The Opportunity rover landed on the Red Planet in January of 2004. Though it was only scheduled to have a primary mission duration of about 92 days, it is now close to reaching its 4000th day on Mars, having travelled over 40 kilometers (25 miles). However, the crew running the mission at Jet Propulsion Laboratory have recently had difficulties with the rover's flash memory, essentially causing Opportunity to have a bit of memory loss when it comes to storing data long-term. The crew now plans to reformat the drive in order to restore function, a plan they are confident will allow the mission to continue.
The rover is equipped with seven flash memory banks, which permit data to be written and stored for a long period of time, even if the rover shuts down. As needed, new data can overwrite what is currently stored there. However, this is somewhat similar to writing on paper with a pencil and then erasing to use the paper again; after some time, the paper will begin to wear out.
The faulty memory bank comes with an irritating hitch, because when the memory bank fails, Opportunity reboots in the tried-and-true method of turning a computer off and then back on to alleviate errors. However, this doesn't actually fix the problem with the memory bank and just interrupts all of the long-term processes it runs that are unable to restart automatically once it boots back up. This necessitates that the ground crew manually turn those back on following every reboot, which is a couple of times per hour.
The solution is to eliminate use of that seventh data bank entirely, skipping back to the first bank after the sixth has been used up. To make up for the memory deficit, Opportunity will start using its random access memory (RAM) which is useful for temporary applications. However, if Opportunity shuts down to reboot before sending the RAM data to JPL, the data will be lost with no chance of recovery. However, once the seventh flash memory bank is not being used, the crew might be able to come up with a better fix.
"The mission can continue without storing data to flash memory, and instead store data in volatile RAM," said Mars Exploration Rover Project Manager John Callas said in a press release. "While we're operating Opportunity in that mode, we are also working on an approach to make the flash memory usable again. We will be sure to give this approach exhaustive reviews before implementing those changes on the rover."
Though Opportunity is no spring chicken and is showing various signs of aging, the rover is still going pretty strong and expanding our body of Martian knowledge a bit more everyday. While there isn't currently an estimated time for Opportunity's journey to come to an end, the crew at JPL is trying their best to ensure that every day counts with this amazing rover.
