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Phoenix scoops up soil on Mars

The NASA lander gathers the sample to test it for evidence that the Red Planet could have held life.

June 07, 2008|John Johnson Jr. | Times Staff Writer

After nearly two weeks of testing and preparation, NASA's Phoenix lander on Friday began its first day of scientific work at Mars' north pole, where the lander's robotic arm delivered a scoop of soil to an oven that will search for evidence that the Red Planet was once habitable.

The scoop, taken from a spot dubbed Baby Bear next to the lander, was then ordered to pause over one of the eight tiny ovens attached to the Thermal and Evolved-Gas Analyzer, known as TEGA. Engineers on Earth paused the sequence to make sure the material didn't spill and contaminate other instruments.

Engineers were planning to send the command to dump the material late Friday, beginning the weeks-long process of analyzing Mars' soil chemistry.

Phoenix is the first spacecraft sent to an alien world to hunt for water, the key to life as we understand it. NASA's orbiting Mars Odyssey spacecraft has found the signature of large amounts of ice at the north pole.

During the three-month, $420-million mission managed by the Jet Propulsion Laboratory in La Canada Flintridge, Phoenix will dig down to the ice layer and deliver samples to a variety of scientific instruments that will test for organic compounds that could indicate Mars once might have been, or might be, home to rudimentary life forms.

Organic compounds contain carbon, often in combination with hydrogen, nitrogen and oxygen. Carbon is important because it is one of a few elements that can build long and complex molecules necessary to make living organisms.

Since the 756-pound, 7-foot-tall Phoenix lander touched down May 25, scientists have been doing test digs in preparation for scientific work.

Comparing the Martian science group to a football team practicing for opening day, JPL's robotic-arm expert, Matt Robinson, said that "our pre-season has been five years long. You can imagine we're raring to go."

A picture of the soil in the scoop beamed back to Earth showed the familiar reddish-brown dirt, with an inch-size clump containing whitish streaks that some scientists think could be ice.

Most researchers, however, believe it's a salt of some kind. The skeptics say such small amounts of ice would quickly evaporate when exposed to the sun through a process known as sublimation, which converts the ice directly to a gas, skipping the liquid phase.

Even if the ice has not yet shown itself, scientists are confident they landed in the right place. Besides the Mars Odyssey findings, pictures of the lumpy landscape around the lander show ridges bordered by trenches that are characteristic of permafrost regions at Earth's poles. The soil also is clumpy, easily forming clods, which can result from the presence of water.

Each of the eight ovens is about an inch long, with an opening about the size of a pencil lead. "These are very small ovens, but powerful," Peter Smith of the University of Arizona, lead scientist on the mission, said during a media briefing Friday.

TEGA will gradually heat the samples, eventually to 1,000 degrees Fahrenheit, to study the gases given off in a mass spectrometer.

Samples will also be sent to the Microscopy, Electrochemistry and Conductivity Analyzer, which will dissolve the soil in water and test its acidity, among other things. The microscopy part of the instrument will examine Martian soil particles at a scale never before seen on another planet.

Because it will take several days to go through the various TEGA tests, the first scientific results will probably not be available until the end of next week, Smith said.


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