Posted by tourdemars to Mars Exploration Rovers at January 29, 2009 12:25 PM

NASA engineers are scratching their heads over some unexpected behavior from the long-lived Spirit rover, which began its sixth year exploring Mars this month. Spirit failed to report in to engineers at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., last weekend, prompting a series of diagnostic tests this week to hunt the glitch's source. The aging Mars rover did not beam home a record of its weekend activities and, more puzzlingly, apparently failed to even record any of its actions on Sunday, mission managers said.