Natalie Wolchover, Space.com (May 24, 2011)
"When there's no answer, again and again, at some point you have to stop calling. NASA announced Tuesday (May 24) that it will cease its daily attempts to contact Spirit, a robotic rover on Mars that went incommunicado last year.
" 'Planned communications will be done on May 25 but there may be some passive communication attempts after that,' NASA spokesperson Veronica MacGregor told SPACE.com today.
"Project manager John Callas of NASA's Jet Propulsion Laboratory told reporters today that the last commands will be sent up Wednesday, and orbiting spacecraft will listen for a return signal through the end of May. Spirit's electronics have likely become permanently damaged by Mars' harsh winter, however, and chances of a last-minute response are slim.
"The decision to let the Mars rover Spirit rest in peace marks the official end of its successful six-year mission.
"The rover far surpassed the space agency's expectations by functioning more than 20 times longer than predicted - its mission was planned to last three months - and driving 4.8 miles across the Martian surface, 10 times longer than planned...."
NASA gives a sort of overview of the twin Mars rovers' mission in its "Spirit and Opportunity" page. You'll find more links at the Mars Exploration Rover Mission home page.
Spirit mostly studied rocks and soil, winding up in the Columbia Hills of Mars: where rocks may have been affected by briny water.
Water on Mars is a sort of good news/bad news proposition.
The good news is that where there's water there might be life: which would be a major find. Even if Mars never supported life, water resources there mean one less thing to carry along if/when humanity decides to visit the planet.
The bad news is that water, when it freezes, can break things. Like pipes: or solar panels on the Phoenix lander. ("Phoenix Mars Lander Is Silent, New Image Shows Damage," Phoenix Mars Mission, Lunar and Planetary Science Laboratory/NASA (May 25, 2010))
Ending on an 'up' note, the Phoenix lander kept going longer than planned - and scientists are still going over data it sent back.
- "Viking Life Experiments: Another Look at Organic Stuff on Mars"
(January 6, 2011)
- "Another Martian Cave: Discovered by Seventh Graders"
(June 22, 2010)
- "Mars Rover to Mars: a Video"
(November 28, 2009)
- "Mars Robot Spirit Rebooted Itself - Twice"
(April 15, 2009)
- "Phoenix Mars Lander: the Video"
(June 16, 2008)
Other posts, about
- "Mars Exploration"