NASA's long-dormant Phoenix Mars Lander is broken and officially down for the count, with new images taken by an orbiting probe showing severe damage to the spacecraft's solar panels due to the harsh Martian winter.
Repeated attempts by NASA in recent months to reestablish contact with Phoenix following its winter hibernation were unsuccessful, with no peeps coming from the lander.
The discovery led NASA to declare that its Phoenix's mission has officially ended its prolonged mission. [Dead spacecraft on Mars.]
"The Phoenix spacecraft succeeded in its investigations and exceeded its planned lifetime," said Fuk Li, manager of the Mars Exploration Program at NASA's 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 touched down in the arctic plains of Vastitas Borealis in Mars' northern hemisphere on May 25, 2008 and spent several months digging up the Martian soil, confirming the presence of water ice beneath the surface.
Last week, NASA's Mars Odyssey orbiter flew over the Phoenix landing site 61 times during a final attempt to communicate with the lander. No transmission from the lander was detected. Phoenix also did not communicate during 150 flights in three previous listening campaigns earlier this year.
Slim chance of resurrection
Phoenix was not designed to survive the dark, cold, icy winter of the Martian arctic and mission managers were not optimistic they would hear from the spacecraft again after it fell silent in November 2008, when the sun dipped too low in the sky for Phoenix to get enough sunlight to power itself and temperatures plummeted.
At the time, the $475 million lander had already survived two months longer than planned. However, the slim possibility Phoenix survived could not be eliminated without listening for the lander after abundant sunshine returned.
The new photo of Phoenix taken this month by the High Resolution Imaging Science Experiment, or HiRISE, camera on board the Mars Reconnaissance Orbiter suggests the lander no longer casts shadows the way it did during its working lifetime.
"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."
Apparent changes in the shadows cast by the lander are consistent with predictions of how Phoenix could be damaged by harsh winter conditions. It was anticipated that the weight of a carbon-dioxide ice buildup could bend or break the lander's solar panels. Mellon calculated hundreds of pounds of ice probably coated the lander in mid-winter.
Phoenix's icy success
During its mission, Phoenix confirmed and examined patches of the widespread deposits of underground water ice detected by Odyssey and identified a mineral called calcium carbonate that suggested occasional presence of thawed water.
The lander also found soil chemistry with significant implications for life and observed falling snow.
The mission's biggest surprise was the discovery of perchlorate, an oxidizing chemical on Earth that is food for some microbes and potentially toxic for others.
"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."
The perchlorate results are shaping subsequent astrobiology research, as scientists investigate the implications of its antifreeze properties and potential use as an energy source by microbes.
- Images: Phoenix on Mars!
- Mars Is a Spacecraft Graveyard
- SPACE.com Special Report: Phoenix Mars Lander