NASA Rover Dims Hopes for Martian Methane    The Curiosity rover used a laser to sample freshly drilled rock dust on Mars. It has not found methane.

NASA's Curiosity rover has failed to find significant signs of methane in the Martian atmosphere, mission scientists reported on Thursday. The new rover information suggests that earlier reports of Martian methane—once seen as a possible sign of microbial life on the planet—may have been off target.