Long-lived Opportunity rover breaks extraterrestrial mileage record

Opportunity passes Lunokhod Crater on its trip to Marathon Valley.

NASA/JPL-Caltech/Cornell/Arizona State Univ.

Before the big publicity splash made by the Mars Science Laboratory and Curiosity, the big stars on Mars were the two Mars Exploration Rovers, Spirit and Opportunity. The pair of 400 lb (185 kg) semi-autonomous machines were dropped onto Mars in January 2004 and were initially designed with an operational lifespan of 90 sols (a sol is a Martian day, equivalent to about 24 hours and 39.5 minutes), but they managed to drastically exceed that lifespan through careful piloting and resource management. In fact, although Spirit fell silent in March 2010, Opportunity continues to be responsive—and as of yesterday, it has traveled 25.01 miles (40.25 km) across the Martian surface, setting a new record for off-world travel.

Distances driven by other off-world vehicles.

NASA/JPL-Caltech

The previous record dates back to 1974 when the Soviet Lunokhod 2 rover zipped across about 24.2 miles (39 km) of dusty lunar terrain in about four months. Opportunity’s progress has been much slower, due to a combination of a low travel speed (usually about 10 mm per second, with a top speed of 50 mm per second, about 600 feet per hour) and regular stops to perform observations.

In the ten years that Opportunity has cruised the Martian craters and valleys, the faithful robot has contributed tremendously to our understanding of the composition and history of Mars, including transmitting back data that provides significant support to the idea that Mars once had oceans of liquid water.