of Mars, there is the posibility that microbal life may have at one time existed there. The so-called pyramids and face on Mars are (in my opinion) patterns of shadow and poor pixel resolution of normal rock features (not evidence of life).

abrown: . . . . Thu, Jul 18, 7:29PM PDT (-0700 GMT)
Well, if Elvis is out there, why don't you get *him* to fix the antenna? :)

Spacenut: . . . . Thu, Jul 18, 7:11PM PDT (-0700 GMT)
I am a middle school science teacher, and the Galileo homepages have been a gold mine for my teaching! I would like to see some real-time information during the moon encounters. Couldn't someone put up the status every hour or so during the encounters? I think it would be very interesting to my students for us to see what kind of info you scientists are getting that lets you know what's going on with the orbiter and its instruments. The next Ganymede encounter is during the first week of school and I plan to really grab the kids' attention with it. I have used your orbital elements data to program my planetarium program to show Galileo's view as it approaches Ganymede (just a simple sphere in this case). Please help us out with some current updates while the action is happening

Steve Collins Galileo Backroom (Attitude Control): . . . . Thu, Jul 18, 7:17PM PDT (-0700 GMT)
Spacenut: There is a plan to do another online from jupiter session later in the tour. I'm going to see if I can talk folks into opening up a webchat during the next flyby, like we had for JOI, but the encounter happens over a period of several days and it takes a while to get the science data back, in some ways it's not really a real-time activity. I've got an idea: What if we had a "webchat scribe" in the room when the science folks get their first look at some of the pictures?

Elizabeth Alvarez, GLL Imaging Outreach Coordinator, NOAO: . . . . Thu, Jul 18, 7:17PM PDT (-0700 GMT)
Spacenut: Please access the SEPO page button pull up the info. on education and send us your feedback. I think that establishing contact w/ you might be useful for both groups. The main Galileo page does do FREQUENT updates during the encounter and reduces the frequency in between encounters. Did you check out the 'Countdown to Ganymede' section during the last encounter? That will be repeated for subsequent encounters, and I think that's the kind of up to the hour info. you're requesting.

Seattle: . . . . Thu, Jul 18, 7:26PM PDT (-0700 GMT)
Even though the data is not coming down in real time, it's still fun to follow the sequence of events as the encounter progresses. During the recent Ganymede flyby, the JPL Galileo web page feature a computer-generated image showing the view from the spacecraft which was update every five minutes during the preiod of several hours around closest approach. Even though the images were synthetic, it was very exciting to watch the globe of Ganymede getting bigger and bigger, eventually covering distant Jupiter and finally filling the entire field of view as the spacecraft swept by.

Gene: . . . . Thu, Jul 18, 7:13PM PDT (-0700 GMT)
Will there be any picture attempts to get a better handle on Jupiter's ring system?

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 7:13PM PDT (-0700 GMT)
Gene, we will be imaging the rings of Jupiter.

Jim Kaufman, Galileo Imaging Team, JPL: . . . . Thu, Jul 18, 7:17PM PDT (-0700 GMT)
Gene: Yes, we'll be looking at the Jovian rings during the 3rd orbit. Expect to see the images sometime in Dec 1996 to Jan 1997.

scorpion: . . . . Thu, Jul 18, 7:13PM PDT (-0700 GMT)
this is offbeat..but how about a manned mission to mars??

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 7:16PM PDT (-0700 GMT)
Scorpion - Dan Golden (head of NASA) has just such an idea, tentatively slated for a 2018 launch date

abrown: . . . . Thu, Jul 18, 7:18PM PDT (-0700 GMT)
Are they cgoing to post a Voyager Image of IO showing the same region as the Galileo Image, So we can see the effect of the volcanic activity over time? I would really enjoy that. Also, thanks, Stephen, for your detailed answer.

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 7:20PM PDT (-0700 GMT)
abrown: Posting a Voyager image with comparable coverage to the new Galileo image of Io sounds like a fine idea -- i'm sure the web site maintainers are working on it!

Brenda Edins: . . . . Thu, Jul 18, 7:22PM PDT (-0700 GMT)
My eight-year-old would like to know what kinds of gases around Jupiter are also around Ganymede?

Brenda Edins: . . . . Thu, Jul 18, 7:23PM PDT (-0700 GMT)
His name is Jeremy.

Jim Kaufman, Galileo Imaging Team, JPL: . . . . Thu, Jul 18, 7:34PM PDT (-0700 GMT)
Brenda Edins (& Jeremy): Jupiter is made of about 90% hydrogen and 10% helium, with a few extras (like methane and ammonia) thrown in for good measure.

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 7:29PM PDT (-0700 GMT)
Jeremy, I do not know the answer to your question, but Ganymede itself does not have an atmosphere.

Brenda Edins: . . . . Thu, Jul 18, 7:37PM PDT (-0700 GMT)
Thank you everyone for broadening my horizons. And thanks especially to Kelly! You make a young man, who is VERY interested in space, quite happy. I am sure my students will benefit from your web page this fall. Thanks again and happy exploring!

Geoff Collins, Brown University/Galileo Imaging Team: . . . . Thu, Jul 18, 7:24PM PDT (-0700 GMT)
Alright, I'm on the East Coast and I gotta get up early tomorrow. Later, y'all! It's been fun!

Steve Collins Galileo Backroom (Attitude Control): . . . . Thu, Jul 18, 7:25PM PDT (-0700 GMT)
Thanks Geoff

Net Surfer: . . . . Thu, Jul 18, 7:28PM PDT (-0700 GMT)
Hello everyone.

Richard Carroll: . . . . Thu, Jul 18, 7:29PM PDT (-0700 GMT)
About ballooning being tougher in high gravity: it seems to me the balloon might weigh twice as much, but the atmosphere it displaces weighs twice as much, too. So gravity is irrelevant! Of course, GEtTING there might be harder.

Steve Hauck, Wash. U., St. Louis: . . . . Thu, Jul 18, 7:30PM PDT (-0700 GMT)
A Nav. question if anyone can (or already has answered it)... For an Europa extended mission, how much delta V (rel. to Jupiter) would be required to place Galileo in orbit? Secondly, what percentage of the propellant available at the end of the primary mission might this take? Thanks.

Matthew Fishburn, Imaging Team, NOAO: . . . . Thu, Jul 18, 7:38PM PDT (-0700 GMT)
Steve Hauck: The extended mission to Europa would not be to put Galileo in orbit around Europa but just to keep encountering Europa as we orbit Jupiter. The last planned orbit in the nominal mission takes us past Europa and thus we can keep encountering Europa for many more orbits without using very much fuel.

Steve Hauck, Wash. U., St. Louis: . . . . Thu, Jul 18, 7:41PM PDT (-0700 GMT)
Matthew Fishburn: Thanks for the answer.

Peter Hylen - Stockholm - pethyl@saaf.se: . . . . Thu, Jul 18, 7:30PM PDT (-0700 GMT)
Bye, bye - thanks from Sweden, it's bedtime (4:30 a.m.) Seeya!

scorpion: . . . . Thu, Jul 18, 7:31PM PDT (-0700 GMT)
kelly thanks for your answer to that question... just one more here..due to the failure of the mars geological orbiter mission a few years ago. will there be a replacement mission and when??..

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 7:32PM PDT (-0700 GMT)
scorpion - there is a replacement (actually two spacecraft will replace the defunct Mars Observer) it is called Mars Global Surveyor and the first one will be launched in early November this year (on the 6th I believe)

Net Surfer: . . . . Thu, Jul 18, 7:31PM PDT (-0700 GMT)
Kelly Bender: Can you send me any images e-mail?

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 7:33PM PDT (-0700 GMT)
Net surfer: you can get all the images that have been released so far from the imaging team's page at button

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 7:33PM PDT (-0700 GMT)
Net Surfer - go to the imaging team web page button to get our images

Net Surfer: . . . . Thu, Jul 18, 7:34PM PDT (-0700 GMT)
Kelly bender: Thanks

Ted Stryk: . . . . Thu, Jul 18, 7:31PM PDT (-0700 GMT)
How far does the historical data of photometric and photographic data on Io that could show change go back (i.e. to Voyager, to Pioneer, ect.)

Jim Kaufman, Galileo Imaging Team, JPL: . . . . Thu, Jul 18, 7:36PM PDT (-0700 GMT)
Ted Stryk: The Voyager missions visited Jupiter in 1979. I haven't heard of any Pioneer images of Io (but that may ignorance on my part). All of the planning maps we use for designing the observations were made from Voyager data.

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 7:40PM PDT (-0700 GMT)
Ted Stryk: I looked up Pioneer, and it looks like though Pioneer 10 flew through the Jovian system in 1973, it was mostly intended as proof that a spacecraft could make it out there. It did some fields and particles experiments, but I don't think it did any imaging of the satellites. It did provide more precise masses for the Galilean satellites.

Ted Stryk: . . . . Thu, Jul 18, 7:41PM PDT (-0700 GMT)
I was referring more to groundbased historical data on Io. I just used the spacecraft names (Voyager, Pioneer (Pioneer 11 returned the only Io image, which just showed albedo features)) for a time frame.

Steve Collins Galileo Backroom (Attitude Control): . . . . Thu, Jul 18, 7:36PM PDT (-0700 GMT)
Well, folks, there's a pizza out there with my name on it... Aloha

Jim Kaufman, Galileo Imaging Team, JPL: . . . . Thu, Jul 18, 7:37PM PDT (-0700 GMT)
Steve Collins Galileo Backroom (Attitude Control): Ummmmm.... pizza!

Gregory LaBorde - Galileo Testbed and Systems Engineer: . . . . Thu, Jul 18, 7:39PM PDT (-0700 GMT)
All units, converge on Steve's cubicle. For those of you who may be wondering, Steve looks EXACTLY like Dilbert's "friend" Wally.

scorpion: . . . . Thu, Jul 18, 7:36PM PDT (-0700 GMT)
will there be an unmanned landing mission to mars similiar to the viking missions to search for microbiotic life?.

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 7:39PM PDT (-0700 GMT)
scorpion - there will be several landers sent to Mars in the next decade Pathfinder will be launched later this year (early December) with its airbag landing system and rover. Other landers will be launched in following years. All trips to Mars will look for evidence of extinct or extant life

Bill Arnett: . . . . Thu, Jul 18, 7:37PM PDT (-0700 GMT)
Since Galileo has detected evidence of magnetic fields on Ganymede and Io what is the betting that Callisto might have one, too? Are any special observations of Callisto's magnetic environment planned that weren't planned before? Generally, how much do Galileo's plans change based on the data already received?

Jim Kaufman, Galileo Imaging Team, JPL: . . . . Thu, Jul 18, 7:42PM PDT (-0700 GMT)
Bill Arnett: I believe that the magentometer folks would not be suprised to find a magnetic field at Callisto. Kelly: You are the resident Callisto expert. Any other opinions? As for changing planned observations.... it is very unlikely that major changes to the observations will be done to accomodate new "discoveries". Because of the tape recorder problems, designing the observational sequences has become a VERY time consuming operation. For the most part, the observations were already designed before the tape recorder failed (Oct. 1995). Now we are modifying these plans to accomodate the limping tape recorder. There will be small changes made to the pointing of some observations, but these are just small tweaks.

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 7:47PM PDT (-0700 GMT)
Bill and Jim, I believe that the mag team is doing the same types of observations at all the satellite (so the observation at Ganymede that 'noticed' the possible magnetic field is likely already scheduled for Callisto). Callisto has the lowest density of the four moon - only 2 gm/cm3, meaning it is icier than Ganymede. It may not even have a differentiated interior - which probably is necessary for a magnetic field. I would be VERY surprised if Callisto does have a magnetic field.

Net Surfer: . . . . Thu, Jul 18, 7:39PM PDT (-0700 GMT)
Kelly Bender: What do you think was the best accomplishment of the Galileo?

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 7:41PM PDT (-0700 GMT)
Net Surfer - everything the mission has done so far is wonderful - finding the moon of the asteroid Ida was a real surprise. I think Galileo is going to be a lot like Voyager - a real WOW mission with lots of great new surprises

Gregory LaBorde - Galileo Testbed and Systems Engineer: . . . . Thu, Jul 18, 7:40PM PDT (-0700 GMT)
Galileo rocked the boat. He lit and kept lit the fire of scientific inquiry and refused to be stifled by the repressive institutions of his day.

Gary Williams: . . . . Thu, Jul 18, 7:41PM PDT (-0700 GMT)
I'm a grad student at the Air Force Institute of Technology developing a virtual solar system modeler which includes Galileo. I would like to validate Galileo's orbit propagation against NASA derived positions for a few test cases. Either Jupiter centered or heliocentric coordinates would be ok. The virutal environment is excellent, but I would like to ensure the accuracy is acceptable as well. I'm using the orbital elements posted on your web site. Is there anyone there who would be willing to help me out? Thanks!

Jim Kaufman, Galileo Imaging Team, JPL: . . . . Thu, Jul 18, 7:47PM PDT (-0700 GMT)
Gary Williams: Contact Lou D'Amario. (818-354-3209) He is the Navigation Team Chief.

Gary Williams: . . . . Thu, Jul 18, 7:53PM PDT (-0700 GMT)
Jim - Thanks for the information. I think it's great you're hosting this chat session. Keep up the great work :)

Jim Kaufman, Galileo Imaging Team, JPL: . . . . Thu, Jul 18, 7:56PM PDT (-0700 GMT)
Gary Williams: You are very welcome.

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 7:54PM PDT (-0700 GMT)
Jim, are you the host!?!

im Kaufman, Galileo Imaging Team, JPL: . . . . Thu, Jul 18, 7:57PM PDT (-0700 GMT)
Kelly Bender, Galileo Imaging Team, ASU: Host?!? Me? No.

Gary Williams: . . . . Thu, Jul 18, 7:57PM PDT (-0700 GMT)
Cynthia - I just joined. My thanks to Jim were meant for the entire NASA team online tonight. BTW, I noticed you're with the imaging team. Do you folks have any new shots of any of the Jovial moons might be used for a texture map on a sperical model of the moon?

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 8:01PM PDT (-0700 GMT)
Gary Williams: there are plans to use Galileo images to fill in the gaps in the global Voyager coverage of the satellites, so by the end of the mission we should have images of the complete surfaces of the satellites (or at least most of them). These images could then be made into texture maps.

Gary Williams: . . . . Thu, Jul 18, 8:02PM PDT (-0700 GMT)
Thanks Cynthia. Keep up the great work!

Kevin Shand: . . . . Thu, Jul 18, 7:41PM PDT (-0700 GMT)
Are any ideas formulated to explain the unexpected phenomena which was observed inside Jupiter? What will be done next in the mission?

Sky Bauman: . . . . Thu, Jul 18, 7:43PM PDT (-0700 GMT)
I noticed that Io, in the released image by Galileo, has two small bumps on its edge, similar to the first volcano plumes discovered by Voyager. Do you think the bumps in the Galileo picture are active volcanos, and if so, could these be the same volcanos Voyager discovered?

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 7:48PM PDT (-0700 GMT)
Sky Bauman: if you play with the contrast on the newly-released io color image, you can see at least one bright linear feature sticking over the terminator (the day/ night line). We've done some calculations, and think it might be a ridge sticking up above the dark side, which could be as high as 3 km!

Ted Stryk: . . . . Thu, Jul 18, 7:46PM PDT (-0700 GMT)
Has Galileo been occulted by Io, or will it be?

Matthew Fishburn, Imaging Team, NOAO: . . . . Thu, Jul 18, 7:54PM PDT (-0700 GMT)
Ted Stryk: The only time Galileo might have been occulted by Io would have been during the Io flyby as Galileo first was approaching Jupiter and I don't believe it was.

Net Surfer: . . . . Thu, Jul 18, 7:49PM PDT (-0700 GMT)
Well......I have to go. BYE!!!

abrown: . . . . Thu, Jul 18, 7:51PM PDT (-0700 GMT)
It's been a very interesting discussion. Thanks, and good luck on the rest of the mission!

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 7:52PM PDT (-0700 GMT)
Net Surfer, abrown: thanks for stopping by!

Nicholas : . . . . Thu, Jul 18, 7:52PM PDT (-0700 GMT)
Has there been any estimates as to how mountanous Io is?

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 7:54PM PDT (-0700 GMT)
Nicholas: from Voyager data, we know that the tallest mountains on Io are over 9 km high.

Ted Stryk: . . . . Thu, Jul 18, 7:52PM PDT (-0700 GMT)
Will pages similar to the ganymede page be made for the other moons?

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 7:56PM PDT (-0700 GMT)
Ted Stryk: right now, most of the data we have is Ganymede data (the first orbit was called G1 (Ganymede 1), after all...). As soon as we have lots of data for the other satellites, I'm sure that web pages will be made for them. Keep checking the sepo page for details! button

Matthew Fishburn, Imaging Team, NOAO: . . . . Thu, Jul 18, 7:58PM PDT (-0700 GMT)
Ted Stryk: Similar web pages to the ones up now for Ganymede will be added for the other large moons as we get more data and images on these moons.

Bill Arnett: . . . . Thu, Jul 18, 7:53PM PDT (-0700 GMT)
Is it possible to use a gravity assist to kick Galileo out of Jupiter's equatorial plane so as to get images and fields data of its polar regions? Would this be a worthwhile extended mission?

Jim Kaufman, Galileo Imaging Team, JPL: . . . . Thu, Jul 18, 7:55PM PDT (-0700 GMT)
Bill Arnett: I don't know how much propellant will be left by the end of the nominal mission and whether that will be enough to accomplish the job. With some gravitational assists it may be possible, but I think it would take a long time. I think it would certainly be interesting, however.

Ted Stryk: . . . . Thu, Jul 18, 7:55PM PDT (-0700 GMT)
Was any dust data obtained during the Io encounter?

Gregory LaBorde - Galileo Testbed and Systems Engineer: . . . . Thu, Jul 18, 7:58PM PDT (-0700 GMT)
I believe the dust detector count at the Io flyby on Dec 7 was _enormous._ Check on the project homepage for more information.

Nicholas : . . . . Thu, Jul 18, 7:56PM PDT (-0700 GMT)
Does Io have the most mountanous terrain of the 4 largest moons, or does it's continuous re-surfacing keep things relatively flat?

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 7:58PM PDT (-0700 GMT)
Nicholas - I believe that Io does have the greatest range of topography of the four satellites. Volcanic activity builds topography as much as it smooths out the lows. The flatest moon is Europa.

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 7:58PM PDT (-0700 GMT)
Nicholas: Io does indeed have the highest mountains of any of the Galilean satellites. The fact that it is currently volcanically active means that new topography is continually being created.

Oliver: . . . . Thu, Jul 18, 7:56PM PDT (-0700 GMT)
Hi and Congrats to evetyone involved. I have a question re: the radiation environment. Are the levels on the Galilean satellites compatible with manned exploration ?

Joe C.: . . . . Thu, Jul 18, 7:57PM PDT (-0700 GMT)
I've only been on the internet for a week, but some of these space related sites are fantastic. Keep up the great work and keep us informed!

John Hurley: . . . . Thu, Jul 18, 7:58PM PDT (-0700 GMT)
Great work everyone, keep it up we are all behind you!

Jim Hill: . . . . Thu, Jul 18, 7:58PM PDT (-0700 GMT)
Just listening from Washington State.....

Jim Kaufman, Galileo Imaging Team, JPL: . . . . Thu, Jul 18, 7:59PM PDT (-0700 GMT)
Well gang....... my fingers are now just bleeding stumps. I'm going to sign off now. This was my first experience at "chatting" and it was actually quite fun! Adios!

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 8:00PM PDT (-0700 GMT)
Bye Jim, I , too, have got to run. No dinner yet and the husband needs help getting the little ones to bed. Thanks for you help. This was fun!

Ted Stryk: . . . . Thu, Jul 18, 8:00PM PDT (-0700 GMT)
Thanks to all the Galileo people for your exellent answers! I really appreciate it. Keep up the good work!

anonymous: . . . . Thu, Jul 18, 8:02PM PDT (-0700 GMT)
I guess this is about over and also wanted to thank you not only for your work but for your willingness to come online to talk about it.

Ted Stryk: . . . . Thu, Jul 18, 7:59PM PDT (-0700 GMT)
Has the ultraviolet data from the Io encounter been anylized (didn't the extreme UV instrument obtain data?)

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 8:02PM PDT (-0700 GMT)
I guess this chat is "officially" over soon...any last imaging questions?

Ted Stryk: . . . . Thu, Jul 18, 8:02PM PDT (-0700 GMT)
If anyone is still there, one last quick question: Will there be any images of any of the satellites outside the galileans?

Kelly Bender, Galileo Imaging Team, ASU: . . . . Thu, Jul 18, 8:03PM PDT (-0700 GMT)
Ted, my final input for tonight. We will be imaging Metis, Thebe, Andrasta and Almathea (and maybe Lysithea but I don't really remember)

Ted Stryk: . . . . Thu, Jul 18, 8:04PM PDT (-0700 GMT)
Kelly Bender: Thanks so much for answering my question late.

John Hurley: . . . . Thu, Jul 18, 8:04PM PDT (-0700 GMT)
How about plans for close up shots of the rings?

Matthew Fishburn, Imaging Team, NOAO: . . . . Thu, Jul 18, 8:03PM PDT (-0700 GMT)
Ted Stryk: Yes, a few of the smaller moons (and the rings) will be imaged but not in as much detail as the large moons.

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 8:06PM PDT (-0700 GMT)
John Hurley: The rings will be imaged on a later orbit (don't remember which, offhand...)

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 8:03PM PDT (-0700 GMT)
Everyone: thanks for the encouragement! Keep checking out our web sites -- they'll have the latest info.

Mike: . . . . Thu, Jul 18, 8:03PM PDT (-0700 GMT)
The Galileo page even has my mom interested in astronomy. Thanks!

Nicholas : . . . . Thu, Jul 18, 8:02PM PDT (-0700 GMT)
What about Europa's surface whipe's out it's craters?

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 8:05PM PDT (-0700 GMT)
Nicholas: Europa seems to have a young, very icy surface which just flows and removes traces of most craters. We should be getting hi-res Europa data very soon which will give us a great place to look for small craters that Voyager might have missed.

Jim Hill: . . . . Thu, Jul 18, 8:04PM PDT (-0700 GMT)
Thanks for letting me "listen" in I learnded a lot. I am going to save this session for further reference.....Thanks again.

Marc: . . . . Thu, Jul 18, 8:03PM PDT (-0700 GMT)
If there are still non-galileo folks out there, I'd appreciate a quick listing of where you learned about this WebChat. Thanks

anonymous: . . . . Thu, Jul 18, 8:05PM PDT (-0700 GMT)
I learned about the webchat from the Galileo homepage

Ted Stryk: . . . . Thu, Jul 18, 8:05PM PDT (-0700 GMT)
Matthew Fishburn: thanks to you also Marc: I learned about it from the Galileo Home Page

Nicholas : . . . . Thu, Jul 18, 8:06PM PDT (-0700 GMT)
Marc... I saw a posting on Usenet about this event.

Jim Hill: . . . . Thu, Jul 18, 8:07PM PDT (-0700 GMT)
I learned about this chat from updates-jup@quest.arc.nasa.gov

John Hurley: . . . . Thu, Jul 18, 8:07PM PDT (-0700 GMT)
I learned about it from a posting from the Astro mailing list.

Marc: . . . . Thu, Jul 18, 8:08PM PDT (-0700 GMT)
Thanks for the feedback about where you learned about this WebChat

anonymous: . . . . Thu, Jul 18, 8:07PM PDT (-0700 GMT)
if anyone is still there... what is the closest to any of the moons that the probe will get??

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 8:08PM PDT (-0700 GMT)
anonymous: I'm afraid I don't know offhand...I'd guess on the order of hundreds of kilometers?

Ron Baalke, Galileo Outreach, JPL: . . . . Thu, Jul 18, 8:09PM PDT (-0700 GMT)
I'm letting the Galileo WebChat session run over to 8:15PM, so if you have any more questions, ask them now. This entire Chat session will be archived on the Galileo home page.

Ted Stryk: . . . . Thu, Jul 18, 8:09PM PDT (-0700 GMT)
Marc: Exellent job with Online from Jupiter

John Hurley: . . . . Thu, Jul 18, 8:09PM PDT (-0700 GMT)
Thanks Cynthia, I will keep checking the web pages for the orbit.

anonymous: . . . . Thu, Jul 18, 8:09PM PDT (-0700 GMT)
ok thanks..cynthia

Nicholas : . . . . Thu, Jul 18, 8:08PM PDT (-0700 GMT)
How 'quickly' does Europa tend to remove it's 'average' crater? Thousands of years? Millions of years?

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 8:09PM PDT (-0700 GMT)
Nicholas: it's hard to put any sort of absolute timescale to the features on Europa, since we have no frame of reference. We can say that the surface appears "young" because there are very few craters, but exactly how young is another story. Hopefully, if we get better data on the distribution of small craters from the hi-res europa data, we'll be able to answer that a bit more precisely....

Trevor Abbott: . . . . Thu, Jul 18, 8:09PM PDT (-0700 GMT)
A question from Melbourne, Australia: Have the pictures of Europa been received yet and if so do these also shown it as craterless as the voyager shots did.

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 8:11PM PDT (-0700 GMT)
Trevor Abbott: We haven't gotten back the new pictures of Europa yet (at least, I haven't seen them!), but we shoudl get them in a matter of weeks or less. The Voyager coverage showed on the order of 5 craters on teh surface of Europa...we're hoping that the hires galileo data will reveal some small craters that voyager missed.

Ted Stryk: . . . . Thu, Jul 18, 8:11PM PDT (-0700 GMT)
Are Galileo color images tri-color, or does it use more/fewer filters?

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 8:13PM PDT (-0700 GMT)
Ted Stryk: Galileo has six filters on the camera - violet, green, red, and approx. .75 microns, .9 microns, and 1 micron.

Ted Stryk: . . . . Thu, Jul 18, 8:13PM PDT (-0700 GMT)
In the typical color images, how many filters are used?

Cynthia Phillips, Imaging team (LPL/ U. Arizona): . . . . Thu, Jul 18, 8:14PM PDT (-0700 GMT)
Ted: the color images that go out to the public are usually combinatinos of violet, green, and either red or one of the near-IR filters. This makes a semi-realistic image.

Ted Stryk: . . . . Thu, Jul 18, 8:15PM PDT (-0700 GMT)
Cythia: Thanks so much for answering my late questions. Another thanks to Jeff Kaufman and everyone else on the Galileo project. Goodnight.

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Galileo WebChat - July 18, 1996 7PM - 8PM PDT

Galileo WebChat - July 18, 1996
7PM - 8PM PDT