“We spent the last week checking out Side A and preparing it for the swap,” said Steven Lee of JPL, Curiosity’s deputy project manager. “It’s certainly possible to run the mission on the Side-A computer if we really need to. But our plan is to switch back to Side B as soon as we can fix the problem to utilize its larger memory size.”
NASA’s Mars’ robots are having a terrible couple of months! Earlier this summer, the Opportunity rover stopped communicating with Earth after a global dust storm swept the planet and prevented sunlight from fueling its solar panels. NASA hasn’t heard from the rover since June, and engineers are listening daily for faint pings.
Then, mid-September, the other rover, Curiosity, experienced a technical glitch that has prompted engineers to temporarily turn off all its science instruments while they run diagnostics.
Since then, engineers at the Jet Propulsion Laboratory “have been working to address an issue on Curiosity that is preventing it from sending much of the science and engineering data stored in its memory,” wrote Ashwin Vasavada, the project scientist for Curiosity. “The rover remains in its normal mode and is otherwise healthy and responsive.”
According to Vasavada, the problem appeared in the rover’s main computer. The issue means that Curiosity can’t properly store or send data it collects from its science instruments.
The rover is still able to transmit some data, including about its well-being. It can uplink information to a Mars orbiter as it passes overhead, or beam it directly to the Deep Space Network, a series of antennas back on Earth. Vasavada said engineers have instructed Curiosity to send more data about its status, which doesn’t require the rover to dip into previously stored information.
Fast forward to this week, JPL engineers in Pasadena, California, commanded Curiosity to switch to its second computer. The switch will enable engineers to do a detailed diagnosis of a technical issue that has prevented the rover’s active computer from storing science and some key engineering data since Sept. 15.
Like many NASA spacecraft, Curiosity was designed with two, redundant computers—in this case, referred to as a Side-A and a Side-B computer—so that it can continue operations if one experiences a glitch. After reviewing several options, JPL engineers recommended that the rover switch from Side B to Side A, the computer the rover used initially after landing.
The rover continues to send limited engineering data stored in short-term memory when it connects to a relay orbiter. It is otherwise healthy and receiving commands. But whatever is preventing Curiosity from storing science data in long-term memory is also preventing the storage of the rover’s event records, a journal of all its actions that engineers need in order to make a diagnosis. The computer swap will allow data and event records to be stored on the Side-A computer.
Side A experienced hardware and software issues over five years ago on sol 200 of the mission, leaving the rover uncommandable and running down its battery. At that time, the team successfully switched to Side B. Engineers have since diagnosed and quarantined the part of Side A’s memory that was affected so that computer is again available to support the mission.
“At this point, we’re confident we’ll be getting back to full operations, but it’s too early to say how soon,” said Lee. “We are operating on Side A starting today, but it could take us time to fully understand the root cause of the issue and devise workarounds for the memory on Side B.
The Daily Galaxy via NASA and The Atlantic
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