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Race against the clock on Mars

Scientists hope to finish their Phoenix experiments before winter shuts down the solar-powered lander.

September 13, 2008|John Johnson Jr. | Times Staff Writer

With the waning of the Martian summer, electrical power to NASA's Phoenix lander has begun to decline, so scientists are racing to finish their experiments before the dark and cold of winter ends the mission.

"We're now at the point . . . where we have to struggle to do each of the things we need to do," said Barry Goldstein, the Phoenix project manager at the Jet Propulsion Laboratory in La Canada Flintridge.

Goldstein emphasized that scientists were confident they could complete the remaining projects before the lander runs out of power, currently expected in mid- to late November.

But the increasingly early sunsets have underscored the fact that Phoenix carried a death sentence when it landed near Mars' north pole May 25.

Phoenix's central mission has been to test the soil and water at the pole to determine whether the planet was once, or still might be, habitable for rudimentary life forms.

One of its key tasks has been to test Martian ice for various chemical compounds in the lander's thermal and evolved-gas analyzer, or TEGA.

In particular, scientists want to know the levels of hydrogen and deuterium in the water, which indicate how it was formed and under what conditions, according to William Boynton of the University of Arizona.

But except for a single soil sample that contained a tiny bit of ice, inserting the material into the pencil-thin TEGA ovens has proved much more difficult than expected.

Ice has tended to stick to the scoop attached to Phoenix's robotic digging arm.

Scientists have recently devised a new delivery method that they think will work, Goldstein said.

In the next two to three months, the earlier setting of the sun will rob Phoenix's solar power arrays of the time needed to replenish the craft's batteries.

At the same time, Phoenix's power demands will go up because of the need to run its heaters longer to keep key instruments from freezing.

As the end approaches, Phoenix will become a simple weather station, because checking wind speed and temperature uses the least energy of any of the instruments.


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