New photos sent back by the spacecraft show its 8-foot-long robotic arm hovering over a miniature oven, ready to dump seven tablespoons inside where the soil sample will be heated and studied for its chemistry.
Scientists hope to measure the amount of water and type of minerals in the arctic soil to determine whether the environment could support primitive life. In particular, they are looking for hints of carbon, hydrogen, oxygen and nitrogen in the sample.
"We're very curious whether the ice that we think is just under the surface here has been melted and modified the soil," said chief scientist Peter Smith of the University of Arizona, Tuscon, who leads the $420 million mission.
Phoenix, which landed in Mars' northern plains on May 25, cannot directly detect past or present life.
The scooping of soil and its transfer to the oven were delayed a day after a Mars satellite that relays instructions from Earth to Phoenix went into safe mode. Once the lander drops the sample into the oven to bake up to 1,800 degrees it will take several days for scientists to complete an analysis.
In the meantime, scientists planned for Phoenix to dig two other trenches next week and deliver scoops to its microscope and wet chemistry lab to analyze.
