NASA's Odyssey Set To Begin

NASA managers Friday put the odds of favorable weather conditions on Saturday for the launch of the Mars Odyssey probe at 95 percent.

The National Aeronautics and Space Administration is to launch the orbiter from Cape Canaveral Air Force Station, Florida.

The Delta II launch vehicle will fly up the east coast of North America and over Europe. Spacecraft separation will occur above the Middle East.

The Odyssey launch will make the $297 million orbiter mission NASA's first trip to Mars since the loss of two spacecraft on Mars in 1999.

The Delta booster rockets that will thrust the probe into space have been fueled and a team of U.S. space experts has set up a communications station on the Mediterranean island of Crete to relay live video images and telemetry from the orbiter back to the launch site.

"We have run the tests of the video link back to the U.S. and everything is fine. It is on standby and ready to go for Saturday's launch," program manager Air Force Maj. Jim Vaught said.

The team will provide NASA with crucial telemetry for planning future launches and missions, and provide detailed information on the rocket if something goes wrong.

Odyssey, a 5.6-foot-tall and 8.5-foot-wide spacecraft weighing 1,600 pounds, will travel 77.5 million miles for approximately 200 days before reaching Mars on October 24.

Over the following 76 days, the spacecraft will dip into the upper atmosphere of Mars some 273 times, using a complex — and somewhat risky — aerobraking procedure designed to put the Odyssey into a two-hour circular orbit at an altitude of about 400 kilometers.

Then, reports CBS News Space Consultant Bill Harwood, the real work will begin: a full Martian year of observations to map the mineralogy and chemical composition of Mars' frigid surface, to measure the planet's radiation environment and to assemble a medium-resolution photographic atlas of the entire world.

The spacecraft will start its primary mapping of Mars in January 2002 and is expected to complete it by July 2004.

After completing its primary mission, the Odyssey orbiter will provide a communications relay for future American and international landers, including NASA's Mars Exploration Rovers, scheduled for launch in 2003. A main rocket carries a camera.

CBS News Correspondent David Axelrod reports that it's been four years since NASA's last big Mars success — the signals sent from Mars by the Pathfinder probe — so the stakes for this mission are high. But the NASA-industry team is confident of success.

"With any planetary missiolike this, you get that range of emotions from excitement to nervousness," said Jeffrey Plaut, deputy project scientist of the Mars Odyssey mission at the Jet Propulsion Laboratory.

In September 1999, NASA's Mars Climate Orbiter crashed into the Red Planet because English units were used for critical reorientation rocket firings instead of metric units as required. It was one of NASA's most embarrassing blunders.

Three months later a companion spacecraft, the Mars Polar Lander, disappeared without a trace during descent to the surface. Engineers believe the lander's engines shut down too early because of an electrical glitch.

In the wake of the failures, NASA's Mars exploration program underwent a painful reassessment and restructuring.

"We went through and identified every parameter that could be critical to mission success and then went forward and did a verification of all these parameters both internally, within the team, and also with an outside group," Plaut said.

As a result, the kind of communications breakdown that lead to the Mars Climate Orbiter's demise "is very unlikely to crop up again," he said.

But getting into the proper orbit will not be easy. The aerobraking procedure must be completed within 90 days to ensure the Odyssey probe ends up in a polar orbit carrying it over the Earth-facing side of the planet at what amounts to mid afternoon local Mars time.

That will ensure proper lighting on Odyssey's large solar array and maximize the return from the spacecraft's suite of science instruments.

Odyssey is equipped with three sets of instruments: gamma-ray and neutron spectrometers; a radiation monitor; and a medium-resolution camera system capable of visible and infrared observations.

The neutron spectrometer will look for signs of ice in the Martian soil while the gamma-ray spectrometer will measure the abundance of rock-forming elements like silicon, iron, magnesium, potassium, calcium and others.

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