Mars probe in Florida for launch preparations

By Irene Klotz

CAPE CANAVERAL, Florida (Reuters) - A robotic probe designed to touch and analyze Martian water for the first time is being prepared for launch at the Kennedy Space Center in Florida, officials said on Tuesday.

The craft, known as Phoenix, is expected to land in the northern polar region of Mars and dig beneath the soil. Launch is scheduled for August 3 from Cape Canaveral Air Force Station.

Bolstered by evidence that Mars once had liquid surface water, scientists are keen to recover an actual sample to see if the materials for life exist.

A fleet of satellites and rovers has been scouring the surface of Mars to try to determine if the planet was habitable at some point in its past.

Scientists also want to understand the environmental and climatic changes that turned what is believed to have been a warm, watery world into the cold, dry desert that exists today.

Phoenix will add a microscopic perspective to the mix.

Upon reaching Mars in May 2008, the spacecraft is to land just as the winter ice begins to recede around the polar cap. Scientists expect the probe will touch down on newly exposed soil, but their true target lies just beneath the surface.

Among Phoenix's tools are devices to scoop and drill, photograph and chemically analyze soil and ice samples.

"We expect hard, icy soil right beneath the ground," planetary scientist and Phoenix researcher Ray Arvidson, with Washington University in St. Louis, said in an interview.

Samples will be dissolved in water to look for salts, which likely would have been deposited during watery conditions in the past.

Phoenix's onboard laboratory also includes small ovens to break down minerals in the samples for chemical analysis.

ICE THEORIES

NASA's first foray for signs of the ingredients for life on Mars was conducted during the twin 1976 Viking missions, but those landers touched down in dry regions. Satellites have since revealed widespread ice near the planet's poles.

Some scientists believe a vast frozen ocean is buried beneath the ice. Another theory says Mars' polar ice solidified from atmospheric water vapor, not a widespread ocean.

Phoenix will be able to make isotopic measurements of the hydrogen and oxygen molecules and perhaps resolve this puzzle.