“We changed how the rover uses flash memory in an attempt to correct problems the rover had been experiencing,” said John Callas, project manager for Opportunity at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., in a news release “Although we are a little disappointed at the occurrence of an amnesia event only five days after reformatting, we are not surprised. There is still no clear understanding of what is causing the problems. Only time will tell if we have been successful in mitigating the most serious flash problems.”
The problem was thought to be centered around one of the seven memory banks in Opportunity’s flash memory — the rover’s on board “hard drive” of sorts, where data can be stored even if the rover is powered down. Rather than being lost, mission telemetry can be stored when the rover is switched off to preserve battery life during the Martian nights.
But late last year, the rover would “forget” valuable data, caused by a corrupt flash data bank. As a consequence, random resets would occur throughout the day. This was hindering the mission’s progress, prompting mission engineers to adopt a “no-flash mode” where Opportunity would avoid use of its flash memory, instead temporarily storing data to its volatile memory and regularly transmitting the data back to Earth before downtime.
Like the RAM on your PC or Mac, the volatile memory only provides temporary storage of data, becoming wiped when the rover powers down.
After uploading new software to avoid the use of the 7th flash memory bank, on March 20, engineers reformatted Opportunity’s memory. Although the rover isn’t currently exhibiting some of the worst symptoms associated with the amnesia, it appears that its memory problems are far from over.
From Discovery News
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