Sandy/NASA Chat Host: . . . . Thu, May 15, 8:48AM PDT (-0700 GMT) Hello Everyone! Join us at 9 a.m. Pacific, TODAY, for a chat with Mars expert Phil Christensen. Phil is a planetary geologist and a principal investigator for the Thermal Emission Spectrometer instrument onboard the Mars Global Surveyor spacecraft. See you in about 15 minutes!!!

Gergely/Zrinyí(Middle),Hungary: . . . . Thu, May 15, 8:53AM PDT (-0700 GMT). Hello Sandy!

Sandy/NASA Chat Host: . . . . Thu, May 15, 8:58AM PDT (-0700 GMT) Gergely: Hello, or is it Good Evening?!

Gergely/Zrinyí(Middle),Hungary: . . . . Thu, May 15, 8:59AM PDT (-0700 GMT) Sandy : It's evening.

Levente/Zrinyi(middle)Hungary: . . . . Thu, May 15, 9:00AM PDT (-0700 GMT) Hello everyone!

Sandy/NASA Chat Host: . . . . Thu, May 15, 9:00AM PDT (-0700 GMT) Hello Levente! Welcome! Today's WebChat with Phil Christensen will begin in about 5 minutes

Daniel/Zrinyi/middle/Hungary: . . . . Thu, May 15, 9:04AM PDT (-0700 GMT) Hello Sandy! Hello Philip! We're glad to have a WebChat with you.

phil/mars geologist: . . . . Thu, May 15, 9:05AM PDT (-0700 GMT) hi everyone I'm here

Sandy/NASA Chat Host: . . . . Thu, May 15, 9:06AM PDT (-0700 GMT) Ok, everyone, who has the first question for Phil?

Gergely/Zrinyi Middle, Hungary: . . . . Thu, May 15, 9:09AM PDT (-0700 GMT) Phil: what does mean the AFT (optics) abbreviation?

phil/mars geologist: . . . . Thu, May 15, 9:11AM PDT (-0700 GMT) Gergely, the AFT abbreviation refers to the back, or aft portion of the instrument. There is also a "fore" (forward) part of the optics as well.

Daniel/Zrinyi/middle/Hungary: . . . . Thu, May 15, 9:12AM PDT (-0700 GMT) How large is the TES exactly?

phil/mars geologist: . . . . Thu, May 15, 9:13AM PDT (-0700 GMT) Daniel, the TES is 21 cm by 34 cm by 40 cm. It weighs about 15 kg (30 lbs).

Levente/Zrinyi(middle)Hungary: . . . . Thu, May 15, 9:12AM PDT (-0700 GMT) Does the athmosphere disturb the TES by the measuring of the Martian surface very much?

phil/mars geologist: . . . . Thu, May 15, 9:14AM PDT (-0700 GMT) Levente, Yes the atmosphere does cause problems. We have to see through the atmosphere in order to see the surface. The main problem is CO2 gas, water gas and water clouds. Fortunately, the atmosphere of Mars is much thinner that the Earth, so it is alot easier to see through.

Gergely/Zrinyi: . . . . Thu, May 15, 9:16AM PDT (-0700 GMT) Phil: what is the resolution of the TES in meters on the surface of the Mars and micrometers in the spectrum?

phil/mars geologist: . . . . Thu, May 15, 9:18AM PDT (-0700 GMT) Gergely, The surface resolution is 3 km - we will map the entire planet at this resolution. The spectrometer has a resolution of about 0.1 micrometers and will separate the infrared light into 143 different wavelengths from 6 to 50 micrometers.

phil/mars geologist: . . . . Thu, May 15, 9:19AM PDT (-0700 GMT) Gergely: Do you think we will have good enough resolution on the surface to identify features?

Gergely/Zrinyi: . . . . Thu, May 15, 9:23AM PDT (-0700 GMT) Phil: About your question. I don't understand, the TES does make photos or spectrum to identify features?

phil/mars geologist: . . . . Thu, May 15, 9:28AM PDT (-0700 GMT) Gergely, We measure the spectrum of points on the surface that are 3 km in size. We map a continuous strip on each orbit, so that after 200 days we have mapped the entire planet and have an image in 145 spectral bands.

Gergely/Zrinyi: . . . . Thu, May 15, 9:21AM PDT (-0700 GMT) Phil: how can you determine the distribution of rock and grain sizes based on the TES spectrum? And how can you determine the amount of the surface covered rocks and boulders. I have read it is possible.

phil/mars geologist: . . . . Thu, May 15, 9:24AM PDT (-0700 GMT) Gergely, WE can determine the grain and rock distribution from the spectrum - mostly by determining the temperature of the surface using the infrared energy, and comparing the temperature to models of what the temperature would be for different grain sizes. By the way, what grade are you in?

Gergely/Zrinyi,: . . . . Thu, May 15, 9:29AM PDT (-0700 GMT) I'm grade in 9, but I like the physics very much.

phil/mars geologist: . . . . Thu, May 15, 9:31AM PDT (-0700 GMT) Gergely, I'm glad to hear you like physics - it is very important to know if you want to study the planets.

Daniel/Zrinyi/middle/Hungary: . . . . Thu, May 15, 9:21AM PDT Excuse me, but do you speak German? My English is not so good.

phil/mars geologist: . . . . Thu, May 15, 9:25AM PDT (-0700 GMT) Daniel, Sorry, but I only speak English and Martian!

Levente/Zrinyi(middle)Hungary: . . . . Thu, May 15, 9:21AM PDT (-0700 GMT) What was the most surprising result during your research of the surface of Mars?

phil/mars geologist: . . . . Thu, May 15, 9:26AM PDT (-0700 GMT Levente, The most surprising to date has been the discovery of water on Mars. Now we want to find out how much there is and where it is today. Were there ever hot springs, lakes or oceans? We will try to do this by looking for minerals that may have formed in these regions.

Levente/Zrinyi(middle)Hungary: . . . . Thu, May 15, 9:24AM PDT (-0700 GMT) How reliable are the results of the TES's measures?

phil/mars geologist: . . . . Thu, May 15, 9:30AM PDT (-0700 GMT) Levente, The results will be very reliable for determining the temperature of lthe surface and atmosphere. As for measuring the composition of the surface from the spectra data, this method has never been tried before from space so we don't exactly know how well it will work. It works great in a lab, so we hope we can identify minerals on the surface of Mars

Levente/Zrinyi(middle)Hungary: . . . . Thu, May 15, 9:31AM PDT (-0700 GMT) What kind of result will the TES will serv - what do you hope? (Could you explain it?)

phil/mars geologist: . . . . Thu, May 15, 9:33AM PDT (-0700 GMT) Levente, We hope to determine what minerals are on the surface of Mars. On Earth we learn alot about the Earth's history from studying the rocks and minerals. For example, all of the concrete used in buildings comes from rocks called limestone that are made up of a mineral called calcite. If we find calcite on Mars, then we will know that billions of years ago, Mars had oceans as well.

Gergely/Zrinyi, Middle, Hungary: . . . . Thu, May 15, 9:35AM PDT (-0700 GMT) Phil: I have graphics of some rocks and minerals (basalt, andesite, rhyolit, granite, sandstone, limestone). Can you send me electronically some original spectra of other rocks and minerals?

phil/mars geologist: . . . . Thu, May 15, 9:37AM PDT (-0700 GMT) Gergely, I have a set of mineral spectra and a few rocks that I would be very happy to send you. Please send me your email and I'll get them to you.

Gergely/Zrinyi, Middle, Hungary: . . . . Thu, May 15, 9:39AM PDT (-0700 GMT) Phil: I would be very happy. Would you send them to my teacher's following email address: juhaszt@alpha.dfmk.hu

phil/mars geologist: . . . . Thu, May 15, 9:41AM PDT (-0700 GMT) Gergely, Ok, I got it - I will send them to you.

Levente/Zrinyi(middle)Hungary: . . . . Thu, May 15, 9:36AM PDT (-0700 GMT) Are you planning another instruments at the moment too?

phil/mars geologist: . . . . Thu, May 15, 9:40AM PDT (-0700 GMT) Levente, Yes I am working on two instruments that will be similar to lthe TES. One will go on a rover and will determine the composition of all the rocks the rover can see. Then we will know which rocks to drive over to and sample. The other is for an orbiter that will be similar to the TES, but will be able to see things as small as 200 m in size.

Sandy/NASA Chat Host: . . . . Thu, May 15, 9:44AM PDT (-0700 GMT) Anymore questions for Phil? He needs to go back to work soon.

Gergely/Zrinyi: . . . . Thu, May 15, 9:44AM PDT (-0700 GMT) Phil: I have read about the failure of the Mars Observer. I have read your introduction to the webchat, too. But I would like to ask you about your feeling about this events.

phil/mars geologist: . . . . Thu, May 15, 9:48AM PDT (-0700 GMT) Gergely, The failure of Mars Observer was more disappointing than I can describe. I still haven't fully recovered. Fortunately, because we were able to try again, we have been able to move on. One thing about space exploration is that it is very difficult and there will be failures. But the important thing has been to remember that asking the questions and seeking the answers about Mars is what is important, and we just have to keep trying.

Levente/Zrinyi(middle)Hungary: . . . . Thu, May 15, 9:45AM PDT (-0700 GMT) Is the TES on the MGS different from the Observer's one? (I mean, have you changed anything?)

phil/mars geologist: . . . . Thu, May 15, 9:48AM PDT (-0700 GMT) Levente, The TES on MGS is identical to the one on Mars Observer.

Daniel/Zrinyi/middle/Hungary: . . . . Thu, May 15, 9:47AM PDT (-0700 GMT) I'm Tibor from Hungary with Daniel's computer. Sandy, Phil: Thank you for the chat. There are here 8 students, but we use only three computers. Don't be sad. The webchat is very important and interesting.

Sandy/NASA Chat Host: . . . . Thu, May 15, 9:49AM PDT (-0700 GMT) Hello Tibor! Phil and I are both very happy that you and your classmates are able to join us today! It's great chatting with all of you. You're asking some terrific questions!

Sandy/NASA Chat Host: . . . . Thu, May 15, 9:50AM PDT (-0700 GMT) Anymore questions? If not, Phil will go back to his work.

Daniel/Zrinyi/middle/Hungary: . . . . Thu, May 15, 9:51AM PDT (-0700 GMT). Bye Sandy, bye Phil.

Levente/Zrinyi(middle)Hungary: . . . . Thu, May 15, 9:51AM PDT (-0700 GMT) ...then a little bit about the MOLA. Will it work during the whole mission?

phil/mars geologist: . . . . Thu, May 15, 9:53AM PDT (-0700 GMT) Levente, MOLA should work great! Knowing exactly how deep channels are, etc, will help alot in determining how water would have flowed on lthe surface. There will be lots of other discoveries from MOLA as well.

phil/mars geologist: . . . . Thu, May 15, 9:55AM PDT (-0700 GMT) Hey, It's been great talking to everyone. Hope to talk to all of you again soon. Phil.

Levente/Zrinyi(middle)Hungary: . . . . Thu, May 15, 9:56AM PDT (-0700 GMT) Thanks for everything. I've enjoyed the chat very well! I hope to have a lot of other chats in the future! Good bye Phil, Sandy and everyone!

Sandy/NASA Chat Host: . . . . Thu, May 15, 9:56AM PDT (-0700 GMT) Goodbye everyone! I'll let you know when the next WebChat is! Take care and hope to be chatting with you soon! sandy