NASA expects to have the Curiosity rover back up and exploring Mars “in a few days” time the space agency has announced, with the fix for the unexpected downtime “very straightforward” according to the mission lead. A software error was blamed for the rover being put into automatic fault-protection mode – freezing all activity – when a file was artificially inflated in size and thus failed a software check.
Curiosity has two computers – A-side and B-side – which it can switch between for the sake of redundancy. To ensure stability, files on both machines are regularly compared, making sure the systems are identical and thus the rover’s behavior the same no matter which computer is in control at the time.
However, a glitch in software caused one of the files to increase in size, after another, unrelated file was appended to it. That caused the automatic checks to fail the system, and Curiosity to be put into safe mode while teams back on Earth investigated.
According to Curiosity project manager Richard Cook, the fix should be swift. “We can just delete that file,” he explained, “which we don’t need any more, and we know how to keep this from occurring in the future.”
However, while the software tweaks are simple, waking Curiosity back up will be staggered over the space of a few days. It only leaves a relatively short window before the rover’s next period of isolation: as of April 4, the Jet Propulsion Lab will cease all remote commands for a four week period, as Mars will be blocked from a direct line of sight with the Earth by the sun. The team is concerned that commands might be corrupted by the obstruction.