Image: Phoenix Mars Lander
Cory Waste  /  AP file
This artist's rendition, provided by NASA and the Jet Propulsion Laboratory, shows the Phoenix lander on the arctic plains of Mars.
updated 11/5/2008 1:59:09 PM ET 2008-11-05T18:59:09

Compared to NASA's long-lived Mars rovers, still scurrying around the Red Planet almost five years past warranty, the ice-sampling Phoenix Mars Lander, now in a communications coma five months after touchdown, may appear to be a bit of a dud.

But there is nothing engineers could have done to fix the fundamental problem. Phoenix, which is stationed near the planet's northern pole, is running out of sunlight, a death knell for a solar-powered probe.

When Phoenix landed on May 25, it was the start of summer on the Martian arctic circle, land of the midnight sun.

The probe worked well enough for NASA to extend its planned 90-day mission until the end of September, and later to mid-November. But with summer slipping into autumn and the sun dipping below the horizon for longer and longer periods of time, Phoenix has been struggling to generate enough power from its solar cells to keep functioning. It is dark now for more than seven hours a day.

"We're in hospice mode," Phoenix principal investigator Peter Smith, with the University of Arizona in Tucson, told Discovery News.

At best, NASA hopes to eke out a week's more monitoring of the changing conditions on Mars. The probe, whose prime mission was to chemically analyze ice and soil samples so scientists can determine if Mars was ever suitable to host life, is also equipped with meteorological instruments and cameras.

There will be no more data coming back from Phoenix's miniature ovens and wet chemistry sets, which were used to assess ice and soil near the landing site.

"We have all the data we're going to get," Smith said.

Analysis is under way, and Smith said the team's goal is to announce results at a scientific meeting in December.

"We didn't get every single thing we could have because of the complexity of delivering soil up there into the chambers," Smith added.

The Martian soil turned out to be unexpectedly clumpy so that it clogged filters and complicated efforts to place samples into Phoenix's science chambers for processing.

The impediments, however, did not compromise the goals of the mission.

Smith said he's not yet ready to state if Mars was suited for life, but he added, "I think there is going to be enough data to make a final pronouncement."

Some of the Phoenix team's finding already have been announced. They include:

  • Confirmation of water ice on the planet's surface. Water is considered to be a key ingredient for supporting life.
  • An alkaline, rather than acidic, soil. On Earth, the pH of soil is important. Food plants, for example, thrive in acidic or neutral soil. So do bacteria. The finding does not necessarily nix the chances for life on Mars. "Life is very adaptable and can exist in many extreme environments," said Phoenix deputy project scientist Deborah Bass, at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
  • A lack of sulfur compounds, or sulfates, in the soils near the Phoenix landing site. The Mars rovers Spirit and Opportunity found sulfates around their landing sites on the planet's equatorial region.
  • Soil grains show signs of weathering and varying chemical compositions.
  • A chemical in the soil called perchlorate, which on Earth exists in places with very little rainfall. Scientists are trying to determine what effect perchlorates could have on the prospect for life on Mars.

"It's been a very successful mission," Smith said.

© 2012 Discovery Channel


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