The Software Bug That Almost Killed Curiosity Just Six Months In

A buggy computer almost denied us a wealth of scientific knowledge.


The Mars rover Curiosity rover has increased our knowledge of the Red Planet exponentially, but it almost stopped working entirely after a mere six months of exploration. That's one of the revelations from an interview between CBS' 60 Minutes and NASA's Jet Propulsion Laboratory.

Curiosity landed on Mars on August 6, 2012, after fifty years of probes and other rovers. But the car-sized Curiosity, with its ability to scoop up dirt samples, drill into boulders, and an X-ray spectrometer, could analyze the planet far beyond photos.

To manage all this, the rover has two "computer brains," which Rob Manning, chief engineer at JPL, refers to in the interview as "pilot" and "co-pilot." The rover is constantly abuzz with activity, from engineering and housekeeping to analysis telemetry and periodic event reports. But, six months into the mission, Pilot started "acting a bit like it had an attitude," Manning says.

Pilot has the ability to run a self-diagnostic. Curiosity developed a "some sort of memory problem" and Pilot should have known to give control over to Co-Pilot. Yet Pilot "refused to give up control," Manning says.

"The computer has developed an attitude in a way that we have never seen before," he says. "When we told it to go take a nap, it refused to take a nap. Then it refused to take pictures. Then it refused to do more science throughout the day. It just stopped doing these things. And we said, 'What the heck is going on?'"

Faced with a renegade computer, Manning had one play left: Kill Pilot in hopes that Co-Pilot would be jolted awake. It was a risky move. If Co-Pilot didn't wake up, the entire $2.5 billion mission would have been over and it would be that much harder to justify further jaunts into space. "We're waiting for the copilot to wake up," Manning says, "and then turn on its radio to let us know that it was alive. We should get a signal. Nothing. Another minute goes by. Nothing. Four minutes go by."

Finally, the silence broke. The signal came through, Co-Pilot had taken over, and has been running things to this day. Pilot has since been fixed and stands ready as a replacement. And Curiosity is free to explore Martian mud.

Source: 60 Minutes via Space

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