An artist's concept of Mars Odyssey at the Red Planet. Photo: NASA/JPL

NASA's 2001 Mars Odyssey spacecraft, now 18.5 million kilometers (11.5 million miles) from Mars on its way to a rendezvous with the red planet on Oct. 23, remains in overall good health. Flight controllers have turned off the Martian radiation environment experiment after the instrument did not respond during a downlink session last week.

Following unsuccessful attempts to reset the radiation instrument, the mission manager and project officials have decided to form a team to further study the anomaly over the next several weeks and propose a course of action to recover the instrument following Mars orbit insertion on Oct. 23.

Managers suggested that the most important thing now is for the team members to devote their attention to achieving a successful Mars orbit insertion, a demanding maneuver that will require a focused team effort over the next few months.

"We have limited information on the nature of the problem with the radiation experiment. The investigative team will develop a fault tree containing a list of potential causes for the behavior," said David A. Spencer, Odyssey's mission manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The spacecraft's other science payloads are working as expected. The thermal emission imaging system is made up of an infrared imager and a visible camera, and the gamma ray spectrometer instrument package contains a gamma ray sensor, neutron spectrometer and high-energy neutron detector.

On Friday, Aug. 17, the team opened and closed the valves in the spacecraft's main engine to verify that it is working properly prior to Mars arrival. On Oct. 23, the main engine will burn for 24 minutes so the spacecraft will be captured into orbit around the planet.

Today, Odyssey is traveling at 24 kilometers per second (54,600 miles per hour) relative to the Sun.

The 2001 Mars Odyssey mission is managed by JPL for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena. The Odyssey spacecraft was built by Lockheed Martin Astronautics, Denver. NASA's Johnson Space Center, Houston, built and manages the Martian radiation environment experiment. The thermal emission imaging system is managed by Arizona State University, Tempe, and the gamma ray spectrometer is managed by the University of Arizona, Tucson.