Powerful Mars Orbiter Makes a Comeback
NASA's Mars Reconnaissance Orbiter passes over the planet's south polar region in this artist's concept illustration. The orbiter's shallow radar experiment, one of six science instruments on board, is designed to probe the internal structure of Mars' polar ice caps, as well as to gather information planet-wide about underground layers of ice, rock and, perhaps, liquid water that might be accessible from the surface. Phobos, one of Mars' two moons, appears in the upper left corner of the illustration. Image
Credit: NASA/JPL/Corby Waste

NASA's most powerful Mars orbiter has bounced back from some hard luck around the red planet this year, and scientists are eager to resume the orbiter's detailed observations of Mars in the new year.

After a series of glitches that began in February, mission managers put the Mars Reconnaissance Orbiter (MRO) into a protective "safe mode" in August. The spacecraft was resurrected earlier this month and resumed its science operations last week, much to the delight of Mars scientists, who have waited patiently for the orbiter to return to duty.

"It's good to have the instruments back on," said MRO mission manager Dan Johnston of NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif. "This has been a long stand-down. Now we're ready to resume our science and relay mission."

Repeat resets

MRO's troubles began on Feb. 23, when the orbiter underwent a quick reset. It was followed by an event on June 4 that "was virtually identical to the first one," said Jim Erickson, the spacecraft's project manager at JPL.

Engineers still don't know exactly what caused those rapid resets. They initially thought that a solar particle or cosmic ray struck the probe.

In August, another, different reset hit MRO and the craft temporarily switched over to its backup computer. Whether or not all the resets are related and caused by the same problem still isn't known.

With the repeated events this year, mission managers wanted to take precautions against the unlikely but potentially mission-ending event of having two resets happen within a minute of each other. On Nov. 30, they beamed up a software upgrade to the orbiter's non-volatile memory, where information is preserved even if another reset interrupts its power.

"Above all else, we have to make sure the spacecraft is safe," Erickson told SPACE.com.

Engineers ran a few more checks and eventually brought MRO out of its safe mode on Dec. 8. On Dec. 16, mission managers announced that the orbiter was back in business and ready to resume science operations, though engineers will be watching for any more resets.

Year ahead

Erickson said that during the safe mode interlude, scientists were chomping at the bit to get the valuable orbiter back. MRO has taken the most detailed images yet of the Martian surface from on orbit and has made key findings that add to the understanding of the geology and history of water on Mars.

The timing for MRO's return is fortuitous for its continued observations as well.

"It is northern spring in the northern hemisphere on Mars, and we are eager to take advantage of the good visibility provided by the relatively dust-free atmosphere present at this season," said JPL's Rich Zurek, MRO project scientist. "A major goal of the mission is to look at changes on Mars. For example, the instruments will observe the changing polar caps, examining the extent and composition of the retreating north polar frosts and the growth of the south polar cap during this period."

MRO is also important for its relay capabilities with other Martian spacecraft, particularly NASA's twin rovers, Spirit and Opportunity. Those functions have also resumed, NASA said.

MRO's mission, which began after it reached Mars in 2006, is extended through 2010. Mission controllers will send in proposals for further extensions in January, and those will be decided in February, Erickson said.

Erickson is confident that MRO's capabilities will be in demand for quite some time – especially with new missions, such as the Mars Science Laboratory, coming up – and mission engineers plan to do everything they can to watch the craft and keep it safe and running.

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