The Curiosity rover has experienced its first setback in what has been an almost too-good-to-be-true start to the mission. NASA is reporting that a sensor on its weather station module has sustained damage — and that it likely happened when stones were thrown up during its rocket-powered landing. NASA says the damage is not a major problem and that it will merely degrade their measurements.

Writing in AstroEngine, Ian O'Neill reports:

During Mars rover Curiosity's dramatic landing on Aug. 5, the rocket-powered sky crane blasted debris onto the rover's deck. The first question that came to mind concerned the safety of exposed and potentially vulnerable instrumentation. I was in the very fortunate position to raise my concerns during the Aug. 9 NASA news briefing. The response from MSL mission manager Mike Watkins was cautious optimism that little to no damage was caused by the unexpected ejection of material from the ground.

Alas, it would seem that some damage was sustained.

"It does appear that some small rocks became lofted in the winds that were generated by the plumes during landing and probably just fell upon the rover deck," said Curiosity deputy project scientist Ashwin Vasavada, with NASA's Jet Propulsion Laboratory in Pasadena, Calif., during a conference call on Tuesday (Aug. 21).

"Some of these rocks may have fallen on these exposed circuit boards and damaged the wires. That's just one potential cause. We don't know for sure and we don't really have a way of assessing that at this point any further," he added.

It appears that one of the booms on the Mars Science Laboratory's Rover Environmental Monitoring Station (REMS) - located on the rover's mast - may have been the hardware that got sandblasted or smashed by Mars rocks. REMS now only has one (of two) booms operational. The booms' purpose is to take measurements of wind speed on the Martian surface. Although this is a setback (and, so far, the ONLY setback), mission scientists are confident they'll find a workaround.