According to mission controllers at the NASA Jet Propulsion Laboratory (JPL), in Pasadena, California, the Mars Odyssey orbiter put itself into a state known as a safe mode on July 11. This usually happens when some sort of damage occurs.
The purpose of the safe mode is to prevent any type of damage from spreading through a spacecraft's systems. In the case of Odyssey's latest glitch, the vehicle remained in this protective mode from 1 pm PDT (1900 GMT) on July 11 to 10 am PDT (1500 GMT) on July 12.
While such an event would not normally elicit too strong a reaction among mission controllers, this one is different because it comes on the heels of an important modification that was recently brought to the aging orbiter.
Several hours later, experts were able to upload a series of commands that took Mars Odyssey off safe mode, and had it re-orient itself towards Mars again. According to JPL researchers, the issue originated in a reaction wheel.
The vehicle has three such free-moving wheels, which it uses to maintain altitude. The problem that affected it during the recent orbital adjustment maneuver was that the engine burn used to switch its orientation placed too much stress on just one of the reaction wheels.
Computers immediately initiated safety protocols, and put the spacecraft in an expecting state, until further commands were uploaded. The orbit-trim maneuver, which lasted 1.5 seconds, was carried out on Wednesday, July 11.
“We are on a cautious path to resume Odyssey's science and relay operations soon. We will also be assessing whether another orbit trim maneuver is warranted,” says JPL Mars Odyssey project manager, Gaylon McSmith.
The spacecraft was launched towards Mars in 2001, and is the oldest satellite still in operations around the Red Planet. It is joined in orbit by the NASA Mars Reconnaissance Orbiter (MRO) and the European Space Agency's (ESA) Mars Express.
Via: Mars Odyssey Entered Safe Mode Again
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