The Mars rover Opportunity has been suffering from a glitch that's causing what NASA scientists describe as memory and data loss -- or a robotic "amnesia" -- since early December. Now, they're nearly ready to send aloft a software update they hope will rectify the problem.
The danger lies not in the distance the software fix will have to travel but in replacing critical software in a machine that technicians have no way to actually lay their hands on.
"The distance isn't that big a deal, because we're used to talking with the rovers over that distance, but you have to be so careful," said Ashwin Vasavada, the new project scientist for Mars Rover Curiosity, the much younger sibling to Opportunity. "If it doesn't boot right, it may never talk to you again. [Software upgrades] have to be done extremely carefully."
The answer to getting it right is repeated testing, added Vasavada, who took over as the leader of the Curiosity team on Monday.
"They practice a lot with test beds on Earth and you have to carefully boot into the new flight software while retaining the old version, in case there's a problem," he explained. "It's something we plan to do every few years on the rover missions so we can fix bugs and add new features. It's just a moment of added risk."
This software update, though, isn't routine since it's needed to fix Opportunity's memory problem.
NASA hasn't reported specifically when it will try to fix the rover's memory problem, but scientists hope it will be in about a week.
NASA reported that Opportunity's troubles began in December, immediately after engineers reformatted the robot's flash memory. They quickly prompted the rover to shift to a working mode that avoids use of its flash data-storage system.
Engineers tried repeated computer resets, but the rover's flash memory remained intermittent, according to the space agency.
Flash memory is important on Opportunity because it's able to retain data even when the rover's power is shut off during its overnight power-conserving "sleep" time, NASA noted. Without flash memory, the robot can continue driving across the Martian surface and working on its regular scientific operations.
However, it's not able to store data over night. That means every day any information gathered is stored temporarily in the machine's RAM and then it must be sent to Earth so it's not lost when Opportunity powers down.
"The mission can continue without storing data to flash memory, and instead store data in volatile RAM," Mars Exploration Rover Project Manager John Callas said in a statement last month. "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."
This won't be the first time that scientists have had to make a long-distance fix on Opportunity.
In 2013, NASA programmers had to send new commands to Opportunity to get the rover to resume operations after it had put itself into stand-by mode. The fix worked and Opportunity was quickly back up and running.
Opportunity and its robotic twin rover, Spirit, both landed on Mars early in 2004. Both machines were designed to work in the harsh conditions for only three months.
Spirit lasted for more than seven years, only being given up for dead in 2011 after it got stuck in the dirt a year before that.
Opportunity, though, has remained working, studying the Martian surface long after scientists had expected it to stop functioning.
Early last year, the old rover sent back evidence of an ancient wet and mild environment on Mars that is much older than scientists had previously thought existed there.
It was another clue that has led scientists to believe that Mars could have once sustained life.