Future settlers may one day tap recently discovered water deposits lining the floors of lunar craters, but be warned: traveling through the pits may result in nasty electrical shocks.
That’s because crater walls effectively block plasma streaming from the sun, leaving little electrically charged matter to cancel out static buildup from a rover on the move, an astronaut walking, or any other activity that generates friction.
“The last thing you want to do is drive a rover wheel and have it charging up and then have an astronaut walking by and have it discharge,” Bill Farrell, a plasma physicist at NASA’s Goddard Space Flight Center in Greenbelt, Md., told Discovery News.
“At the atomic, molecular and even the micron level, the moon is actually pretty active. There are all kinds of weird processes that go on. It’s subtle, but it’s there,” Farrell said.
The research is applicable far beyond the moon. The physics applies for any small, virtually air-less body, like an asteroid, says Farrell who heads a team of scientists making a computational analysis of the moon’s electrical fields.
The study also provides an explanation for why columns of dust rise from the moon’s surface, a phenomena reported by the Apollo astronauts and other lunar missions. Farrell says electrostatic forces may be able to levitate dust and material from inside craters, creating a far easier method for obtaining samples for analysis than sending probes inside pits.
“When you have strong negative surface potential, you could have lifted and lofted dust at the edges of these fields,” Farrell said. “The dust is being ejected.”
Other lunar scientists are working to mesh the computational analysis of lunar electric fields with detailed topographical maps being compiled from data collected by NASA’s Lunar Reconnaissance Orbiter.
“It’s like weather prediction,” University of Maryland’s Timothy Stubbs told Discovery News. “You don’t know what solar wind is coming, but we can take some typical space weather conditions and see what happens to (lunar) surfacing charging.”
“In terms of making sure people are safe, we can run our model around any particular landing site that people are interested in. Some sites are more dangerous than others,” he added. “We’re trying to make it as computationally predictive as possible so that it can one day be a real-time predictive tool.”
NASA plans to launch a lunar mission known as LADEE in 2012 to sample lunar dust and gases. The information will be folded into computer models Farrell and colleagues have designed of how the moon’s surface becomes electrically charged.
“Now that we have some model of the moon’s polar environment, we’re kind of going off in a couple of different directions,” Farrell said.