Mars Curiosity goes into safe mode due to software error

Mars Science Lab Rover

Mars Science Lab Rover

New ‘Safe Mode’ Status of Curiosity Expected to be Brief

There have been no new images from the rover due to a ground commanded safe mode on February 27th, 2013. Just as we were expecting new data to flow an issue with the on board software caused to rover to safe itself. Unfortunately starting on April 4 there will be a four-week moratorium on sending commands due to solar system geometry of Mars passing nearly directly behind the sun from Earth’s perspective. This could delay any new images until some time in May if the systems are not restored quickly. The moratorium is a precaution against interference by the sun corrupting a command sent to the rover. NASA’s Mars rover Curiosity is expected to resume science investigations in a few days, as engineers quickly diagnosed a software issue that prompted the rover to put itself into a precautionary standby status over the weekend.Curiosity initiated this automated fault-protection action, entering “safe mode” at about 8 p.m. PDT (11 p.m. EDT) on March 16, while operating on the B-side computer, one of its two main computers that are redundant to each other. It did not switch to the A-side computer, which was restored last week and is available as a back-up if needed. The rover is stable, healthy and in communication with engineers.

The safe-mode entry was triggered when a command file failed a size-check by the rover’s protective software. Engineers diagnosed a software bug that appended an unrelated file to the file being checked, causing the size mismatch.

“This is a very straightforward matter to deal with,” said the project manager for Curiosity, Richard Cook of NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “We can just delete that file, which we don’t need any more, and we know how to keep this from occurring in the future.”

The mission’s science observations have been on hold since a memory glitch on the A-side computer on Feb. 27, which prompted controllers to command a swap from the A-side computer to the B-side computer. That operator-commanded swap put Curiosity into safe mode for two days. The rover team restored the availability of the A-side as a backup and prepared the B-side to resume full operations.

Cautiously bringing Curiosity out of safe mode status on the B-side is expected to take a couple of days.

About the author

Recipient of many prestigious NASA Awards including the Exceptional Public Service Medal and the Robert H. Goddard award. Experience includes working for NASA, as a contractor, in satellite design, construction and operations. Expert in the satellite operations concepts and ground systems including command, control, and science data processing.