The Spirit rover appears to have some memory and mobility problems. Yes, she’s getting old, and it appears she has symptoms of aging similar to humans. On Sunday, during her 1,800th Martian day, or sol, information radioed from Spirit indicated the rover had received its driving commands for the day but had not moved. That can happen for many reasons, including the rover properly sensing that it is not ready to drive. However, other behavior on Sol 1800 was even more unusual: Spirit apparently did not record the day’s main activities into the non-volatile memory, the part of its memory that persists even when power is off. It’s almost five years to the day when Spirit had memory problems with her “flash drive,” but back then, she was just a youngster.
The team operating NASA’s Mars Exploration Rover Spirit plans diagnostic tests this week to see why she did not report some of its weekend activities, including a request to determine its orientation after an incomplete drive.
On Monday, Spirit’s controllers at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., chose to command the rover on Tuesday, Sol 1802, to find the sun with its camera in order to precisely determine its orientation. Not knowing its orientation could have been one possible explanation for Spirit not doing its weekend drive. Early Tuesday, Spirit reported that it had followed the commands, and in fact had located the sun, but not in its expected location.
“We don’t have a good explanation yet for the way Spirit has been acting for the past few days,” said JPL’s Sharon Laubach, chief of the team that writes and checks commands for the rovers. “Our next steps will be diagnostic activities.”
Among other possible causes, the team is considering a hypothesis of transitory effects from cosmic rays hitting electronics. On Tuesday, Spirit apparently used its non-volatile memory properly.
Despite the rover’s unexplained behavior, Mars Exploration Rovers’ Project Manager John Callas of JPL said Wednesday, “Right now, Spirit is under normal sequence control, reporting good health and responsive to commands from the ground.”
Spirit has a history of being a drama queen, but just the same, I’m keeping my fingers crossed that she pulls through this latest mess alright.