The rover has spent the Martian winter resting up and charging its lithium ion batteries, and during that sojourn things have been a tad windy in its locale; on Thursday NASA released a recent selfie taken by the rover showing it looking very clean indeed.
"In its sixth Martian winter, NASA's Mars Exploration Rover Opportunity now has cleaner solar arrays than in any Martian winter since its first on the Red Planet, in 2005," the agency said. "Cleaning effects of wind events in March boosted the amount of electricity available for the rover's work."
The windy cleaning has been so effective that power generation has been boosted by more than 70 percent compared with two months ago, to more than 615 watt hours. The rover needs about 100W of solar power to function, so the clean means it's good to go for a long time yet.