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[tech4all] What a Little Moon Dust Can Do

What a Little Moon Dust Can Do

By Amit Asaravala
02:00 AM Apr. 04, 2005 PT

SUNNYVALE, California
If the Bush administration's plan to set up a base
on the moon is to become a reality, scientists will
first have to devise a way to deal with a tiny but
ubiquitous enemy: lunar dust.

Lunar dust is extremely abrasive -- and unavoidable --
as astronauts quickly learned during the Apollo
missions of the 1960s and '70s. Within hours, the dust
covered the astronauts' spacesuits and equipment,
scratching lenses and corroding seals.
Fortunately for the astronauts, their contact with
lunar dust was short enough that it didn't cause any
major problems. But explorers living on a moon base
for weeks or even months at a time are not likely to
get away so clean.

Under prolonged exposure, the explorers would be at
risk for everything from mechanical failures in
spacesuits and airlocks to lung disease, said
researchers last week at a NASA workshop focused on
the issue.

"Dust is the No. 1 environmental problem on the moon,"
said Apollo 17 astronaut Harrison Schmitt, who
reported having a severe allergic reaction to moon
dust during his mission in 1972. "We need to
understand what the (biological) effects are, because
there's always the possibility that engineering might
fail."

Moon dust is much more jagged than dust on Earth
because there's no water or wind on the moon to toss
it around and grind down its edges. It's created when
meteorites, cosmic rays and solar winds slam into the
moon, turning its rocks into powdery topsoil.

The Apollo astronauts couldn't help but get covered in
the stuff as they struggled to stay upright on the
moon's surface, where the force of gravity is
one-sixth of that on Earth. Later, they tracked the
dust back into their space capsules and inhaled it
when they took off their helmets.

"When you go weightless again, it shook up from the
floorboards," said Schmitt. "It smelled like spent
gunpowder."

Though no astronauts have reported coming down with
any illnesses due to their contact with lunar dust --
save for Schmitt's brief allergic reaction -- samples
brought back to Earth have some peculiar properties
that worry researchers.

For one, some of the dust particles are only a few
microns wide. This makes it easy for the particles to
get deep into the lungs and stay there. Scientists
worry that this could eventually lead to fatal lung
diseases similar to silicosis.

Also, the dust is littered with bonded shards of glass
and minerals known as agglutinates, which were formed
in the heat of meteorite impacts. Agglutinates have
not been found on Earth, and scientists worry that the
human body may not be able to expel them efficiently
if inhaled.

"They have sharp angles, with arms that stick out and
little hooks," said David McKay, chief scientist for
astrobiology at NASA's Johnson Space Center. "It's
like Velcro."

McKay and other speakers at the workshop offered
suggestions for limiting astronauts' exposure to dust
-- for instance, by setting up showers or
electrostatic devices that pull the dust off the
astronauts' suits. But they cautioned that solutions
like these would be hasty without further research
into the biological effects of lunar dust.

American researchers have hardly bothered to study the
topic since the United States ended the Apollo program
in 1972. And foreign studies on samples from the
Soviet Luna program have been widely rejected on the
grounds that the studies were flawed.

Getting studies rolling again will not be easy.
Laurent Sibille, a research scientist with NASA's
Marshall Space Flight Center, estimates that
researchers will need 100 tons of space dust for
testing in the run-up to a new moon mission.

The Apollo astronauts brought back less than 1 percent
of that amount, and the original 25 tons of fake
"simulant" dust that NASA created for researchers is
now gone, with the exception of one bucketful at
Johnson Space Center.

Sibille and other speakers called on NASA and the
aerospace industry to begin developing a new simulant
as soon as possible.

Understanding how lunar dust affects humans is
imperative to any future missions, said Russell
Kerschmann, life sciences chief at NASA's Ames
Research Center.

"How much of a problem this is, we don't know," said
Kerschmann. "And that's a problem."

Source:
http://www.wired.com/news/space/0,2697,67110,00.html

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posted by Bharath @ 12:27 PM