Bob Congdon

Over the weekend, scientists traced the problem over the weekend to a glitch in its flash memory. Engineers were working around the flash memory problem by telling the rover to store data in its random-access memory instead.

[Mission Manager Jennifer] Trosper said the "too many files" problem was the current leading theory for why Spirit failed last week. She said mission planners had not expected the rover's flash memory to accumulate so many data files during its trip to Mars and investigations on the surface.

"This is a new problem that we've encountered, based on having many files," she said.

During the weeks-long process of reviving Spirit, hundreds of unneeded files from Spirit's cruise phase would be deleted, she said, and controllers would keep a closer eye on memory management for Spirit as well as Opportunity. "We will be more conscious of this limit that we have," she said.