Flight controllers operating NASA’s Mars Science Laboratory rover Curiosity have switched over to the one-ton, nuclear-powered robot’s redundant computer. This was caused after a memory issue arose in Curiosity’s primary computer.
On Thursday, Feb. 28, at approximately 11:30 a.m. EST, the rover was placed into safe mode. This is a precautionary mode that reduces the rover’s activities to the bare minimum. In the following days the rover will be brought back up to its normal operating level.
Like its predecessor, the Mars Exploration Rover Spirit, the problem appears to have originated in the rover’s flash memory within the affected computer.
“We switched computers to get to a standard state from which to begin restoring routine operations,” said Richard Cook, Curiosity’s project manager.
NASA’s spacecraft and robotic explorers are built to be extremely resilient and have redundancies built into their various systems. Each of Curiosity’s computers, known as A-side and B-side, also has redundant subsystems. This philosophy has proven itself out during many of NASA’s more famous missions.
So as it stands, Curiosity is operating on its B-side computer. This is the same computer that was used during the rover’s transit phase from Earth to the Red Planet. After Curiosity touched down on the surface of Mars in August 2012, it was switched over to its primary A-side computer, which was used up until Wednesday of last week.
“While we are resuming operations on the B-side, we are also working to determine the best way to restore the A-side as a viable backup,” said JPL engineer Magdy Bareh, who leads the mission’s anomaly resolution team.
The team noted the issue when it was seen that, while the rover was communicating with its handlers back on Earth, it was not sending recorded data. Reviewing the current status information, Curiosity’s controllers saw that she had not switched over to her daily “sleep” mode. The problem is somewhat (although, obviously, far more complex in this case) familiar to those of us dealing with computer files here on Earth. It was described by NASA as such:
Diagnostic work in a testing simulation at JPL indicates the situation involved corrupted memory at an A-side memory location used for addressing memory files.
Curiosity was sent to Mars to conduct scientific research to determine whether or not Mars—more specifically the area around the rover’s landing site at Gale Crater—was ever suitable for life. Curiosity, unlike her cousins Spirit and Opportunity and their ancestor Sojourner, is nuclear powered (previous Martian rovers were and are powered by solar arrays). Her mission is scheduled to last two years.