To say that the Mars Exploration Rover Opportunity had a good run is an understatement as it still has been exploring the Red Planet for more than a decade now, 10 years and some months more than the 3-month mission it was first assigned in 2004. Like anything, the rover is subjected to wear and tear. For the Opportunity, its long-overdue stay in Mars has led to memory problems, giving the rover bouts of "amnesia."
There are two types of memory used by the Opportunity rover: volatile and non-volatile. The easiest way to understand these types of memory is to associate them with what computers on Earth normally use: RAM and flash memory. Volatile memory forgets everything stored on it when the rover powers off while non-volatile memory remembers everything stored on it.
To ensure all data gathered by the Opportunity is secured, the rover uses non-volatile memory. This way, should it power down during reboots or Marian nights, all its information will remain stored. Unfortunately, non-volatile memory has limitations--it can only be used so many times, wearing out with use.
Ten years is definitely a long time so it's not exactly surprising that Opportunity is having memory problems now. While NASA is ready to let go of the rover should its memory completely fail, the agency is not giving up. In fact, it has figured out a way to help keep the Opportunity going.
Software engineers from NASA's Jet Propulsion Laboratory have isolated the problem, identifying the seventh of the seven non-volatile memory banks the rover is using as the culprit behind the data loss. By programming the Opportunity to ignore the seventh memory bank and focus instead on the six working ones, the rover should be able to avoid memory loss, ensuring all data gathered are beamed back to Earth when the Mars Odyssey satellite makes an orbital pass.
According to NASA Project Manager John Callas, the software update that will program the rover to avoid the seventh memory bank should be completed in a couple of weeks.
Opportunity is located 650 meters away from Marathon Valley; so-called because it marks the point the rover will exceed a marathon on Mars once it gets there. As it is though, the rover has traveled more than 26 miles and is the current off-world record-holder for any rover, driven by an astronaut or robotic.
Marathon Valley also contains an assortment of clay minerals believed to have been formed during a time when Mars had plenty of pH-neutral surface water so Opportunity reaching the location will also mean a trove of information for NASA scientists.
