NASA Finally Resurrects Sick Mars Orbiter
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 has finally revived its most powerful Mars orbiter from its months-long slumber due to a computer glitch.

The spacecraft, NASA?s Mars Reconnaissance Orbiter, slipped into a protective ?safe mode? in late August, stalling its science observations but safeguarding the $720 million probe from further damage. Instead of rousing the orbiter within a few days, as in past glitches, NASA engineers spent months trying to find the source of the probe?s inexplicable computer rebooting malfunctions.

"The patient is out of danger, but more steps have to be taken to get it back on its feet," said Jim Erickson, the spacecraft?s project manager at NASA?s Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

JPL engineers beamed the 4-year-old orbiter a vital software upgrade last week to patch a potentially mission-killing scenario in the spacecraft?s onboard computer. That scenario, the unlikely occurrence of back-to-back computer reboots, could have sent the powerful Mars orbiter offline for good, mission managers said.

The satellite?s resurrection began Nov. 30 with the software update, and new commands are being sent this week to check the spacecraft?s science operations. Actual science observations may resume in earnest next week, mission managers said.

Computer glitches have plagued the Mars Reconnaissance Orbiter this year. In addition to the latest computer reboot in August, the probe suffered similar malfunctions in February and June. Engineers initially thought they were caused by cosmic rays or solar particles interfering with the probe?s electronics. In August, the orbiter also unexpectedly switched to a backup computer, a different kind of malfunction, for a short while.

The Mars Reconnaissance Orbiter is NASA?s youngest spacecraft orbiting the red planet and the most powerful probe ever to observe the Martian surface. The orbiter launched in 2005 and arrived at Mars in 2006. Since then, it has beamed more data and images of the planet to Earth than all other Mars missions in history combined.

The spacecraft completed its primary mission in late 2008 and is currently in the middle of an extended mission that runs through mid-2010.

It is not the only Mars probe to encounter difficulties this year. NASA?s Mars rover Spirit has been stuck wheels-deep in Martian sand since April. Engineers at JPL have been trying several methods of extricating it, but have been waylaid by wheel stall and tilt issues.

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