NASA engineers are preparing a radical fix that could help the Opportunity Mars rover regain its fading faculties and continue its Red Planet mission.
The rover, which has spent ten years rolling across the Martian plains, has been having memory problems for the last six months because the cells in its flash memory have been overwritten so many times they are starting to fail.
"Now we're having these events we call "amnesia", which is the rover trying to use the flash memory, but it wasn't able to, so instead it uses the RAM," Mars Exploration Rover Project Manager John Callas told Discovery News. "It stores telemetry data in that volatile memory, but when the rover goes to sleep and wakes up again, all [the data] is gone. So that's why we call it amnesia – it forgets what it has done."
In August, NASA tried reformatting the memory, but in the last month the situation has grown very serious. When the rover tries to write to the defunct flash memory, it reboots and loses the commands sent by Mission Control that day.
"Basically the rover stops what it was doing because it wasn't sure what caused the reset," said Callas. "So that interrupts our science mission on the surface of Mars. It's like you're trying to drive on a family trip – the car stalls out every five minutes. You don't make much progress that way!"
Just before the Christmas break, three days' worth of commands were sent to Opportunity, but the rebooting problems meant that only the first day's activities were completed – and even worse, the rover stopped communicating with Earth. Thankfully, the rover is now operational again, but Callas said NASA is "very, very worried."
To solve the problem, NASA engineers want to perform a partial lobotomy of the rover. Its flash memory is divided into seven banks, and it's the seventh that is causing the problem. If they can isolate and shut down that last memory bank, Opportunity should kick back into gear.
That's essential, because the mappers of Mars have discovered that the rover is just 650 meters away from something very interesting indeed. Ahead of Opportunity, in the feature dubbed Marathon Valley, are what looks like ancient clay beds that would have been deposited when the planet was more moist.
These clay beds are much older than those currently being explored by the Curiosity rover. That more modern machine has already detected that they were once lake beds and, if Opportunity can reach them, the results of its testing could help solidify the science of Mars' early climate.
The NASA engineers are designing the memory hack at the moment and, it is hoped, the software fix can be downloaded to the rover in the next few weeks. Then it'll be fingers crossed to see if the rover can carry on trucking.
"The rover has been amazingly healthy considering how much we've used it ... we thought the mobility system would have worn out a long ago but it's in great health," Callas said.
"But anything could fail at any moment. It's like you have an aging parent, that is otherwise in good health – maybe they go for a little jog every day, play tennis each day – but you never know, they could have a massive stroke right in the middle of the night. So we're always cautious that something could happen." ®