Like an old friend that won’t wake up, the Mars rover Spirit refuses to answer calls from home. After six years of friendly conversation, Earth must now look away.
Winter was hard this year: three months of dark sand storms shrouded in howling winds with temperatures that dipped below 220 degrees Fahrenheit. With no energy left in her batteries, and now way to clear the accumulated sand off of her solar panels to collect more, little Spirit had no choice but to freeze to death in the harsh, Martian winter.
It sounds like science fiction, but Mission Planners and Controllers at Jet Propulsion Laboratory figure that this is what finally ended the extraordinary career of the Mars rover Spirit. Designed to last just three months, the plucky robot explorer lasted over six years.
Spirit, and her twin rover Opportunity, were parachuted onto the Martian surface in January of 2004. But, while Opportunity’s landing site was clearly understood and well mapped out, Spirit came down on a hard, windswept volcanic plain – entirely different from the ancient lakebed that she was expected to find. Shortly after touchdown she experienced an electronic anomaly that almost shut her off completely. But engineers and controllers at home kept her going.
After two years of mapping, photographing, and analyzing the Martian surface, the right front wheel, one of six on the five-foot long little rover, jammed while crossing a crater. Suddenly, the rover’s life expectancy seemed quite short. But mission controllers ran her backwards across the rocky terrain, dragging the damage wheel behind her. The little robot explorer, looking like a long, low Wall-E, soldiered on, making new discoveries and adding to the database of Martian knowledge.
The beginning of the end came for Spirit in her fourth Martian winter. During a run for a south-facing slope before the winter storms hit she found herself mired in a vast sand pit. She was already experiencing problems with a second wheel when she lost traction in the sand. With no way to turn herself to face the south and get her solar arrays facing the sun she stalled and sat out the winter totally exposed to the worst Mars has to offer.
Spirit’s insides are sealed against the weather, but the seals require internal heaters to remain intact. Her solar panels became caked with dust and sand, eliminating her battery recharge function. With no power, the heaters most likely failed, causing the seals to fail, and the internal communications systems to freeze and fail.
NASA and JPL sent well over 1,200 query signals to the disabled explorer through March, April, and May of this year. None were answered.
Faced with new projects and budgetary demands, it was decided that communication with the intrepid Spirit rover would officially end in May. That is not to say that if Spirit somehow found enough energy to signal the Mars Orbiter or Earth that NASA wouldn’t take steps to revive her. But the active days of communication are over for this remarkable, untiring machine.