A computer problem onboard the Mars rover Curiosity has forced NASA scientists to put the rover into safe mode while they try to bring a backup system online and try to figure out what is wrong with the main computer.
"We are doing multiple things at the same time," Jim Erickson, Curiosity's deputy project manager, told Computerworld. "All we know is the vehicle is telling us that there are multiple errors in the memory. ... We think it's a hardware error of one type or another but the software did not handle it gracefully. We'd like to have our vehicles withstand hardware trouble and continue to function."
Erickson explained that last week engineers watching the rover's telemetry noticed certain applications would begin and then terminate mid-sequence. The problem appears to be a file corruption.
Scientists put Curiosity, which landed on Mars last August, into a minimal-activity safe mode last Wednesday. Since then they have been working on three different issues.
They are trying to switch the rover over onto its redundant, onboard computer system, referred to as the B-side. And while trying to repair the problem on the main system, Erickson noted that engineers are also trying to shore up the rover's software so it can better withstand hardware glitches.
"We are bringing the B-side online and getting it ready to conduct science experiments, and conduct all the driving and other activities that we normally do," Erickson said.
He added that NASA should know within two weeks if it will be able to bring the main computer back to full operation.
"I wouldn't say we're concerned but we'll go through the process and find out what happened and go from there," said Erickson. "If we have to stay on the B-side, there will be no change in science capabilities but we'd have only one side to work with and wouldn't have resilience. But we'll take what the reality is."
NASA is on a deadline to get the rover's computer repaired because as of April 4, the agency will not be able to communicate with any of the Mars rovers or orbiters for a month.
Erickson explained that NASA was approaching the solar conjunction, when the Sun will be in the path between the Earth and Mars for about a month. With the Sun in the way, NASA won't be able to send daily instructions to the rover, or receive data and images in return.
That means NASA will have to send all operational instructions for that monthlong span to Curiosity before the solar conjunction begins. And it will keep the rover stationary, as well as keeping its work to a minimum.
"It will continue functioning but it will be doing limited activities," said Erickson. "It won't move but we will have it doing limited science that won't include taking the drill out or anything. We'll have it doing imaging, using the mass cam and the chem cam."
