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Mars Team Online WebChat

Date: July 8, 1997

Featuring: Jeff Plescia
Research Scientist
Jet Propulsion Laboratory, Pasadena, CA


Tibor/Zrinyi Middle Hungary: . . . . Tue, Jul 8, 1:26AM PDT (-0700 GMT)
Hello Sandy, We are going to meeting you this evening/morning. Unfortunately our email server don't serve :-) so I can't get and send letters. We were following the events on the Mars. What a good work!

Sandy/NASA CHAT HOST: . . . . Tue, Jul 8, 8:09AM PDT (-0700 GMT)
Good Morning Tibor in Hungary! So glad you could join us! The chat will begin in about 55 minutes. For more info on Jeff Plescia go to: button

Tue, Jul 8, 8:38AM PDT (-0700 GMT)
This is Raghu from Bangalore, India

B. Raghuvir: . . . . Tue, Jul 8, 8:40AM PDT (-0700 GMT)
How is the Sojourner doing currently?

Sandy: NASA Chat Host: . . . . Tue, Jul 8, 8:42AM PDT (-0700 GMT)
Good Morning Raghu in India! Welcome to today's "Mars Team Online" webchat! Be sure to type your name "Raghu/India" in the small box below this large chat box. That will your name will appear before all of your comments and everyone will know who you are.

B. Raghuvir: . . . . Tue, Jul 8, 8:43AM PDT (-0700 GMT)
What has been the progress of the Sojourner?

Sandy: NASA Chat Host: . . . . Tue, Jul 8, 8:43AM PDT (-0700 GMT)
B. Raghuvir: We're not taking questions yet. It's still 15 minutes before our guest is here and before the chat starts. Chat with you shortly...

Trish/Jessup Elem.: . . . . Tue, Jul 8, 8:45AM PDT (-0700 GMT)
Hi Sandy

Sandy: NASA Chat Host: . . . . Tue, Jul 8, 8:46AM PDT (-0700 GMT)
Hi Trish! Welcome to you and your kids :-) We'll be starting in about 15 minutes...

Trish/Jessup Elem.: . . . . Tue, Jul 8, 8:46AM PDT (-0700 GMT)
Thanks. We wanted to be ready.

B. Raghuvir: . . . . Tue, Jul 8, 8:48AM PDT (-0700 GMT)
Hi Trish, This is raghu from India.

Jeff Plescia: . . . . Tue, Jul 8, 8:50AM PDT (-0700 GMT)
Hi. I'm ready when you all are.

Trish/Jessup Elem.: . . . . Tue, Jul 8, 8:50AM PDT (-0700 GMT)
Hi raghu. We are from Jessup Elementary. Maryland, USA. This is our first web chat.

Sue, Sonora, CA: . . . . Tue, Jul 8, 8:51AM PDT (-0700 GMT)
Hi everyone. This is Sue in Sonora, CA. Good morning, Sandy.

B. Raghuvir: . . . . Tue, Jul 8, 8:51AM PDT (-0700 GMT)
Mine too, great isn't it to be on mars for the first time?

D. Brennen/PHS: . . . . Tue, Jul 8, 8:51AM PDT (-0700 GMT)
Hello! I am D. Brennen From Fort Worth, Texas.

B. Raghuvir: . . . . Tue, Jul 8, 8:53AM PDT (-0700 GMT)
hello Sonora, this is raghu from india.

Sandy: NASA Chat Host: . . . . Tue, Jul 8, 8:53AM PDT (-0700 GMT)
EVERYONE: Good Morning and welcome to another "Mars Team Online" WebChat. Jeff Plescia from NASA's Jet Propulsion Laboratory in Pasadena, California is our Mars expert today.

B. Raghuvir: . . . . Tue, Jul 8, 8:55AM PDT (-0700 GMT)
Hello Jeff, How is Sojourner doing?

Jeff Plescia: . . . . Tue, Jul 8, 8:55AM PDT (-0700 GMT)
Hi. I'm here at JPL. Just a bit of news about Pathfinder. The rover is operating successfully, it has taken a number of pictures and performed some chemistry measurements on some soil and rocks. Any questions?

Dave/Barre: . . . . Tue, Jul 8, 8:56AM PDT (-0700 GMT)
Hello Sandy, Jeff, and everyone else. I'm Dave White from Barre,VT. Question for Jeff: Since the evidence for the Antarctic meteorite originating on Mars came from chemical analysis data provided by Viking, will Pathfinder data help confirm that evidence and begin a data base that might help locate to area on Mars that the meteorite came from?

Jeff Plescia: . . . . Tue, Jul 8, 8:57AM PDT (-0700 GMT)
Dave: The chemistry data from the APX will help make a stronger case for the SNC meteorites coming from Mars. But we really need to make isotope measurements which will require a sample return.

Jennifer/Jessup Elem.: . . . . Tue, Jul 8, 8:56AM PDT (-0700 GMT)
Hi Jeff. We are the Jessup Elementary Space club and we have plenty of good questions.

D.: . . . . Tue, Jul 8, 8:57AM PDT (-0700 GMT)
Why is the surface rusting?

Jeff Plescia: . . . . Tue, Jul 8, 8:58AM PDT (-0700 GMT)
D: The surface of Mars has a considerable amount of iron and a lot of oxidants. So, over time, the materials weathers, and the iron turns into iron oxide - rust.

Suzy/Jessup Elem.: . . . . Tue, Jul 8, 8:58AM PDT (-0700 GMT)
If mars has volcanos and the volcanos were to erupt what would happen to mars?

Jeff Plescia: . . . . Tue, Jul 8, 8:59AM PDT (-0700 GMT)
Suzy: Mars has many volcanoes. They range in age from billions of years to a few hundred million years. They may still be active today. They would produce lava like in Hawaii on earth or possibly small cinder cones.

Sue/Sonora: . . . . Tue, Jul 8, 8:58AM PDT (-0700 GMT)
Hi, Jeff. How will you be examining the picture from Barnacle Bill and do you have any results yet?

Jeff Plescia: . . . . Tue, Jul 8, 9:00AM PDT (-0700 GMT). . . [48 ]
Sue: Barnacle Bill is a bit bluer than the other rocks. We will get the chemistry data today.

LuisAlves@Portugal/Europe: . . . . Tue, Jul 8, 8:58AM PDT (-0700 GMT)
Hello everyone!

B. Raghuvir: . . . . Tue, Jul 8, 8:58AM PDT (-0700 GMT)
What has been the progress on finding water on the mars?

Jeff Plescia: . . . . Tue, Jul 8, 9:01AM PDT (-0700 GMT)
Raghu: Pathfinder itself can not detect water below the surface. So, it is still a mystery as to where the water from the floods went. The assumption is that it is all below the surface.

Students/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 8:58AM PDT (-0700 GMT)
Hello Sandy!

Kovi&Levi/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:00AM PDT (-0700 GMT)
Hello to everybody!

LuisAlves@Portugal/Europe: . . . . Tue, Jul 8, 9:00AM PDT (-0700 GMT)BR> Jeff: Have you discovered any new think you didn't know already?

Jeff Plescia: . . . . Tue, Jul 8, 9:05AM PDT (-0700 GMT)
Luis: Yes, we have now seen the surface of Mars in a geologic environment very different from the Viking site. That will tell us about the geology and geochemsitry of the planet. Also, it appears to be a bit warmer than it was when Viking was there.

Sandy: NASA Chat Host: . . . . Tue, Jul 8, 9:00AM PDT (-0700 GMT)
Hello Students from Hungary! I'm really glad to see you're here today!

Carolyn/Jessup Elem.: . . . . Tue, Jul 8, 9:00AM PDT (-0700 GMT)
Could a substance other than water have eroded the rocks?

Jeff Plescia: . . . . Tue, Jul 8, 9:02AM PDT (-0700 GMT)
Carolyn: The only real plausible material to erode the surface in water. People have suggested wind and even hydrocarbons but they are not consistent with the data.

B. Raghuvir: . . . . Tue, Jul 8, 9:01AM PDT (-0700 GMT)
There has been a lot of news of life on Mars. Has sojourner found anything?

Jeff Plescia: . . . . Tue, Jul 8, 9:03AM PDT (-0700 GMT)
Raghu: The rover has no life detection experiments. The only evidence would come from something observed in the scene, say a fossil (but this is very very unlikely).

Sue/Sonora: . . . . Tue, Jul 8, 9:02AM PDT (-0700 GMT)
Just how far (what distance) do you think Sojourner will move on the surface?

Jeff Plescia: . . . . Tue, Jul 8, 9:06AM PDT (-0700 GMT)
Sue: The rover will stay within a few tens of meters of the lander for a while. There has been some suggestion to send it off to the horizon later in the mission (a kilometer or so). It can not get out of sight of the lander because it has to communicate back to the lander.

Students/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:02AM PDT (-0700 GMT)
Hello Jeff! How many airbags were there on the lander?

Jeff Plescia: . . . . Tue, Jul 8, 9:08AM PDT (-0700 GMT)
Students in Hungary: Off hand, I do not remember how many airbags there, I will check.

Loretta/Jessup Elem.: . . . . Tue, Jul 8, 9:02AM PDT (-0700 GMT)
How can you learn about Earth's past by studying Mars?

Jeff Plescia: . . . . Tue, Jul 8, 9:09AM PDT (-0700 GMT)
Loretta: The ancient surface of earth that would date to say 3-4 BY has largely been destroyed by erosion and plate tectonics. But Mars has retained that ancient crust. So we could find material there that preserves the ancient chemistry (how the planet f ormed) and the ancient climate.

B. Raghuvir: . . . . Tue, Jul 8, 9:03AM PDT (-0700 GMT)
If you find any kind of living organisms out there, what next?

Jeff Plescia: . . . . Tue, Jul 8, 9:10AM PDT (-0700 GMT)
Raghu: If we found a living organism, I'm certain we would move up plans for a sample return mission. It would also give great impetus to a human mission.

LuisAlves@Portugal/Europe: . . . . Tue, Jul 8, 9:04AM PDT (-0700 GMT)
I known Nasa is sending an orbiter to mars. Can it scan mars for water in the underground?

Jeff Plescia: . . . . Tue, Jul 8, 9:11AM PDT (-0700 GMT). . . [85 ]
Luis: The 2001 orbiter will carry a neutron spectrometer which will be able to tell if there is any water within the upper meter. Later, maybe 2003-2007 we will send a radar mapper which will be able to find water to depths of many kilometers below the su rface.

Audrey/Jessup Elem.: . . . . Tue, Jul 8, 9:04AM PDT (-0700 GMT)
How long will the lander and rover stay on mars?

Jeff Plescia: . . . . Tue, Jul 8, 9:12AM PDT (-0700 GMT)
Audry: The lander and rover will stay on Mars forever. They will probably last for a couple of months, until winter.

Dave/Barre: . . . . Tue, Jul 8, 9:04AM PDT (-0700 GMT)
Jeff: Earlier today, Donna Shirley talked oxidizers (other than water) that might be responsible for the rust dust. Do you have a likely candidate for what that oxidizer might be?

Kovi&Levi/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:05AM PDT (-0700 GMT)
Is a strong wind able to turn over the MPF? I mean the whole spacecraft lies on the airbags and not on the surface of the Mars.

Jeff Plescia: . . . . Tue, Jul 8, 9:13AM PDT (-0700 GMT)
Kovi / Levi: The airbags have been deflated and retracted, so Pathfinder rests on the surface now. The wind is not strong enough on Mars to turn the lander or rover.

LuisAlves@Portugal/Europe: . . . . Tue, Jul 8, 9:06AM PDT (-0700 GMT)
For water H2O, there must be oxygen !So there were oxygen on mars?

Jeff Plescia: . . . . Tue, Jul 8, 9:14AM PDT (-0700 GMT)
Luis: This is some oxygen in the atmosphere today, 0.0013 by volume. The oxygen may have been more abundant in the past.

Teela/Jessup Elem.: . . . . Tue, Jul 8, 9:06AM PDT (-0700 GMT)
Would cells on Mars be able to live without water?

Jeff Plescia: . . . . Tue, Jul 8, 9:15AM PDT (-0700 GMT)
Tella: Life everywhere seems to require water. So we make the assumption that life on Mars would require water as well.

Darrell/Jessup Elem.: . . . . Tue, Jul 8, 9:07AM PDT (-0700 GMT)
Has any bacteria been found in the rocks?

B. Raghuvir: . . . . Tue, Jul 8, 9:08AM PDT (-0700 GMT)
You landed on moon now on Mars. Nothing has revolutionised that big step for mankind. how will this help?

Jeff Plescia: . . . . Tue, Jul 8, 9:17AM PDT (-0700 GMT)
Raghu: Sending humans to Mars will expand our intellectual horizons and satisfy our need to explore.

Students/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:08AM PDT (-0700 GMT)
Why did you select the Yogi Rock to measure by the APXS?

Jeff Plescia: . . . . Tue, Jul 8, 9:18AM PDT (-0700 GMT)
Students from Hungary: Yogi was selected because it was a large rock and it was close to the lander. We do not want to venture too far away at first. Plus, it looks different from Bill.

D.: . . . . Tue, Jul 8, 9:10AM PDT (-0700 GMT)
Why is mars rusting?

Jeff Plescia: . . . . Tue, Jul 8, 9:10AM PDT (-0700 GMT)
D: The surface is rusting because the iron in the rocks is oxidized from weathering. Viking saw some oxidants in the soil like hydrogen peroxide (but we're not sure). Any source of oxygen will work.

Heather/Jessup Elem.: . . . . Tue, Jul 8, 9:11AM PDT (-0700 GMT)
How long do you think it has been since there was water on Mars?

Jeff Plescia: . . . . Tue, Jul 8, 9:19AM PDT (-0700 GMT)
Heather: There are two schools of thought about large amounts of water - one is that is has been serveral billion years since large floods, the other (the minority) believe that in the recent past there were oceans in the northern hemisphere. But, smaller quantities of water may have been present in some of the small valley networks within the last few hundred millions years.

D.: . . . . Tue, Jul 8, 9:12AM PDT (-0700 GMT)
Why does NASA think the meteor that hit earth with the bacteria came from mars?

Jeff Plescia: . . . . Tue, Jul 8, 9:16AM PDT (-0700 GMT)
D: No bacteria has been found on the surface of Mars by Viking and Pathfinder can not look. The suggestion comes from the Mars meteorites. There is alot of controversy about the Mars meteorites and whether the things that suggest life are from Mars or as you suggest from the Earth. Much of the evidence was found inside the meteorite below the crust that formed when it passed through the atmosphere. Other meteorites do not have such evidence suggesting that it may be real from Mars.

Students/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:12AM PDT (-0700 GMT)
Do you know how many times did the lander jump up from the surface during the landing?

Jeff Plescia: . . . . Tue, Jul 8, 9:23AM PDT (-0700 GMT)
Students In Hungary: The lander bounced at least three times, about 10-15 meters each time. Then there were some small bounces and some rolling. The ramps are made of light-weight metal. They were stored rolled up.

Kovi&Levi/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:12AM PDT (-0700 GMT)
I couldn't find any g measuring from landing of the MPF. Is there any? This is important because we could calculate how the spacecraft landed.

Michelle/Jessup Elem.: . . . . Tue, Jul 8, 9:13AM PDT (-0700 GMT)
When the water disappeared on mars, will the scientists look into the center of mars to find where the water went?

Shanika/Jessup Elem.: . . . . Tue, Jul 8, 9:15AM PDT (-0700 GMT)
How long will it take for the Pathfinder to come back to Earth?

Jeff Plescia: . . . . Tue, Jul 8, 9:23AM PDT (-0700 GMT)
Shanika: The Pathfinder will not come back to Earth. It will stay on Mars forever.

B. Raghuvir: . . . . Tue, Jul 8, 9:15AM PDT (-0700 GMT)
How has the Rover been developed?

Jeff Plescia: . . . . Tue, Jul 8, 9:24AM PDT (-0700 GMT)
Raghu: The rover was developed by JPL over many years by trying to build rovers of different size, with different power sources, and with different technologies. They finally settled on this design, because it fit the mission objectives.

Kovi&Levi/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:17AM PDT (-0700 GMT)
Could you identify Twin Peaks in the images taken by the Vikings?

Jeff Plescia: . . . . Tue, Jul 8, 9:26AM PDT (-0700 GMT)
Kovi & Levi: The peaks might be identifiable. The Viking orbiter data has typcial resolutions of 100-200 meters per pixel (locally better). If they are a couple of kilometers across, then they would be visible. But, they have not yet been identified in th e Viking pictures. The MGS orbiting camera due in the fall will be able to see the hills.

Suzy/Jessup Elem.: . . . . Tue, Jul 8, 9:17AM PDT (-0700 GMT)
If there is life on mars, in the future could we live there too?

Jeff Plescia: . . . . Tue, Jul 8, 9:26AM PDT (-0700 GMT)
Suzy: If there is life on Mars, it's in a special place - below the surface or inside rocks. We could live on Mars, but we would have to wear spacesuits (the air is too thin and it's generally too cold).

Audrey/Jessup Elem.: . . . . Tue, Jul 8, 9:19AM PDT (-0700 GMT)
How long did it take for the ship to get to Mars?

Jeff Plescia: . . . . Tue, Jul 8, 9:27AM PDT (-0700 GMT)
Audry: Pathfinder was launched in December 1996 and arrived a few days ago, so 7 months.

B. Raghuvir: . . . . Tue, Jul 8, 9:20AM PDT (-0700 GMT)
If bacteria has been found then, then that should have completed that mssion? Then what has Viking accomplished?

Jeff Plescia: . . . . Tue, Jul 8, 9:28AM PDT (-0700 GMT)
Raghu: Viking did not find evidence of life on Mars... and Pathfinder does not have the capability to find life. The objectives of Pathfinder were to test new technology and demonstrate roving across the surface, as well as to explore a new site.

Sue/Sonora: . . . . Tue, Jul 8, 9:20AM PDT (-0700 GMT)
From what you have seen, are there new elements to be found in the Mars rocks/surface?

Jeff Plescia: . . . . Tue, Jul 8, 9:29AM PDT (-0700 GMT)
Sue: We believe we know all the chemical elements that exist. We would expect to discover a new element on Mars. But we do not know the amounts that occur on Mars. Understanding the amount of different elements will allows us to understand what the rocks are made of and how the planet formed.

Kovi&Levi/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:21AM PDT (-0700 GMT)
What are the ramps made of? What helped to keep the ramps straight? (if they were stored rolled up...)

Jeff Plescia: . . . . Tue, Jul 8, 9:30AM PDT (-0700 GMT)
Kovi, Levi: The ramps were rolled up metal. When they were released the unrolled and little latches closed to keep it out.

marsplus/UW: . . . . Tue, Jul 8, 9:21AM PDT (-0700 GMT)
What have you learned about the geology of Mars so far from Pathfinder?

Jeff Plescia: . . . . Tue, Jul 8, 9:31AM PDT (-0700 GMT)
Marsplus at UW: We've learned that there are a variety of rocks types and soil types and that the surface looks much different from what we saw at the Viking site. We have gotten new chemistry data which will tell us about the rocks. We think we now know what a martian flood plain looks like.

Students/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:21AM PDT (-0700 GMT)
What is the function of the post on the calibration target?

Jeff Plescia: . . . . Tue, Jul 8, 9:32AM PDT (-0700 GMT)
Students in Hungary: The post is part of the antenna structure.

Julie/Jessup Elem.: . . . . Tue, Jul 8, 9:21AM PDT (-0700 GMT)
What do you think happened to the water on mars?

Jeff Plescia: . . . . Tue, Jul 8, 9:33AM PDT (-0700 GMT)
Julie: The water on Mars either sank into the ground (like rain will do) and some of it was broken up in the atmosphere and escaped to space.

D.: . . . . Tue, Jul 8, 9:22AM PDT (-0700 GMT)
gtg (got-to-go) See ya'! Had a great time Bye Jeff!

Sandy: NASA Chat Host: . . . . Tue, Jul 8, 9:22AM PDT (-0700 GMT)
EVERYONE: Please hold up on your questions for about 5 minutes to let Jeff catch up. We are about 20 questions behind and are trying to answer everyone... Thanks :-)

B. Raghuvir: . . . . Tue, Jul 8, 9:22AM PDT (-0700 GMT)
If there has been signs of water, then why NASA is not going ahead with a manned mission to Mars?

Jeff Plescia: . . . . Tue, Jul 8, 9:34AM PDT (-0700 GMT)
Raghu: NASA plans a human mission to Mars in about 2013. Right now we are building the space station and when that is done, the idea would be to go to Mars. Also, we want the human mission to go to best possible place and we still need to explore the pla net with robot spacecraft.

marsplus/UW: . . . . Tue, Jul 8, 9:22AM PDT (-0700 GMT)
How do you choose the rocks for Pathfinder to examine?

Jeff Plescia: . . . . Tue, Jul 8, 9:34AM PDT (-0700 GMT)
Marsplus UW: We choose the rocks based on their shape, size, color, and texture.

Kovi&Levi/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:23AM PDT (-0700 GMT)
Do you think, that the Mars has only one tectonical plate?

Jeff Plescia: . . . . Tue, Jul 8, 9:35AM PDT (-0700 GMT)
Kovi, Levi: Yes, it appears that Mars has only one plate. We do not see subduction zones and spreading centers as we do on earth.

D.: . . . . Tue, Jul 8, 9:24AM PDT (-0700 GMT)
gtg (got-to-go) See ya'! Had a great time Bye Jeff!

Jessica/Jessup Elem.: . . . . Tue, Jul 8, 9:25AM PDT (-0700 GMT)
Does Mars have an equator?

Jeff Plescia: . . . . Tue, Jul 8, 9:35AM PDT (-0700 GMT)
Jessica: Yes, Mars has an equator - like on the Earth, it's half way between the north and south poles.

Suzy/Jessup Elem.: . . . . Tue, Jul 8, 9:27AM PDT (-0700 GMT)
Does the meteorite show any evidence of where the water was?

Dave/Barre: . . . . Tue, Jul 8, 9:27AM PDT (-0700 GMT)
Jeff: NASA scientists are saying that the water that covered the flood plain where Pathfinder is located was thousands of meters deep! How can they predict a depth?

Jeff Plescia: . . . . Tue, Jul 8, 9:36AM PDT (-0700 GMT)
Dave/Barre: The depth is based on the depth of the channel as measured at its edges (outside the landing view) the height of islands in the stream, and by the amount of erosion. The depth was probably only hundreds of meters.

Suzy/Jessup Elem.: . . . . Tue, Jul 8, 9:31AM PDT (-0700 GMT)
What kind of samples have they collected so far from mars from the pathfinder?

Jeff Plescia: . . . . Tue, Jul 8, 9:37AM PDT (-0700 GMT). . . [164 ]
Suzy: They have sampled soil and Barnacle Bill so far.

LuisAlves@Portugal/Europe: . . . . Tue, Jul 8, 9:32AM PDT (-0700 GMT)
There is a Winter Summer circle on Ares valley?

Jeff Plescia: . . . . Tue, Jul 8, 9:37AM PDT (-0700 GMT)
Luis: Mars has seasons just like the Earth does. The year on Mars is twice as long as it is on the earth.

B. Raghuvir: . . . . Tue, Jul 8, 9:32AM PDT (-0700 GMT)
There has been so may pics sent back by Rover. Has there been any concrete conclusion?

Jeff Plescia: . . . . Tue, Jul 8, 9:38AM PDT (-0700 GMT)
Raghu: We've only been on the surface for a few days so it's too soon for definitive answers.

Sue/Sonora: . . . . Tue, Jul 8, 9:33AM PDT (-0700 GMT)
Why is the data from Viking so much different from what you are getting now from Pathfinder?

Jeff Plescia: . . . . Tue, Jul 8, 9:39AM PDT (-0700 GMT). . . [171 ]
Sue: The difference between Viking and Pathfinder is where the spacecraft were sent. Viking was sent to a site which was hoped to be very safe (they were worried about crashing). Since Pathfinder landed on airbags, the surface could be much rougher so the y picked a big channel.

michelle/Jessup Elem.: . . . . Tue, Jul 8, 9:33AM PDT (-0700 GMT)
How did mars get its name?

Jeff Plescia: . . . . Tue, Jul 8, 9:40AM PDT (-0700 GMT)
Michelle: The name for the planet goes back to ancient times and the word Mars is the Greek for war.

Scott/xxxxx: . . . . Tue, Jul 8, 9:34AM PDT (-0700 GMT)
What did the alpha proton exp. find about the Barnacle Bill rock?

Jeff Plescia: . . . . Tue, Jul 8, 9:40AM PDT (-0700 GMT)
Scott: The APX data will not be sent down until later today.

Students/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:34AM PDT (-0700 GMT)
What is the greatest distance the rover can go away from the lander?

Jeff Plescia: . . . . Tue, Jul 8, 9:41AM PDT (-0700 GMT)
Students in Hungary: The rover can go to the horizon, maybe a kilometer or so. The rover must be in radio contact with the lander and the lander must be able to see the rover to guide it.

Kovi&Levi/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:34AM PDT (-0700 GMT)
In the pictures we can see some rocks lying on the surface.I read two opinions how they were formed: 1. water formed them or 2. meteor collosion. Which one is true or was there first the water and then the meteorites?

Jeff Plescia: . . . . Tue, Jul 8, 9:42AM PDT (-0700 GMT)
Kovi, Levi: The rocks on the surface at the site may have been carried there by a big flood - that's one idea, the other is that they were ejected from a nearby impact crater. It's too early to tell. The chemsitry may help us tell if they are all the same - as from a single point in an impact crater, or all different as you would get in a flood.

LuisAlves@Portugal/Europe: . . . . Tue, Jul 8, 9:36AM PDT (-0700 GMT)
Why will the rover last just a few months? The "winter" will froze the chips?

Jeff Plescia: . . . . Tue, Jul 8, 9:43AM PDT (-0700 GMT)
Luis: The rover only has solar power to keep it going and keep it warm. During the winter it will get too cold and it will freeze. The question is whether it will thaw out in the spring and work again.

Loretta/Jessup Elem.: . . . . Tue, Jul 8, 9:37AM PDT (-0700 GMT)
How did water get on mars?

Kovi&Levi/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:37AM PDT (-0700 GMT)
Are the APXS measures available on Internet and what are the URL's?

Jeff Plescia: . . . . Tue, Jul 8, 9:44AM PDT (-0700 GMT)
Kovi, Levi: I think the data will be available, but I'm not sure. Look at the pathfinder home page at: button

marsplus/UW: . . . . Tue, Jul 8, 9:38AM PDT (-0700 GMT)
Do you have theories about the interior of Mars? Does it have a core, mantle?

Jeff Plescia: . . . . Tue, Jul 8, 9:45AM PDT (-0700 GMT)
Marsplus: Mars has a core, mantle and a crust. We believe this based on the moment of interia data and the gravity field.

Dave/Barre: . . . . Tue, Jul 8, 9:39AM PDT (-0700 GMT). . . [170 ]
Thanks Sandy/Jeff! I have to go.

marsplus/UW: . . . . Tue, Jul 8, 9:40AM PDT (-0700 GMT)
What can you tell about the soil, since the dust storms would have mixed soil from many places?

Jeff Plescia: . . . . Tue, Jul 8, 9:46AM PDT (-0700 GMT). . . [189 ]
Marsplus: We hoping to find some soil that is locally derived and not mixed. The Viking Chemistry results indicated the material was identical at the two sites which suggested that the soil was globally mixed.

Loretta/Jessup Elem.: . . . . Tue, Jul 8, 9:40AM PDT (-0700 GMT)
What computer language do you use to communicate with the rover?

Jeff Plescia: . . . . Tue, Jul 8, 9:46AM PDT (-0700 GMT)
Loretta: I think they use UNIX, but I will have to check.

Sue/Sonora: . . . . Tue, Jul 8, 9:41AM PDT (-0700 GMT)
Thank you, Jeff. What I don't understand is why Viking would send back information about the planet and then the data you are getting now indicates something different. For example, why would it be warmer; why would it be redder...?

Jeff Plescia: . . . . Tue, Jul 8, 9:48AM PDT (-0700 GMT)
Sue: Mars is a dynamic place like the earth. If you visit Arizona in the summer and then Canada in the summer, it will be cooler in Canada and the geology will be different and so the surface will look different.

B. Raghuvir: . . . . Tue, Jul 8, 9:41AM PDT (-0700 GMT)
Can you send me the APX data at vir@banac1.toi.ernet.in?

marsplus/UW: . . . . Tue, Jul 8, 9:42AM PDT (-0700 GMT)
Will there be any way on future missions to open some rocks and look inside?

Jeff Plescia: . . . . Tue, Jul 8, 9:48AM PDT (-0700 GMT)
Marsplus: The 2001 rover will have the ability to drill into rocks and recover samples.

B. Raghuvir: . . . . Tue, Jul 8, 9:42AM PDT (-0700 GMT)
Thanks jeff and sandy go to go.

Trish/Jessup Elem.: . . . . Tue, Jul 8, 9:43AM PDT (-0700 GMT)
Thank you Jeff and Sandy. We really enjoyed the chat.

LuisAlves@Portugal/Europe: . . . . Tue, Jul 8, 9:44AM PDT (-0700 GMT)
"the lander must be able to see the rover to guide it.". So, telemetry processing is made on the lander, not on the rover! Isn't it?

Jeff Plescia: . . . . Tue, Jul 8, 9:50AM PDT (-0700 GMT)
Luis: The rover executes the commands that are sent up from the Earth through the lander. The rover can navigate on its own locally (as around individual rocks) and has some computational ability. The people on Earth decide where to send the rover.

Scott/xxxxx: . . . . Tue, Jul 8, 9:48AM PDT (-0700 GMT)
What did the alpha proton exp. find about the Barnacle Bill rock?

Jeff Plescia: . . . . Tue, Jul 8, 9:50AM PDT (-0700 GMT)
Scott: We have not gotten the data from the APX back yet.

Sandy: NASA Chat Host: . . . . Tue, Jul 8, 9:50AM PDT (-0700 GMT)
EVERYONE: Jeff's fingers are getting pretty tired! In the last five minutes are there a couple more questions he could answer?

Sue/Sonora: . . . . Tue, Jul 8, 9:50AM PDT (-0700 GMT)
Thanks Sandy and Jeff, this was great. If there is time for one last question, can you explain what the histogram on the images coming down from the pathfinder represent?

Jeff Plescia: . . . . Tue, Jul 8, 9:52AM PDT (-0700 GMT)
Sue: The histogram represents the distribution of brightness of the pixels. If the scence were all gray then there would be a spike, but since there are light and dark spots the distribution is variable. Each pixel has a number assigned to it to indicate the brightness in the pixel.

Sandy: NASA Chat Host: . . . . Tue, Jul 8, 9:53AM PDT (-0700 GMT)
Thanks to everyone for your great questions! A special thanks to Jeff for being our Mars expert today and for answering all of the questions. Thanks Jeff!

Jeff Plescia: . . . . Tue, Jul 8, 9:53AM PDT (-0700 GMT)
It's be fun answering your questions. I'm glad everyone is so interested in Mars and Pathfinder. Stay tuned, there should be some more pictures and data in the next few days.

Scott/xxxxx: . . . . Tue, Jul 8, 9:53AM PDT (-0700 GMT)
How can we search for life by analyzing the rock with the alpha spectrometer?

Jeff Plescia: . . . . Tue, Jul 8, 9:54AM PDT (-0700 GMT)
Scott: No the APX will only tell us the elemental composition. It will not tell us about life.

marsplus/UW: . . . . Tue, Jul 8, 9:53AM PDT (-0700 GMT)
Thanks for answering our questions!! It has been fun.

Sandy: NASA Chat Host: . . . . Tue, Jul 8, 9:54AM PDT (-0700 GMT).
marsplus/UW: You're most welcome. Glad you could join us. Sign up for next week's chat!

Sue/Sonora: . . . . Tue, Jul 8, 9:55AM PDT (-0700 GMT)
Thanks Sandy & Bye Jeff.

Sandy: NASA Chat Host: . . . . Tue, Jul 8, 9:55AM PDT (-0700 GMT)
Bye Sue! Thanks for joining us! Sign up for next week's chat!

Students/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:56AM PDT (-0700 GMT)
Good bye Sandy and Jeff! See ya next week! Thanx for the chat!

Sandy: NASA Chat Host: . . . . Tue, Jul 8, 9:57AM PDT (-0700 GMT)
Students/Zrinyi/Middle/Hungary: Chat with you next week! Thanks for all your great questions!

Kovi&Levi/Zrinyi/Middle/Hungary: . . . . Tue, Jul 8, 9:57AM PDT (-0700 GMT)
It was very nice to meet you. We enjoyed this chat very much! Thanks for everything! See you next week!

Sandy: NASA Chat Host: . . . . Tue, Jul 8, 9:59AM PDT (-0700 GMT)
Kovi&Levi/Zrinyi/Middle/Hungary: I was great chatting with you too! Be sure to come back next week. (Sign up in advance!)

LuisAlves@Portugal/Europe: . . . . Tue, Jul 8, 10:07AM PDT (-0700 GMT)
Bye Jeff, have a good day work.

LuisAlves@Portugal/Europe: . . . . Tue, Jul 8, 10:08AM PDT (-0700 GMT)
Bye Sandy, Thank you very much for my "place" on this web-chat.

Sandy: NASA Chat Host: . . . . Tue, Jul 8, 10:41AM PDT (-0700 GMT)
Good bye Luis! It was good to have you with us again today! Sign up for next week if you can!


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