Maybe Martians have a sense of humor
Mystery of Mars rover's 'carwash' rolls on
NASA's Mars rover Opportunity seems to have stumbled into something akin to a carwash that has left its solar panels much cleaner than those of its twin rover, Spirit. A Martian carwash would account for a series of unexpected boosts in the electrical power produced by Opportunity's solar panels.
The rovers landed on Mars in January 2004 with solar cells capable of providing more than 900 watt-hours of electricity per day. Spirit's output has dropped to about 400 watt-hours, partly because Martian dust has caked its solar panels.
Opportunity's output also declined at first - to around 500 watt-hours - but over the past six months it has regained power (New Scientist print edition, 30 October). Lately, its solar cells have been delivering just over 900 watt-hours.
Rover team leader Jim Erickson at NASA's Jet Propulsion Laboratory in Pasadena, California, told New Scientist that a process still not understood has repeatedly removed dust from the solar panels. "These exciting and unexplained cleaning events have kept Opportunity in really great shape," he says.
Whatever the process, it has taken place while Opportunity was parked during the Martian night. On at least four occasions over a six-month period, the rover's power output increased by up to 5% overnight. At the time, the team speculated that wind may have swept the dust off the panels or frost may have caused it to clump, exposing more of the panels.
