The Mars Exploration Rovers' fourth Martian winter is proving to be the harshest one yet and Spirit and Opportunity are getting colder than ever before. With temperatures on the Red Planet dropping in April and the Martian winter solstice still two weeks away, the season has turned into a shivering nail-biter.
Spirit had been communicating on a once-per-week schedule in recent weeks. During the designated time for the rover to communicate with NASA's Mars Odyssey orbiter passing overhead on March 30, Odyssey heard nothing from the rover.
March seems to have come in like a lamb and gone out like a lion on the Red Planet this year as the Mars Exploration Rovers trudged deeper into their fourth winter. While Opportunity finished up work at Concepcin Crater and shifted into gear back on the road to Endeavour Crater, Spirit finished up winter preparations and carried out a limited winter agenda before shifting, it appears, into hibernation mode.