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Dust Devils on Mars May Threaten Explorers 20 May 2004 
Dust devils are like miniature tornadoes, about 10 to 100 meters wide with 20- to 60-mile-per-hour (32- to 96-km/hr) winds swirling around a hot column of rising air. "Dust devils are common on Mars, and NASA is interested in them as well as other phenomena as a possible nuisance or hazard to future human explorers," said Dr. William Farrell of NASA's Goddard Space Flight Center in Greenbelt, Md. "If Martian dust devils are highly electrified, as our research suggests, they might give rise to increased discharging or arcing in the low-pressure Martian atmosphere, increased dust adhesion to space suits and equipment, and interference with radio communications." NASA's Mars Testbed missions in the coming decade may be able to investigate whether such is the case. Dust particles become electrified in dust devils when they rub against each other as they are carried by the winds, transferring positive and negative electric charge in the same way you build up static electricity if you shuffle across a carpet. Scientists thought there would not be a high-voltage, large-scale electric field in dust devils because negatively charged particles would be evenly mixed with positively charged particles, so the overall electric charge in the dust devil would be in balance.
To date, none of the
robotic Mars landers and rovers that have operated on the Martian surface
have experienced any consequences of this phenomena, including the rovers
Spirit and Opportunity. However, more complex landed laboratories, such as
the Mars Science Laboratory (MSL), slated to launch in 2009, may be far
more sensitive to electrical disturbances than previous missions. As such,
this research is a key stepping stone to more advanced robotic and human
exploration of Mars. |
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