Mars is a hostile, dry planet wit a void of an atmosphere. Not the most inviting place, is it? So imagine spending the better part of a decade, trudging along its rocky terrain, in search of life and other celestial abnormalities. Now picture yourself having to recall and remember every piece of data collected, every factoid found. That'd be incredibly difficult, wouldn't it? Well, NASA's Mars rover has been on such an odyssey and now it is showing its age―in fact, its memory is fading.
The Opportunity, a fitting name for the rover on Mars, has onboard two sets of memory: "volatile" and "non-volatile." The first, "volatile" memory is reminiscent of RAM on a computer, completely wiping itself out with every shut-down. Not a problem in the long-run. But the latter memory, the described "non-volatile" memory is far, far more imperative for data collection, telemetrically interpreted inputs, and overall proper function.
"The difference is non-volatile memory remembers everything even if you power off, in volatile memory everything goes away," said Mars Exploration Rover Project Manager, John Callas, of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "So volatile memory is like the traditional RAM you have in your computer; non-volatile memory uses flash memory technology." And, much like the human brain, it degenerates with time and stress.
"The problems started off fairly benign, but now they've become more serious[―]much like an illness, the symptoms were mild, but now with the progression of time things have become more serious," said Callas. "So 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 ... 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."
According to Callas, the rover now is storing vital, quantitative data in its RAM memory... which is flashed clean with every reboot. Not a great characteristic for a data-collecting, multi-million dollar NASA rover.
But, there's hope in the form of a software update. The problem has been linked to the system's failing 7th bank of memory. The idea of the update is to trick the system into forgoing the 7th bank of memory, instead inputting information into the remaining―and "healthy"―6 banks of memory; this update will be installed within the upcoming weeks. But, even then, nothing's too certain with the senior rover.
"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," added Callas.
The Mars Exploration Rover Opportunity began its journey in January 2004, nearly 11 years ago from today.