Lander Sees Mars Under Microscope

Surface Soil Has a Variety of Particles, Which May Offer Clues to Planet's Past

NASA's Phoenix Mars lander got its first really close-up look at the planet yesterday as one of its microscopes focused on a slide coated with dust kicked up during the landing.

Images of the dust beamed 171 million miles away to Earth showed particles of varying size and colors ranging from semi-translucent white to glassy black.

"We are able to see the variety there is in what appears to be just reddish-brown soil," Tom Pike, a mission geologist from Imperial College London, told reporters during a teleconference yesterday.

"We are looking to use these particles as a way to read the history of the site," added Michael H. Hecht, a scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Phoenix is now sitting on a plateau in Mars's northern polar region. The lander will eventually test the soil -- and a layer of ice believed to exist just inches below the surface -- in dozens of ways. The seven-foot-tall, 772-pound lander carries two types of microscopes, a "wet chemistry" set to test soil properties, and tiny ovens that will vaporize and analyze compounds in the samples.

The researchers hope to learn whether Mars might have been habitable in past ages when conditions were more favorable to life. At the moment, they are not. The planet now has a thin, nearly oxygen-free atmosphere, and temperatures in Phoenix's neighborhood are currently ranging from 13 below zero to 116 below zero.

The mission is especially interested in Mars's water, virtually all ice now, and carbon-containing compounds that may be in the soil. The chemical properties of those compounds may provide hints about whether they were made by living organisms or instead rained down as debris from space. It is unlikely, though, that any experiments on this mission can establish with certainty that microbes or other life forms ever survived there.

The mission has suffered a few hitches since the Phoenix landed with spectacular ease and precision on May 25.

On Wednesday, a satellite called Odyssey that is orbiting Mars and relaying instructions from Earth briefly stopped communicating with Phoenix because of a problem with its computer memory. A door to one of the ovens that will heat up samples of Martian soil is not opening quite completely. A digging session with Phoenix's robotic arm left dirt in the shovel when the load was dumped, prompting scientists to take an extra day to practice the maneuver. One image taken by Phoenix's cameras shows an unattached metal spring, which mission leader Peter H. Smith of the University of Arizona said "nobody is laying claim to."

None of these problems is serious, and the mission is still on schedule.

"In the nominal 90-day mission, we are prepared to lose up to one-third of the days," said Chris Lewicki, Phoenix mission manager at the Jet Propulsion Laboratory.

Over the next several days, the researchers plan to analyze the Martian atmosphere using the "thermal and evolved gas analyzer" (TEGA), part of the robotic laboratory mounted on the lander's deck. It contains a device called a mass spectrometer that measures the atomic weight of molecules and helps determine their concentration.