Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:04AM PDT (-0700 GMT). . . [574 ] Good Morning Everyone! Welcome to the third "Live From Mars" WebChat. This morning we have Dan Johnston with us from the Jet Propulsion Laboratory in Pasadena, California.

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:05AM PDT (-0700 GMT). . . [575 ] Dan Johnston has been a member of the Mars Global Surveyor Mission and Navigation Design Team since the beginning of the mission. His primary responsibilities include: 1) the launch vehicle mission design and planning, 2) the spacecraft trajectory (flight path) development, and 3) the aerobraking operations planning.

Shasta in Redding CA: . . . . Thu, Nov 14, 8:05AM PDT (-0700 GMT). . . [576 ] Good Morning!!

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:05AM PDT (-0700 GMT). . . [577 ] Dan: Can you give us a brief update of Mars Global Surveyor?

lma/lisbon/portugal: . . . . Thu, Nov 14, 8:07AM PDT (-0700 GMT). . . [578 ] hello everyone

Dan / JPL: . . . . Thu, Nov 14, 8:07AM PDT (-0700 GMT). . . [579 ] The MGS spacecraft was launch last Thursday 11/7 from Cape Canaveral. The spacecraft is functioning well with only one anomaly - a solar panel hinge has not deployed fully.

Tornado Kids: . . . . Thu, Nov 14, 8:07AM PDT (-0700 GMT). . . [580 ] Hello Dan, How do you achieve a controled crash by aero braking?

Dan / JPL: . . . . Thu, Nov 14, 8:08AM PDT (-0700 GMT). . . [581 ] Today 11/14 the spacecraft is 1,857,210 km from Earth and traveling at a speed of 3.22 km/sec

Dan / JPL: . . . . Thu, Nov 14, 8:10AM PDT (-0700 GMT). . . [582 ] Hi Tornado -- once we start the aerobrake the spacecraft will most definitely hit the surface of Mars unless we pull the orbit of the spacecraft up before the impact time.

Shasta: . . . . Thu, Nov 14, 8:10AM PDT (-0700 GMT). . . [583 ] Dan: How thick is the Martian atmosphere compared to the Earth?

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:11AM PDT (-0700 GMT). . . [584 ] How much time is left for you to figure out what's wrong with the solar panel before it becomes a real problem?

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:13AM PDT (-0700 GMT). . . [586 ] Welcome John Bayne in Australia! What grade are you in and what in particular are you studying about Mars in your class?

Dan / JPL: . . . . Thu, Nov 14, 8:14AM PDT (-0700 GMT). . . [587 ] Shasta - I don't have a good answer for your question. The martian atmosphere is very thin compared to Earth's.

Shasta: . . . . Thu, Nov 14, 8:14AM PDT (-0700 GMT). . . [588 ] Well, as far as using the atmosphere to slow the Global Surveyor down, how long would that take?

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:15AM PDT (-0700 GMT). . . [589 ] Dan: As a navigation expert, how exactly do you map out a flight plan for a spacecraft?

lma/lisbon/portugal: . . . . Thu, Nov 14, 8:15AM PDT (-0700 GMT). . . [590 ] Can you give us the probability of success of the mision?

John Bayne: . . . . Thu, Nov 14, 8:16AM PDT (-0700 GMT). . . [591 ] Dan: I've heard about a satellite soon to be launching which will examine the top of the sun, but intstead of just heading for the sun, it's going to orbit around Jupiter to get the trajectory - why is this necessary?

Dan / JPL: . . . . Thu, Nov 14, 8:17AM PDT (-0700 GMT). . . [592 ] Shasta -- the active aerobrake will take about 4 months -- We will aerobrake at a altitude of about 65 miles.

Tornado/Kids: . . . . Thu, Nov 14, 8:17AM PDT (-0700 GMT). . . [593 ] Mars' atmosphere is only 1/100 as thich as Earths, we learned that in science today,Lee

: . . . . Thu, Nov 14, 8:17AM PDT (-0700 GMT). . . [594 ] i want to talk with someone

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:18AM PDT (-0700 GMT). . . [595 ] John: We're going to have to save your question for another WebChat as this one is focused on the Mars Global Surveyor spacecraft that was launched to Mars last week.

Randy/homeschool: . . . . Thu, Nov 14, 8:18AM PDT (-0700 GMT). . . [596 ]

Shasta: . . . . Thu, Nov 14, 8:18AM PDT (-0700 GMT). . . [597 ] Is the Space Craft affected by the pull of the Sun's gravity just like the planets are?

John Bayne: . . . . Thu, Nov 14, 8:18AM PDT (-0700 GMT). . . [598 ] Hi Sandy! I'm 15 y.o. in grade 10, but I don't do LFM in school - I do it for the fun of it outside school time.

Shasta: . . . . Thu, Nov 14, 8:19AM PDT (-0700 GMT). . . [599 ] The Mars Global Surveyor that is....

Saul: . . . . Thu, Nov 14, 8:19AM PDT (-0700 GMT). . . [600 ] I have a question. How do the radio transmittions get to mars without getting jarbled?

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:19AM PDT (-0700 GMT). . . [601 ] "I want to talk with someone": If you will put your name in the white box next to the words "Your Handle" and then ask a question related to Mars and then hit the "Chat Button" we will talk to you!

nosferatu: . . . . Thu, Nov 14, 8:19AM PDT (-0700 GMT). . . [602 ] who is randy

Dan / JPL: . . . . Thu, Nov 14, 8:20AM PDT (-0700 GMT). . . [603 ] Sandy -- the flight plan of the spacecraft is mapped out in terms of the orbit characteristics of the actual trajectory. The orbit of the spacecraft is effectively an ellipse and we describe the motion of the spacecraft on the ellipse.

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:21AM PDT (-0700 GMT). . . [604 ] nosferatu: This is a NASA Mars WebChat ONLY! Thanks.

Randy/homeschool: . . . . Thu, Nov 14, 8:21AM PDT (-0700 GMT). . . [605 ] How large is the margin of error

Randy/homeschool: . . . . Thu, Nov 14, 8:21AM PDT (-0700 GMT). . . [606 ] On the trajectory that is

Jordan: . . . . Thu, Nov 14, 8:22AM PDT (-0700 GMT). . . [607 ] Are any samples of soil going to be picked up on Mars?

Dan / JPL: . . . . Thu, Nov 14, 8:22AM PDT (-0700 GMT). . . [608 ] Yes Shasta the spacecraft if affected by the pull of the sun just like the planets -- in fact on 11/10 we departed the sphere of influence of the Earth -- we are no dominated by the pull of the Sun as we start the 10 month journey to Mars.

Saul: . . . . Thu, Nov 14, 8:23AM PDT (-0700 GMT). . . [609 ] What do you think the sattielites to Mars will find?

nosferatu: . . . . Thu, Nov 14, 8:23AM PDT (-0700 GMT). . . [610 ] do you think there is life in mars?

Dan / JPL: . . . . Thu, Nov 14, 8:23AM PDT (-0700 GMT). . . [611 ] Jordan -- MGS is a an orbiter mission so we will not be examining or returning samples from the Martian surface.

Shasta: . . . . Thu, Nov 14, 8:23AM PDT (-0700 GMT). . . [612 ] I was wondering that. There is no way to travel in a straight line without the influence of another body. Correct?

nosferatu: . . . . Thu, Nov 14, 8:25AM PDT (-0700 GMT). . . [613 ] i put my nickname as you said to me, now answearme please

Saul: . . . . Thu, Nov 14, 8:25AM PDT (-0700 GMT). . . [614 ] What exactly will the MSG be recording?

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:26AM PDT (-0700 GMT). . . [615 ] nosferatu: Your nickname is fine :-) Your questions will get answered, it just takes a bit of time as there are 9 schools participating and as you can see, there are a lot of questions for Dan to answer all by himself!

Dan / JPL: . . . . Thu, Nov 14, 8:27AM PDT (-0700 GMT). . . [616 ] Saul - It's difficult to say exactly what we will find at Mars -- We expect to greatly increase our knowledge of the planet over previous missions there and we will chart the planets surface for future missions there.

Tim, Tyler and Jared: . . . . Thu, Nov 14, 8:28AM PDT (-0700 GMT). . . [617 ] Hi, We are 6th graders from Montrose Colorado. We have some questions for Dan.

Shasta: . . . . Thu, Nov 14, 8:28AM PDT (-0700 GMT). . . [618 ] Currently, are you monitoring the progress of the MGS? And, how often do you check the MGS?

Mark Stokes/Inverness CA: . . . . Thu, Nov 14, 8:29AM PDT (-0700 GMT). . . [619 ] Hi Dan - does the thinness of the Mars atmosphere affect the construction of the spacecraft, as in using lighter/ thinner materials?

Randy/homeschool: . . . . Thu, Nov 14, 8:29AM PDT (-0700 GMT). . . [620 ] How much does tyhis mission cost

Jordan: . . . . Thu, Nov 14, 8:30AM PDT (-0700 GMT). . . [621 ] Are the weather patterns of Mars going to be studied?

Saul: . . . . Thu, Nov 14, 8:30AM PDT (-0700 GMT). . . [622 ] What is the MSG made out of?

Dan / JPL: . . . . Thu, Nov 14, 8:31AM PDT (-0700 GMT). . . [623 ] Shasta - the spacecraft is monitored continuously at every tracking pass. Spacecraft Team just reported their status and everything goes well.

Shasta: . . . . Thu, Nov 14, 8:31AM PDT (-0700 GMT). . . [624 ] Every tracking pass? how often is that?

lma/lisbon/portugal: . . . . Thu, Nov 14, 8:32AM PDT (-0700 GMT). . . [625 ] What is tracking pass?

Tornado/Kids: . . . . Thu, Nov 14, 8:32AM PDT (-0700 GMT). . . [626 ] We know from your biography, that you grew up in the Air Force. Did you ever fly some fast airplane? Aubrey 2nd grade

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:33AM PDT (-0700 GMT). . . [627 ] A lot of you have some very basic questions about Mars and the missions to Mars. If your questions don't get answered please go to the "Live From Mars" Web site and see all of the really cool stuff-- especially the "Kid's Corner"!

Dan / JPL: . . . . Thu, Nov 14, 8:33AM PDT (-0700 GMT). . . [628 ] Mark -- The maritan atmoshpere does affect the construction of the spacecraft because we aerobrake. The materials the spacecraft is constructed of much withstand the heat of the aerobrake. The must also be ligthweight in order for use to launch on the Delta rocket.

Tim,: . . . . Thu, Nov 14, 8:33AM PDT (-0700 GMT). . . [629 ] How does the orbiter stay on track?

Dan / JPL: . . . . Thu, Nov 14, 8:35AM PDT (-0700 GMT). . . [630 ] Shasta- Currently we have continious coverage of the spacecraft -- it is handed over from tracking station to tracking station for the first 30 days. The tracking stations are at Canberra, Austraila, Madrid, Spain, and Goldstone, CA.

Mark Stokes/Inverness, CA: . . . . Thu, Nov 14, 8:36AM PDT (-0700 GMT). . . [631 ] Thanks, Dan. In aerobraking, do you have backup "brakes" such as thrusters or even parachutes in case you need them?

Jordan: . . . . Thu, Nov 14, 8:37AM PDT (-0700 GMT). . . [632 ] Does each tracking station do the same things or do they have different jobs?

Dan / JPL: . . . . Thu, Nov 14, 8:37AM PDT (-0700 GMT). . . [633 ] Tim - the orbiter will stay on track because we will perform maneuvers to keep it on track. The sun and the planets will continually try to pull the spacecraft off of its flight path. On the way to Mars we will perform 4 maneuvers which will keep us on track.

lma/lisbon/portugal: . . . . Thu, Nov 14, 8:37AM PDT (-0700 GMT). . . [634 ] Where can i found information about the tracking stations? how much people work in there? How much people is around the MGS p.

Saul: . . . . Thu, Nov 14, 8:38AM PDT (-0700 GMT). . . [635 ] What manuevers will the space craft do?

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:38AM PDT (-0700 GMT). . . [636 ] Lma: I will try to find some info on tracking stations for you...

lma/lisbon/portugal: . . . . Thu, Nov 14, 8:39AM PDT (-0700 GMT). . . [637 ] thank you Sandy

Tim,: . . . . Thu, Nov 14, 8:40AM PDT (-0700 GMT). . . [638 ] How will the orbiter take pictures?

Dan / JPL: . . . . Thu, Nov 14, 8:40AM PDT (-0700 GMT). . . [639 ] Mark- For the aerobrake there are no parachutes. The spacecraft has thrusters which we will to maintain altitude during the 4 month aerobrake - For aerobraking we will use the area of the solar panels as a drag surface -- the panels have attached to them small "drag flaps" which increase the effective area of the spacecraft and allow the spacecraft to fly higher altitudes for the aerobrake.

Dan / JPL: . . . . Thu, Nov 14, 8:41AM PDT (-0700 GMT). . . [640 ] Tim - the MGS spacecraft contains a camera so the surface of the planet will be imaged.

lma/lisbon/portugal: . . . . Thu, Nov 14, 8:42AM PDT (-0700 GMT). . . [641 ] Will the "un-openess" of the solar panels afect the process?

Mark: . . . . Thu, Nov 14, 8:42AM PDT (-0700 GMT). . . [642 ] Re: Tim's questions: what kind of camera and film for imaging?

Saul: . . . . Thu, Nov 14, 8:43AM PDT (-0700 GMT). . . [643 ] How do send radio messages to MGS without some of them getting slightly jarbled?

Dan / JPL: . . . . Thu, Nov 14, 8:43AM PDT (-0700 GMT). . . [644 ] Saul - The first maneuver the spacecraft will perform will be next Thursday 11/21. The maneuvers correct the flight path of the spacecraft and return us to our desired trajectory.

Tim,: . . . . Thu, Nov 14, 8:44AM PDT (-0700 GMT). . . [645 ] How long is the canyon?

Shasta: . . . . Thu, Nov 14, 8:44AM PDT (-0700 GMT). . . [646 ] How weak is the signal as it gets closer to Mars?

Dan / JPL: . . . . Thu, Nov 14, 8:44AM PDT (-0700 GMT). . . [647 ] Saul - The spacecraft also performs other maneuvers which control the attitude (i.e. pointing) of the spacecraft.

Jordan: . . . . Thu, Nov 14, 8:45AM PDT (-0700 GMT). . . [648 ] When will the other maneuvers take place?

lma/lisbon/portugal: . . . . Thu, Nov 14, 8:46AM PDT (-0700 GMT). . . [649 ] How much Is the MGS inteligent?

Dan / JPL: . . . . Thu, Nov 14, 8:46AM PDT (-0700 GMT). . . [650 ] Shasta - the signal will stay strong at Mars by adjusting power limits in the telecom subsystem. It will take a radio signal 14 minutes to get to Mars when the spacecraft arrives there next September -- so we have to plan ahead.

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:47AM PDT (-0700 GMT). . . [651 ] Valles Marineris is a collection of enormous, interconnected canyons. They extend roughly east-west over 4000 km. Some spots are 200 km wide and 7 km deep. By comparison, the Grand Canyon is 450 km long, 30 km across and 2 km deep.

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:48AM PDT (-0700 GMT). . . [652 ] Tim: See my answer (#651) to your question regarding "The canyon."

Dan / JPL: . . . . Thu, Nov 14, 8:48AM PDT (-0700 GMT). . . [653 ] Jordan- The other maneuvers will occur next March, April, and August. We will go into orbit about Mars on September 12, 1997.

Saul: . . . . Thu, Nov 14, 8:48AM PDT (-0700 GMT). . . [654 ] What are the steps to getting a job at NASA?

: . . . . Thu, Nov 14, 8:49AM PDT (-0700 GMT). . . [655 ] how big is the canyon compared to the Grand Canyon?

: . . . . Thu, Nov 14, 8:50AM PDT (-0700 GMT). . . [656 ] How much is this mission going to cost?

Dan / JPL: . . . . Thu, Nov 14, 8:50AM PDT (-0700 GMT). . . [657 ] All- The solar panel is nearly fully deployed and produces nominal power. The anomaly with the solar panel is that we want to get it full deployed which means we need to move it by about 10 degrees.

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:50AM PDT (-0700 GMT). . . [658 ] Lma: Go to this URL to find out more about the Deep Space Netwoork (DSN) Tracking Stations around the world (including Spain): button

Shasta: . . . . Thu, Nov 14, 8:52AM PDT (-0700 GMT). . . [659 ] Thanks for all the great info Dan! Its really exciting!!

lma/lisbon/portugal: . . . . Thu, Nov 14, 8:52AM PDT (-0700 GMT). . . [660 ] Can you now control the solar painel deploy?

Tornado/Kids: . . . . Thu, Nov 14, 8:52AM PDT (-0700 GMT). . . [661 ] Thankyou Dan for answering questions about (MGS). It has been very informative.

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:52AM PDT (-0700 GMT). . . [662 ] To "anonymous" who asked about how big the canyon Valles Marineras on Mars is compared to the Grand Canyon on Earth

Tim, jared ,tyler: . . . . Thu, Nov 14, 8:52AM PDT (-0700 GMT). . . [663 ] How big is Mars?

Jordan: . . . . Thu, Nov 14, 8:53AM PDT (-0700 GMT). . . [664 ] Thank you for the info

Dan / JPL: . . . . Thu, Nov 14, 8:53AM PDT (-0700 GMT). . . [665 ] lma/lisbon/portugal -- Options to get the panel fully deployed are being studied. The maine engine burn next week may jar the panel into place.

Randy/homeschool: . . . . Thu, Nov 14, 8:53AM PDT (-0700 GMT). . . [666 ] What is the margin of error

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:53AM PDT (-0700 GMT). . . [667 ] See answer #651 for comparison of Valles Marineras and the Grand Canyon

Dan / JPL: . . . . Thu, Nov 14, 8:54AM PDT (-0700 GMT). . . [668 ] Randy- Define margin of error?

Randy/homeschool: . . . . Thu, Nov 14, 8:55AM PDT (-0700 GMT). . . [669 ] What if U miss Mars

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:56AM PDT (-0700 GMT). . . [670 ] Tim, Jared, Tyler: The diameter of Mars is 4,221 miles.

Dan / JPL: . . . . Thu, Nov 14, 8:57AM PDT (-0700 GMT). . . [671 ] Randy - We won't miss Mars. We have excellent knowledge of the planet's location -- even though it is a moving target.

Tim,: . . . . Thu, Nov 14, 8:57AM PDT (-0700 GMT). . . [672 ] What kind of fuel does the orbiter use?

Dan / JPL: . . . . Thu, Nov 14, 8:58AM PDT (-0700 GMT). . . [673 ] Tim - The spacecraft uses nitrogon tetraoxide with hydrazine for the main engine and just hydrazine for the thrusters.

Sandy/NASA WebChat Host: . . . . Thu, Nov 14, 8:59AM PDT (-0700 GMT). . . [674 ] Ok, it's 9 a.m. PST and Dan has to go back to monitoring the Mars Global Surveyor. Thank you very much for your time Dan. And thanks to everyone around the world who participated! Look for us again next week for WebChat #4 with Exobiologist Jack Farmer: Wed. Nov. 20, 8 a.m. PST. Read his bio and be prepared with questions. Talk to you soon!

John Bayne: . . . . Thu, Nov 14, 9:00AM PDT (-0700 GMT). . . [675 ] Thanks for the great chat Dan!

Dan / JPL: . . . . Thu, Nov 14, 9:00AM PDT (-0700 GMT). . . [676 ] This is JPL signing off -- Talk to y'all in a few weeks.

Tim,: . . . . Thu, Nov 14, 9:01AM PDT (-0700 GMT). . . [677 ] How much does the orbiter weigh?

lma/lisbon/portugal: . . . . Thu, Nov 14, 9:01AM PDT (-0700 GMT). . . [678 ] Thanks to Dan & Sandy.