Odds Slim for Resurrecting Defunct Mars Lander

Today, NASA will begin attempts to re-establish contact with the long-defunct Phoenix Mars Lander, which has been enveloped in the frost of the northern Martian winter for more than a year now. But chances are slim the probe will phone home.

The agency's Mars Odyssey orbiter will listen for any radio signals from the frozen spacecraft on the surface that would indicate it survived the months-long deep freeze, though mission scientists aren't optimistic about the odds.

"It is very unlikely that Phoenix has survived the cold winter, but it is worth the chance to try," Peter Smith, Phoenix principal investigator, told SPACE.com.

Phoenix, which landed on the surface of the red planet on May 25, 2008, has been out of commission since November 2008, when the plummeting temperatures and accumulating frost in the Martian arctic took the spacecraft offline.

The Phoenix mission lasted for two months longer than its original three-month mission and confirmed the presence of water ice under the surface of the planet, which has helped characterize the planet's past potential for habitability.

The $475 million lander's hardware was not designed to survive the temperature extremes and ice-coating load of an arctic Martian winter.

On Mars, as on Earth, the sun is lower in the sky in the winter. For Phoenix, this meant dwindling supplies of energy for its solar panels during the final days of its mission. Eventually that energy ran out, and mission controllers lost contact with the spacecraft.

As winter set in, the lander also gradually became covered in frost. More ice crystals likely stuck to the lander after it took its last pictures. But just how buried in ice the lander became isn't known.

A photograph of Phoenix taken by NASA?s Mars Reconnaissance Orbiter in orbit on Jan. 6 showed the lander blanketed in carbon dioxide frost. The view, taken as early spring begins on Mars, showed a vast region of frost and bare ground.

Phoenix?s solar arrays are not visible in the new photo, likely because they were still covered in frost, mission managers said.

Phoenix is programmed with a built-in reboot system ? called its "Lazarus mode" ? that would allow it to try to start itself back up again as soon as its solar arrays had collected enough energy.

But whether the lander will be able to use this mode is uncertain.

The cold temperatures and frost could have caused the electronics aboard the lander to become brittle and crack. If the electronics were busted during the winter, it's unlikely that Phoenix will be able to live up to its name and make a comeback.

When Phoenix went silent more than a year ago, mission managers expect never to hear from it again. But they're still going to give it a try and see if Phoenix makes any peeps.

Odyssey will pass over the Phoenix landing site approximately 10 times each day during three consecutive days of listening this month and two longer listening campaigns in February and March.

During the later attempts in February or March, Odyssey will transmit radio signals that could potentially be heard by Phoenix, as well as passively listening.

If Phoenix signals its survival, Odyssey will try to lock on to its signal and see what the lander is capable of doing. NASA will base any further decisions on the lander on that information.

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