At 12:14 p.m. Pacific Time today, Odyssey fired its thrusters for 25 seconds and decreased the velocity of the spacecraft by less than 2 meters per second (less than 4 miles per hour).

On Monday, January 28, Odyssey fired its thrusters for 15 seconds, increasing its speed by just over 1 meter per second (about 2.5 miles per hour).

"These small orbit trim maneuvers complement the larger maneuvers we executed two weeks ago and tweak the orbit to get just the right altitude and ground track coverage that we desire. The net effect is that we move the periapsis point, the point nearest the planet, directly over the south pole and keep it there," said Bob Mase, Odyssey's lead navigator at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We are now in our final mapping orbit and we don't expect to perform any additional maneuvers to change the orbit."

Engineers are continuing to check out the spacecraft systems and science instruments in preparation for the science mapping mission that will begin in February. Two of the science instruments, both neutron spectrometers that are part of the gamma ray spectrometer suite, are currently operating and collecting science data about the composition of the Mars surface.

JPL manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. Principal investigators at Arizona State University in Tempe, the University of Arizona in Tucson, and NASA's Johnson Space Center, Houston, Texas, operate the science instruments. Additional science investigators are located at the Russian Space Research Institute and Los Alamos National Laboratories, New Mexico. Lockheed Martin Astronautics, Denver, Colo., is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena. NASA's Langley Research Center in Hampton, Va., has provided aerobraking support to JPL's navigation team during mission operations.

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