At a NASA-sponsored briefing for journalists last December, scientists with the Mars Exploration Rover missions described the various hazards that could cut short the planned, twin 90 (Earth) day operations on the red planet and limit the amount of data shipped home by the robotic vehicles from their respective landing sites. The biggest threat, the scientists said, was dust from the Martian surface, which would degrade the landers’ solar arrays, eventually cutting electric power and causing the batteries to fail.