Mars lander's 1st soil sample may not be analyzed

By Amanda Beck

SAN FRANCISCO (Reuters) - Dirt that the Phoenix Mars Lander scooped recently from the planet's surface may be too clumpy to be analyzed by the machine's onboard system, NASA reported on Saturday.

A robotic arm retrieved a cup-sized sample of Martian dirt on Friday and placed it on the lander's Thermal and Evolved-Gas Analyzer, or TEGA, which was scheduled to spend about a week determining the soil's water and mineral content.

The TEGA features a screened opening that prevents large particles from clogging it. Only those thinner than 1 mm (0.04 of an inch) can pass through, and an infrared beam verifies whether they have entered the instrument.

The beam has not yet confirmed any activity and researchers are not sure why, NASA said in a statement.

Scientists suspect the soil may be clumped together too tightly, NASA said.

"In the future, we may prepare the soil by pushing down on the surface ... then sprinkle a smaller amount over the door," Ray Arvidson, the team's science lead, said in the statement.

Engineers are also looking for a way to shake some of the current sample down into the TEGA oven, where it would be heated and analyzed.

Scientists may send instructions to vibrate the compartment after they inspect the problem for a day or two, spokeswoman Sara Hammond said.

The lander will also gather other soil samples, examine them with a microscope and mix them with water to determine their composition, Hammond said.

The $420 million lander spent 10 months journeying from Earth and touched down on Mars 12 days ago. Its three-month mission was proposed after the Mars Odyssey detected frozen water below the Martian surface in 2002.

This is the lander's first attempt to analyze soil, which might contain salt left behind by evaporated water or ice.

The single-use compartment will go unused if scientists are unable to coax any particles to fall down, but there are seven others like it onboard, Hammond said.

(Reporting by Amanda Beck; Editing by John O'Callaghan)