Mars Phoenix ends in dust, but purpose lives on

— -- NASA's Phoenix Mars lander has reached the end of the road.

Scientists feared the worst when the craft, which touched down on the Red Planet in May to collect and analyze soil samples, was engulfed by a dust storm.

Mission officials announced Monday that the lander appears to have shut down for good.

"At this time, we are no longer communicating with the vehicle," says mission chief Barry Goldstein of the Jet Propulsion Laboratory in Pasadena, Calif. "We are going to continue listening. But at this point no one on the team has expectations of hearing anything."

The $520 million spacecraft did its work in around-the-clock sunshine during the summer in the Martian Arctic.

A dust storm two weeks ago cut off sunlight to the probe's solar panels, which drained battery power. The storm prevented a recharge, and the spacecraft kept trying to communicate until Nov. 2, when it fell silent.

"NASA got what it wanted of this mission," says Doug McCuistion, director of the Mars Exploration Program.

The probe lasted past its planned 90-day lifetime in August and met all original objectives. Phoenix detected ice, measured soil chemistry and recorded the first snowfall observed on Mars.

Orbiting spacecraft will continue listening for a signal for the next three weeks, Goldstein says. After that, the Martian winter would keep battery levels from ever recovering.

"This has been a great mission, the thrill of my life," says chief mission scientist Peter Smith of the University of Arizona-Tucson. Scientists now will prepare reports on whether the landing site could ever be a "habitable zone" amenable to life, given the water and non-acidic soil conditions discovered by the probe.