PASADENA, Calif. – It’s a proposed science instrument for
Mars that anyone who’s ever left the lawn mower out in the rain can understand.
Called MAOS – the Mars Atmospheric Oxidant Sensor – it’s as small and lightweight as a real mouse. But it asks one big question: how quickly do things rust when exposed to the atmosphere on Mars?
The Mars Atmospheric Oxidant Sensor
To find out the oxidation potential of the atmosphere, the experiment proposes exposing a grid of eight different types of thin films to Martian dust, air and the ultraviolet rays that bathe the planet.
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| If selected, the Mars Atmospheric Oxidant Sensor -- MAOS -- would be the sole NASA instrument on the British Beagle 2 Mars lander.
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As each of the 384 sensors oxidizes, scientists would then monitor the individual film by passing a current across it and calculating any change in its resistance. Periodic measurements would chart those changes, which can then be compared to lab results obtained here on
Earth.
"We’ll calculate the resistivity to tell us what’s going on," said Aaron Zent, MAOS’ principal investigator at NASA’s Ames Research Center. (The instrument owes its heritage to several previous instruments, including the Mars Oxidation Experiment lost on the ill-fated Russian Mars ‘96 mission.)
The surface of Mars isn’t a tawny, rusty red for nothing, something in its soil acts as a strong oxidant – perhaps a superoxide as proposed in the September 15 issue of the journal Science. One possible source for that chemical could be the atmosphere itself, Zent said.
MAOS, which weighs 1.75 ounces (50 grams) and sits in a box just 2.8 inches (7 centimeters) a side, is delightfully modest in concept. While on Mars, it will simply open up to the atmosphere and rust, requiring minimal work on the part of the science team monitoring it.
"The beauty is you don’t have to do anything with it. You can put it out for a month and measure it just once for a second," said Michael Hecht, the MAOS project manager at NASA’s
Jet Propulsion Laboratory.
Any answers the experiment might give will help scientists better understand the odds of finding on Mars any traces of organic life, which strong oxidants could easily destroy. The oxidants could also pose a threat to future human missions to Mars, where the chemical or chemicals could chew up polymers used in many
spacesuit parts.
The MAOS team has submitted the instrument proposal to
NASA’s Discovery program for funding.
If selected, possibly as early as December, the chemi-resistor-based oxidation potential sensor could become the sole NASA instrument on the
British Beagle 2 Mars lander, slated for launch in 2003 as part of the European Space Agency’s Mars Express mission. MAOS would be incorporated in Beagle 2’s Environmental Sensor Suite of instruments.
"We’re the tail of the dog," Hecht said.
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