Mars Probe Promises Up-Close Look

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May 9, 2007 — NASA is preparing to dispatch a new member to a fleet of Mars probes that are unveiling details of a global climate change so severe that lakes, oceans and rivers were stripped away, leaving only cold and hostile deserts.

The new scout, named Phoenix, has a different perspective than its previous, sister crafts. It will put Mars under a microscope.

Phoenix, which arrived at the Kennedy Space Center in Florida Monday night, is designed to give scientists their first look at Martian water. The probe will have to dig for its quarry, but, if successful, the results could redirect Mars exploration efforts for decades to come.

The overarching goal for the mission, now scheduled for launch on Aug. 3, is to determine if Mars has the ingredients for life.

"If Mars had the right stuff, it was habitable and life arose, it's a full planetary-scale experiment that would help us understand better where we came from," planetary scientist and Phoenix co-investigator Ray Arvidson, with Washington Universtiy in St. Louis, said in an interview.

"But if Mars was habitable and had all the right stuff — all the ingredients, the water — and life didn't arise, then why not, and what's special about having life on Earth? I think those are fundamentally important questions for humankind," Arvidson said.

Phoenix is expected to land in the northern polar region of Mars and dig beneath the soil for ice that will be analyzed for organic molecules. The touchdown should happen in May 2008, just as springtime arrives in the northern hemisphere.

Among Phoenix's tools are devices to scoop and scrape in the soil, as well as to drill into the subsurface ice.

"We expect hard icy soil right beneath," Arvidson said.

Samples will be dissolved in water to look for salts, which likely would have been deposited during exposure to water in the past. Phoenix's onboard laboratory also includes small ovens to break down minerals in the samples and chemical analyzers.

"We're looking for organic molecules and also the overall nature of water-bearing minerals," Arvidson said.

NASA conducted similar experiments during the 1976 Viking missions, but those landers touched down in dry regions. Satellites have since revealed widespread ice on Mars near the planet's poles.

"Viking was born in the 1960s when maps of Mars still had canals on them. It was very, very primitive," Arvidson said.

Some scientists believe a vast frozen ocean is buried beneath the polar ice. Another theory posits that Mars' polar ice are the solidified remains of atmospheric vapors, not a widespread ocean. Phoenix will be able to make isotopic measurements of the hydrogen and oxygen molecules and perhaps resolve this puzzle.

"It's likely that we'll get interesting results from the soil samples," Arvidson said.