The problem is in a flash memory system and may have been the result of a radiation hit, he added.

“If I were to guess the most likely cause, that would be it,” Cook said.

Engineers want to restore Curiosity’s damaged computer system so that it can be returned to service as a backup. The rover had been using its A-side computer system since before landing.

The B-side system, now in operation, was last used during Curiosity’s nine-month cruise from Earth to Mars.

Results of the rover’s chemical analysis of the rock sample remain set for release on March 12, lead scientist John Grotzinger wrote in an email to Reuters.

Scientists chose the rock in part because it is shot through with what appear to be minerals that form in the presence of water. Water is believed to be necessary for life.