Curiosity Mars rover recovering from memory glitch
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Last Updated: Tuesday, March 05, 2013, 12:39
  
Washington: NASA's Mars rover Curiosity is undergoing a brain transplant - a complex sequence of steps to switch operations to a backup flight computer- amid ongoing analysis to figure out how to resolve memory corruption discovered last week in the rover's active computer.

According to CBS News, the memory glitch interrupted science operations, forcing flight controllers to put the craft in a low-activity "safe mode" while the computer switch was implemented.

Richard Cook, the Mars Science Laboratory project manager at the Jet Propulsion Laboratory in Pasadena, Calif., told the channel that the computer swap was going well and that limited science operations should resume shortly.

"We spent the weekend kind of getting back, not totally to regular operations, but at least out of the immediate safe mode kind of a thing," he said.

"We got it out of safe mode, got back to using the high-gain antenna, so we're well along the way to restoring things," he added.

When last Wednesday Curiosity failed to send back science data as expected and then failed to put itself to sleep during scheduled downtime, engineers review telemetry and discovered data corruption in the solid-state memory used by the rover's active flight computer.

Curiosity is equipped with two redundant computer systems, known as "side A" and "side B." Each one is capable of carrying out the rover's mission and only one operates at a time with the other on standby as a backup.

The B-side computer was checked out during the cruise from Earth to Mars while the A-side computer has been running operations since before landing last August.

Cook said the switchover to side B is a complex procedure and that engineers are taking their time to make absolutely sure the process is carried out correctly.

"We have some more work to do to upload configuration files and parameters, things like that, so it's going to be another few days or so to kind of get things totally recovered. But basically, it's going well," he said.

Once the B-side computer is fully up and running, limited science operations should resume.

But Cook said the engineering team wants to have a better idea of what went wrong with the A-side memory before going "full throttle" on the B-side computer.

Engineers suspect the memory glitch might have been caused by space radiation, a "single-event upset" in which an energetic particle made it through radiation-hardened components and changed the state of one or more memory addresses.

If that theory is correct, booting the A-side computer and its software would be expected to re-write the memory blocks, presumably flushing the corrupted data. In that case, assuming no other problems, the A-side computer would be deemed healthy and cleared to serve as backup to the B-side computer.

But before attempting a full re-boot, Cook said, engineers plan to power-up the A-side machine Wednesday, without loading software, to check the status of the non-volatile memory.

If the memory problem cannot be corrected, programmers could attempt to bypass the corrupted locations with a software patch.

ANI


First Published: Tuesday, March 05, 2013, 12:37


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