Watching Lunar Dust Settle

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As space exploration missions go, FLASH would be a bargain, costing well under $10 million. It would be the first student-built spacecraft to leave the Earth's orbit, says Peter Schultz, an impact specialist at Brown University. The impact could be bright enough to reveal a great deal of detail about the composition of the lunar surface, and the brightness of the flash, from an object of precisely known mass and velocity, would provide the first data "to calibrate all those lunar flashes" seen regularly by telescopes equipped with high-speed video and computerized image analysis, says Schultz.

Last November, Robert Suggs of NASA's Marshall Space Flight Center saw such a lunar flash using a 10-inch telescope -- and thousands of amateurs have telescopes that size or larger. Suggs says that few professional astronomers observe the moon any more: "We tend to think of it as a known quantity. But there is still knowledge to be gained there."

Of course the chances of an astronaut on the moon being hit by a meteorite are vanishingly small. But we don't know much about how lunar dust is kicked up by impacts and how far it spreads. Because of the potential risks from such dust plumes, which might obscure the view from lunar telescopes or clog the gears of machinery, NASA's planetary protection officer, John Rummel, says that in the future there will need to be clear rules and procedures for nations, and even private companies, to register plans for lunar impacts, and to make sure they don't interfere with any other planned lunar activities.

Fortunately, contamination is not a real concern on the moon because the surface has already been determined to be completely sterile. Any terrestrial organisms that might be introduced from spacecraft would not spread or multiply, according to Rummel. From a biological perspective, "the moon is not interesting in itself," he says, and the only requirement at this time for anyone planning a lunar impact is "to keep track of where it goes." A central database should be established to catalogue such sites.

Once there start to be active research sites and human landings on the moon, Rummel says, the main point is that "everybody's going to have to be polite about where they put things" to make sure they don't contaminate each others' sites.