Mars Rover Prepares to Touch a Rock



It's almost time for NASA's Curiosity rover to make contact with a Martian—a Martian rock, that is.

The rover, now six weeks into its mission on the Red Planet, is preparing to place its Alpha Particle X-Ray Spectrometer (APXS) against a rock to analyze its composition. Powered by 0.7 milligram of radioactive curium 244, APXS irradiates samples with alpha particles (nuclei of helium atoms) and x-rays to make sensitive measurements of chemical makeup.

"We're now at a point where we want to start to do some surface-contact science," mission project manager Richard Cook of the NASA Jet Propulsion Laboratory in Pasadena, Calif., said during a September 19 teleconference.