NASA’s Mars rover Opportunity has been working well into its golden years — after nearly 11 years roaming the Red Planet, it has survived more than 40 times past its warranty. But now, this trusty veteran explorer is experiencing some worrisome memory loss.
The long-lived rover has been having some senior moments, according to John Callas, project manager for the Mars Exploration Rover mission (as Opportunity and its defunct twin Spirit are formally known).
The episodes of amnesia stem from faulty flash memory — the kind of memory in your digital camera that allows your pictures to stay saved even after your device is turned off.
But flash memory doesn’t last forever, and the seventh, final bank in the flash memory appears to be malfunctioning.
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“Flash memory has a limited lifetime,” Callas said. “It only allows so many read-write cycles before it starts to wear out some of the cells. And after 11 years of operation on Mars, we now suspect we’re seeing a wear-out of some of those cells.”
This leads to a pair of problems. Since the rover can’t use the seventh memory bank, it uses its random-access memory — or RAM, the kind of memory your computer uses when it’s on for temporary data storage. The problem is, as soon as the rover (or your computer) is switched off, the information stored in RAM is lost.
So if the rover turns off before sending all of that data back to the Jet Propulsion Laboratory in La Cañada Flintridge, Calif., then those data are lost forever.
The second snag is that the flash memory issue also causes the rover to reboot — and when it reboots, it stops the long-term activities the team had planned for the rover and simply waits for further instructions.
“It’s like you’re taking a family trip and your car stalls, and every time your car stalls you have to call Triple-A — but now it’s stalling every 20 miles,” Callas said. “You’re not going to make much progress.”
Opportunity, which along with its twin Spirit arrived at the Red Planet in early 2004, set out to find signs of past water on Earth’s dry, dusty next-door neighbor. It did that and more.
Opportunity was never meant to last this long, and it’s picked up a number of scars along the way. It’s been described as arthritic, with a gimpy elbow and a somewhat disabled front wheel, but that hasn’t kept the robot from logging roughly 26 miles on the Red Planet.