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Phoenix dumps dirt into TEGA, and no dirt goes in |
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Written by Derek Kessler on
Sunday, 08 June 2008
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 It was just all going so well. Too well, it seems. Having resolved communications difficulties back with Earth by switching to a different Martian satellite, Earth-bound mission controllers at the University of Arizona instructed the lander to take the small soil sample it had scooped up out of the Martian arctic and dump it into one of the eight Thermal and Evolved Gas Analyzer (TEGA) ovens. But none of the soil seems to have made it through the screen into the oven.
The TEGA uses the small ovens to heat soil samples until they give off vapors, which are then analyzed to determine their chemical contents. The hope is that some organic compounds, such as methane, may be present in the icy soil and be released by the baking.
The ovens are covered by a small screen meant to keep out larger particles of the soil. It is equipped with a vibrator to shake the soil through, much like gold sifters did when searching mountain streams for gold nuggets. Images from the camera mounted on the 2.35-meter-long arm show that the soil sample landed right on the screen, and instruments indicate that the sifting vibrator shook the screen as designed.
Dirt not going into the TEGA oven.
A small light sensor inside the oven, however, failed to detect any dirt falling into the chamber. The mission controllers are puzzled by the development, which none of their ground-tests of Phoenix hardware indicated would be a problem. Even so, there are a few options as to what caused the failure: the Martian soil may be too dense or compacted for the vibrator to break it up and for significant-enough quantities to make it through, or the vibrator itself may not be working and sent incorrect readings that it was.
Either way, mission control plans to take a few days off from using the ovens while they investigate the causes. In the meantime, they’ll use the robotic arm and scoop to do some more practice digging. If it turns out that this TEGA oven is a loss, Phoenix is still equipped with seven other ovens to do the job.
Discuss: TrekUnited Forum
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