After days of theorizing as to the cause, engineers today produced a seemingly simple diagnosis: computer files left over from the "cruise phase" of the mission (i.e. the journey from Earth to Mars orbit) had not been deleted from the rover's flash memory and were taking up valuable space, sending Spirit into revolt. In fact, Spirit dated its readable transmission information as the year 2053. "There are not a lot of scenarios that put us in 2053," said Jennifer Trosper, mission manager at JPL