Orbiter puts itself into standby safe mode

Engineers have diagnosed the cause of the safe-mode entry as the spacecraft's proper response to unexpected performance by an electronic encoder. That encoder controls motion of a gimbal that adjusts the position of the solar array. Odyssey switched to a redundant encoder, and there is no sign of any mechanical problem with the gimbal.

Commands from Earth have switched Odyssey back to using its high-gain antenna. The programmed response to the detected problem on July 14 initially shifted the spacecraft to slower communication via its low-gain antenna.

The spacecraft team recovered downward-pointing operations, out of safe mode, on Friday, July 16. "We expect to be back to full operations this week," said Odyssey Project Manager Phil Varghese of NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Odyssey has been orbiting Mars since 2001. In addition to its own major scientific discoveries and continuing studies of the planet, the Odyssey mission has played important roles in supporting the missions of the Mars rovers Spirit and Opportunity and the Phoenix Mars Lander.

The rover Opportunity was not able to transmit data to ground controllers via Odyssey while the orbiter was in safe mode. Science activities were delayed, but critical activities have not been affected.

JPL, a division of the California Institute of Technology in Pasadena, manages Mars Odyssey for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. Additional information about Odyssey is at http://www.nasa.gov/mission_pages/odyssey .