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The transcript of the 2015 NPR podcast NASA Hopes A Hack Will Overcome Mars Rover's Memory Gap says:

You know how it goes - you're getting a little older, your memory starts to go, you forget where you put the car keys or whether you've turned off the oven. And you can't remember what happened to all the telemetry data you collected while exploring the surface of Mars. All right, you might not experience that last one, but NASA's Mars rover, Opportunity, is experiencing what NASA scientists are calling amnesia. Opportunity has been on the planet's surface for more than a decade. That's pretty old in rover years. And it's having problems with one of its memory banks. When the rover tries to save data to that faulty bank, the data gets lost, or worse - it reboots and forgets the commands NASA has been sending it. NASA's working on a software hack to make the rover ignore the defective memory bank and once they get it fixed, they're hoping Opportunity can hold on just a little bit longer before it bites the red dust. The project manager told "Discovery News" that some of Opportunity's most important explorations could be just ahead in the Marathon Valley. The Marathon Valley, by the way, is named that because the rover will have rolled more than 26.2 miles across Mars if it makes it. Not bad for an old fella.

I assume that this was an uploaded software patch sent to Opportunity via the Deep Space Network. What is the nature of this patch? How did it change the way Opportunity uses its memory, and if it's known, did it result in an improvement?

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They reformatted the flash memory area and, after finding the defective memory bank, modified the software in the rover to avoid using that area.

The hack in itself reduces the amount of available memory (you lose one bank), but as the rover was avoiding flash memory entirely, you have a net gain by being able to reenable it.

https://www.jpl.nasa.gov/news/news.php?feature=4517

According to JPL it did work.

After avoiding use of the rover's flash memory for three months, the team operating NASA's 11-year-old Mars Exploration Rover Opportunity has reformatted the vehicle's flash memory banks and resumed storing some data overnight for transmitting later.

The team received confirmation from Mars on March 20 that the reformatting completed successfully. The rover switched to updated software earlier this month that will avoid using one of the seven banks of onboard flash memory. Some of the flash-memory problems that prompted the team to adopt a no-flash mode of operations in late 2014 were traced to Bank 7. The remaining six banks provide more nonvolatile memory capacity than the rover has used on all but a few days since landing on Mars in January 2004.

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  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$ – called2voyage Jun 15 '18 at 20:26

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