NASA's Phoenix scoops Martian soil

The robotic arm of NASA's Phoenix Mars Lander has delivered a partial scoopful of clumpy Martian soil to the oven on its Thermal and Evolved-Gas Analyzer instrument, or TEGA.

TEGA has eight separate tiny ovens to bake and sniff the soil to assess its volatile ingredients, such as water.

What the Lander's robotic arm did was that it delivered a partial scoopful of clumpy soil from a trench informally called 'Baby Bear' to the number 4 oven on TEGA, on June 6, which was 12 days after landing.

A screen covers each of TEGA's eight ovens.

The screen is to prevent larger bits of soil from clogging the narrow port to each oven so that fine particles fill the oven cavity, which is no wider than a pencil lead.

Each TEGA chute also has a whirligig mechanism that vibrates the screen to help shake small particles through.

Only a few particles got through when the screen on oven number 4 was vibrated on June 6, 8 and 9.

According to Phoenix co-investigator Bill Boynton of the University of Arizona, Tucson, the oven might have filled because of the cumulative effects of all the vibrating, or because of changes in the soil's cohesiveness as it sat for days on the top of the screen.

'There's something very unusual about this soil, from a place on Mars we've never been before,' said Phoenix Principal Investigator Peter Smith of the University of Arizona.

'We are interested in learning what sort of chemical and mineral activity has caused the particles to clump and stick together,' he added.

Plans prepared by the Phoenix team for the Lander's activities include sprinkling Martian soil on the delivery port for the spacecraft's Optical Microscope and taking additional portions of a high-resolution colour panorama of the Lander's surroundings.