Galileo WebChat - October 30, 1996
4:00 PM - 7:00 PM PST

Rebecca Westbrook, Outreach: . . . . Wed, Oct 30, 3:47PM PDT (-0700 GMT)
Test.

Rebecca Westbrook, Outreach: . . . . Wed, Oct 30, 3:48PM PDT (-0700 GMT)
Welcome back to the Galileo Webchat. I've turned this on a little early in order to make sure everything is working ok.

Bruce McL: . . . . Wed, Oct 30, 3:57PM PDT (-0700 GMT)
Hello, just joining (early) for my first chat ever.

Rebecca Westbrook, Outreach: . . . . Wed, Oct 30, 3:59PM PDT (-0700 GMT)
Hi, Bruce. I think we'll need to wait a few minutes for the Galileo team members to join, but I think they'll introduce themselves when they do.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:00PM PDT (-0700 GMT)
Hi Bruce, good to see another SIE here.

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 4:00PM PDT (-0700 GMT)
And updating my handle for more proper visibility/identification.

Steven Tyler, Galileo Alum: . . . . Wed, Oct 30, 4:00PM PDT (-0700 GMT)
Logging on

anonymous: . . . . Wed, Oct 30, 4:00PM PDT (-0700 GMT)
hello! i'm franco from italy. Could i know if galileo will visit IO after the 11 orbit tour,to take detailed images of its volcanic surface?

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:02PM PDT (-0700 GMT)
Hi, I'm Jon from Melbourne (you guessed that from my handle eh?). Congratulations on a fantastic project. Thanks also to you lovely US tax payers. Any one of you guys happy to answer a physics question?

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:03PM PDT (-0700 GMT)
Franco: There are plans for additional orbits around Europa. I believe Io at the end. This of course is dependent on congressional funding.

Geoff: . . . . Wed, Oct 30, 4:03PM PDT (-0700 GMT)
Hello everyone and congrats. You have done a great job at Jupiter. How is the propellant margin going? enough for an extended mission?

anonymous: . . . . Wed, Oct 30, 4:03PM PDT (-0700 GMT)
I wanted to say congratulations for getting data that already surpasses Voyager. I find Jupiter to be a fascinating place now more than ever. I was wondering if the spots on the northern hemisphere of Europa that doesn't have the cracks are the craters that scientists have been talking about.

Joe Bauman: . . . . Wed, Oct 30, 4:04PM PDT (-0700 GMT)
Hi -- As the science writer for a Salt Lake City newspaper, I have been waiting with great anticipation to photos from the close fly-by of Ganymede. Although that moon was buzzed on Sept. 6, nothing showed up on the Internet for well over a month. When something did appear, recently, it was extremely limited -- nothing like the wealth of photos I imagine everyone expected. My questions are: 1) Was something amazing discovered that the scientists are not ready to release? 2) If not, why did so many wait so long for so little? Thank you, Joe Bauman

david: hello

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:04PM PDT (-0700 GMT)
Jon, I'll give the physics questions a try. I won't gurantee that I can answer all your questions.

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 4:04PM PDT (-0700 GMT)
In the proposed Galileo Extended Mission (GEM) Galileo would visit Europa 8 times, Calisto twice, and then IO (twice if it survives.)

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 4:04PM PDT (-0700 GMT)
Welcome, Franco: Yes, after the main tour, we would like to do an extended mission (GEM = Galileo Europa Mission) if we can get the money. That would give us several more Europa encounters, some Callisto flybys, and at least one more Io close pass. More than that and the high radiation is expected to fry our electronics.

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:05PM PDT (-0700 GMT)
Here's the question (I've been pondering on it since doing my honours degree in Physics a few years back)... It may seem silly but I like it... If the 'space' between Earth and our Sun was air not a vacuum, would we be able to hear the Sun? If so, how loud? Wisper or H-Bomb nearby?

A.P.: . . . . Wed, Oct 30, 4:05PM PDT (-0700 GMT)
I was wondering if scientists have determined if Ganymede does have its own magnetic field.

Joe Bauman: . . . . Wed, Oct 30, 4:05PM PDT (-0700 GMT)
PS: I meant I was anticipating THE photos, not To photos. Sorry. -- Joe Bauman

Steve: . . . . Wed, Oct 30, 4:06PM PDT (-0700 GMT)
Will the Cassini spacecraft do any of the tasks Galileo can no longer perform (e.g., Jupiter rotation movies), and will Cassini do any close flybys of any of the Galilean satellites during its jupiter flyby?

Bob Barry, Engineer - Anomaly Response Team: . . . . Wed, Oct 30, 4:06PM PDT (-0700 GMT)
Hi, Bob Barry here online...

Geoff: . . . . Wed, Oct 30, 4:07PM PDT (-0700 GMT)
I'm amazed at what you have done. Is there going to be any more activity on the Live from Galileo area? That was a great help in keeping the people entertained at the observatory.

Steven Tyler, Galileo Alum: . . . . Wed, Oct 30, 4:07PM PDT (-0700 GMT)
anonymous...there is a proposal (as yet unfunded) to do that in 1999. The idea is to have eight Europa passes after the end of the main mission. These would be from December 1997 through January 1999. Then we'd use 4 Callisto passes for the perijove reduction campaign (May 1999 through September 1999) Finally, we'd have an Io encounter in October of 1999 (orbit 24!). If our craft is still alive after that, we would have one or more additional Io passes. These passes would all be at around 500 km closest approach to Io...we'd get great resolution.

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:07PM PDT (-0700 GMT)
I do like this time difference, it's 11am on the 31st here. Nice and sunny too.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 4:07PM PDT (-0700 GMT)
Joe, with the low gain antenna mission, the images are recorded during the encounter period of about 7 days (the buzz) and then played back during the about 1 month long cruise period often delaying images by about a month

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:08PM PDT (-0700 GMT)
Jon: Hmm....it is a bit odd. To have sound propogate, you need longitudinal pressure waves. So the question really is wheter the sun is capable of generating such waves, if there were air between the sun and the earth.

Andre': . . . . Wed, Oct 30, 4:08PM PDT (-0700 GMT)
I want to say that you all have done an excellent job of returing images and data that exceeds Voyager. I was wondering if scientists have determined if Ganymede has its own magnetic field

Lou D'Amario, Galileo Navigation: . . . . Wed, Oct 30, 4:09PM PDT (-0700 GMT)
Signing on.

Jim Erickson, Science & Sequence Office: . . . . Wed, Oct 30, 4:09PM PDT (-0700 GMT)
Hi, checking in.

franco mallia: . . . . Wed, Oct 30, 4:09PM PDT (-0700 GMT)
are there plans for additional orbits around europa or close flyby of it? first images by galileo ganimede 1 and 2 are marvelous, there will be great discoveries in the next future! many congratulations!

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 4:10PM PDT (-0700 GMT)
Steve: Right now Cassini has no plans for Jovian observations. However, since it flys by Venus twice and then Earth before it uses Jupiter to slingshot it on to Saturn, there is time to consider adding science at Jupiter.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:10PM PDT (-0700 GMT)
Jon: Melbourne, Oz: Now the "Solar Wind" is an entirely different pheonmina, having to do with charged particles (mainly protons) and magnetic fields that flow from the sun.

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 4:10PM PDT (-0700 GMT)
Hi Joe Bauman: So far we have done two flybys of Ganymede, late June and early Sept. Many pictures were released from the first flyby, but after the second many of the scientists were very busy getting ready for the science conferences, so spending the time to prepare things for instant release was difficult. Unfortunately, with our limited data transmission rates, a "wealth" of photos is never likely to happen (though each one is a great treasure! ;-)

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:10PM PDT (-0700 GMT)
Leo: Maybe you should be in politics? But seriously, I assumed such a huge nuclear reaction would be producing a fair number of such waves :-)

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 4:12PM PDT (-0700 GMT)
Short who am I I develop the flight software for the control and data subsystem CDS. This is the computer to which most of the changes for the low gain mission were made. At JPL for last 17 years Most on Galileo, but some on Magellan and Craf/Cassini

Lou D'Amario, Galileo Navigation: . . . . Wed, Oct 30, 4:12PM PDT (-0700 GMT)
franco: There are 8 remaining close satellite encounters in the baseline tour. Three of them are with Europa: E4 (altiitude = 697 km), E6 (580 km), and E11 (1125 km). There will be many close-up pictures of Europa.

Joe Bauman: . . . . Wed, Oct 30, 4:12PM PDT (-0700 GMT)
Thank you for your reply. Still, I am concerned that so little has been posted and it's nearly two months since the start of the encounter. Are people holding back on any images? And when can we expect to see many more, including both sides of stereo photos? PS: please know that all of us are extremely proud of NASA and think you've done a fabulous job! I don't mean to sound critical, but I am curious. Thanks again, Joe Bauman

Teddy Morse: . . . . Wed, Oct 30, 4:12PM PDT (-0700 GMT)
Hello my name is Theodore Morse and I am doing a science project on Jupiter I was hoping that you would not mind if I asked you some questions?

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:13PM PDT (-0700 GMT)
Jon: Melbourne, Oz: Politics...I'll have to think about that one. I'm no solar physicist, but I believe the nuclear reactions take place deep inside the sun's core. Also, I don't think they are explosive in nature because it's a sustained fusion reaction.

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 4:14PM PDT (-0700 GMT)
Hi Steve, Cassini will be circling Saturn, not Jupiter, but will probably be able to do many more wonders (at Saturn). My understanding is that the Cassini craft won't be set up for data taking until it gets to Saturn, so any Jupiter science will be very limited (budgets and staffing being what they are).

Dave Bates, Attitude and Articulation Control: . . . . Wed, Oct 30, 4:14PM PDT (-0700 GMT)
Hi, I'm signing on.

Geoff: . . . . Wed, Oct 30, 4:14PM PDT (-0700 GMT)
Can you tell how close Galileo was to its true aimpoint? I seem to remember that you were within 1 mile of the spot on the first flyby, right?

david: is there any hope at all in re covering galileo?

Rocketgirl: . . . . Wed, Oct 30, 4:15PM PDT (-0700 GMT)
Some press people have been complaining that there has been limited info and pictures from the G2 flyby posted on the Galileo Website. Why is this ? Where are the latest pix of Ganymede ?

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 4:15PM PDT (-0700 GMT)
Teddy, Fire away thats why we're here

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 4:15PM PDT (-0700 GMT)
Andre: The concensus is that Ganymede does have its own magnetic field. Because of its strength, it is probably caused by a dynamo effect of some kind, either an iron core or some new mechanism. It is also possible that it is caused by remnant magnatism from materials which solidified while Ganymede was in Jupiter's magnetic field.

Steven Tyler, Galileo Alum: . . . . Wed, Oct 30, 4:15PM PDT (-0700 GMT)
Steve - Cassini will indeed fly past Jupiter (if all goes well) on December 30, 2000. But it won't be all that near Jupiter...it will be 10 million km away at closest approach...that's 139 Jovian radii. A closer approach would save fuel, but would get Cassini to Saturn at a later date. This distance is much too large for any close flybys of Jovian satellites...we're pretty much out of the Jovian magnetosphere too.

Franco Mallia: . . . . Wed, Oct 30, 4:16PM PDT (-0700 GMT)
when will callisto 3 and europa4 images be available on the web?

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 4:16PM PDT (-0700 GMT)
Hi Folks, signing in for the second chat o' day

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:16PM PDT (-0700 GMT)
Jon: Melbourne, Oz: There are convective flows comming from the sun's interior that may cause logitudinal pressure disturbances, assumming your conditions. How about some Jupiter or Galileo questions?

JML: . . . . Wed, Oct 30, 4:17PM PDT (-0700 GMT)
What's going to happen to Galileo after it's 11 orbit tour?

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:17PM PDT (-0700 GMT)
Leo: Ok, I remember from my Physics days that a photon takes about 12 million years to reach the surface of the sun, then, whoosh, it's here in 9 minutes. I guess my question will have to remain one of the great unanswered. If any of you guys have a spare few moments with your slide rules, maybe drop me a line at jbrown@edipost.auspost.com.au Congrats again on a great job (some of the people here seem to want me to ask if you've seen Elvis 'out there'). It's hard to get good staff these days!

Lou D'Amario, Galileo Navigation: . . . . Wed, Oct 30, 4:17PM PDT (-0700 GMT)
Geoff: The target altitude for the G1 flyby was 843.8 km. The actual flyby altitude was 835.0 km, a miss of -8.8 km (-5.5 mi).

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 4:17PM PDT (-0700 GMT)
David Not sure what you mean. If you mean return to earth-- no chance -- not enough fuel. If you mean open the high gain antenna, not very likely although it is still being investigated.

Vancouver: . . . . Wed, Oct 30, 4:18PM PDT (-0700 GMT)
Hello Galileo folk! Congratulations on a terrific mission so far! I am amazed at how you have been able to do so much real (and real interesting!) science, from so far away, using such a beleagered (sp?) probe! Checking the Galileo news is part of my daily routine - your net site is much appreciated!

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 4:18PM PDT (-0700 GMT)
Hi. Outreach Manager signing in. I'd love to hear from the Planetarium/Museum types about your needs in talking about Galileo and Jupiter...

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:18PM PDT (-0700 GMT)
Leo, Sorry Jupiter questions coming up...

Nancy Vandermey, SEQ-Systems: . . . . Wed, Oct 30, 4:19PM PDT (-0700 GMT)
Franco: CAllisto-3 closest appraoch is next Monday, playback doesn't start for another week after that (11 Nov), so no images until probably late November. Europa 4 (E4) closest approach is mid-December, and telemetry is really bad in E4, so don't expect many pictures until February or March 97

Steve: . . . . Wed, Oct 30, 4:20PM PDT (-0700 GMT)
Could Cassini's radar experiment directly detect a liquid water ocean under Europa's crust?

david: Tal Brady: what I ment was haveing another space craft go out and pic it up is that posible?

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:21PM PDT (-0700 GMT)
Jon: Melbourne, Oz: Thanks for your support, we need it.

Teddy Morse: . . . . Wed, Oct 30, 4:21PM PDT (-0700 GMT)
Thanks! first Why does jupiter rotate so quickly?

Brent Fox: . . . . Wed, Oct 30, 4:21PM PDT (-0700 GMT)
Hello, How does the configuration of instruments on the Jupiter atmospheric probe and Cassini's Titan probe compare?

Andre': . . . . Wed, Oct 30, 4:21PM PDT (-0700 GMT)
Thanks for the response. What kind of data will Galileo take of Europa. Will it take any mass measurements or images?

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 4:22PM PDT (-0700 GMT)
Joe and Rocketgirl, Some images from G2 are still on the spacecraft, being played back. Many are on the ground being investigated by the imaging team. I'm not on the team, so I don't speak for them but the web and the press releases seem to me to be showing more images than I saw from voyager. We are getting only a few hundred per orbit and many of these are combined into larger ones for release. For instance some of the red spot images are made up of 12 - 24 separately taken images.

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:22PM PDT (-0700 GMT)
All: Have you all been working on the project since day one or did you come to the project new? I assume the excitement must be amazing if you've been working on the job for years. I'm sure I can speak for the whole planet (!) when I say I'm *very* jealous!

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 4:22PM PDT (-0700 GMT)
The Callisto encounter is next week, and we will also get our closest flyby of Io that we can take images of (250,000 km). The images from this encounter will be recorded, and the playback will start on Nov 11. At about one image per day, it will be late November/early December before we get the closest-approach images on the ground, and then they must be processed.

Nancy Vandermey, SEQ-Systems: . . . . Wed, Oct 30, 4:24PM PDT (-0700 GMT)
Jon: I just started at JPL in February, I'm one of the newest Galileo team members.

Franco Mallia: . . . . Wed, Oct 30, 4:24PM PDT (-0700 GMT)
here in italy it's 1.21 a.m. so it's too late, thank you for your answers i hope to chat with you next time, many congratulations for your marvelous job. Goodnight!

Lou D'Amario, Galileo Navigation: . . . . Wed, Oct 30, 4:24PM PDT (-0700 GMT)
Jon: Melbourne, Oz: I've been working on Galileo for 19 years.

Joe Bauman: . . . . Wed, Oct 30, 4:25PM PDT (-0700 GMT)
So far the closeup images of Ganymede itself posted from the G2 encounter total no more than three. I am aware that some views of the Great Red Spot were posted, but that's not what I'm talking about. After all, every mission to Jupiter has photographed the spot, but there's been only one chance to get extreme closeups of Ganymede. Thanks again, Joe Bauman

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:25PM PDT (-0700 GMT)
Nancy: You are *very* lucky (but I guess you know that)! Anyone happy to answer a question about the onboard software?

Jim Erickson, Science & Sequence Office: . . . . Wed, Oct 30, 4:25PM PDT (-0700 GMT)
Jon- I've been on the project for 17 years. Anyone else?

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:25PM PDT (-0700 GMT)
Jon: Melbourne, Oz: I've been on Galileo for 4 years. I always wanted to work at JPL, and after graduate school, I started my search. This was in 1992 when the recession in the US was at it's peak. Anyways, 9 months later, I got in.

Nick@Vancouver, B.C.: . . . . Wed, Oct 30, 4:26PM PDT (-0700 GMT)
How significantly might you be able to raise the bits per second (bps) transmission rate with the new Australian/US array you are testing out? You are at 160 bps right now, I think?

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 4:26PM PDT (-0700 GMT)
david, Not with todays technology. Galileo is large and heavy and jupiter is so far that it takes a hugh amount of fuel to get there and then more to get back. We can't build and launch them that big yet. Also we could only put it in a museum at this point and no one wants to pay for that.

anonymous: . . . . Wed, Oct 30, 4:26PM PDT (-0700 GMT)

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 4:26PM PDT (-0700 GMT)
Andre': all of Galileo's instruments will be looking at Europa, looking for surface properties, topography, composition, the presence of a magnetic field, any atmosphere, and what the interior is made of.

Jane: . . . . Wed, Oct 30, 4:26PM PDT (-0700 GMT)
I'm not a Planetarium/Museum type but I do speak at elementary schools about NASA and space. I check the Galileo homepage regulerly for the latest info but what I really need are hard copies of some of the photos. Are they available?

anonymous: . . . . Wed, Oct 30, 4:26PM PDT (-0700 GMT)
Lou, I work on aircraft and some of them have a hard time finding Ilinois so your five mile miss is great. It must be nice to see your planning come out so close.

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 4:26PM PDT (-0700 GMT)
Hi Joe Bauman. As Bruce McL stated earlier, folks are working as fast and hard as they can to get the pictures and other data out to the public as soon as possible. We, here on NIMS, are still analyzing and processing our data from both orbits. I feel confident that this is true of all other science teams. It is not an effort to hide discoveries found but to provide the public with the best possible information. The results are coming out as quick as possible.

Josh: . . . . Wed, Oct 30, 4:26PM PDT (-0700 GMT)
cool

Dave Bates, Attitude and Articulation Control: . . . . Wed, Oct 30, 4:27PM PDT (-0700 GMT)
Jon- I've been on Galileo for 5 years. When Lou started, I was in second grade.

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 4:27PM PDT (-0700 GMT)
Jon: The Galileo project has been going on since 1979 when it was awarded funding for planning and development. The launch was in October 1989 and I came on board in 1993 after graduating from college. It has truly been exciting!

Jim Erickson, Science & Sequence Office: . . . . Wed, Oct 30, 4:28PM PDT (-0700 GMT)
Nick@Vancouver, B.C. - We have the capability on the spacecraft right now to send the data at 160 bps, but without the array, the most likely max is at 120 bps, for brief periods of time.

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:28PM PDT (-0700 GMT)
Leo: I visited JPL a few years back when I was backpacking around the world. I'm originally from the UK and was *very* excited at reaching Pasadena and the holy grail...JPL. But they said I need an appointment. Doh! I was pretty sad about that. Anyway, I am a s/w engineer and was wondering how you guys/girls ensure that code changes don't crash the system up there. Do you have a core heartbeat piece of code that you never change in flight?

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 4:28PM PDT (-0700 GMT)
Nick the highest rate won't go above 160 at all. We will just be able to use the higher rates more often. We spend a lot of time between 32 and 80 bps now

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 4:28PM PDT (-0700 GMT)
Jon: Melbourne, Oz: It is pretty exciting working on one of these mission. I worked on Galileo starting in 1978, but left and was doing other things for over 12 years. Its good to get back for the fun stuff. I also worked on Viking and Voyager before that.

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 4:28PM PDT (-0700 GMT)
Hey, Josh, got any questions?

Josh: . . . . Wed, Oct 30, 4:28PM PDT (-0700 GMT)
Anyone here on the Cassini Project?

Lou D'Amario, Galileo Navigation: . . . . Wed, Oct 30, 4:28PM PDT (-0700 GMT)
Let's not forget that 2 days after the targeted Callisto 4 flyby next Monday, we have a 34,000 km flyby of Europa, which should provide some good pictures of that intriguing surface.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:29PM PDT (-0700 GMT)
Jane: I speak at elemetary schools too. I know that Galileo Outreach has a postcard of the Great Red Spot that's available.

david:
why doesn't jupeter [sp] have a suurface like earth does?

Steven Tyler, Galileo Alum: . . . . Wed, Oct 30, 4:29PM PDT (-0700 GMT)
Steve, the Cassini radar experiment will help in determining whether or not there are lakes or oceans of methane on Titan. One would suspect that there are such oceans because there's a lot of methane in Titan's atmosphere. That methane would be destroyed by sunlight in 10 million years or less unless it were replenished. This kind of instrument could help detect a liquid surface on Europa. But imaging radar would have a hard time detecting water so far below an icy surface. We've looked at the Arctic and Antarctic and seen water under ice, but only when the water was within meters of the surface.

Rocketgirl: . . . . Wed, Oct 30, 4:30PM PDT (-0700 GMT)
Tal, I was visiting JPL during the Jupiter encounter in 1979 and I can tell you that we were swamped with images then !! Way more than Galileo. We got a new picture every few minutes. That's why it seems like things are now moving at glacial pace when they have had G2 images for weeks and we still can't see them !

Teddy Morse: . . . . Wed, Oct 30, 4:30PM PDT (-0700 GMT)
Thanks first why does Jupiter spin so rapidly?

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 4:30PM PDT (-0700 GMT)
Teddy, I don't know if anyone knows the answer to why Jupiter spins so fast .. Any science guys want to comment

Verne: . . . . Wed, Oct 30, 4:30PM PDT (-0700 GMT)
After the completion of the extended mission, it it possible to keep Galileo going on power-conservation mode (similar to Voyager's) for another 6-8 years? In that case, it can be used as a relay station for a future Discovery mission Europa lander.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:30PM PDT (-0700 GMT)

Bartman: . . . . Wed, Oct 30, 4:30PM PDT (-0700 GMT)
Is the spacecraft position on the Ganymede fly-byes known exact enough to create the 3D models of the surface using the two sets of photos automatically using some stereo algorithm, or is there a lot of manual work involved, such as aligning, etc?

Josh: . . . . Wed, Oct 30, 4:31PM PDT (-0700 GMT)
What is the target date for launch of Cassini?

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 4:31PM PDT (-0700 GMT)
Jon of Melbourne.. I've been on the project since October 1988. You're right, it is exciting finally getting prime mission data after 8 years.

: . . . . Wed, Oct 30, 4:31PM PDT (-0700 GMT)
Jon: I've also been on GLL since 1979! Recently, I've started supporting the Pluto Express/Europa Orbiter activity. See if you can access the Europa Orbiter presentation on another page here ==> button

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:32PM PDT (-0700 GMT)
Dan Erickson: You may well win the prize for the luckiest person alive! When you're stuck in traffic do you ever feel like saying "Look, it's Dan the man from JPL, get out of my way!" ?

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 4:32PM PDT (-0700 GMT)
Jane: Yes, hard copies of Galileo images are available through our Public Information Office. You can call them at (818) 354-5011. They should be able to help you. Thanx for your inquiries and hope that all your students are absorbing all that's going on with the Space Agency. It's truly exciting!

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:32PM PDT (-0700 GMT)
Teddy: I don't think we really know why it spins so fast.

Geoff: . . . . Wed, Oct 30, 4:32PM PDT (-0700 GMT)
Hi Leslie, I'm the pres of a local Amateur astronomer group in IL and we do public sessions twice a month and several of our members do school groups. I've used the Live from Hubble and Galileo info to try and reach groups and use it as openers before observing sessions. The cub scout groups like the activities especially the one to demo how CCD images are made up (after some refining of the insructions)

Teddy Morse: . . . . Wed, Oct 30, 4:33PM PDT (-0700 GMT)
secondly Would you say that Jupiter could become a star as its fate?

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 4:33PM PDT (-0700 GMT)
Verne, with our real low downlink rate I don't think anyone would want to use Galileo as a relay

Sky Bauman: . . . . Wed, Oct 30, 4:33PM PDT (-0700 GMT)
Since the Ganymede 1 flyby, I read that the faults on Ganymede probably are a result of water freezing and expanding beneath the surface of Ganymede. In light of the discoveries in the Ganymede 2 flyby, does this theory still hold?

Steve: . . . . Wed, Oct 30, 4:33PM PDT (-0700 GMT)
Thanks for the info, best of luck, and great job!

Nick@Vancouver, B.C.: . . . . Wed, Oct 30, 4:33PM PDT (-0700 GMT)
Thanks for the answer. As a Canadian, I can't vote in your election, but I think NASA is some of the best money any country ever spent. Aside from anything else, NASA is terrific good publicity for the USA. Feel free to quote me.

Steven Tyler, Galileo Alum: . . . . Wed, Oct 30, 4:33PM PDT (-0700 GMT)
I worked on Galileo from 1978 through 1985 and returned in 1994. I left Galileo this month for Cassini.

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:34PM PDT (-0700 GMT)
I tried the button but get the old 403 Forbidden message. Did you mean to have the URL: /PIE/index.html ? Anyone want to comment on my s/w question?

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 4:34PM PDT (-0700 GMT)
Jon: Melbourne, Oz: We test and test and test our code. We have simulators and breadboards. And yes, we don't change anything we don't have to. We also have two separate "strings" of processors in the Command and Data Subsystem. Either string could keep the spacecraft safe by itself, although it couldn't do much science. When we make major changes such as the changes after we got into orbit, we load one string with the new software and make sure it is working before we load the other. Oh yes, and we pray alot.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:34PM PDT (-0700 GMT)
Someone else asked about a solid surface on Jupiter. Jupiter may have a solid core deep in its interior. If it does, it around 10-15 earth masses.

Jim Erickson, Science & Sequence Office: . . . . Wed, Oct 30, 4:34PM PDT (-0700 GMT)
Josh- Cassini's launch window is from 10/6/97 to 11/4/97.

Stephen in Seattle: . . . . Wed, Oct 30, 4:34PM PDT (-0700 GMT)
NASA folks: Your sites are my favorite places on the Web. I've always loved following NASA ever since Apollo 11, when I was six. I'm now a 33-year-old engineer, reasonably happy with my job, but I would pack up and move in a minute if I could get a job with NASA (besides scrubbing toilets, I mean). Unfortunately, I don't have the least idea how to find out what jobs are available or apply to NASA. I've written to several people in the past year, and haven't gotten any response. Can you give me some ideas?

Josh: . . . . Wed, Oct 30, 4:34PM PDT (-0700 GMT)
Is anyone involved in the Deep Space Network going to be giving a lecture/ information session in Atlanta, GA anytime soon?

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:36PM PDT (-0700 GMT)
Teddy Morse: No, I don't think Jupiter has enough mass to cause gravitational compression to generate the nuclear fusion necessary for it to become a star.

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:36PM PDT (-0700 GMT)
Nick@Vancouver, B.C. I agree! I must say that I always think of NASA as a global exploit, not just a US achievement. It's the sort of beautiful application of peaceful technology that builds on the discoveries of others in such a special way. It makes me proud to be a human.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 4:36PM PDT (-0700 GMT)
Teddy, No very likely. Jupiter just doesn't have enough mass to become a star. It would need more mass than the rest of everything else in the solar system except the sun, so there isn't even enough stuff in the whole solar system to make a second sun out of Jupiter. Its close to a sun but not quite close enough

Josh: . . . . Wed, Oct 30, 4:36PM PDT (-0700 GMT)
Thanks, Jim. Would you happen to know on which vehicle Cassini will be launched?

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 4:37PM PDT (-0700 GMT)
Jane: Newell Color Lab at (213)380-2980 has the 8x10s and slides of everything that we have released to the press. Shortly, we will also have slide sets available at the NASA Teacher Resource Centers.

Jim Erickson, Science & Sequence Office: . . . . Wed, Oct 30, 4:38PM PDT (-0700 GMT)
Josh- Yes, they are planning to use a Titan 4.

Bob Barry, Engineer - Anomaly Response Team: . . . . Wed, Oct 30, 4:38PM PDT (-0700 GMT)
Jon: I suspect that message means that the URL was a "JPL internal" web page which is not accessable from off Lab.

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:38PM PDT (-0700 GMT)
Dan: I have a masters in software engineering. We didn't cover praying but I believe that is often used in big sites following a new s/w release :-)

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 4:38PM PDT (-0700 GMT)

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:38PM PDT (-0700 GMT)
Stephen in Seattle: I understand that one can find a job by reading newsgroups. Nancy, you got your job through the newsgroup, right?

Nancy Vandermey, SEQ-Systems: . . . . Wed, Oct 30, 4:38PM PDT (-0700 GMT)
Steven in Seattle: I got my job here by looking in the la.jobs newsgroup!

Andy in Sweden: . . . . Wed, Oct 30, 4:38PM PDT (-0700 GMT)
Hi there! I have just entered here and are very curious about if the high gain antenna will be able to fix? Or is it stuck for good?

Steven Tyler, Galileo Alum: . . . . Wed, Oct 30, 4:39PM PDT (-0700 GMT)
Josh - actually, although Cassini's launch window still starts on 10/6/97, some people are proposing to start the window a couple of days later so that the Cassini Earth flyby will be at a higher altitude.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:39PM PDT (-0700 GMT)
Josh: I believe Cassini will be launched on a Delta-Titan IV.

Jim Erickson, Science & Sequence Office: . . . . Wed, Oct 30, 4:39PM PDT (-0700 GMT)
Teddy- The rest of the mass in the solar system (besides the sun) all adds up to around 2/3 the mass of Jupiter. Jupiter is around 1/100 of the necessary mass for being a sun (last theory I heard).

Verne: . . . . Wed, Oct 30, 4:39PM PDT (-0700 GMT)
Is it possible that Jupiter is heated by a very limited fusion reaction occurring in its core?

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 4:40PM PDT (-0700 GMT)
Andy The antenna is not likely to be fixed

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 4:40PM PDT (-0700 GMT)
Stephen in Seattle: NASA is "downsizing" right now. The good news is that some things which NASA used to do itself are being done by aerospace companies like Boeing. I believe they have a nice piece of the space station work.

Jane: . . . . Wed, Oct 30, 4:40PM PDT (-0700 GMT)
Is the Public Information Office at JPL? I work at NASA Langley and I'll be at JPL in December. I'd love to pick up some pictures while I'm there.

Lou D'Amario, Galileo Navigation: . . . . Wed, Oct 30, 4:41PM PDT (-0700 GMT)
Josh: I believe Cassini will be launched on a Titan-IV/Centaur.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:41PM PDT (-0700 GMT)
Josh: Correction, a Titan IV/Centaur.

Josh: . . . . Wed, Oct 30, 4:41PM PDT (-0700 GMT)
How would the higher altitude affect the mission?

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 4:41PM PDT (-0700 GMT)
Andy: Looks like it's stuck for good. We won't be able to use it as our flight software is based on using the Low Gain antenna. Even if we were able to use it, it would take more resources than we have to convert over to a High Gain mission.

Nick@Vancouver, B.C.: . . . . Wed, Oct 30, 4:41PM PDT (-0700 GMT)
Is USGS still in the business of making paper maps from space probe discoveries? I haven't located any Venus maps using Magellan data. Have you guys decided that paper is obsolete in the age of the Net? I hope not.

Andy in Sweden: . . . . Wed, Oct 30, 4:41PM PDT (-0700 GMT)
Tal Brady: That was very bad news! Thanks for your answer!

Andre': . . . . Wed, Oct 30, 4:42PM PDT (-0700 GMT)
I am very glad and excited that you all are offering us this chat to talk to you. The Galileo homepage is my favorite site on the Web. When will the next press conference be if there is one scheduled?

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 4:42PM PDT (-0700 GMT)
Personal intro/background: I started working at JPL in 1977 on the Viking Mars lander/orbiter, moved on to Voyager/Saturn, did some early Galileo ground system development ('81-'82), spent some time on Mars Observer (_way_ pre-launch!), (...misc...) then came back to Galileo a few months after launch (at the Venus flyby) where I've been ever since. In my (limited) free time, I dabble in the theater (stage), hiking, and gardening. Education = BS in Astronomy from Caltech ('77). First space mission was Mariner Mars 71, where I worked on the geodetic survey (locating craters in the images = undergrad grunt work ;-) time on Mars Observer, Earl

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 4:42PM PDT (-0700 GMT)
Jane: Yes, the Public Info Off. is here at JPL.

Steven Tyler, Galileo Alum: . . . . Wed, Oct 30, 4:42PM PDT (-0700 GMT)
Josh- Cassini will be launched on a Titan IV/Centaur which has Solid Rocket Motor Upgrades.

Sky Bauman: . . . . Wed, Oct 30, 4:42PM PDT (-0700 GMT)
How much would it cost to continue the Galileo mission after the spacecraft completes its first eleven orbits? Is Congress likely to fund for a continuation of the mission?

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:42PM PDT (-0700 GMT)
Bob: I do like the title Anomaly Response Team. Is that on your passport?

Josh: . . . . Wed, Oct 30, 4:43PM PDT (-0700 GMT)
Teddy- and Verne -- I believe in order to start fusion, a celestial body has to have at least 0.08 solar masses. I believe Jupiter is 1/100 of that.

Zach : . . . . Wed, Oct 30, 4:43PM PDT (-0700 GMT)
Is there volcanos on any other volcanic moons besides IO?

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 4:43PM PDT (-0700 GMT)
Josh, have a look at the Cassini home page for more detailed info: button

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:43PM PDT (-0700 GMT)
Jane: Yes, JPL has a public information office. Contact Kim Lievense at 818-354-0112

Andy in Sweden: . . . . Wed, Oct 30, 4:44PM PDT (-0700 GMT)
Has the problem with the high antenna caused a lot of problems for the project?

Icelander: . . . . Wed, Oct 30, 4:44PM PDT (-0700 GMT)
Thanks for a great job! Will the Tucson lectures, by any chance, be made available on the Net for those of us out in the cold?

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 4:44PM PDT (-0700 GMT)
Zach: As far as we know, Io is the only volcanic active moon in our Solar System

Lou D'Amario, Galileo Navigation: . . . . Wed, Oct 30, 4:45PM PDT (-0700 GMT)
Sky Bauman:

anonymous: . . . . Wed, Oct 30, 4:45PM PDT (-0700 GMT)
Hi. I'm Brian. Will there be any stereo pair type images made of any of jupiters moons (the side by side images you combine in your head to get a 3d effect)?

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 4:45PM PDT (-0700 GMT)
Zach: I believe Voyager found evidence of ice volcanism on Neptune's satellite Triton (if I remember my 'ancient/1989' history).

Josh: . . . . Wed, Oct 30, 4:45PM PDT (-0700 GMT)
Zach, Triton supposedly had some sort of volcanic activity.

Verne: . . . . Wed, Oct 30, 4:46PM PDT (-0700 GMT)
Isn't Venus volcanically active? / Can Triton's ice geysers be classified as volcanoes?

Teddy Morse: . . . . Wed, Oct 30, 4:46PM PDT (-0700 GMT)
Thank you baoth for answering my questions but I have more next Do you think we will ever find life on Jupiter ,like aliens andmicroscopic stuff that could live on jupiter?

Bob Barry, Engineer - Anomaly Response Team: . . . . Wed, Oct 30, 4:46PM PDT (-0700 GMT)
Jon: The anomaly response team is an "ad hoc" team which is formed whenever we have an unexpected spacecraft behavior which may indicate we have a spacecraft hardware or software failure. We gather experts from all areas, examine the symptoms from telemetry data, and try to figure out what happened. It's a neat job!

Josh: . . . . Wed, Oct 30, 4:47PM PDT (-0700 GMT)
BTW, what is the current moon count for Jupiter?

Lou D'Amario, Galileo Navigation: . . . . Wed, Oct 30, 4:47PM PDT (-0700 GMT)
Sky Bauman: An extended mission, called GEM for Galileo Europa Mission, is being proposed. It would contain 8 additional Europa flybys, followed by several Callisto flybys to pump the orbit down for a final plunge to Io. The GEM would last two yeras with a budget of (I think) $30 million dollars.

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 4:47PM PDT (-0700 GMT)
Andy: The only set back that we have is our slow data rate from the Low Gain. The problem for us in terms of the High Gain is that we are not able to use it like we planned.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:47PM PDT (-0700 GMT)
Time for an introduction. I started work at JPL 4 years ago, working for the DDS/MAG science team and another team doing science planning. Now I work on the Sequence team, with Bruce and Nancy. The SEQ team is the team responsible for producing the "sequence of commands" that are uploaded to the spacecraft. I have a BS in physics from Cal Poly Pomona (a California State University), and a MS in physics from Rensselaer Polytechnic Institute in Troy, NY

Stephen in Seattle: . . . . Wed, Oct 30, 4:47PM PDT (-0700 GMT)
On the fantastic Io image recently made available (jaw-dropping -- I'm using it as my computer wallpaper, and I get comments all the time from coworkers), it looks like there's a mountain on the eastern limb about 20 degrees north. This assumes the image shows the planet's axis as vertical, with north up. If that really is a mountain, it's got to be pretty darned big. Anyone have a comment on this? Is it just a photographic flaw, or maybe a cloud of some sort?

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 4:47PM PDT (-0700 GMT)
Zach: we think there could be geysers spewing dirty water from an ocean underneath Europa's surface. Voyager 2 found evidence of nitrogen geysers on Neptune's moon Triton.

Lou D'Amario, Galileo Navigation: . . . . Wed, Oct 30, 4:48PM PDT (-0700 GMT)
Josh: There are currently 17 known moons of Jupiter: 16 natural ones and one artificial one (Galileo).

Larry Dorau: . . . . Wed, Oct 30, 4:48PM PDT (-0700 GMT)
The pcitures of broken blocks of ice on Europa were amazing. Looks just like someone dropped a rock through the ice and then it refroze. The false color image was beautifl. WHAT A PLACE!!

Andre': . . . . Wed, Oct 30, 4:48PM PDT (-0700 GMT)
What instruments does Galileo have that neither Voyager spacecraft had?

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:48PM PDT (-0700 GMT)
Josh: 16 moons the last time I checked.

Andy in Sweden: . . . . Wed, Oct 30, 4:49PM PDT (-0700 GMT)
Thank you for your answers!

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:49PM PDT (-0700 GMT)
Lou: Oops, I forgot about the artificial one ;-)

Lou D'Amario, Galileo Navigation: . . . . Wed, Oct 30, 4:49PM PDT (-0700 GMT)
Leo: Just keeping you awake.

Josh: . . . . Wed, Oct 30, 4:49PM PDT (-0700 GMT)
I was just curious if Galileo might have found a new satellite orbiting the planet.

Zachary drew: . . . . Wed, Oct 30, 4:50PM PDT (-0700 GMT)
I am interested in the volcanos on Io. If the volcanos on IO are made from tides then why arent there volcanos on our moon?

Future: . . . . Wed, Oct 30, 4:50PM PDT (-0700 GMT)
Greetings everyone! Why is it that planets like Mars,Titan,Venus, Ganymede,Europa, and Mercury have so different atmospheres? like Mars and Titan for example, they are similar in size but Mars is bigger and closer to the sun than Titan, yet Titan has a thicker denser Atmosphere than Mars! the same goes for Titan vs. Ganymede, it seems to be more than just the diameter and gravity of planets that determine how dense the atmosphere is going to be. Does the Scientist understand exactly how and why atmospheres are formed round planets?...

salomon: . . . . Wed, Oct 30, 4:50PM PDT (-0700 GMT)
David, Do areospace engineers use the word stoage or storage Because mecanical engineers use it? And do engineers make better lovers?

Steven Tyler, Galileo Alum: . . . . Wed, Oct 30, 4:50PM PDT (-0700 GMT)
Josh - the higher altitude is just fine for the mission. Depending upon what day we launch, there's an ideal altitude at closest approach to Earth. At the start of the launch window, that altitude is pretty low, and increases the (very small) chance that we could collide with Earth. To increase the minimum altitude and maintain the early launch date would use up way too much fuel. The only risk in postponing the launch (which means we use less fuel) is that we might run out of the window and have to go to a backup mission and take 9 years to reach Saturn and be practically in the ecliptic (so if we lose control of Cassini near Earth, it would go into orbit around the Sun and hit Earth sooner or later). The primary mission is much better in both respects.

Lou D'Amario, Galileo Navigation: . . . . Wed, Oct 30, 4:50PM PDT (-0700 GMT)
Josh: To my knowledge, no new satellites have been discovered, unless the science folks are keeping something under their hats.

Ashwin Vasavada, SSI Atmos. Sci.: . . . . Wed, Oct 30, 4:50PM PDT (-0700 GMT)
Hi everyone! Back for more. Regarding Andre's question, the imager (SSI) has infrared filters that Voyager did not have that allow us to see different levels in Jupiter's atmosphere.

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 4:50PM PDT (-0700 GMT)
All: Thanks for the great work. I have to go and do some work now. I'm at work (11:46am) and "I'm just chatting on the Web" doesn't wash with my boss as an excuse. Adios... :-)

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 4:51PM PDT (-0700 GMT)
Verne: Magellan wasn't able to identify surface changes on Venus during its tour of three orbits when mapping its surface. However, this doesn't mean it is not volcanically active. Geysers are not defined as volcanoes as volcanoes tend to spew material that cause surface changes and geysers just spew out material i.e. water and so on.

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 4:51PM PDT (-0700 GMT)
Hi Andy in Sweden. The problem with the high gain antenna certainly has provided us with some challenges and many sleepless nights coding and testing new software but then Tal and Dan can tell you volumes about that.

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 4:52PM PDT (-0700 GMT)
Stephen, I'm not sure exactly the feature you are referring to, but there are many volcanoes on Io, currently active or otherwise, so this could be a currently quiet one!

Bob Barry, Engineer - Anomaly Response Team: . . . . Wed, Oct 30, 4:52PM PDT (-0700 GMT)
Andy: The HGA failure has surely caused major problems for the GLL project. However, the recovery from this problem - the redesign of the spacecraft software, and enhancement of the Deep Space Network capability, and many additional changes which have made possible the current GLL orbital mission using the Low Gain Antenna is a recovery which ranks right along with Apollo 13 (which I also worked on).

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 4:52PM PDT (-0700 GMT)
Stephen in Seattle: The lump you see is probably the plume from one of Io's volcanos. I doubt that our imaging resolution is good enough at the distances we now are from Io to give us physical relief. Remember that seeing a volcanic plume just off the limb of Io is the way that the Voyager team first discovered that Io is volcanically active.

Zachary drew: . . . . Wed, Oct 30, 4:52PM PDT (-0700 GMT)
Could there be life on any of jupiters moons?

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 4:52PM PDT (-0700 GMT)
Teddy Morse: It is hard to imagine life forming in the gas ball of Jupiter. Jupiters moons, however are another story. The discovery of broken iceflow terrain on Europa led some to believe that there might be liquid water or warm ice beneath the surface. Perhaps life could have evolved her when Europa was a bit warmer and adapted to the changing conditions.

david:
salomon is that ? to me? I am just a student

Ashwin Vasavada, SSI Atmos. Sci.: . . . . Wed, Oct 30, 4:53PM PDT (-0700 GMT)
Future: Great question. It would be nice if there were some easy answer. Each planet has had a unique history and as scientists we try to piece together that history based on present observations. We have some ideas, for example Mercury's atmosphere probably was blown off by the earlier, more active sun. And Jupiter has a large atmosphere for the same reason - being far away it was able to retain its full complement of Hydrogen, for example. There are many other factors involoved. Any specific questions?

Lou D'Amario, Galileo Navigation: . . . . Wed, Oct 30, 4:54PM PDT (-0700 GMT)
Signing off. Have to go home and get some food & rest. The navigators will be working late tonight to design the final maneuver to fine-tune the trajectory for the Callisto 3 encounter next Monday.

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 4:55PM PDT (-0700 GMT)
Andre': Galileo is also equipped with a Near Infrared Mapping Spectrometer that can collect data up to 408 wavelengths and can also produce temperature maps that allow us to determine hot and cool regions on a body. We can also determine surface composition on all of the moons and determine composition in Jupiter, too.

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 4:55PM PDT (-0700 GMT)
Hi Andre'. Galileo also has NIMS which has a slight overlap in wavelengths with the camera. It's a new instrument (Galileo vintage) and a more advanced model will fly on the Cassini mission.

Teddy Morse: . . . . Wed, Oct 30, 4:55PM PDT (-0700 GMT)
but one of my resourses for my project said tha over Jupiters core was a lake of frozen water and ammonia

Zachary drew: . . . . Wed, Oct 30, 4:55PM PDT (-0700 GMT)
What is the hottest of jupiters moons?

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 4:55PM PDT (-0700 GMT)
Zachary drew: The tidal stresses that Io feels are from the combination of Jupiter's VERY strong pull, and the three other Galilean satellites pulling in other directions. The stresses therefore change constantly and push and pull. Earth is a very small body compared to Jupiter, and there are no other moons to complicate the picture, so the gravitational pull is very constant on our moon.

Steven Tyler, Galileo Alum: . . . . Wed, Oct 30, 4:55PM PDT (-0700 GMT)
Zachary...some of us are hopeful about life in a water ocean under Europa's ice. The temperature would be right, we'd have the water, and there might be underwater volcanos to supply heat, similar to some underwater volcanoes on Earth. Also, it MIGHT be easy for single-cell life to originate. Multi-cellular creatures...I doubt it.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:56PM PDT (-0700 GMT)
Zachary drew: Many scientist have speculated that Europa may have life underneath it's icy surface. This is because Galileo's images have revealed possible water oceans.

Nick@Vancouver, B.C.: . . . . Wed, Oct 30, 4:56PM PDT (-0700 GMT)
Hi again. Will USGS be producing updated maps of the Galilean moons? They did a whole bunch using Voyager data - I assume you folk use them quite a bit...

anonymous: . . . . Wed, Oct 30, 4:56PM PDT (-0700 GMT)
Sorry david I meant the meesage for Dave Bates!

Josh: . . . . Wed, Oct 30, 4:57PM PDT (-0700 GMT)
Wouldn't the thin atmosphere of the moons prevent any life from forming. I mean, the exposure to the Sun's radiation would kill any developing life forms on the satellites, right?

Andy in Sweden: . . . . Wed, Oct 30, 4:57PM PDT (-0700 GMT)
Bob Barry: That was very good news to here! But has not the slow data rate resulted in less data from Jupiter then planed?

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 4:57PM PDT (-0700 GMT)
Zachary: There's always the possibility that there's life on other bodies i.e. Jupiter's moons. However, at this time, it's highly remote but not impossible.

Teddy Morse: . . . . Wed, Oct 30, 4:57PM PDT (-0700 GMT)
but one of my resourses for my project said tha over Jupiters core was a lake of frozen water and ammonia then is that false and when somthing is liveng on a planet it is used to the livestyles and might not need any water to live.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 4:58PM PDT (-0700 GMT)
Teddy, No one is really sure about the core, but pressure and temperatures and radiation at the core make life on jupiter seem unlikely. The probe we dropped into Jupiters atmosphere got crushed, melted and then vaporizer and it was partly made of titanium

Steven Tyler, Galileo Alum: . . . . Wed, Oct 30, 4:58PM PDT (-0700 GMT)
Josh - the ice would be a good radiation shield for life on Europa

Ashwin Vasavada, SSI Atmos. Sci.: . . . . Wed, Oct 30, 4:58PM PDT (-0700 GMT)
Josh - I'm almost afraid to bring this up, but regarding thin atmospheres and how they can't shield the surface from harmful UV rays - that's what they say about Mars...

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 4:58PM PDT (-0700 GMT)
Zachary, Io is by far the warmest of all Jupiter's moons because of the volcanic activity. Temperatures as high as 1000 degrees K have been measured.

anonymous: . . . . Wed, Oct 30, 4:59PM PDT (-0700 GMT)
Hi. I'm Brian. Will there be any stereo pair type images made of any of jupiters moons (the side by side images you combine in your head to get a 3d effect)?

Jim Erickson, Science & Sequence Office: . . . . Wed, Oct 30, 4:59PM PDT (-0700 GMT)
Time to sign off, and pick up my child. Bye all.

Larry Dorau: . . . . Wed, Oct 30, 4:59PM PDT (-0700 GMT)
Are there any 3D images of the red spot like there are of Ganymede?

Teddy Morse: . . . . Wed, Oct 30, 4:59PM PDT (-0700 GMT)
but one of my resourses for my project said tha over Jupiters core was a lake of frozen water and ammonia then is that false and when somthing is liveng on a planet it is used to the livestyles and might not need any water to live.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 4:59PM PDT (-0700 GMT)
Teddy Morse: I think the very high temperatures in Jupiter's core would prevent any water from freezing.

david:
shure no problem

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 5:09PM PDT (-0700 GMT)
Larry Dorau: we don't have 3d images of Jupiter's Great Red Spot, but we do have false color that tells us how high the clouds are. See: button But that's a great idea for a product we could do, I'll look into it!

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 5:09PM PDT (-0700 GMT)
Teddy Morse: I would love to go to Mars.

Alan Cooper: . . . . Wed, Oct 30, 5:09PM PDT (-0700 GMT)
Hello, My name is Alan Cooper from N.J. I was wondering if anyone there knows Paul Fisher?

Salomon: . . . . Wed, Oct 30, 5:09PM PDT (-0700 GMT)
Dave Bates, Do Engineers make better lovers?

Josh: . . . . Wed, Oct 30, 5:09PM PDT (-0700 GMT)
I would visit Earth. I could live there without any special equipment.

Andy in Sweden: . . . . Wed, Oct 30, 5:09PM PDT (-0700 GMT)
It´s good news to her that as much as 70% of the original amount of expected data from Jupiter can be collected even though the data rate from the LGA is so slow! Thanks for your answers!

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 5:10PM PDT (-0700 GMT)
Teddy, Mars because I could do more there than the other planets, since its more like earth

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 5:10PM PDT (-0700 GMT)
Josh, I grew up in Ft Worth Texas - is that close enough?

Zachary drew: . . . . Wed, Oct 30, 5:10PM PDT (-0700 GMT)
What got you interested in progect gaeilo?

Steven Tyler, Galileo Alum: . . . . Wed, Oct 30, 5:11PM PDT (-0700 GMT)
Teddy. Earth, obviously. It's the prettiest planet by far. Venus looks like hell. Mars is a distant second choice. Mercury a distant third choice. Can I try another stellar system?

Josh: . . . . Wed, Oct 30, 5:11PM PDT (-0700 GMT)
Leslie, at least you understand "Southern English."

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 5:11PM PDT (-0700 GMT)
Hi, everybody! Logging in from Chicago to see how this Webchat thing works. Question: Will there be a press conference soon for findings from the Ganymede 2 encounter?

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 5:11PM PDT (-0700 GMT)
Someone asked how big Galileo is. Galileo weights 2,223 kg (4891 lbs). Over 40% of the orbiter's mass at launch is for propellent!

Teddy Morse: . . . . Wed, Oct 30, 5:11PM PDT (-0700 GMT)
dear Tal Brady do you think that we will ever make our home Jupiter? if so how would we get there?

Nancy Vandermey, SEQ-Systems: . . . . Wed, Oct 30, 5:11PM PDT (-0700 GMT)
Alan Cooper: Paul Fisher participated in this morning's chat session

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 5:11PM PDT (-0700 GMT)
Galileo weigh about 2.5 tons and is a little bigger than a minivan

Eric: . . . . Wed, Oct 30, 5:12PM PDT (-0700 GMT)
How about Vulcan?

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 5:12PM PDT (-0700 GMT)
Zachary drew: From the tip of the antenna mast to the base of the atmospheric probe (now long gone) the Galileo spacecraft is/was 5.3 meters high. The magnetometer boom (the long, spindly truss) sticking out to the side ends 11 meters from the center of the spacecraft. The length of that boom allows the very sensitive magnetic sensors to get at magnetic fields as far away from the metals and electrical currents in the main spacecraft as possible.

Zachary drew: . . . . Wed, Oct 30, 5:12PM PDT (-0700 GMT)
IS there a way a human could survive on jupiter?

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 5:13PM PDT (-0700 GMT)
Josh: Ahhhh dew tawk it, yeh!

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 5:13PM PDT (-0700 GMT)
Alan Cooper: Yes, I know Paul Fisher. He used to work on Galileo, and now teaches science in NJ, as well as doing some consulting work for Galileo.

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 5:13PM PDT (-0700 GMT)
Hi Bartman, The Near Infrared Mapping Spectrometer detected biological processes during one of the Galileo flybys of Earth. Some mention was made of chlorophyll.

Nick@Vancouver, B.C.: . . . . Wed, Oct 30, 5:13PM PDT (-0700 GMT)
One more question, re: Europa. Has any figured out the mechanics of the "dirty water first, clean water later" deposition process on Europa's triple bands? And brace yourselves for "unlikely hypothesis of the day": could the dark outside bands possibly be surface or near-surface (photosynthetic?) microbial colonies, neccessarily located close by ice faults penetrating to the sub-surface ocean, because of the access they provide to seeped-up minerals and liquid water? Does spectrometry or anything else _rule out_ the bands having a biological origin/being biological? (yes, I know this is Burrough's "canals on mars" fantasy come back to haunt me in the 90's.) Still, I'd like to know if its _completely_ impossible, or just very very improbable.

Alan Cooper: . . . . Wed, Oct 30, 5:13PM PDT (-0700 GMT)
I know that because I was a part of it and afterwards he told me that you would be back tonight. Did you know him personally or still talk to him?

Alan Cooper: . . . . Wed, Oct 30, 5:13PM PDT (-0700 GMT)
I know that because I was a part of it and afterwards he told me that you would be back tonight. Did you know him personally or still talk to him?

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 5:13PM PDT (-0700 GMT)
Teddy Morse: We know so little about planet formation and the conditions which could lead to life that we are all just speculating here. One of the wonderful things about the space program is that we keep getting surprised. That is, we keep learning. Galileo's images of Ganymede destroyed many theories based on Voyager's images. Life might have such a variety of forms and chemistries that we will have trouble recognizing alien life at first.

Josh: . . . . Wed, Oct 30, 5:13PM PDT (-0700 GMT)
Zachary drew: I guess someone could survive on Jupiter. . . with about 500 tons of spacecraft around them.

Zachary drew: . . . . Wed, Oct 30, 5:14PM PDT (-0700 GMT)
Could someone fit inside the gaeileo satilite?

anonymous: . . . . Wed, Oct 30, 5:14PM PDT (-0700 GMT)
Yes, where are images of Amalthea ?? Were any pictures taken of it in any of the flybys yet ?? Interesting object.

Teddy Morse: . . . . Wed, Oct 30, 5:14PM PDT (-0700 GMT)
dear Steven Tyler, first I would ask you not to use that language ?and another yes you could use another stellar system (if there is one)

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 5:14PM PDT (-0700 GMT)
Teddy Probably not on Jupiter, but maybe we could live in heated pressure domes on Ganymede. Similar to what we might do on the moon someday. We might use a solar sail ship built in orbit or an ion propulsion ship to get there.

anonymous: . . . . Wed, Oct 30, 5:14PM PDT (-0700 GMT)
Yes, where are images of Amalthea ?? Were any pictures taken of it in any of the flybys yet ?? Interesting object.

Andy in Sweden: . . . . Wed, Oct 30, 5:14PM PDT (-0700 GMT)
This question might not be relevant to Jupiter and Gallileo. But is there anyone here that can tell me why Mars Observer failed?

Jim T (S/C and ground radios): . . . . Wed, Oct 30, 5:14PM PDT (-0700 GMT)
Sorry to be so late signing in. Josh in Atlanta, if you're still listening in, I could give you information about the DSN. I won't be in Atlanta any time soon that I know of, but I'm as close as your e-mail. Just hail f.h.taylor@jpl.nasa.gov, and ask away. I've been on Galileo virtually from Day 1, and certainly through all the design changes that occurred in the 10 years between project start and launch. From a communications point of view, having to work with only the low gain antenna certainly has been a challenge. Life has been anything but boring, having to try to predict our downlink signal levels (for data rate planning) to within a few percent.

Steven Tyler, Galileo Alum: . . . . Wed, Oct 30, 5:14PM PDT (-0700 GMT)
Salomon...according to Dilbert, engineers are impervious to both romance and mirth. Sounds like a bad recipe for being a good lover.

Stephen in Seattle: . . . . Wed, Oct 30, 5:14PM PDT (-0700 GMT)
Future: I'm not a NASA person -- I only wish I were -- but it seems that a planet much closer to the sun would tend to have its volatiles driven off, just from solar heating. Mercury has almost no atmosphere at all, and Venus' atmosphere looks to be made of pretty heavy molecules, lots of carbon and oxygen. (Any NASA folks, please feel free to rub my nose in it if I'm wrong.)

Brian: . . . . Wed, Oct 30, 5:15PM PDT (-0700 GMT)
Thanks Bruce for the stereo pair answer. Now another question. In a past chat I read about concerns regarding the total radiation dose from jupiter damaging the ship. Does the radiaion protection you have slowly erode away?

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 5:15PM PDT (-0700 GMT)
Icelander: Callisto's cratering tells the age of Callisto and Ganymede's cratering tells the age of Ganymede. However, this does not mean that the cratering from both bodies can't be compared to give relative age between the two moons. Europa on the other hand tells a different story. There appears to be some shifting of ice and it's surface could be "newer".

anonymous: . . . . Wed, Oct 30, 5:15PM PDT (-0700 GMT)
About atmospheres on Ganymede and Titan: another good question. Atmospheres are supplied by comets and vulcanism and eroded by the solar wind and by freezing out on the surface, among other things. Mars' atmosphere is in equilibrium with the polar caps- lower the temperature and more atmosphere freezes out. Titan's atmosphere may be due to what is on the surface, too. Perhaps there is an ocean of exotic carbon compounds. There are no easy answers here...

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 5:15PM PDT (-0700 GMT)
Alan Cooper: Unfortunately the last time I spoke to Paul was on this chat line this morning. Are you one of his students?

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 5:15PM PDT (-0700 GMT)
Nick, BC: a quick answer. We think that cracks develop in the icy crust, that the ocean underneath, which is contaminated with minerals and "dirt" can spew up through. It then freezes and falls back to the surface, leaving the dark edges on the cracks.

david: Alan Cooper this is david dunlop that onoying freshmen

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 5:16PM PDT (-0700 GMT)
Hey, Leo, that was our Launch weight. By now we've done over 30 maneuvers, and dropped the probe (339 kg), so our total propellant weight is now in the high tens of kg (anybody from NAV care to chip in?)

Zachary drew: . . . . Wed, Oct 30, 5:16PM PDT (-0700 GMT)
I think you should send the Gaeileo satilite to saturn?

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 5:16PM PDT (-0700 GMT)
Alan Cooper, Yes, I know Paul Fisher and his family. His science students are lucky individuals indeed.

Future: . . . . Wed, Oct 30, 5:16PM PDT (-0700 GMT)
Ashwin: Well what about Ganymede? it's the largest moon in the solar-system almost as big as Mars, and bigger than Titan, Why doesent it have a dense atmosphere like Titan or even denser? What other laws of physics are in effect, besides gravity?

Nancy Vandermey, SEQ-Systems: . . . . Wed, Oct 30, 5:16PM PDT (-0700 GMT)
Amalthea is targeted in C3, also another small moon Thebe. I believe Thebe was imaged in G2 but the image was saturated - at least I remember SSI submitting a late "sequence change request' to adjust some parameters in C3

Steven Tyler, Galileo Alum: . . . . Wed, Oct 30, 5:16PM PDT (-0700 GMT)
Teddy, sorry for the comment about Venus, but it reminds me so much of Dante's Inferno.

Galileo enthusiast, Norway: . . . . Wed, Oct 30, 5:16PM PDT (-0700 GMT)
Nancy, Craters really? I am not talking about the 30 km crater. More southwards, and there are also spiraling structures. 'Science' is talking about 'subcrustal convection'?

Stephen in Seattle: . . . . Wed, Oct 30, 5:17PM PDT (-0700 GMT)
Can anyone tell me about the filters used to image Io?

david:
science might be fun if I was pasing

Alan Cooper: . . . . Wed, Oct 30, 5:17PM PDT (-0700 GMT)
Yes I was last year. He was (and still is) my favorite. What do you think of him?

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 5:17PM PDT (-0700 GMT)
Zachary, If we took out the electronics (computers) someone could probably fit, but galileo is not presurized so you have to bring your own air

??????: . . . . Wed, Oct 30, 5:17PM PDT (-0700 GMT)
I think gaelio is the best space progect ever made!!!

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 5:17PM PDT (-0700 GMT)
Bruce: Yea, you're right ;)

Teddy Morse: . . . . Wed, Oct 30, 5:18PM PDT (-0700 GMT)
dear Tal Brady, what is a solar sail ship and a on propulsion ship?

Alan Cooper: . . . . Wed, Oct 30, 5:19PM PDT (-0700 GMT)
Mr. Fisher brought many cool pictures and up to the minute info on Galileo last year.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 5:19PM PDT (-0700 GMT)
Alan Cooper: I only know Paul Fisher from work, and he was aways willing to help. Just a cool guy to work with. You are indeed lucky to have him as your teacher.

ZACHARY DREW: . . . . Wed, Oct 30, 5:19PM PDT (-0700 GMT)
When are you going to send gaelieo into jupiters atmosphere?

Stephen in Seattle: . . . . Wed, Oct 30, 5:20PM PDT (-0700 GMT)
Any plans or ideas for a Jupiter glider or two? Any problem with using Jovian panels for a power source for a glider/plane? I've got this great idea, see, and if I can just sell it to someone...

Ashwin Vasavada, SSI Atmos. Sci.: . . . . Wed, Oct 30, 5:20PM PDT (-0700 GMT)
That last post about atmospheres was from me. One more time - there are no easy answers to your question. Another thing to remember about Jupiter's moons is that they are in an INTENSE radiation environment. Perhaps Ganymede's atmosphere was stripped away by ion bombardment - this process is known to strip away the atmospheres of earth, Mars, etc.

Teddy Morse: . . . . Wed, Oct 30, 5:21PM PDT (-0700 GMT)
Dear Steven tyler , If you could ever change anything in space what would it be?

david:
I ahav eto go now I am one of Paul Fishers students this year and was here earlyer today

Andre': . . . . Wed, Oct 30, 5:21PM PDT (-0700 GMT)
I heard the Hubble recently discovered an oxygen atmosphere on Ganymede and that Galileo detected an ionosphere. Does any other data from Galileo confirm an atmosphere?

Nancy Vandermey, SEQ-Systems: . . . . Wed, Oct 30, 5:21PM PDT (-0700 GMT)
Galileo enthusiast, Norway: try the photo caption here: button

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 5:21PM PDT (-0700 GMT)
Yes I know Paul, last saw him when he was out here several weeks ago

ZACHARY DREW: . . . . Wed, Oct 30, 5:22PM PDT (-0700 GMT)
How long would Gaelieo last in jupiters atmosphere?

Bob Barry, Engineer - Anomaly Response Team: . . . . Wed, Oct 30, 5:23PM PDT (-0700 GMT)
Zachary: I always loved science in school, but never "selected" a space mission to work on. A visit to a friend in New Orleans for Marti Gras led to a job on Apollo at Cape Kennedy. I followed some of my friends to work on Skylab in Houston. Then, went for a hiking weekend in Denver where I accepted a job on the Viking Project with some of the same people. This resulted in my moving to JPL for the Viking Operations. Later, friends talked me into Pioneer Venus as a JPLer (my grades at school would surely not have been acceptable to JPL at the time of my graduation). After that, I moved over to Galileo in 1979 (some of the same people), and would have left the project right after the planned '86 launch... But, anomalies and responses have kept me occupied for the last 10 years!

Nick@Vancouver, B.C.: . . . . Wed, Oct 30, 5:24PM PDT (-0700 GMT)
Must go. Thank you for taking the time to chat! Best of luck with the mission (and with your budget)!

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 5:24PM PDT (-0700 GMT)
No the radiation protection doesn't erode there isn't much shielding. The parts just get more and more radiation until they stop working usually rather suddenly but not all at once.

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 5:24PM PDT (-0700 GMT)
Zachary drew: Actually, there aren't too many hollow spots on the craft. We were somewhat limited in volume, since we had to fit into the shuttle bay, so we couldn't have a lot of room built in. It was certainly never designed to carry a person, so no need to put in a spot for one (or two, or...)

Nancy Vandermey, SEQ-Systems: . . . . Wed, Oct 30, 5:24PM PDT (-0700 GMT)
You can view some of tonight's participants here: button

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 5:24PM PDT (-0700 GMT)
Zachary: The Galileo would last a few seconds before it vaporized high in the atmosphere.

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 5:24PM PDT (-0700 GMT)
Stephen in Seattle: The filters on Galileo's imaging camera are both in the visual and near infrared wavelengths: clear@611 nm, violet@404nm, green@559nm, red@671nm, and infrareds@734nm,756nm,887nm,986nm. Our filters can give truer colors than did Voyager.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 5:24PM PDT (-0700 GMT)
Stephen in Seattle: A Jovian glider? Do you mean a glier in Jupiter's atmosphere? I don't think you can use ordinary solar panels to gather Jovian radiation for energy. Jupiter's energy output is not in visable light, rather it's in the radio frequency.

Teddy Morse: . . . . Wed, Oct 30, 5:25PM PDT (-0700 GMT)
yes How ling would Gaelieo last in Jupiters atmosphere. Tal?

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 5:25PM PDT (-0700 GMT)
Nick: Thank You!

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 5:27PM PDT (-0700 GMT)
Leo, I think much of Jupiter's radiation is also in the infrared wavelengths, right?

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 5:27PM PDT (-0700 GMT)
Nancy: Sticking a "button" into your dialogue is a neat trick, but I get the response "You don't have permission to access /galilhttp://photojournal.jpl.nasa.gov/cgi-bin/PIAGenCatalogPage.pl?PIA00294 on this server." That's okay, though, we can probably find photo p47169 some other way.

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 5:28PM PDT (-0700 GMT)
Bill: put "button in front of the other address, and you will see it. You can also just back up from this chat page, and there is a click button there.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 5:29PM PDT (-0700 GMT)
Leslie: You are correct, comming from graviational compressional heating I believe. But I think when people read that Jupiter puts out more energy than it takes in, that energy is mostly in the millimeter/microwave region.

Stephen in Seattle: . . . . Wed, Oct 30, 5:29PM PDT (-0700 GMT)
Leslie Lowes: Why does Jupiter's atmosphere look a beautiful sky blue in the Io full-disk picture recently released? Obviously, this isn't exactly "true" color. Was the "red" filter really an IR filter at a hydrogen absorption wavelength? (This is what I guessed to some friends, and I'm going to have to eat my words if I'm wrong. But in any case I want to know the REAL answer.)

Dale in Fairbanks: . . . . Wed, Oct 30, 5:30PM PDT (-0700 GMT)
Is there a True color photograph of IO. I can't believe it really look like the pictures published.

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 5:31PM PDT (-0700 GMT)
Steven in Seattle: Do you have any thoughts on how we could slow a glider down enough so that it wouldn't burn up on entry? Once it slowed down enough, if we stayed high enough, the glider might survive until it ran out of power. It could use thermals for lift, but it would need to power the electronics somehow. Hmmm...

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 5:31PM PDT (-0700 GMT)
Alan Cooper, yes, we still e-mail from time to time. You should go by his classroom and tell him he's your favorite teacher. He'd be pleased.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 5:32PM PDT (-0700 GMT)
Teddy the ships I was talking about are from future plans for getting spacecraft to the outer planets. The don't exist yet but work is being done here and at other centers to develop them. People versions will probably not show up for 50 years. A solar sail uses the light energy of the sun to move a spacecraft, like a sail boat uses wind energy to move the boat on the ocean. An ion proopulsion system uses the push from charged particles generated on the spacecraft to move the spacecraft. They used to have little ion drive spinners in some museums where a pinwheel was spun by shining UV light on the wheel. Your library may have some recent space science books with better descriptions than mine.

Andy in Sweden: . . . . Wed, Oct 30, 5:33PM PDT (-0700 GMT)
It is VERY interesting to listen (read) to all your answers to all interesting questions. But unfortunatly I have to leave you all for my bed. The time here is 2:30 am and I have to get at least some sleep before getting up and going to work tomorow (today)! Also thank you for your answers! Good luck with the continuation of the Gallileo project!!

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 5:33PM PDT (-0700 GMT)
Zachary drew: The main Galileo s/c (our contraction for spacecraft) will (hopefully) never enter Jupiter's atmosphere. The probe entered the atmosphere near the equator back almost a year ago (!!) Dec 7/8 1995, the same day we entered Jupiter's orbit.

Stephen in Seattle: . . . . Wed, Oct 30, 5:34PM PDT (-0700 GMT)
Leo Cheng: Yeah, I had a glider/plane in mind, something to buzz around Jupiter, explore grand vistas, sample gasses, try aerodynamic tricks at 2.2 g's...that sort of thing. I'm guessing that there exists some photovoltaic substance or other that works at radio frequencies. Is this wrong? If it is correct,then we've got a heck of a source of power for Jovian exploration right on site.

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 5:35PM PDT (-0700 GMT)
Dale: Yes, there's on the Galileo web site that shows an almost true color of Io. It's quite impressive.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 5:36PM PDT (-0700 GMT)
Zackery and Teddy, The probe lasted less than 1 hour and it was designed to enter the aatmosphere, The orbiter would only last a few seconds.

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 5:36PM PDT (-0700 GMT)
Dale in Fairbanks, The color photo of Io is actually pretty close to the real thing. This information was provided by Jim Kaufman of the SSI team.

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 5:37PM PDT (-0700 GMT)
Dale, Fairbanks and Stephen, Seattle: You can see Io's NATURAL color if you look at the image at: button It compares the real color to one that has been enhanced. Remember that the Voyager camera was unable to reproduce true color, although it was close,

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 5:37PM PDT (-0700 GMT)
Steven in Seattle: Maybe a glider could use solar panels and get its power from the Sun, not Jupiter. It would need to store energy for the 5-hour night. Also, since Jupiter is much farther from the Sun, solar power is tougher there than on Earth. Wasn't there a Gossamer ???, a solar powered airplane?

Alan Brown, Menlo Park, CA: . . . . Wed, Oct 30, 5:37PM PDT (-0700 GMT)
Hello, all, I just say that I really enjoy the Galileo web site, particularly in the past week or so. Regarding the images: it's been said that they are being released as quickly as possible, but several weeks pass between the time the data is received and the time we see them. Are they doing some sort of intensive image processing to remove noise and assure accurate shading? or is there some other reason for the delay? What kind of image processing is being done?

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 5:37PM PDT (-0700 GMT)
Dan Erickson and Steven: If last, December, you could slow the Galileo probe to less than 200 MPH on a parachute, then you could probably slow a glider! Launching the glider isn't the hard part. The hard part is keeping above the high-temperature regions for a long time. How about bringing along a supply of oxygen, and burning it with Jupiter's hydrogen in an engine that drives a propeller?

Bryan in Kansas: . . . . Wed, Oct 30, 5:37PM PDT (-0700 GMT)
Do you have orbital diagrams made up for the proposed GEM? What are the encounter dates and geometries? Will there be any close passes, and pictures, of Ganymede?

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 5:38PM PDT (-0700 GMT)
The revisit of the PPR Ganymede temperature map question/answer. Yes, it was just the color scale values given to the data and nothing more.

Teddy Morse: . . . . Wed, Oct 30, 5:38PM PDT (-0700 GMT)
so you think the theries about the planet x and the balck hole pulling venus and pluto out of ther orbits is true? If so then why isn't the black hole sucking in our sun and all they other planets ? and if its a planet the why haven't we seen it though our telescopes yet?

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 5:39PM PDT (-0700 GMT)
Stephen in Seattle: At radio/microwave/millimeter frequencies, one would need to use an ordinary radio/microwave/millimeter recevers that we use for communications here on earth. The problem with using it as an energy collector is that you would need a very large parabolic dish to focus energy necessary for electrical power.

Josh: . . . . Wed, Oct 30, 5:39PM PDT (-0700 GMT)
Hello again.

Bryan in Kansas: . . . . Wed, Oct 30, 5:39PM PDT (-0700 GMT)
Do you have orbital diagrams made up for the proposed GEM? What are the encounter dates and geometries? Will there be any close passes, and pictures, of Ganymede?

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 5:40PM PDT (-0700 GMT)
Bryan in Kansas: Yes, there are orbital plot diagrams that were made for GEM. However, I don't know if they're on the web.

Anton Ivanov: . . . . Wed, Oct 30, 5:40PM PDT (-0700 GMT)
Test

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 5:41PM PDT (-0700 GMT)
Anton: I see your test message

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 5:42PM PDT (-0700 GMT)
Bryan, we do Ganymede again in the regular mission. I don't think its in the current GEM plans

Andre': . . . . Wed, Oct 30, 5:42PM PDT (-0700 GMT)
I heard that the Hubble Space Telescope discovered an oxygen atmosphere on Ganymede and Galileo detected an ionosphere. Does any other Galileo data confirm an atmosphere? What kind of instruments are needed to detect an atmosphere?

Joshua, Georgia Tech student: . . . . Wed, Oct 30, 5:42PM PDT (-0700 GMT)
Will this still be functioning after 7 p.m.?

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 5:43PM PDT (-0700 GMT)
Tal, et al. -- We do Ganymede again on orbits 7 & 8

Anton Ivanov, Caltech Planetary: . . . . Wed, Oct 30, 5:43PM PDT (-0700 GMT)
Ashwin lost connection for a while we were checking. Question by the way. About the magnetic field on Ganymede. Did the guys checked if it can be induced by rotation of Ganymede in the magnetic field of Jupiter. If Ganymede has an iron core it is quite plausible.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 5:43PM PDT (-0700 GMT)
Teddy Morse: I doubt that there's any black holes near our solar system. We would have detected it by the gravitational perturbances it would have on the Sun and Jupiter. They would be effected first because they are the massive objects in our solar system.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 5:44PM PDT (-0700 GMT)
Teddy Morse: The more massive objects, I should say.

Stephen in Seattle: . . . . Wed, Oct 30, 5:45PM PDT (-0700 GMT)
Dan Erikson: (ON SLOWING DOWN THE GLIDER) Why couldn't we use repeated gravity assists from Jupiter and its moons? Would the spacecraft just be traveling too darned fast to accurately target the moons and Jupiter? It seems that six or eight judiciously-executed gravity assists could slow down a spacecraft in short order.

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 5:45PM PDT (-0700 GMT)
That is, Ganymede next April & May (1997)

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 5:45PM PDT (-0700 GMT)
I think some of the fields and particles instruments indicated that there might be a thin atmosphere on Ganymede, but I don't think any of Galileo's imaging or remote sensing instruments 'saw' one and they probably could not see a real thin one.

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 5:45PM PDT (-0700 GMT)
Joshua: I don't think so..However, Leslie Lowes would be able to tell you.

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 5:45PM PDT (-0700 GMT)
Alan Brown, While it may seem a long time between releases of images to the public, it doesn't seem that way to the folks doing the processing and preparation of the photos being released. Noise and radiation artifacts are removed as a part of the processing.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 5:46PM PDT (-0700 GMT)
Stephen, Even gravity assists take fuel

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 5:47PM PDT (-0700 GMT)
Steven in Seattle: I wonder if we could deploy a set of balloons which could get blown around the high atmosphere relaying data to an orbiter? Carrying oxygen and using the atmospheric hydrogen, as you suggest, but as a fuel cell might be a way to get electricity as well as propulsion.

Bryan in Kansas: . . . . Wed, Oct 30, 5:48PM PDT (-0700 GMT)
Are you getting back more data from the Ganymede 2 segment than you planned? Specifically, will you get the additional color segments of Europa?

Stephen in Seattle: . . . . Wed, Oct 30, 5:48PM PDT (-0700 GMT)
Leo Cheng: (ON RF PHOTOVOLTAICS) So you're saying that Jupiter's RF emissions just aren't intense enough to power a small motorized propellor? Some other JPL'er mentioned taking along a highly compressed oxidizer, which sounds like a great idea.

Dale in Fairbanks: . . . . Wed, Oct 30, 5:48PM PDT (-0700 GMT)
Will the Galileo program be abruptly terminated when its mission is completed or will it linger on like pioneer and voyager. Is there funding to keep monitoring it?

Icelander: . . . . Wed, Oct 30, 5:48PM PDT (-0700 GMT)
Paul Herreras, thanks for your answer. I just thought that since some scientists think the old lunar record could eventually be extrapolated to the other terrestial planets in order to estimate ages, ancient Callisto might have a similar function in the Jupiter system. (As a working hypothesis anyway)

Teddy Morse: . . . . Wed, Oct 30, 5:50PM PDT (-0700 GMT)
Does any of the moons(or satilites) of Jupiter bigger than Earth? Its moon?

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 5:51PM PDT (-0700 GMT)
In case anybody has sent a chat directed to me and I didn't answer. Send it again. I'm not getting about 25% of the messages posted

Andre': . . . . Wed, Oct 30, 5:51PM PDT (-0700 GMT)
Did Galileo detect any haze layers or material remnants from the Shoemaker-Levy comet collision?

Stephen in Seattle: . . . . Wed, Oct 30, 5:51PM PDT (-0700 GMT)
Dan Erickson: (Sorry for misspelling your name before) Balloons would allow us to do lots of cool gas-sampling and observing in situ, but our intentional mobility is lacking except in the vertical direction. However, a balloon's certainly better than nothing. Maybe we'd find a pattern of winds at different heights that would effectively allow us to go where we wanted... Anyway, I wish the oxygen idea was mine, but it was one of your guys'.

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 5:51PM PDT (-0700 GMT)
Bryan, all the data being returned from the second orbit is now on the ground. Someone out there correct me if necessary. There will be no additional color data return for Europa in G2. Update Europa - data received was full disk 3 colors at 6.9 km resolution.

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 5:52PM PDT (-0700 GMT)
Dale in Fairbanks: We would like it to go on for a while. Funding is not approved yet, but we are developing a proposed extended mission (GEM = Galileo Europa Mission) which would make several (~8) more close passes to Europa, possibly a few of Callisto (I think) ending with at least one more close Io pass. Too much time spent in near Io puts us so near Jupiter that we get heavily radiated and our components (mostly the electronics/computers) are expected to fail.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 5:52PM PDT (-0700 GMT)
Stephen in Seattle: Perhaps I should direct you to other sources, since I'm not an expert in Jovian RF emmisions. Are there anyone out there who can help us out?

Paul Fisher, On-Call Science Systems Engineering: . . . . Wed, Oct 30, 5:52PM PDT (-0700 GMT)
Good afternoon/evening. I'm back with my other hat on.

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 5:53PM PDT (-0700 GMT)
Dale: Currently, there's a plan to extend the Galileo mission beyond the primary mission. This is called GEM (Galileo Europa Mission) and it will last approximately 2 years provided it gets funded. GEM will do a lot of Europa science including the other satellites.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 5:54PM PDT (-0700 GMT)
Teddy the earth is bigger than any of Jupiters moons. Ganymede and Callisto are bigger than our moon. Io is about the same size and europa is smaller than our moon

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 5:54PM PDT (-0700 GMT)
Dan Erickson and Steven in Seattle: Balloons might be even harder to deploy than a glider in Jupiter's atmosphere. However, the Vega probes managed to do this on Venus, so the Russians and French have solved this problem somehow! Personally, I'd take along a small nuclear reactor and have a hot- hydrogen balloon that could stay up for a very long time.

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 5:54PM PDT (-0700 GMT)
Hi Paul, welcome back!

anonymous: . . . . Wed, Oct 30, 5:54PM PDT (-0700 GMT)
Dale and Andre': There are plans for an extended mission, if Congress approves it. The mission would focus on Europa because of the possibility of there being liquid water there. There would also be some very close passes of Io if the spacecraft holds up. The mission would last another two years or so. Call your congressperson! Regarding the SL9 hazes, the images were pretty tricky. We needed to get high latitude images with very little smear. Stay tuned for results - we're working on them now.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 5:55PM PDT (-0700 GMT)
Paul Fisher: We had one of your ex-students here earlier. He said you were his favorite teacher. Marcia, did you get his name?

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 5:55PM PDT (-0700 GMT)
Hi Paul, I've been conversing with two of your students. Seems you're doing a marvelous job...

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 5:55PM PDT (-0700 GMT)
Teddy Morse: None of Jupiter's moons are larger than the Earth, but Io (3630km), Ganymede (5262km), and Callisto (4800km) are larger than our moon (3476km)

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 5:55PM PDT (-0700 GMT)
Steven in Seattle: We could get some help with gravity assists, but we would still need propulsion for the carrier craft/orbitter and probably a heat shield for the glider/probe. The problem is that all of this makes the launched spacecraft big. Big means expensive to launch. NASA feels it can't afford expensive missions just now. Keep thinking about it. If we can find a way to get the delta V without a lot of mass for a heat shield or propellant, a Jupiter atmosphere glider would be an exciting mission.

Stephen in Seattle: . . . . Wed, Oct 30, 5:55PM PDT (-0700 GMT)
Tal Brady: I know gravity assists require fuel, but don't you think we could cut down on the fuel by a large amount with gravity assists? The alternative, as I see it, is to take along enough fuel to slow the probe down. Come to think of it, on a Hohmann transfer orbit (sorry if I butchered the spelling), couldn't you just let Jupiter "catch up" at apoapsis and get an almost-"free" Jupiter orbit, with very little fuel usage? If so, then a relatively small amount of fuel, coupled with parachutes/balloons, might make glider insertion much more tractable.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 5:55PM PDT (-0700 GMT)
Hiya Paul a student or two of yours dropped by earlier, but I think they're gone now.

Ashwin Vasavada, SSI Atmos. Sci.: . . . . Wed, Oct 30, 5:55PM PDT (-0700 GMT)
Sorry that last post about GEM and sl9 was from me!

Joshua, Georgia Tech student: . . . . Wed, Oct 30, 5:56PM PDT (-0700 GMT)
Leaving to do homework

Joshua, Georgia Tech student: . . . . Wed, Oct 30, 5:56PM PDT (-0700 GMT)
Leaving to do homework

Teddy Morse: . . . . Wed, Oct 30, 5:56PM PDT (-0700 GMT)
Tal, Did you help out in any of the Voyager projects and if so what did you do?

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 5:56PM PDT (-0700 GMT)
Leo and Paul... Alan Cooper, I believe and a Freshman named David.

Paul Fisher, On-Call Science Systems Engineering: . . . . Wed, Oct 30, 5:56PM PDT (-0700 GMT)
They're just preparing for next Monday's test ;-)

Dale in Fairbanks: . . . . Wed, Oct 30, 5:58PM PDT (-0700 GMT)
For you glider/balloon guys, how would a balloon be bouyant in an hydrogen atmosphere? to power your glider, beam microwaves down from an orbiting powerplant. RF transmission of power is proven.

Leo Cheng, SEQ Integrator: . . . . Wed, Oct 30, 5:58PM PDT (-0700 GMT)
It's time for me to go. I had a great time. Thank you for your support of Galileo. We need it!

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 5:58PM PDT (-0700 GMT)
Question for anybody at JPL: At 4:31 a nameless person mentioned something about a Europa Orbiter project that's starting up. Can you tell me how to find more information about this? Who's involved?

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 5:58PM PDT (-0700 GMT)
Paul Fisher: Are you giving extra credit for time spent chatting with us?

Galileo enthusiast, Norway: . . . . Wed, Oct 30, 5:58PM PDT (-0700 GMT)
OK, Nancy doesn't believe my subsurface theory. But what about the two big dark spots some distance NNE of the 30 km crater (looking like OG), why do they have light interiors. And why can you see sort of movement past them in several directions (by the ice)? Is it because they are rock from under the ice sticking up? How can they be be explained?

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 5:59PM PDT (-0700 GMT)
Bryan in Kansas: More information on the GEM proposal: The Galileo Project Science Group is currently evaluating orbital tour options. At the end of the prime mission, the spacecraft orbit is such that it will return to Europa. This makes Europa an easy target for continuing with the GEM. There are three phases to GEM: (1) a series of Europa encounters (8 - 9), (2) a series of Callisto encounters (3-4) that focus on getting us to the third phase... (3) Return to Io. Once we have selected a tour, I imagine that the data you are looking for will be made more public. Stay tuned!

Stephen in Seattle: . . . . Wed, Oct 30, 5:59PM PDT (-0700 GMT)
NASA folks: This is like being a kid in a candy store! You don't know how I envy you. Please be gentle with me if I get too excited and type something stupid. Anyway, regarding equipment damage from radiation: I know this is probably a very basic question, but exactly why does radiation destroy electronics? Also, how do you "harden" the electronics against radiation?

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 6:00PM PDT (-0700 GMT)
Bill Higgins: You can look into the Galileo website and I believe there may be some mention of the GEM ( Galileo Europa Mission) project.

GaryRob: . . . . Wed, Oct 30, 6:00PM PDT (-0700 GMT)
Any new information about possible liquid ice on Europa? Gary Robbins, Orange County Register

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 6:01PM PDT (-0700 GMT)
Norway, missed the original question... Try again, maybe someone will answer. It's really busy...

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 6:01PM PDT (-0700 GMT)
Stephen, I not very good at orbits, but I think you still have a relative velocity matching problem with that type of orbit. I agree mostly with Dan's comment above. Although we can cut down on the size with clever gravity assists. Costs are still an issue gravity assists mean longer journeys and longer journeys cost more. NASA's looking for cheaper missions for the near future. So we have to be really clever to go back to Jupiter with anything large or complicated.

GaryRob: . . . . Wed, Oct 30, 6:02PM PDT (-0700 GMT)
Ahem...I meant to say liquid water on Europa...Gary Robbins

Paul Fisher, On-Call Science Systems Engineering: . . . . Wed, Oct 30, 6:03PM PDT (-0700 GMT)
Marcia: No ... I'm counting on their innate curiousity about a fascinating project ... call me naive.

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 6:03PM PDT (-0700 GMT)
Stephen: I can answer your second question. We shield the the insturments to protect them from radiation bombardment. We apply blankets that help do this.

Stephen in Seattle: . . . . Wed, Oct 30, 6:03PM PDT (-0700 GMT)
Leo Cheng: Thanks for your answers.

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 6:04PM PDT (-0700 GMT)
Paul Herrera: No, the "Europa Orbiter" was mentioned along with Pluto Express. I think it's the answer (well, AN answer) to the question "What spacecraft do you send to Jupiter after Galileo?" I'd like to know more about plans for a hypothetical Europa-orbiting spacecraft.

Ashwin Vasavada, SSI Atmos. Sci.: . . . . Wed, Oct 30, 6:04PM PDT (-0700 GMT)
Stephen - until someone gives you the 'real answer', I'll try. Particles accelerated or directed by Jupiter's magnetic field impact the instruments with high velocities and high energies. These impacts can bounce other atoms out of place in the hardware, creating permanent defects in the crystal latices that make up the hardware electronics. That's at least one way radiation damage occurs. The way to protect is to shield the electronics so the high-energy particles are absorbed there.

Dale in Fairbanks: . . . . Wed, Oct 30, 6:04PM PDT (-0700 GMT)
I haven't heard much about jupiter's ring. Did the space craft detect it?

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 6:04PM PDT (-0700 GMT)
GaryRob: No hard evidence as of yet. However, the fourth orbit should reveal interesting data...stay tuned!!

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 6:05PM PDT (-0700 GMT)
Teddy, no I did not work on Voyager I wasn't at JPL when it was launched, but my friend Dan who is also on the web did and on the Mars viking too so did Bob Barry who is also on now. Iworked on Magellan which orbited Venus doing radar mapping. I helped do some of the software for that.

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 6:05PM PDT (-0700 GMT)
GaryRob: No new information to report about possible liquid ice on Europa. If it were there, the Near Infrared Mapping Spectrometer would find it. Ask again after the next orbit. C3 starts Monday.

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 6:05PM PDT (-0700 GMT)
Teddy Morse: I worked on the Voyager Project, creating simulators to test the flight software and commands. Did you know that both spacecraft are still operating and the Voyager I is expected to reach the Heliopause by 2004? At the Heliopause, galactic radiation overpowers the solar wind. The mission is noe called the Voyager Interstellar Mission (VIM.)

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 6:06PM PDT (-0700 GMT)
Dale: We know there are rings around Jupiter based on the Voyager data. Also, there are observations planned that will "look" at the rings of Jupiter with the Spacecraft. That should be interesting!!

Paul Fisher, On-Call Science Systems Engineering: . . . . Wed, Oct 30, 6:07PM PDT (-0700 GMT)
Bill Higgins: You may also look through the general NASA website or JPL site for descriptions of future missions. THere have been Europa missions propsed in the t for the Discovery class of mission ('low' cost). I don't believe a Europa mission has been selected yet however.

Stephen in Seattle: . . . . Wed, Oct 30, 6:07PM PDT (-0700 GMT)
Paul Herrera: Thanks for your answers. Are these blankets made of some kind of dense metal or something? What kind of radiation is being shielded against? If it's charged-particle radiation, are magnetic fields ever used as a shield?

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 6:07PM PDT (-0700 GMT)
GaryRob, I assumed you meant liquid water. I should say by "on Europa", I mean the surface of Europa.

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 6:08PM PDT (-0700 GMT)
Bill Higgins: There is relatively little information specific to GEM on the Galileo Web page. There are some general statements regarding extended mission in the FAQ, but I don't think it is what you are looking for. I guess we will have to do something about that in the near future. Thanks for the interest.

Teddy Morse: . . . . Wed, Oct 30, 6:08PM PDT (-0700 GMT)
Sorry to say but I have to go now THANK YOU for your time and answering my questions, this was for my Jupiter project just so you know!!

Icelander: . . . . Wed, Oct 30, 6:08PM PDT (-0700 GMT)
I read somewhere that the latest resurfacing of Europa is thought to be around 30 millions years old. Does that still hold true? Are the Voyager photos of Europa good enough to permit a similar comparaison as the one you've been doing between Voyager and Galileo photos of Io?

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 6:10PM PDT (-0700 GMT)
Stephen, Thats not a dumb question thats a hard question. For Galileo we made the electronics out of special materials Silicon on Sapphire CMOS, using a very large (for electronics) mask size so high energy particles are so large compared to the gates. We had these parts built is special rad hard process runs that I don't begin to understand and I think only about 3 specialists at Sandia ever did. And then we tested the heck out of them and selected the best ones. This is a real oversimplification but sort of describes it.

Galileo enthusiast, Norway: . . . . Wed, Oct 30, 6:10PM PDT (-0700 GMT)
Marcia, the original question was about the curving and circular/spiraling features on the southern ice floe area. Can these features be explained by active volcanoes in the possible subsurface ocean? 'Science' is talking about 'small scale subcrustal convection'?

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 6:10PM PDT (-0700 GMT)
Gary: Nobody is sure whether there is liquid water within Europa, but it seems likely, and certainly Galileo data will tell us more about this in the next couple of years. The first close Europa encounter isn't till December, I think. Meanwhile, there's a conference next month in California on Europa's Ocean. It should be interesting to see astronomers and oceanographers talk to one another! Keep an eye on the press.

Dale in Fairbanks: . . . . Wed, Oct 30, 6:10PM PDT (-0700 GMT)
I heard on the radio that Aurora was discoverd on some moons as well Jupiter itself. Is this true?

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 6:11PM PDT (-0700 GMT)
Steven in Seattle: Hard radiation (particles) can disrupt the crystal structure of semiconductor material. Perhaps a more important effect is that particle passing through a circuit split molecules and atoms into ions and electrons which then get attracted by the charges in the circuit. I'm not sure of the exact mechanism, but sometimes these charges can collect in sensitive areas which raise or lower the transistor thresholds. After enough of this, they don't function very well as digital switches.

: . . . . Wed, Oct 30, 6:11PM PDT (-0700 GMT)
Bill Higgins: JPL has done a quick internal study on a Europa mission which would have a high degree of commonality with the proposed Pluto Express spacecraft.

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 6:11PM PDT (-0700 GMT)
Stephen: Your welcome. These blanket are made of special insulators and fabric that was actually developed here at JPL. The radiation that is being shielded against are highly charged electrons that are being "carried" by Jupiter's magnetic field.

Bartman: . . . . Wed, Oct 30, 6:11PM PDT (-0700 GMT)
Dan Erickson: Is the radiation beyond the heliopause believed to be much like ambient "light", with no direction (that is, when enough samples are taken), or would the expansion of the universe or the spiral of the milky way give it a relative direction to our solar system?

Ashwin Vasavada, SSI Atmos. Sci.: . . . . Wed, Oct 30, 6:11PM PDT (-0700 GMT)
Icelander: There are some comparisons being done between Voyager and Galileo images of Europa. We do not expect to see any changes due to geological processes. What we do see are changes due to the different angles and lighting conditions under which the images were taken. Geologists at ASU and U of Arizona are studying this.

Andre': . . . . Wed, Oct 30, 6:13PM PDT (-0700 GMT)
Are there craters in the northern hemisphere of Europa? To me the northern part that has no cracks has several craters.

Stephen in Seattle: . . . . Wed, Oct 30, 6:13PM PDT (-0700 GMT)
Ashwin Vasavada: Ah, so it's physical damage on the atomic level to the silicon. Do you know what is done to protect the electronics besides blankets? I seem to remember reading a report about military electronics, and how they were "hardened" to withstand high radiation levels.

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 6:13PM PDT (-0700 GMT)
Stephen in Seattle: To harden a circuit, the sensitive areas must be reduced in size relative to the rest of the circuit. Also oxides are thinned and other measures are taken to help the errant charges to dissipate.

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 6:13PM PDT (-0700 GMT)
Dale in Fairbanks: We can indeed see Jupiter's ring, but as with Voyager's discovery photographs, our best view is when we look towards the sun and see the rings through 'forward scattering', when they can appear quite bright. Because of the sensitivity of our optical instruments, however, we can't easily or safely point towards the sun. We have to wait until our orbit takes us into Jupiter's shadow. This first occurs in our tour during this upcoming encounter with Callisto, and on Nov. 9th we have such an occurrance, and we will be doing some ring observations. Look for the data hopefully by the end of the year.

Jim T (spacecraft and ground radios): . . . . Wed, Oct 30, 6:13PM PDT (-0700 GMT)
Stephen in Seattle - your question about what exactly radiation does to electronics is a good one. I can give you one example from an analysis of our Galileo radio receiver. Early in September, a few days after the Ganymede-2 close passage by Jupiter, the radio got flaky, requiring a wider ground transmitter sweep to lock it up in frequency. A few days later, when we deliberately pulled the radio way off in frequency, this symptom disappeared. The working model that we have now is that one of the transistors in an operational amplifier got sodium ionic contamination during its manufacture -- apparently a common problem in those days (mid 70s). During the passage by Jupiter, a radiation particle pushed a clump of this contamination to near the base-emitter junction of the transitor. This caused the transistor to lose quite a bit of gain, and its performance in the receiver's tracking loop was degraded. Later, the frequency pull that I mentioned drove enough current through the transistor that the ionic clump moved back away from the junction and the transitor regained its normal function. We are ANXIOUSLY awaiting the next near passage by Jupiter, in early November, to see if the receiver problem recurs. By the way, we have a second completely redundant receiver that we could use if this first one should become unusable. And good fault protection software that would autonomously switch the spacecraft on to the second receiver.

Bob Barry, Engineer - Anomaly Response Team: . . . . Wed, Oct 30, 6:13PM PDT (-0700 GMT)
Bill Higgins: I'm not hiding my name, I just lost my "handle" when I went out to some other sites.

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 6:15PM PDT (-0700 GMT)
Dan: I'm back (lunch break). So Voyagers I and II are still going. They don't build like they used to eh? (sic) What sort of data are you receiving from them? How often do they transmit? How many light hours are they away now? I bet you're glad receiver technology has kept pace eh?

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 6:15PM PDT (-0700 GMT)
Icelander: That could be true in terms of the resurfacing. But the Voyager pictures are not able to reveal as much as the Galileo pictures and spectra will. The instruments on board Galileo have much better resolution.

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 6:15PM PDT (-0700 GMT)
Icelander: Voyager images led us to believe that Europa's surface was quite smooth. As you can see by the Europa images that have been released, that is no longer a true assumption. There will be some comparison done eventually however the Galileo images and Voyager images are over different territory. Stay tuned for later orbits.

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 6:15PM PDT (-0700 GMT)
Paul Fisher: It would be a heck of a challenge to put a payload into orbit around Europa for $150 million, which is currently the limit for Discovery missions. Conventional wisdom is that you need a plutonium RTG to provide power, and that's very expensive. I have met Joel Sercel, who's involved in developing very large inflatable reflectors at JPL. Maybe some such breakthrough could make lightweight solar power possible.

Ashwin Vasavada, SSI Atmos. Sci.: . . . . Wed, Oct 30, 6:18PM PDT (-0700 GMT)
1

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 6:18PM PDT (-0700 GMT)
Bartman: I'm really guessing here, but I believe that the high energy radiatiion is expected to have discrete sources, such as quazars or the center of the galaxy. The far infrared radiation corresponding to very low temperatures may be remnant from the Big Bang. I don't even recall what instruments are on Voyager and what they can detect. If you want to pursue this farther, send me a message at Daniel.E.Erickson@jpl.nasa.gov with your email address. I can forward your question to a Voyager scientist.

Stephen in Seattle: . . . . Wed, Oct 30, 6:18PM PDT (-0700 GMT)
Tal Brady and Dan Erickson: Again, thanks for the info. I gather that all of NASA's electronics, at least for Jovian spacecraft, are made to specs. Kind of cuts down on off-the-shelf price advantages, I imagine. The part about radiation creating more charge carriers and interfering with the current is also very interesting. Who thinks these things up, anyway? :)

Ashwin Vasavada, SSI Atmos. Sci.: . . . . Wed, Oct 30, 6:20PM PDT (-0700 GMT)
Any questions about the observations of Jupiter's atmosphere?

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 6:21PM PDT (-0700 GMT)
Bill Higgins: The payload is already up there i.e. Galileo. After the primary mission, the Galileo mission will be come a low cost discovery mission with less staff to help with the planning and execution of the sequences.

Bob Barry, Engineer - Anomaly Response Team: . . . . Wed, Oct 30, 6:21PM PDT (-0700 GMT)
I've got to leave now for a meeting in another part of town... Thanks for your interest, and great questions!

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 6:21PM PDT (-0700 GMT)
Bob "no longer anonymous" Barry: Thanks for the information. Earlier you gave a Web address for Europa Orbiter info, but it didn't work for me.

Paul Fisher, On-Call Science Systems Engineering: . . . . Wed, Oct 30, 6:22PM PDT (-0700 GMT)
Bill Higgins: You are quite correct. My error. I believe the proposals I saw were for the class of mission above Discovery (<450 Million) and involved repeated fly-bys rather then an attempt to go into orbit. Hanging out in that radiation environment would be a challenge in itself.

Paul Herrera, Near Infrared Mapping Spectrometer (NIMS) Team: . . . . Wed, Oct 30, 6:22PM PDT (-0700 GMT)
Well, signing off now. Have fun everybody! Until next time (soon I hope). :-)

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 6:22PM PDT (-0700 GMT)
Stephen, Yes thats mostly true. Some of the Mars pathfinder hardware is really right of the shelf. The CPU in the Galileo CDS is a special rad hard version of a comercial processor called the 1802 and developed by RCA in the 70's but its a long way from the shelf.

Andre': . . . . Wed, Oct 30, 6:23PM PDT (-0700 GMT)
Are there craters in the northern hemisphere of Europa? To me the northern area that has no cracks has several craters.

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 6:23PM PDT (-0700 GMT)
Norway, The Europa contingent could handle this question much better than me. Unfortunately, they don't seem to be chatting. What I can tell you is that up to this point, there have been no active volcanoes discovered on Europa. If such a thing were to exist, our best opportunity of "seeing" this would be in the E4 and E6 orbits coming up in early 1997.

Jim T (spacecraft and ground radios): . . . . Wed, Oct 30, 6:24PM PDT (-0700 GMT)
Jon, Melbourne, Oz - Yep, the DSN is still tracking both VGR-1 and VGR-2. I took a peek at their report from this morning, and I see that "your" station DSS-45 tracked VGR-2, while stations near Madrid and at Goldstone tracked VGR-1, all in the last 24 hours. All these stations are 34-meters, compared to the 70-meter and arrayed stations that we use for Galileo tracking. VGR has the big advantage over Galileo that it has a working high gain antenna! The Voyager downlink is X-band, and I think both of them transmit about 160 bits per second. I don't know offhand just how far away the Voyagers are, but I do know that one of the Galileo team members made predictions for signal levels for Voyager out to the year 2020. The ground receivers can readily support Voyager out that long, but it all depends on how long the financing lasts. I think I heard that one or the other of the Voyagers is near the "heliopause" now, that boundary between the solar wind and the interstellar medium.

Bruce McL/Galileo SEQ: . . . . Wed, Oct 30, 6:24PM PDT (-0700 GMT)
Well, dinner calls, and I've already put in my standard 12 hours today. Thanks, all, for chatting, and thanks for your support and interest. --bruce

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 6:25PM PDT (-0700 GMT)
Andre', Yes, the Europa images did show some craters. This was an exciting find and not exactly expected.

Stephen in Seattle: . . . . Wed, Oct 30, 6:26PM PDT (-0700 GMT)
Speculative question for JPL'ers and NASA'ers: If we're designing a long-term atmospheric probe for Jupiter (balloon, glider, kite, Goodyear blimp, whatever), what are the MUST-HAVE items? What are the LIKE-TO-HAVE items? For EM imaging and measurements, which wavelengths are most important? Finally, how would these answers change if the blimp were going to Saturn, Uranus, or Neptune? (Sorry if this sounds like an essay question.)

Andre': . . . . Wed, Oct 30, 6:26PM PDT (-0700 GMT)
Thanks for having the chat; it was fun!

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 6:26PM PDT (-0700 GMT)
All: How many of you work on the project would you estimate?

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 6:26PM PDT (-0700 GMT)
Paul Herrera: Re Galileo as a low-cost Discovery mission-- I never thought of it that way! One problem: I'd expect that Galileo uses a lot of Deep Space Network resources. Would telemetry dominate the cost of an extended mission? Would there be an emphasis on low-bit-rate instruments, and very few SSI and NIMS images?

Bartman: . . . . Wed, Oct 30, 6:27PM PDT (-0700 GMT)
Why was there a low gain antenna on board Galileo in the first place? A back up? Or some sort of secondary communication?

Dale in Fairbanks: . . . . Wed, Oct 30, 6:28PM PDT (-0700 GMT)
How "good" are the Hubble pictures in comparisson to Galileo. A while ago it was stated that Hubble discovered something in the atmosphere of one of the moons. How could this have escaped the Galileo which is right there?

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 6:28PM PDT (-0700 GMT)
Anyone out there with unanswered questions, now might be the time to repeat them. Tal said earlier he is missing some and so am I.

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 6:28PM PDT (-0700 GMT)
Jon: Melborne, Oz: Welcome back the Voyager homepage is button As of September 1 Voyager I was 9.59 billion kilometers from Earth travelling at 17.41 kilometers per hour.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 6:29PM PDT (-0700 GMT)
Bill, probably the demand would be the opposite, less low rate to make max bandwidth for limited images

Stephen in Seattle: . . . . Wed, Oct 30, 6:29PM PDT (-0700 GMT)
Ashwin Vasavada: Can you describe the structure of the Great Red Spot? Also, earlier I asked a question which didn't get answered, regarding the Galileo filters used for the recent full-disk Io image. Can you tackle that? (I'd be happy to repeat it.)

Voyager II, Trois-Rivières, Québec: . . . . Wed, Oct 30, 6:29PM PDT (-0700 GMT)
I'm back! Hello to all members of the marvelous Galileo team. I wonder if i am the the lonely that think so, but at certain moments, i think to these wonderful machines (Galileo and all other Pionneer, Viking, voyager, etc etc) , and they appear to me like semi-Gods...They bring us so much to our knowledge... and they accomplish all this work so lonely, so distantly... i am so amazed by that! Do you know if there is some readings somewhere, that discuss "philosophical" aspects of these man-made wonderful machines?

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 6:31PM PDT (-0700 GMT)
Dan: Thanks. That's the first URL on this chat that's open to us all. You win yet another prize! By the way, 17kph. That's jogging pace. When will it be arriving at Barnards star? I believe that's the next port of call?

Galileo enthusiast, Norway: . . . . Wed, Oct 30, 6:31PM PDT (-0700 GMT)
Marcia, thanks for the answer. Your work are great anyhow!

Bartman: . . . . Wed, Oct 30, 6:31PM PDT (-0700 GMT)
Dan: Don't you mean 17.41 thousand km/h for Voyager?

Stephen in Seattle: . . . . Wed, Oct 30, 6:31PM PDT (-0700 GMT)
Marcia Segura: You're a NIMS person. Were you involved in the imaging of Io, the full-disk picture recently released? I have a question about the blue Jovian atmosphere that hasn't been addressed, and everyone on the chat is probably tired of me asking it by now.

Ashwin Vasavada, SSI Atmos. Sci.: . . . . Wed, Oct 30, 6:31PM PDT (-0700 GMT)
Stephen: I imagine we'd want something very similar to the Galileo Probe. Despite its appeal, a camera would not be that useful, for the same reason that you dont see a bunch of local camera shots on the nightly news. Instead you see a bunch of temperatures from different places - that's what we would want. All that to say the instrument suite would have a mass spectrometer for sure, a net flux radiometer to get at clouds, pressure and temperature sensors. The ideal would be an orbiter above the atmosphere but closer than Galileo to provide images that show context. We could aim the glider for a vortex, the Red Spot, a plume, a belt/zone boundary and take measurements throughout those features. One of the problems with the Galileo probe is the lack of context - only from groundbased images do we have any idea of where the probe went it.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 6:32PM PDT (-0700 GMT)
Bartman, it could be used as backup and since it transmits in a different band as a second engineering telemetry source.

Paul Fisher, On-Call Science Systems Engineering: . . . . Wed, Oct 30, 6:33PM PDT (-0700 GMT)
Bill: *IF* the purpose of the mission is Europa study you would have to go with the instruments which provide the best data on the surface geology which would be the high rate remote sensing instruments.

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 6:33PM PDT (-0700 GMT)
Marcia and Tal: I'll repeat a question. Will there be a press conference for Ganymede 2 soon? Or did the DPS meeting supersede this?

Bartman: . . . . Wed, Oct 30, 6:34PM PDT (-0700 GMT)
Ashwin: From a public relations point-of-view (which certainly NASA has to worry about, unfortunately), if any sort of photos were available from a camera, it may we quite worth it. That's what the public wants.

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 6:34PM PDT (-0700 GMT)
Stephen, Leslie Lowes answered your question about the filters used on Io. Please repeat it Leslie...

Stephen in Seattle: . . . . Wed, Oct 30, 6:37PM PDT (-0700 GMT)
Marcia Segura and Leslie Lowes: I got the answer on WHICH filters are aboard Galileo. My question is: 1) which of those filters were used for the specific full-disk image of Io, and 2) why does the "red" component fail to show anything in the Jovian atmosphere? My theory was that the "red" filter was an IR wavelength that is absorbed by hydrogen, so it didn't show up in the clouds of Jupiter. Am I close? Way off?

Paul Fisher, On-Call Science Systems Engineering: . . . . Wed, Oct 30, 6:37PM PDT (-0700 GMT)
Stephen : I would add to Ashwin's list some spectrometers looking upwards. That would enable you to determine column densities of various molecular species. Of course you have the problem of a ballon in the way.

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 6:37PM PDT (-0700 GMT)
Jon: Melbourne, Oz: Sorry, I guess I lose my brownie points. Thats 17.41 kilometers per second.

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 6:37PM PDT (-0700 GMT)
Re press conferences: I've found the best way to get lots of information on Galileo is to ask a friendly local satellite dish owner to tape the science briefings, which occur at irregular intervals, on NASA TV. I've been expecting one for the second Ganymede encounter, but it hasn't happened. (Or did I miss it?)

Ashwin Vasavada, SSI Atmos. Sci.: . . . . Wed, Oct 30, 6:38PM PDT (-0700 GMT)
Stephen: Images of Io in G2 were taken in violet and green, with lower res images taken in red and in the infrared. I dont know which ones were used to make the 'true color' image. The infrare filter was not sensitive to hydrogen or any other species, just to continuum absorption. Regarding the GRS, it is a huge storm rotating counterclockwise with (presumably) material rising in the center and downwelling in a ring around it. It is very thin, however, probably only 50-100 km thick while 20000 km in diameter. Any specific facts you're interested in?

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 6:38PM PDT (-0700 GMT)
Voyager II: I don't know of such readings, but I would very much like to as well. As the outreach lead for Galileo, I want us to appeal to all dimensions that people are interested in, not just the cold technical aspects. Emotion and wonderment are very much a part of it. We hope to enhance our web page tying in the naming of the moons and craters with the mythological gods they came from, and artwork that has been done on them.

Dale in Fairbanks: . . . . Wed, Oct 30, 6:38PM PDT (-0700 GMT)
Hey, don't get rid of the cameras on future missions! Thats the only thing that can make a meaningful connection to the general public which funds these fantastic space voyages. It allows you to pretend that you are there looking. I'll bet there is alot more information in a picture than gets credit.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 6:38PM PDT (-0700 GMT)
Voyager II, I think 'The Ghost in the Machine' may touch on some of the philosophical aspects of building computers in general. Issac Asimov wrote several SF novels about robots that thouch on the aspects of being a computer. I don't know of any books about the philosophical aspects of the distant gathers of information that we send out but I bet there are some maybe in college book stores

Jim T (spacecraft and ground radios): . . . . Wed, Oct 30, 6:38PM PDT (-0700 GMT)
Bartman - the two low gain antennas on the spacecraft were put there originally so we could simultaneously communicate and maintain the spacecraft's proper orientation to the sun. The LGAs have very wide receiving and transmitting beamwidths -- that goes along with their low gain. During the first several years of the mission, when Galileo was flying inward toward Venus, then past the Earth twice, it had to be oriented in a particular direction toward the sun to keep all of its internal temperatures within bounds. The earth might be 90 degrees away from the sun, and we still could communicate via an LGA. When the spacecraft got well out past Mars' orbit, the sun and the earth are not that far apart in angle as seen from the spacecraft. So the Galileo could have been pointed within the few tenths of a degree of earth demanded by the high gain antenna. As it turns out, of course, needing to have an LGA on the spacecraft was the best luck we ever had. Throughout the spacecraft, the design emphasizes functional redundancy, so that if one capability (like the HGA) fails, we have something that clever engineers or scientists can figure out to serve as a backup. On a very large scale, a whole mission redesign, this is what we did with the LGA.

Stephen in Seattle: . . . . Wed, Oct 30, 6:38PM PDT (-0700 GMT)
Leslie Lowes: I think I neglected to thank you for your previous reply on filters. Thanks!

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 6:38PM PDT (-0700 GMT)
Bill Higgins: There was a press conference at the DPS meeting. I personally haven't heard of anything else planned for G2. I suspect the next big press conference will be the Callisto results. You can check in with the JPL PIO office or the Galileo webpage for updates.

Stephen in Seattle: . . . . Wed, Oct 30, 6:40PM PDT (-0700 GMT)
Paul Fisher: Can't you put a couple of spectrometers on top of the balloon?

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 6:41PM PDT (-0700 GMT)
Leslie, can you answer Bill's question about a G2 press conference. Didn't we have one.

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 6:42PM PDT (-0700 GMT)
Marcia: Thanks. You may be sure that I watch the Galileo web pages carefully and often!

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 6:42PM PDT (-0700 GMT)
I guess it was the DPS

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 6:42PM PDT (-0700 GMT)
Stephen, Ashwin got the questions answered...

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 6:42PM PDT (-0700 GMT)
Jon: Melbourne, Oz: The Voyager spacecraft have nothing to take pictures of, but they are measuring magnetic fields, plasma energy, and radiowaves Some of the radio waves are thought to be coming from the Heliopause. The spacecraft may last until 2020. A long way short of Barnard's Star. The funding may give out even earlier. The project has shrunk from hundreds of operators to less than thirty. Automation of many of the functions and cross-training have helped. The current NASA budget shows the operation staff shrinking to 10. At that level, it would be hard,if not impossible to maintain the knowledge necessary to recover from spacecraft anomallies.

Ashwin Vasavada, SSI Atmos. Sci.: . . . . Wed, Oct 30, 6:43PM PDT (-0700 GMT)
Bartman and Dale, your point is well taken. Believe me, NASA is well aware of it. Forgive me - sometimes as scientists we don't always go for the most popular things, even though our existence depends on public support! With the exception of Ulysses, I don't think NASA will ever drop a camera unless it really has to.

Jim T (spacecraft and ground radios): . . . . Wed, Oct 30, 6:44PM PDT (-0700 GMT)
Voyager II - I was very touched by your "philosophical" thoughts about our spacecraft. Though I can't give you any specific information either, I know a couple of philosophers around here that I would be glad to ask on your behalf. Send your e-mail address to me, and I'll see what I can do for you. I'm at f.h.taylor@jpl.nasa.gov

Stephen in Seattle: . . . . Wed, Oct 30, 6:44PM PDT (-0700 GMT)
Ashwin Vasavada: I downloaded the false-color image (relief image) of the GRS. I'm surprised to hear that it's only 100 km thick. How deep are the "depressions" that surround the GRS? Is there a significant pressure differential between the two regions, or are we just talking different gas species? Also, any ideas what underlies the GRS? Is the underlying layer (or layers) pretty much homogeneous over all the planet?

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 6:44PM PDT (-0700 GMT)
Marcia: How long does it take to get a NIMS (infrared imaging spectrometer) result through the data pipeline? I have the impression that the analysis is rather lengthy. I suppose it depends on whether you're interested in a few spectral channels, or a lot.

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 6:44PM PDT (-0700 GMT)
Stephen in Seattle: I'll take a crack at answering you about the colors. Unfortunately our Io folks and Imaging processing folks are not online. Be back in a minute with a response.

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 6:44PM PDT (-0700 GMT)
Dan: Thanks, a quick shuffti on my slide rules calculates VGR 1 to be about 6.7 light hours away. Rather too far for real time stuff. I wonder if some future mission will ever overtake it? Is it saving data on its mag tape incase or does it just get 'lost' if not transmitted back? I must admit it's wonderful that the technology has lasted so well. I guess it didn't have built-in obsolescence like my TV/toaster/car ?!

Voyager II, Trois-Rivières, Québec: . . . . Wed, Oct 30, 6:45PM PDT (-0700 GMT)
Is the ice discovered on Europa made by "natural" (H2o)water, or some other chemical component?

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 6:46PM PDT (-0700 GMT)
Dan: Oops, I got c wrong from memory. Make that 5 hours way.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 6:46PM PDT (-0700 GMT)
Hey Jon, They just gotta stay around long enough to come back and bug Captain Kirk.

Paul Fisher, On-Call Science Systems Engineering: . . . . Wed, Oct 30, 6:47PM PDT (-0700 GMT)
Stephen: You could probably put some instruments up there but it would certainly complicate you design. Envirnmental controls in two places communication link between the instruments and the rest of the hardware. Not impossible but a little tricky.

Ashwin Vasavada, SSI Atmos. Sci.: . . . . Wed, Oct 30, 6:47PM PDT (-0700 GMT)
Stephen, let me qualify my last post by saying that we dont know how thick anything is yet on Jupiter. The clear areas around the GRS have temperatures that suggest the emission there is coming from about 4-5 bars. This pressure level is about a hundred km below where the top of the spot (the center) is. The cloudy portion of the spot is far above the depression that surrounds it, and has only a few km of relief in it. The center of the spot is about 3-4 km above the edges of the cloudy portion.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 6:48PM PDT (-0700 GMT)
VoyagerII I think the Europa ice is dirty water H20

Ashwin Vasavada, SSI Atmos. Sci.: . . . . Wed, Oct 30, 6:49PM PDT (-0700 GMT)
One other note, the probe found winds that remain constant with depth (to 20 bars). This supports the idea that visible structures on Jupiter's atmosphere are deep.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 6:50PM PDT (-0700 GMT)
Yeah, think of the 'Twister' movie you could make blimping around the red spot with a camera

Stephen in Seattle: . . . . Wed, Oct 30, 6:50PM PDT (-0700 GMT)
Leslie Lowes: Look, you don't have to go to all that trouble. If you folks will just hire me on, I'll ask the imaging team myself! :) Actually, I read an article last week about how so many bright young engineers were leaving NASA for better-paying jobs. Given NASA's recent downsizing, this seemed a little odd. Is it true? If so, does it open up any job possibilities for the Unwashed Masses, or does NASA and JPL keep lists of people salivating at the prospect of getting work there?

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 6:50PM PDT (-0700 GMT)
Tal: How often do you re-program the Galileo? Is it still programmed using the same languages as at launch (I know it's the same assembler but do you program in new higher level languages?) Any plans to run a Java applet 'out there' ? :-)

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 6:50PM PDT (-0700 GMT)
Jon: Melbourne, Oz: 6.7 hours one way sounds about right. If we transmit a command we see the results on the other side of the Earth. Weird huh? I don't think we are saving extra data on the tape. We do have a record on board and a plaque with the signatures of the people who worked on the project. Gee, I hope it isn't captured by an intergalactic forger!

Voyager II, Trois-Rivières, Québec: . . . . Wed, Oct 30, 6:51PM PDT (-0700 GMT)
Does the HGA deployment failure will be a "sufficient" lesson to avoid this type of antenna on all future probes that NASA will send in space, or do you will continue to use it?

Jim T (spacecraft and ground radios): . . . . Wed, Oct 30, 6:51PM PDT (-0700 GMT)
Jon: Melbourne, Oz - The Voyager spacecraft are an inspiration to me on Galileo, probably more than to people on most other subsystems. Almost all of the telecommunication gear is direct inheritance from Voyager (we just used their spares) or along similar designs. I know Galileo has Voyager traveling wave tube amplifiers, Voyager transponders (receivers/transmitters), Voyager telemetry modulator, Voyager command detector, and Voyager-design low gain antenna. The HGA that didn't unfurl was not of Voyager design. Maybe there's a lesson there.

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 6:51PM PDT (-0700 GMT)
Bill and Tal: I didn't see the original question (so many going by, it's great everyone is so interested!), but here's the scoop on press conferences and releases from orbit: July 10 '96: first high resolution pictures from Ganymede August 13 '96: Europa and Io results October 24 '96: "technical" science results from Io and Ganymede at DPS (Division of Planetary Science) meeting December '96 (TBD): probably on magnetospheric findings from the moons Note: when scientists publish their results in scientific journals, often the journals require that no other release of that data take place until the issue of the journal actually comes out. This can complicate things.

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 6:52PM PDT (-0700 GMT)
Bill Higgins: The length of time more or less depends on the size of the data set. The "pipeline" has a few turns in it which involve adding accurate scanplatform pointing and other geometry information in backplanes. NIMS observations sometimes require multiple scans across the target to do a mosaic (such as the Ganymede global map seen on the Galileo web page), each scan has to be matched with the previous one. This is just one of the steps the data goes thru before analysis can begin. This can take hours to days to get just right. At that point you can do spectral comparison from one part of the surface to the other. But labelling compositional units takes much longer. Thanks for the question and insight.

Bartman: . . . . Wed, Oct 30, 6:52PM PDT (-0700 GMT)
As I log off, I'd like to thank all of you at JPL for your fantastic work, and especially for taking the time to do the web chat. I look forward to results on the future orbits. Just remember how lucky you are to be working on the only real frontier left. I hope to use my high-tech hardware/software company as a vehicle to work on the space program (i.e. - through some sort of contract) in the future. Keep up the excellent work.

Jon: Melbourne, Oz: . . . . Wed, Oct 30, 6:54PM PDT (-0700 GMT)
Jal: "Maybe there's a lesson". Methinks more than maybe?

JeffS : . . . . Wed, Oct 30, 6:54PM PDT (-0700 GMT)
Paul Herrera made a great point when he suggested looking at the GEM extension as a discovery mission. We as taxpayers have already covered the cost of the equiptment and transportation. The Galileo team has done a great job of maintaining the equiptment against all odds. It sounds like a lot of the necessary planning for an extension is already being done. It would be foolish to waste this opportunity to get as much info out of Galileo as we can until consumables run out. The money needed for such an important mission extension in such a feature rich environment seems to me to be money well spent. Tell your representatives if you agree at button

Bill Higgins, Beam Jockey, from Fermilab : . . . . Wed, Oct 30, 6:55PM PDT (-0700 GMT)
Who asked about balloons in a hydrogen atmosphere a little earlier? You need to provide a heat source, and make a hot-air (well, hot-H2) balloon, just like the Montgolfier brothers did. You could bring an oxidizer along and burn hydrogen to make a chemical heat source, or you could use a nuclear reactor or radioisotope heat source to keep the balloon aloft. A payload of instruments very similar to the Galileo probe's, but which transmitted for days or months rather than hours, would be useful in understanding the atmosphere. As I said, balloons have been flown on Venus, so there's precedent, but a Jovian balloon or dirigible would be harder to engineer.

Paul Fisher, On-Call Science Systems Engineering: . . . . Wed, Oct 30, 6:57PM PDT (-0700 GMT)
Jon: No Java applets on Galileo but you might want to check out the Web pages for the New Millenium missions, particularly Deep Space 1. Not quite Java but getting close.

Jim T (spacecraft and ground radios): . . . . Wed, Oct 30, 6:58PM PDT (-0700 GMT)
Voyager II - Personally I'd be *very* suprised if any future JPL spacecraft teams even consider complex unfurlable antenna designs. Within the past year, we (JPL) had an experiment on a Space Shuttle, an inflatable antenna. It packs compactly for launch, then just blow it up like a balloon. What I remember from the news releases is that it worked very well indeed, though the dynamics that occurred while it was being inflated proved very interesting to the astronauts.

Dan Erickson, CDS Flt S/W: . . . . Wed, Oct 30, 7:01PM PDT (-0700 GMT)
Bartman: Look into the Small Business Innovative Research (SBIR) program.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 7:04PM PDT (-0700 GMT)
Jon, No higher languages we do have a Macro assembler but thats as high as the CDS gets. One of the instruments has an 1802 that has some programs in forth. Java? coffee in space? It would evaporate. While a lot of different deliveries made up the reprograms, we have put 3 versions of software on the CDS. One for launch, one to support the JOI and probe relay and one for the low gain antenna orbital operations mission going on now. We are currently working on a 4th contingency load to be used if the tape recorder fails.

Tal Brady .. Flight Software: . . . . Wed, Oct 30, 7:07PM PDT (-0700 GMT)
Well been hung up for a while and now its time to trot. So long and thanks for all the fish

Stephen in Seattle: . . . . Wed, Oct 30, 7:07PM PDT (-0700 GMT)
Ashwin: So you're saying that a cyclonic storm 30,000 km wide has an overall relief of FOUR kilometers?! That's amazing! So it's not a bubble, but more of an atmospheric plateau. How do you measure the relief? Galileo doesn't have radar ranging, does it?

Leslie Lowes, Galileo Outreach: . . . . Wed, Oct 30, 7:08PM PDT (-0700 GMT)
Stephen in Seattle: Since the chat is about over, why don't you send me your email, and I'll pass it to a team member for the imaging camera tomorrow. Then you'll get the best answer.

Stephen in Seattle: . . . . Wed, Oct 30, 7:08PM PDT (-0700 GMT)
Leslie Lowes: Look, you don't have to go to all that trouble. If you folks will just hire me on, I'll ask the imaging team myself! :) Actually, I read an article last week about how so many bright young engineers were leaving NASA for better-paying jobs. Given NASA's recent downsizing, this seemed a lhÄtle odd. Is it true? If so, does it open up any job possibilities for the Unwashed Masses, or does NASA and JPL keep lists of people salivating at the prospect of getting work there?

Stephen in Seattle: . . . . Wed, Oct 30, 7:08PM PDT (-0700 GMT)
Leslie Lowes: Look, you don't have to go to all that trouble. If you folks will just hire me on, I'll ask the imaging team myself! :) Actually, I read an article last week about how so many bright young engineers were leaving NASA for better-paying jobs. Given NASA's recent downsizing, this seemed a little odd. Is it true? If so, does it open up any job possibilities for the Unwashed Masses, or does NASA and JPL keep lists of people salivating at the prospect of getting work there?

Stephen in Seattle: . . . . Wed, Oct 30, 7:08PM PDT (-0700 GMT)
Ashwin: So you're saying that a cyclonic storm 30,000 km wide has an overall relief of FOUR kilometers?! That's amazing! So it's not a bubble, but more of an atmospheric plateau. How do you measure the relief? Galileo doesn't have radar ranging, does it?

Stephen in Seattle: . . . . Wed, Oct 30, 7:10PM PDT (-0700 GMT)
Leslie Lowes: Look, you don't have to go to all that trouble. If you folks will just hire me on, I'll ask the imaging team myself! :) Actually, I read an article last week about how so many bright young engineers were leaving NASA for better-paying jobs. Given NASA's recent downsizing, this seemed a lhÄtle odd. Is it true? If so, does it open up any job possibilities for the Unwashed Masses, or does NASA and JPL keep lists of people salivating at the prospect of getting work there?

Marcia Segura, Near Infrared Mapping Spectrometer Team: . . . . Wed, Oct 30, 7:14PM PDT (-0700 GMT)
G'Night All. Until next WEBCHAT Time......