NASA calls it quits on damaged Phoenix lander
Posted: 25 May 2010
NASA gave the Phoenix lander a final chance to phone home last week, but the craft's continuing silence and a new image showing ice damage to its solar panels have forced the space agency to give up hope on the mission.
The Mars Odyssey orbiter flew over the Phoenix landing site 61 times last week. Odyssey was listening for radio signals from the spacecraft that would indicate it had re-awakened after a winter slumber.
But Odyssey heard no signals from Phoenix, NASA announced Monday. Three other campaigns since January also failed to communicate with the lander.
Phoenix was not designed to survive winter near the Martian north pole, where the sun slips below the horizon for months and sheets of carbon dioxide ice encrust the soil. Before this spring's communications passes, NASA officials held onto a sliver of hope the lander would survive the winter and wake up as the sun rose above the horizon.
A new image of Phoenix snapped by the Mars Reconnaissance Orbiter's high-resolution HiRISE mapping camera shows one of the lander's two circular solar panels could have snapped off after several hundred pounds of ice built up on the structure.
The craft's shadow is smaller than in pictures taken from orbit during its operational mission in 2008.
"Before and after images are dramatically different," said Michael Mellon of the University of Colorado in Boulder, a science team member for both Phoenix and HiRISE. "The lander looks smaller, and only a portion of the difference can be explained by accumulation of dust on the lander, which makes its surfaces less distinguishable from surrounding ground."
Before the onset of winter, mission officials predicted the weight of ice on Phoenix could cause its solar panels to bend or break.
"The Phoenix spacecraft succeeded in its investigations and exceeded its planned lifetime," said Fuk Li, manager of Mars programs at the Jet Propulsion Laboratory in Pasadena, Calif. "Although its work is finished, analysis of information from Phoenix's science activities will continue for some time to come."
Phoenix also discovered evidence of occasional thawed water at the landing site, and the mission found a chemical called perchlorate, which set off speculation about the Red Planet's habitability in its ancient past. Perchlorates are toxic to some organisms and provide food for other species on Earth, and its discovery sent a mixed message to scientists trying to determine whether life ever existed on Mars.
"We found that the soil above the ice can act like a sponge, with perchlorate scavenging water from the atmosphere and holding on to it," said Peter Smith, Phoenix principal investigator at the University of Arizona in Tucson. "You can have a thin film layer of water capable of being a habitable environment. A micro-world at the scale of grains of soil -- that's where the action is."
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