Monday, July 16, 2012

Odyssey in Safe Mode 21 Hours July 11-12

The above image is an artist's concept of NASA's Mars Odyssey spacecraft orbiting the planet Mars. Odyssey has been orbiting Mars since October 24, 2001. Image Credit: NASA/JPL-Caltech

NASA continues careful study of its Mars Odyssey orbiter following the events of June. At that time, Odyssey put itself into safe mode (reduced activity, pointed at Earth, and awaited instructions) because of issues with one of its three reaction control wheels. The wheels are used for most of Odyssey’s attitude adjustments, saving the thrusters and their propellant for more important uses. Engineers were able to resolve the problem by decommissioning the glitchy wheel and putting into service a spare wheel which was included in the spacecraft design for just that purpose. Following that, engineers began careful monitoring to be certain that Odyssey (along with NASA’s Mars Reconnaissance Orbiter) can support NASA’s Mars Science Laboratory / Curiosity rover mission, which will land early August.

On July 11th, Odyssey hit a small pothole on the road to recovery. At about 1:00 PM EDT (10:00 AM PDT) Odyssey performed a planned 1.5-second thruster burn for an orbit-trim maneuver. Interestingly, it was the shortest-duration burn since Odyssey’s arrival at Mars a decade earlier. It seems the burn put unanticipated strain one of the three reaction control wheels — possibly that newly activated wheel, but NASA’s report does not make that clear. In any case, Odyssey followed its rules and put itself into safe mode (reduce activity, point at Earth, and await instructions). Fortunately for the mission engineers, Odyssey did not reboot during the hiccup, so they were able to review Odyssey’s diagnostic information and understand what happened and why.

On July 12th, 21 hours after Odyssey initiated safe mode, engineers reoriented the spacecraft toward the Martian surface and began to gradually bring Odyssey back up to normal spacecraft activities. Engineers will be assessing whether another orbit-trim maneuver is warranted.

And now, the mission particulars...

Since its arrival October 2001, the Mars Odyssey orbiter has worked at Mars for more than 10 years, which is longer than any other Mars mission in history. Besides conducting its own scientific observations, it serves as a communication relay for robots on the Martian surface. Odyssey is managed by NASA's Jet Propulsion Laboratory (JPL), Pasadena, for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems in Denver built the spacecraft. JPL and Lockheed Martin collaborate on operating the spacecraft. For more about the Mars Odyssey mission, visit: .

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