By K.C. JonesInformationWeek
The Phoenix's robotic arm scooped up soil and dumped it onto a screen at the opening of a special lab instrument, but the dirt didn't sift through a screen and slide down a funnel, as expected.
Initially, an infrared beam inside the funnel failed to confirm that dirt passed through the screen, but after mechanical shakers went to work a little longer Monday, the beam detected particles. However, the amount of soil that broke apart and passed through the funnel was not enough for the Phoenix's tiny oven to bake and sniff, according to NASA.
A screen, above an open door to the Thermal and Evolved-Gas Analyzer (TEGA), is supposed to allow particles up to 1 millimeter wide to pass through. It is supposed to stop larger particles from clogging the setup, but the dirt proved clumpier than scientists predicted.
"I think it's the cloddiness of the soil and not having enough fine granular material," said Ray Arvidson of Washington University in St. Louis. "In the future, we may prepare the soil by pushing down on the surface with the arm before scooping up the material to break it up, then sprinkle a smaller amount over the door."
A team at the University of Arizona hopes a bit more shaking will do the trick and allow the dirt to enter the TEGA.
"We are going to try vibrating it one more time, and if that doesn't work, it is likely we will use our new, revised delivery method on another thermal analyzer cell," said William Boynton of the University of Arizona, lead scientist for the TEGA instrument.
The revised method, tested for the first time Monday, involves holding the scoop at an angle and sprinkling small specks of dirt by vibrating the scoop. If that works, more dirt will be sprinkled onto the screen later this week.
Scientists involved in the NASA mission want to analyze the dirt for signs of whether Mars is, or ever has been, able to support life.
"We are hoping to learn more about the soil's physical properties at this site," said Arvidson, the mission's digging expert. "It may be more cohesive than what we have seen at earlier Mars landing sites."
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