NEW YORK — NASA’s Mars Odyssey spacecraft, an 11-year-old orbiter circling the red planet, has recovered from a glitch that stalled the probe’s science operations at the beginning of June.

The Lockheed Martin Space Systems-built spacecraft went into protective safe mode June 8 after its onboard computer detected a problem with one of the three reaction wheels that control its orientation. One of these wheels jammed temporarily, so mission controllers instructed Mars Odyssey to use a spare it had onboard.

Mars Odyssey uses a trio of spinning reaction wheels to maintain its orientation in space without the use of thrusters, which consume precious propellant. Prior to testing last week, the spare wheel on Mars Odyssey had been idle since the spacecraft launched in 2001. A shakeout of the wheel spun it up to 5,000 rotations per minute, mission managers said.

With the spare wheel up and running, Mars Odyssey has successfully shifted out of safe mode — which pointed the spacecraft at Earth for better communications — to its normal downward direction facing Mars, called nadir.

“Attitude control in nadir pointing is being maintained with the use of the replacement wheel, and the suspect wheel has been taken out of use,” Mars Odyssey Project Manager Gaylon McSmith of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., said in a statement.

Scientists will continue checking on the performance of the replacement wheel, but expect the spacecraft to resume normal operations soon.

“Remaining steps toward resuming all normal spacecraft activities will probably be completed by next week,” officials said in the June 19 statement.

Mars Odyssey launched in April 2001 aboard a Delta 2 rocket and has been orbiting the planet longer than any other Mars mission in history.

The orbiter has been mapping the surface of Mars to study its chemical and mineral distribution, and it also serves as a relay station to pass on data collected by landers on the planet back to ground stations on Earth. Mars Odyssey is a primary relay station for NASA’s Mars Exploration Rover Opportunity, and will also serve the Mars Science Lab rover Curiosity after it lands in August.



Mars Odyssey Orbiter Goes Into Safe Mode after Glitch