How have NASA's Mars robots lasted 24 times longer than expected (so far)?

NASA's two Mars Rover vehicles were designed to last only 90 days but, six years later, they're still operating.

NASA’s Spirit and Opportunity Mars Rovers are the Energizer Bunnies of outer space; both are still operational after six years, after only being expected to run for 90 days.

Even though the robotic vehicles have shown exceptional longevity in the field, their capabilities would be quickly outpaced by humans on Mars, Steve Squyres, principal investigator of NASA’s Mars Exploration Rover Mission, said at a seminar today sponsored by Federal Computer Week.

“I am a robots guy, but what the Mars Rovers have done in six years a human could do in a week,” Squyres said. When asked whether he would he volunteer for the job, Squyres answered, “In a heartbeat.”

According to Squyres, the Rovers owe their longevity to cautious testing and engineering while in development. “We used no new technologies, only proven technologies,” he said. “And we were very, very cautious in our parts selection, assembly and testing.”


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However, the Rovers’ software is a different story. Some of the programs for moving and operating the Rovers was developed during the five months while the vehicles were on the way to Mars, he said.

NASA also benefited from an unanticipated stroke of luck because winds have been regularly blowing dust and debris from the Rovers' solar panels, prolonging their usefulness, Squyres added.

NASA has spent more than $900 million on the missions of the Rovers. One of the most heralded discoveries so far is that Mars once had abundant water. However, no evidence has been found yet of biological life there, which most likely would have been microbes, Squyres said.

Currently, Opportunity is moving over sand dunes to the 14-mile-wide Endeavour Crater. The Rovers already have explored a number of craters and rock formations, discovering pebble-like hematite and a deposit of pure silica.