Nasa's Mars rover put to sleep after glitch

A computer glitch on Nasa’s Mars rover Curiosity has forced the scientists to put the robot on safe mode while engineers try to fix the problem.

The intentional swap put the rover, as anticipated, into a minimal-activity precautionary status called “safe mode,” Nasa said.

The team will shift the rover from safe mode to operational status in a few days and is troubleshooting the condition that affected operations. The condition is related to a glitch in flash memory linked to the other, now-inactive, computer.

“We switched computers to get to a standard state from which to begin restoring routine operations,” said Richard Cook of Nasa’s Jet Propulsion Laboratory, project manager for the Mars Science Laboratory Project.Like many spacecraft, Curiosity carries a pair of redundant main computers in order to have a backup available if one fails. Each of the computers, A-side and B-side, also has other redundant subsystems linked to just that computer. Curiosity is now operating on its B-side, as it did during part of the flight from earth to Mars.

“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.

The spacecraft remained in communications at all scheduled communication windows, but it did not send recorded data, only current status information.
The status information revealed that the computer had not switched to the usual daily “sleep” mode when planned.

Diagnostic work in a testing simulation at JPL indicates the situation involved corrupted memory at an A-side memory location used for addressing memory files.