NASA declared its Phoenix Mars Lander mission over Nov. 10, a week after the spacecraft sent its last signal from the Martian arctic.

"Phoenix not only met the tremendous challenge of landing safely," said Phoenix Project Manager Barry Goldstein of the agency's Jet Propulsion Laboratory. "It accomplished scientific investigations on 149 of its 152 Martian days as a result of dedicated work by a talented team."

Although controllers plan to continue listening for signals for a few more weeks, they believe it "unlikely" weather conditions on Mars will allow enough sunlight to reach the lander's solar arrays to revive it. Loss of signal always was expected at about this time because of the diminishing sunlight at the high-latitude landing site (Aerospace DAILY, Nov. 7).

Clouds and atmospheric dust exceeded expectations for the mission, further dimming sunlight on the arrays, and temperatures have been colder than expected, at minus 50 to minus 150 degrees Fahrenheit and below.

Phoenix was launched on Aug. 4, 2007, and landed on May 25 at the northernmost Martian site yet reached by any probe. Scientists picked the spot in the belief that water ice lay just beneath the surface there, a condition quickly confirmed by the lander's robotic digger arm and sophisticated instrument suite.

While analysis of Phoenix data is only beginning, early results have advanced scientific understanding about the potential habitability of the planet. Phoenix found two different types of ice, detected snowfall and worked with NASA's Mars Reconnaissance Orbiter to provide ground truth data for weather observations.

"Phoenix provided an important step to spur the hope that we can show Mars was once habitable and possibly supported life," said Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters. "Phoenix was supported by orbiting NASA spacecraft, providing communications relay while producing their own fascinating science."

Photo courtesy of NASA/JPL-Caltech/University of Arizona/Max Planck Institute