NASA slowly shuts down Mars robot as long night approaches

After proving elements needed for life exist on Mars, Lander left to freeze to death

After about five months of collecting information on whether Mars can sustain life, NASA scientists have started to shut down heaters, scientific instruments and even the robotic arm onboard the Phoenix Mars Lander.

Since the Lander is powered by solar cells and the Mars night grows longer and longer this time of year, scientists are remotely powering down as many parts of the Lander as possible to minimize its energy needs so a few instruments can be kept running for maybe another month, said Chris Lewicki, mission manager of the Phoenix Mars Mission.

"As it gets colder and colder, we need to heat more things on the spacecraft and because the days are shorter and the sun is lower in the sky, we have less power to do it," he told Computerworld. "It definitely is winding down. As with most things with old age, you slow down and go to bed earlier and wake up later. The Lander is like that. It'll have shorter and shorter work days and have less to do."

Once the instruments spend months in the frigid cold, it's doubtful they could ever be fired back up.

Lewicki noted that darkness fell for the first time on the Lander at the end of August and now the nights are seven hours long. By the end of November, nights will last 10 or 11 hours and by April 24 hours. And right now, it's about 40 degrees Fahrenheit inside the Lander. As the heaters are shut down, the inside temperature will eventually drop to minus 85 degrees.

The mission manager said the start of the shutdown process is turning out to be a sad time for the Mars team. After all, the Lander has sent more information back to Earth about the Red Planet than any other mission. The Lander found ice just under the surface of the soil, proving that water - a key element to support life - exists there. Scooping up soil with its robotic arm the Mars Lander has also taken and sent back microscopic images of Martian soil.

The Lander has discovered that snow falls from Martian clouds. The snow, which evaporates before it reaches the ground, falls from clouds about 2.5 miles above the planet's surface.

And between soil tests done in the Lander's wet chemistry set and its eight ovens, evidence has been sent back that shows that Martian soil is much like Earth's.  The Martian dirt is very alkaline, with a pH level of between eight and nine. The Lander also found magnesium, sodium, potassium and chloride in the dirt.

"Some kinds of Earth life would be happy to live in these soils," said Samuel Kounaves, a professor at Tufts University and a research affiliate at the Jet Propulsion Laboratory, in an earlier press conference. "Asparagus, green beans and turnips love alkaline soils."

With so much research and information coming out of one robotic machine operating so far from home, Lewicki said it's been difficult to start shutting it down.

"We had no expectation that we'd be able to continue this long," he added. "This is really a first big step for the team in letting go. We have these instruments we've been using for the last five months and we had a lot of interesting ideas left to be done. It's been a bit of a grieving process that will start this week as we see the big changes starting to happen. We'll have to stand back and watch it end."

But the Lander's work isn't totally over.

Lewicki noted that atomic microscope will be kept running, along with the imager and meteorological instruments to measure pressure and temperature in the atmosphere. The lidar instruments, which measure cloud height, will also keep operating for a time.

"We've certainly been as successful as we hoped we would be," he said. "We met all our promises and commitments to NASA. Based on what we've found, we have different questions about Mars that we're trying to answer while we're still there and there will be new questions to answer when we go back again."

Next year, NASA is slated to launch an SUV-size rover on a trip to Mars. With an estimated budget of $2 billion, the Mars Science Laboratory will carry three different kinds of cameras, chemistry instruments, environmental sensors and radiation monitors. According to NASA, all of these instruments are designed to help scientists continue to figure out whether life ever existed on Mars and to prepare to send humans to the Red Planet.

In 2004, President George W. Bush called on NASA to send humans back to the moon by 2020 in preparation for a manned-mission to Mars some day.

Copyright © 2008 IDG Communications, Inc.

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