Mars Odyssey Mission Status 11 Jan 2002

Flight controllers for NASA’s Mars Odyssey spacecraft
sent commands overnight to raise the spacecraft up out of the
atmosphere and conclude the aerobraking phase of the mission.

At 12:18 a.m. Pacific time Jan. 11, Odyssey fired its
small thrusters for 244 seconds, changing its speed by 20
meters per second (45 miles per hour) and raising its orbit by
85 kilometers (53 miles). The closest point in Odyssey’s
orbit, called the periapsis, is now 201 kilometers (125 miles)
above the surface of Mars. The farthest point in the orbit,
called the apoapsis, is at an altitude of 500 kilometers (311
miles). During the next few weeks, flight controllers will
refine the orbit until the spacecraft reaches its final
mapping altitude, a 400-kilometer (249-mile) circular orbit.

“The successful completion of the aerobraking phase is a
major milestone for the project. Aerobraking is the most
complex phase of the entire mission and the team came through
it without a hitch,” said David A. Spencer, Odyssey’s mission
manager at JPL. “During the next month, we will be
reconfiguring the spacecraft to begin the science mapping
mission.” The science mission is expected to begin in late
February.

During the aerobraking phase, Odyssey skimmed through the
upper reaches of the martian atmosphere 332 times. By using
the atmosphere of Mars to slow down the spacecraft in its
orbit rather than firing its engine or thrusters, Odyssey was
able to save more than 200 kilograms (440 pounds) of
propellant. This reduction in spacecraft weight enabled the
mission to be launched on a Delta II 7925 launch vehicle,
rather than a larger, more expensive launcher.

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.
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., is providing aerobraking support to
JPL’s navigation team during mission operations.