Live From Mars WebChat

Date: February 19, 1997

Featuring: Mike Malin
Camera Systems Principal Investigator
Malin Space Science Systems, La Jolla, California


Sandy/NASA Chat Host: . . . . Wed, Feb 19, 9:01AM PDT (-0700 GMT). . . [14 ] Welcome to another Live From Mars WebChat! Today's guest is Mike Malin. He is the principal investigator on three camera systems that will be sent to Mars over the next four years.

Sandy/NASA Chat Host: . . . . Wed, Feb 19, 9:02AM PDT (-0700 GMT). . . [15 ] These camera systems include the high- and low-resolution cameras (one system) on the Mars Global Surveyor 1996 mission, the medium- and low-resolution cameras (the second system) on the Mars Surveyor 1998 Orbiter, and the descent camera (the third system) on the Mars Surveyor 1998 Lander.

Sandy/NASA Chat Host: . . . . Wed, Feb 19, 9:03AM PDT (-0700 GMT). . . [16 ] As principal investigator Mike is responsible for each of these entire experiments, from start to finish. This includes coming up with the idea for each camera, putting together a team of engineers to design and build it and scientists to use it and interpret the pictures, watching over the development of the hardware and software, operating the camera (determining where and when to take pictures, and of what features), analyzing the pictures, and preparing them for distribution to other scientists and the public.

Sandy/NASA Chat Host: . . . . Wed, Feb 19, 9:03AM PDT (-0700 GMT). . . [17 ] Welcome Mike!

Mike/MOC: . . . . Wed, Feb 19, 9:03AM PDT (-0700 GMT). . . [18 ] Hello everyone, I'm ready to answer some questions.

5th grade/Morris MN: . . . . Wed, Feb 19, 9:04AM PDT (-0700 GMT). . . [19 ] How are the cameras on the Surveyor different from the cameras we use?

Zsuzsa/Zrinyi Middle(Hungary): . . . . Wed, Feb 19, 9:04AM PDT (-0700 GMT). . . [20 ] Mike Can I ask you about the rover?

Shannon/7th grade: . . . . Wed, Feb 19, 9:05AM PDT (-0700 GMT). . . [21 ] Have you received any pictures from the Mars Global Surveyor camera yet?

Mike/MOC: . . . . Wed, Feb 19, 9:05AM PDT (-0700 GMT). . . [22 ] 5th Grade Mooris: the cameras are different from the ones you used in the following ways: 1) they have to survive in the very cold and hot temperatures in space (continued)...

Julie/ESD: . . . . Wed, Feb 19, 9:06AM PDT (-0700 GMT). . . [23 ] Since you own your own company are you contracting out to be the principal investigator on the camera systems?

Mike/MOC: . . . . Wed, Feb 19, 9:07AM PDT (-0700 GMT). . . [24 ] 2) they are electronic cameras, they do not use film, but they are not like video cameras. They are more like still digital cameras, but they use line sensors rather than area sensors so we have to build each picture one line at a time, like a scanner or fax machine.

Mike/MOC: . . . . Wed, Feb 19, 9:08AM PDT (-0700 GMT). . . [25 ] Zsuzsa/Zrinyi Middle: Sure, go ahead and ask. I don't know much about but I'll try.

5th grade/Morris MN: . . . . Wed, Feb 19, 9:09AM PDT (-0700 GMT). . . [26 ] How are the pathfinder and the 1998 lander mission different?

Mike/MOC: . . . . Wed, Feb 19, 9:10AM PDT (-0700 GMT). . . [27 ] Julie: No, I'm really contracting IN to be the PI. I proposed as a scientist to study Mars, and offered to use my company to develop the instrument to support my research.

Levente/Zrinyi(Middle) Hungary: . . . . Wed, Feb 19, 9:10AM PDT (- 0700 GMT). . . [28 ] Are the cameras in relation with the navigation system of the MGS? (sorry, my english isn't very good)

Mike/MOC: . . . . Wed, Feb 19, 9:11AM PDT (-0700 GMT). . . [29 ] Shannon: We have received a few pictures from the MOC. They are of the Pleiades star cluster, which we have used to study the focus of the telescope on the camera.

Mike/MOC: . . . . Wed, Feb 19, 9:12AM PDT (-0700 GMT). . . [30 ] 5th grade/Morris: The Pathfinder mission includes a lander and a rover. The MS'98 mission includes a lander only, but with a very sophisticated arm to collect samples. The Pathfinder landing site is in the equatorial region of Mars, and MS'98 will land very near the South Pole of Mars

Marineris: . . . . Wed, Feb 19, 9:12AM PDT (-0700 GMT). . . [31 ] Does the radiation from the sun effect the cameras at all?

Zsuzsa/Zrinyi Middle(Hungary): . . . . Wed, Feb 19, 9:13AM PDT (-0700 GMT). . . [32 ] Mike:What changes would be needed to use the rover on the Moon?

Mike/MOC: . . . . Wed, Feb 19, 9:13AM PDT (-0700 GMT). . . [33 ] Levente: The cameras are not officially part of the navigation system. However, they can and will be used both to calibrate the attitude system, and to locate places on Mars much more accurately then can be done by radio tracking.

Julie/ESD: . . . . Wed, Feb 19, 9:14AM PDT (-0700 GMT). . . [34 ] So the Mars '98 is going to study the polar cap on the South Pole?

Mary/Zrinyi Middle (Hungary): . . . . Wed, Feb 19, 9:14AM PDT (-0700 GMT). . . [35 ] How had been the sols computed?

Shannon/7th grade: . . . . Wed, Feb 19, 9:14AM PDT (-0700 GMT). . . [36 ] Have you built the Mars Surveyor '98 cameras yet, or are you waiting to see how the '96 camera works to see if you have to change the design or something?

: . . . . Wed, Feb 19, 9:14AM PDT (-0700 GMT). . . [37 ] Do these cameras have lenses? If so how do you keep them clean? dust etc

Mike/MOC: . . . . Wed, Feb 19, 9:15AM PDT (-0700 GMT). . . [38 ] Marineris: I'm not sure what you are asking. The visible and infrared radiation heats the camera. The solar wind particle radiation can cause the computer to occassionally upset, but we have designed it to accommodate both of these effects.

Mike/MOC: . . . . Wed, Feb 19, 9:16AM PDT (-0700 GMT). . . [39 ] Zsuzsa: Probabaly very little would have to be changed to use the Pathfinder rover on the Moon. The primary difference is that the Moon is likely to be both much hotter and much colder than Mars, because it doesn't have an atmosphere to spread the temperature more evenly.

5th grade/Morris MN: . . . . Wed, Feb 19, 9:16AM PDT (-0700 GMT). . . [40 ] What planets did the Mariner's orbit that you helped with and how are Surveyor's cameras better?

Mark Stokes: . . . . Wed, Feb 19, 9:16AM PDT (-0700 GMT). . . [41 ] Hi to Mike, Sandy and Andrea. Mike, how are the pictures actually taken? Do you send a message from Earth to a camera and does a computer tell it what to do?

Sandy/NASA Chat Host: . . . . Wed, Feb 19, 9:17AM PDT (-0700 GMT). . . [42 ] Welcome Mark!

Mike/MOC: . . . . Wed, Feb 19, 9:18AM PDT (-0700 GMT). . . [43 ] Julie: The MS'98 mission is landing on an unusual area near the South Pole called the polar layered deposits. These deposits are believed to consist of water ice and intermixed dust. The intent of the mission is to study these materials for evidence of climate history and change. What is ESD?

Mike/MOC: . . . . Wed, Feb 19, 9:18AM PDT (-0700 GMT). . . [44 ] Mary, I don't understand your question.

Zsuzsa/Zrinyi Middle(Hungary): . . . . Wed, Feb 19, 9:19AM PDT (-0700 GMT). . . [45 ] Mike:What new technological and academic methods had been used at the rover?

Mike/MOC: . . . . Wed, Feb 19, 9:19AM PDT (-0700 GMT). . . [46 ] Shannon: The MS'98 cameras are very different from the MGS cameras and must be delivered to the spacecraft BEFORE MGS gets to Mars. So we are presently building them.

Sandy/NASA Chat Host: . . . . Wed, Feb 19, 9:20AM PDT (-0700 GMT). . . [47 ] WHOEVER WROTE THIS QUESTION: "Do the cameras have lenses...?" PLEASE SIGN IN WITH YOUR NAME SO MIKE KNOWS WHO TO SEND HIS ANSWNER TO! THANKS!

Julie/ESD: . . . . Wed, Feb 19, 9:20AM PDT (-0700 GMT). . . [48 ] Mike, ESD stands for Educational Service District 101. We provide many services for the schools of Eastern Washington. I personally work at the telecommunications division. I work on a program called Young Astronauts which goes to many schools accross the US via satellite.

Gergely/Zrinyi Middle (Hungary): . . . . Wed, Feb 19, 9:20AM PDT (- 0700 GMT). . . [49 ] Mike/MOC: Which filter have You used in the electronic cameras?

Mike/MOC: . . . . Wed, Feb 19, 9:21AM PDT (-0700 GMT). . . [50 ] Morris: I was 21 when Mariner 9 went into orbit around Mars. I worked for Bruce Murray, who was one of the leaders of that camera team. I also worked with Bruce on the Mariner 10 mission that went to Venus and Mercury. I worked at JPL during the Viking and Voyager missions.

vince/BOEING: . . . . Wed, Feb 19, 9:22AM PDT (-0700 GMT). . . [51 ] Yes! I asked the question about dust.

: . . . . Wed, Feb 19, 9:22AM PDT (-0700 GMT). . . [52 ] Hi! Sorry, I didn't know that there was a chat today:) For some reason I haven't got the LFM update yet:(

Megan: . . . . Wed, Feb 19, 9:22AM PDT (-0700 GMT). . . [53 ] That was me:)

Mary/Zrinyi Middle (Hungary): . . . . Wed, Feb 19, 9:23AM PDT (-0700 GMT). . . [54 ] How could you measure,how long is a sol?

Mike/MOC: . . . . Wed, Feb 19, 9:23AM PDT (-0700 GMT). . . [55 ] Mark: The camera is told what to do by commanding it from Earth (although we have a mode in which it takes care of itself if it hasn't heard from Earth and it runs out of things to do). We have software that shows where on the planet the orbiter is going to be at any given time and we then tell it what to take.

Sandy/NASA Chat Host: . . . . Wed, Feb 19, 9:23AM PDT (-0700 GMT). . . [56 ] THANKS Vince--we'll get to your question in a minute!

minnow man: . . . . Wed, Feb 19, 9:23AM PDT (-0700 GMT). . . [57 ] Hi Mike, I was wondering approximately how much does it cost to build the cameras?

5th grade/Morris MN: . . . . Wed, Feb 19, 9:23AM PDT (-0700 GMT). . . [58 ] How are surveyor's cameras different from the Mariner's cameras?

Levente/Zrinyi(Middle) Hungary: . . . . Wed, Feb 19, 9:24AM PDT (- 0700 GMT). . . [59 ] What do you think, will the MGS 1996 carry more information about the geologic origin of the Mars? What will you do with the wrong solar panel? Will the MGS carry any information during the aerobraking?

Mike/MOC: . . . . Wed, Feb 19, 9:24AM PDT (-0700 GMT). . . [60 ] Vince: The cameras have either lenses or mirrors, depending on which camera we're talking about. None of my cameras work on the martian surface. The MGS camera, and two of the MS'98 cameras, are in orbit 400 km above the planet. One MS'98 camera will operate during the descent to the surface, but is not intended to take pictures after we land.

Mike/MOC: . . . . Wed, Feb 19, 9:25AM PDT (-0700 GMT). . . [61 ] Zsuzsa: I don't really know too much about the rover, so I cannot answer your question. Sorry.

Sandy/NASA Chat Host: . . . . Wed, Feb 19, 9:26AM PDT (-0700 GMT). . . [62 ] Welcome Megan! Send me an email about the updates and I'll look into the problem.

Mark: . . . . Wed, Feb 19, 9:26AM PDT (-0700 GMT). . . [63 ] Mike - how much time and effort is required to analyze, catalog, and form conclusions about the pictures you take?

Mike/MOC: . . . . Wed, Feb 19, 9:27AM PDT (-0700 GMT). . . [64 ] Gergely: The MGS wide angle (low resolution) cameras have two color filters (one on each camera): red and blue. The MS'98 orbiter cameras have many color filters between the near-ultra violet and the near-infra-red.

vince/BOEING: . . . . Wed, Feb 19, 9:27AM PDT (-0700 GMT). . . [65 ] Do you get a chance to test your cameras in earth orbit before sending them into deep space?

Mike/MOC: . . . . Wed, Feb 19, 9:29AM PDT (-0700 GMT). . . [66 ] Mary: The day on Mars is slighly longer than the day on the Earth. To distinguish between martian days and earth days, we call the martian day a "sol." The length of a sol has been known for quite a while...it is measure by looking at a feature on Mars and waiting until that feature is again seen. This take 24 hr and roughly 36 minutes.

Megan: . . . . Wed, Feb 19, 9:29AM PDT (-0700 GMT). . . [67 ] Ok, thanks Sandi!

Marineris: . . . . Wed, Feb 19, 9:29AM PDT (-0700 GMT). . . [68 ] What is the best resolution of the marsian surface that the cameras of MGS will provide?

Mike/MOC: . . . . Wed, Feb 19, 9:30AM PDT (-0700 GMT). . . [69 ] Minnowman: The Mars Observer camera (the first one...that was lost when Mars Observer disappeared), cost $20 million to design, build, and test. The MGS camera is the spare from MO, and it cost $3.5 million to assemble (it was in pieces) and test. The MS'98 cameras are a new design, and will cost $3.3 million for 3 cameras.

Zsuzsa/Zrinyi Middle(Hungary): . . . . Wed, Feb 19, 9:30AM PDT (-0700 GMT). . . [70 ] Mike:How will the rover get out of the Lander?

Julie/ESD: . . . . Wed, Feb 19, 9:32AM PDT (-0700 GMT). . . [71 ] In your bio you talked about when you got interested in science. But when did you realize you were interested in cameras and photography?

Mike/MOC: . . . . Wed, Feb 19, 9:32AM PDT (-0700 GMT). . . [72 ] 5th Grade Morris: The Mariner cameras used old TV tubes called vidicons, and were able to take pictures only about 800-1000 picture elements on a side. The Surveyor cameras use a new TV technology call CCDs, and the MGS camera uses 3456 and 2048 pixel detectors. There are many other differences.

Gergely/Zrinyi Middle (Hungary): . . . . Wed, Feb 19, 9:33AM PDT (- 0700 GMT). . . [73 ] Mike : What do You think, is there any primitive life on the Mars?

Mark: . . . . Wed, Feb 19, 9:34AM PDT (-0700 GMT). . . [74 ] Mike - 3456 pixels? That's a lot! On what do you view these pictures that can display that many pixels?

Mary/Zrinyi Middle (Hungary): . . . . Wed, Feb 19, 9:34AM PDT (-0700 GMT). . . [75 ] What academic exercises have the penetratos?

Mike/MOC: . . . . Wed, Feb 19, 9:36AM PDT (-0700 GMT). . . [76 ] Levente: MGS will greatly increase our knowledge about the geological evolution and history of Mars. All of its experiments are intended to directly address these quetions. The MGS flight team is presently developing plans to "work around" the problem with the solar panel. At present, while it is a concern, we think the mission will achieve more than 100% of its objectives. Both engineering and science instrument data will be acquired during portions of the aerobraking period. Some of these data will be extremely important to operating the spacecraft DURING aerobraking (keeping it safe), and some will be science data that can only be acquired during this time.

Levente/Zrinyi(Middle) Hungary: . . . . Wed, Feb 19, 9:37AM PDT (- 0700 GMT). . . [77 ] What do you think, how long will be the relay phase? What category does the camera system have?

Mike/MOC: . . . . Wed, Feb 19, 9:38AM PDT (-0700 GMT). . . [78 ] Mark: That's an excellent question. The easy part to answer is how long it takes to process, catalog, and archive the data. While we'll have a quick look at the images shortly after they are received, it will take several weeks to months (but less than 6 month) to process them to the best they'll ever be. Analysis is harder...this depends on how much time I have to look at the pictures, and the problems I am interested in. My personal research involved floods and other water-related events on Mars.

Gergely/Zrinyi Middle (Hungary): . . . . Wed, Feb 19, 9:39AM PDT (- 0700 GMT). . . [79 ] Mike : What the CCD cameras like?

Mary/Zrinyi Middle (Hungary): . . . . Wed, Feb 19, 9:39AM PDT (-0700 GMT). . . [80 ] How will the penetratos brake off?

5th grade/Morris MN: . . . . Wed, Feb 19, 9:39AM PDT (-0700 GMT). . . [81 ] About how many hours a day do you talk on the phone for business purposes?

Mike/MOC: . . . . Wed, Feb 19, 9:40AM PDT (-0700 GMT). . . [82 ] Vince: Neither the MGS nor the MS'98 spacecraft stayed in Earth orbit after they were launched. Both went to Mars within 1/2 an orbit. We tried to image the Earth and Moon shortly after launch (about 20 days after), but our field of view was so small we missed it. Our next chance to checkout the MGS camera will be as we approach Mars.

Mark: . . . . Wed, Feb 19, 9:40AM PDT (-0700 GMT). . . [83 ] To Zrinyi and Mike: what is penetratos?

Julie/ESD: . . . . Wed, Feb 19, 9:41AM PDT (-0700 GMT). . . [84 ] Well, Ive got to go thanks for the answers to my questions. Julie

Mike/MOC: . . . . Wed, Feb 19, 9:41AM PDT (-0700 GMT). . . [85 ] Zsuzsa: The lander opens up like a flower, and the rover is attached to one of the petals. After it opens, a ramp extends down the petal, the rover "sits up" on its wheels, and rolls down.

Mike/MOC: . . . . Wed, Feb 19, 9:43AM PDT (-0700 GMT). . . [86 ] Julie: My interest in cameras and photography comes from the fact that it was fairly easy for a kid to look at pictures and see things. So I was able to think of what I wanted to look for, and then to look at it. As I got into univerity work, it was clear that to take pictures of other planets, I needed to know more about the cameras that take picture, how they work, how they're built, etc.

Mary/Zrinyi Middle (Hungary): . . . . Wed, Feb 19, 9:43AM PDT (-0700 GMT). . . [87 ] Mark: penetratos is a typing mistake instead of penetrator

Zsuzsa/Zrinyi Middle(Hungary): . . . . Wed, Feb 19, 9:44AM PDT (-0700 GMT). . . [88 ] Mike:What is your company?What do you do at your company?Why did you leave there JLP?Do you teach now and where?

Sandy/NASA Chat Host: . . . . Wed, Feb 19, 9:46AM PDT (-0700 GMT). . . [89 ] Bye Julie, thanks for joining us! Hope to hear from you again next week!

Mike/MOC: . . . . Wed, Feb 19, 9:46AM PDT (-0700 GMT). . . [90 ] Gergely: I personally do not think there is any life on Mars. Many of my colleagues disagree. Even primitive life on Earth has evolved considerably to survive in the places we find it on Earth, and this evolution has generally occurred slowly as conditions have changed slowly. On Mars, the conditions are very harsh today, they have been very harsh for a very long time, and they change from being very harsh to being even harsher on very short timescales. This isn't the kind of place life likes.

vince/BOEING: . . . . Wed, Feb 19, 9:46AM PDT (-0700 GMT). . . [91 ] Have to sign off! Thank you very much! I'll be waiting to see the images from MGS.

Mike/MOC: . . . . Wed, Feb 19, 9:48AM PDT (-0700 GMT). . . [92 ] Mark: Good question! We can only look at portions of each MOC picture at a time at full resolution. Of course, we can shrink it down to fit our computer screens, or we can look at it at full resolution, but have to scroll around to see the whole thing. Actually, me and most of my colleagues prefer to print these pictures and look at them on photographic paper, as this is a very high density medium.

Mike/MOC: . . . . Wed, Feb 19, 9:49AM PDT (-0700 GMT). . . [93 ] Mary: I'm not sure what you're asking about the penetrators. Could you be more specific?

Zsuzsa/Zrinyi Middle(Hungary): . . . . Wed, Feb 19, 9:50AM PDT (-0700 GMT). . . [94 ] Mike:What will you do ,if MGS ,MS'98O or MS'98L fail of succes?

Mike/MOC: . . . . Wed, Feb 19, 9:50AM PDT (-0700 GMT). . . [95 ] 5th grade Morris: I spend far too much time on the phone during the day. I would guess, 3 hours a day are on the phone, 3 hrs a day are talking to my employees, 3 hrs a day are working on my Macintosh writing letter, documents, etc., and 2 hrs a day are spent on my workstation processing images and other data.

Levente/Zrinyi(Middle) Hungary: . . . . Wed, Feb 19, 9:51AM PDT (- 0700 GMT). . . [96 ] Does the MGS have different color filters? If yes, is it possible to make 3D pictures from Mars - or you are going to do that in the analyzing phase?

Sandy/NASA Chat Host: . . . . Wed, Feb 19, 9:53AM PDT (-0700 GMT). . . [97 ] Bye Vince. Please join us next week!

Mike/MOC: . . . . Wed, Feb 19, 9:53AM PDT (-0700 GMT). . . [98 ] Zsuzsa: My company designs, builds, and operates the cameras I've proposed to use at Mars and other planets. I left JPL to take a teaching position at Arizona State University, when the US Space Program went into a lull in the late 1970's-early 1980's. I didn't want to study missions, I wanted to DO something. So I pursued my geology interests. I subsequently left ASU to form my own company (about 10 years later), because I felt I could offer the government a lower cost (and therefore improve my chances of being selected).

Levente/Zrinyi(Middle) Hungary: . . . . Wed, Feb 19, 9:54AM PDT (- 0700 GMT). . . [99 ] I think, the time is up so have an other question to you. Could you send me your e-mail address on that I could send more questions, please? Thanks, Levente.

Mike/MOC: . . . . Wed, Feb 19, 9:56AM PDT (-0700 GMT). . . [100 ] Levente: Yes, MGS has color filters (red and blue), from which we will make color pictures. For 3D, we will use pictures taken at different times to create the stereoscopic views. We have two ways of seeing stereo--one uses red for one eye and blue for the other, but this doesn't mean they were originally taken through those filters. The other way is to look at them on the screen with special glasses that let us see stereo.

Sandy/NASA Chat Host: . . . . Wed, Feb 19, 9:56AM PDT (-0700 GMT). . . [101 ] Levente: Thank you so much for joining us today! Please send me your email address and I will tell you how to get all of your Mars-related questions answered by NASA Mars scientists! My email is: sandy@quest.arc.nasa.gov

Sandy/NASA Chat Host: . . . . Wed, Feb 19, 9:57AM PDT (-0700 GMT). . . [102 ] EVERYONE: WE HAVE 5 MINUTES LEFT AND HAVE TIME FOR A FEW MORE QUESTIONS...

5th grade/Morris MN: . . . . Wed, Feb 19, 9:57AM PDT (-0700 GMT). . . [103 ] Do you still like to read science fiction books?

Mike/MOC: . . . . Wed, Feb 19, 10:00AM PDT (-0700 GMT). . . [104 ] Zsuzsa: Well, I have some experience at this...having been involved with Mars Observer. First, I always approach space work with the full knowledge that it is very risky. People forget this, and are surprise when things don't work, but they shouldn't. So, I have enjoyed what I do and will keep doing it even when things don't work quite the way we hope. Second, I am very lucky to be involved with three Mars spacecraft: the likelihood that all three fail is very low. Finally, I have several other projects I'm working on (Pathfinder, Near-Earth Asteroid Rendezvous) and other science projects that can keep me very busy.

Marineris: . . . . Wed, Feb 19, 10:01AM PDT (-0700 GMT). . . [105 ] Has there been a determination as to when humans will explore mars?

Mike/MOC: . . . . Wed, Feb 19, 10:01AM PDT (-0700 GMT). . . [106 ] 5th grade Morris: I still like science fiction, although I don't find I have the time to read as I did when I was younger. I haven't found a lot of recent science fiction I have liked as much as I like the "older stuff," but I do find some things occassionally that I enjoy.

Sandy/NASA Chat Host: . . . . Wed, Feb 19, 10:02AM PDT (-0700 GMT). . . [107 ] Thanks very much to everyone for joining us for today's chat! And especially thanks to Mike for sharing his time with us today. We hope you will join us for another chat in the future Mike! Good luck with your cameras!

Mike/MOC: . . . . Wed, Feb 19, 10:02AM PDT (-0700 GMT). . . [108 ] 'Bye, everyone.

5th grade/Morris MN: . . . . Wed, Feb 19, 10:04AM PDT (-0700 GMT). . . [110 ] Thank you for answering our questions.

Mark Stokes: . . . . Wed, Feb 19, 10:04AM PDT (-0700 GMT). . . [111 ] Many thanks to Mike for your excellent answers and to Sandy and Andrea for another great chat. They keep getting better all the time :-).

Sandy/NASA Chat Host: . . . . Wed, Feb 19, 10:08AM PDT (-0700 GMT). . . [112 ] Good bye Marineris, 5th grade/Morris and Mark. Thank you so much for joining us today! I hope you can join us again next week--on Wed., Feb. 26 at 9 a.m. The Mars expert will be Jim Murphy. Check out his bio.


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