NASA's Mars Rover Curiosity in Safe Mode After Computer Glitch

This self-portrait of NASA's Mars rover Curiosity combines dozens of images taken by the rover's Mars Hand Lens Imager on Feb. 3, 2013. 

The portrait was taken at the rock target "John Klein," where the rover collected the first ever bedrock sample of Mars using its drill on Feb. 8. 

CREDIT: ASA/JPL-Caltech/MSSS

A computer glitch on NASA's Mars rover Curiosity has forced the robot to switch to a backup computer while engineers try to resolve the problem.

In the meantime, Curiosity's science work is on hold, and the spacecraft is in a minimal-activity state known as "safe mode" while its backup computer is updated with the command codes and parameters it needs to take over the rover's full operations.

"We're still early on in the process," said Richard Cook, Curiosity project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We have probably several days, maybe a week of activities to get everything back and reconfigured."

The issue cropped up Wednesday (Feb. 27), when the spacecraft failed to send its recorded data back to Earth and did not switch into its daily sleep mode as planned. After looking into the issue, engineers decided to switch the Curiosity rover from its primary "A-side" computer to its "B-side" backup on Thursday at 5:30 p.m. EST (22:30 GMT).

"Don't flip out: I just flipped over to my B-side computer while the team looks into an A-side memory issue," NASA officials wrote on behalf of the rover via Curiosity's Twitter feed.

The computer problem is related to a glitch in flash memory on the A-side computer caused by corrupted memory files, Cook said. Scientists are still looking into the root cause the corrupted memory, but it's possible the memory files were damaged by high-energy space particles called cosmic rays, which are always a danger beyond the protective atmosphere of Earth.

"The hardware that we fly is radiation tolerant," Cook told SPACE.com, "but there's a limit to how hardened it can be. You can still get high-energy particles that can cause the memory to be corrupted. It certainly is a possibility and that's what we're looking into."

Once Curiosity is up and running again, the rover should have no problem using its B-side computer as its primary computer for a while, officials said. As standard protocol, Curiosity, like many spacecraft, has redundant main computer systems as a safety precaution for just this type of anomaly.

"While we are resuming operations on the B-side, we are also working to determine the best way to restore the A-side as a viable backup," said JPL engineer Magdy Bareh, leader of the mission's anomaly resolution team, said in a statement.

Eventually, the team will want to turn the A-side computer back on and make sure both computers on the rover are healthy.

"We also want to look to see if we can make changes to software to immunize against this kind of problem in the future," Cook said.