Mars Odyssey Reaches Its Destination, and an Anxious Moment
When NASA's 2001 Mars Odyssey spacecraft reaches Mars on October 23, Arizona State University geologist Philip Christensen will be as nervous as a scientist can be, watching a critical experiment enter a key phase. He has an important instrument aboard the spacecraft which is entering a difficult stage in its journey and all he can do is sit and watch television, waiting for word of success or failure.
Make no mistake about it, science can be risky business, particularly when your experiment is millions of miles away - so far away it takes a radio transmission traveling at the speed of light eight and a half minutes just to reach it.
Christensen, Korrick Professor of Geology, whose life's work as a planetary geologist has been intimately involved in the triumphs and the tragedies of exploring Mars. Though recent failures of the Mars Climate Orbiter and Mars Polar Lander spacecraft have received a lot of media attention, Christensen's experience with the difficulties of research in space has an even deeper history.
Christensen has been doing planetary research since he was a student (working with the Mariner 9 and subsequent Viking missions), but his first big research project was directing the thermal emission spectrometer experiment on the Mars Observer mission - years of careful design and planning by Christensen and his team that came to a sudden end on August 21, 1993 as the spacecraft disappeared approaching Mars.
Almost half a decade later, Christensen got another shot with a similar experiment on the Mars Global Surveyor (MGS), which was launched in November of 1996. Though the MGS and Christensen's Thermal Emission Spectrometer have since been spectacularly successful, the mission was not without worry and difficulty. A problem with a solar panel put everything in doubt as the spacecraft entered orbit, and the planned "aerobraking" maneuver had to be extended for a year before an orbit appropriate for the science experiments could be achieved.
Odyssey will arrive at Mars at 7:30 p.m. Pacific Daylight Time on October 23. As it nears its closest point to the planet over the northern hemisphere, the spacecraft will fire its main engine for approximately 20 minutes to allow itself to be captured into an elliptical, or egg-shaped, orbit. This is the only time the main engine is used during the entire mission.
About ten minutes after the engines are fired, the spacecraft will go behind Mars and radio contact will be lost for about 30 minutes, as the engines continue burning. At this point, the engineers and scientists can only wait until the spacecraft comes out from behind the planet. Christensen and his team will simply sit and watch the proceedings on NASA TV, nervously anticipating a new transmission from the orbiting spacecraft - a signal that they can begin relax.
"NASA is very good at this though, and has put forth an incredible effort to insure it works right this time. I have a great deal of confidence in JPL and Lockheed Martin's ability to pull it off."
Following the "orbit insertion," aerobraking will begin, as the spacecraft skims the atmosphere during each orbit's close passes to the planet. Over a three-month period, friction with the atmosphere should slowly bring the into a planned circular orbit 400 km above Mars and allow the science instruments to be turned on. The 2001 Mars Odyssey Mission is managed by the Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Office of Space Science, Washington, DC.
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Odyssey Adjusts Its Attitude Ahead Of Arrival
Pasadena - Oct 14, 2001
Following a s final planned course correction, NASA's 2001 Mars Odyssey spacecraft is on perfect target to enter Martian orbit later this month at 7:26pm Pacific time Oct. 23 (0226 UT Oct. 24).