Phoenix digs up Martian soil

2008-06-07 09:47

Washington - Nearly two weeks after its historic landing, the US Mars probe Phoenix has scooped up its first sample of Martian soil and begun analysing it for water and organic compounds, a Nasa official said on Friday.

The 200-milliliter of Martian earth is topped by a white crust that has set Nasa scientists debating whether it is ice or salt deposits from evaporated water.

"It looks like a good sample for us," Phoenix mission chief scientist Peter Smith told reporters in a telephone conference.

"This is really an important occasion for us, to be poised to make a measurement for the first time of the polar soil that will tell us how much water is in the soil, and secondly what the minerals are that make up the soil," said Smith.

Especially intriguing, he said, is to find out whether ice believed to be under the Martian soil has already melted and changed the composition of the soil.

A chunk of permafrost-like soil of the Martian arctic was scooped up on Thursday by the probe's 2.35 metre titanium and aluminum backhoe-like extension.

It now lies inside the scoop, poised over an instrument called the Thermal and Evolved-Gas Analyzer, or TEGA, where it will be dumped and sealed in for several days of analysis, the scientist said.

"The first step is to dry water out of the sample and find out what percentage of water there is .. The test should tell very quickly," said Smith.

Phoenix is scheduled to collect two more samples of Martian soil over the next few days. One will be analysed by optical microscope, the other by chemical analysis, said Phoenix mission chief Mat Robinson, at Nasa's Jet Propulsion Laboratory, in Pasadena, California.

The scientists stressed that the Phoenix probe is not equipped to test Martian soil for fossils or living microbes.

Since landing on May 25, the spacecraft has already compiled photographs of the stark reddish Martian north pole terrain surrounding it.

Using a panoply of high-tech instrumentation, Phoenix will over the next three months examine the soil and take records of the climate in the Red Planet's arctic, with scientists seeking to understand the history of the presence of water in its three forms there, and hoping to dig up signs of life-supporting organic minerals.

Water was first detected on the Martian north pole by the US Odyssey probe in 2002. It sparked the Phoenix mission.

- AFP