This image from the navigation camera on the mast of NASA Mars Exploration Rover Opportunity shows streaks of dust or sand on the vehicle rear solar panel after a series of drives during which the rover was pointed steeply uphill.
This image from the navigation camera on the mast of NASA Mars Exploration Rover Opportunity shows streaks of dust or sand on the vehicle rear solar panel after a series of drives during which the rover was pointed steeply uphill.