Until Oct. 24, NASA’s Mars Exploration Rover had gone more than six months without an episode of amnesia-like symptoms like those that appeared on four occasions earlier this year.
In these amnesia events, Spirit fails to record data from the day’s activities onto the type of computer memory — non-volatile “flash” memory — that can retain the data when the rover powers down for its energy-conserving periods of “sleep.” The reappearance of this behavior in recent days might delay the start of planned drives by Spirit geared toward extricating the rover from a patch of soft soil where its wheels have been embedded since April.
Spirit sent data Oct. 24 through Oct. 27 indicating that the rover was not using its flash memory. The rover also has alternate memory (volatile, random-access memory) where data can be saved for communicating to Earth if the communication session comes before the next sleep period. Spirit remains in communication with Earth, maintaining good power and temperatures.