[meteorite-list] The Smell of Moondust

From: Axel Emmermann <axel.emmermann_at_meteoritecentral.com>
Date: Tue Jan 31 17:36:41 2006
Message-ID: <KKEDKELDHEAGAPEINLODKEJHDCAA.axel.emmermann_at_pandora.be>

Hello list,

maybe the smell can be explained by the extremely fine nature of the lunar
dust in combination with electrostatic charge.

Just my 2 cents worth in the form of a layman's theory. But jus think about
it for a minute...

Our sense of smell is dependent on electrostatic charge. Free radicals and
very easily ionized compounds react with the endings of the olfactory nerve
(not the "old factory" although that may stink too ;-)))
I think (again, I'm not a doctor) that, for example, we do not smell
ozone... we
smell the charge transfer that marks the "end" of an ozone molecule that
hits our olfactory sense and reverts to odorless oxygen upon contact.
Any charged particle that is fine enough to enter the olfactory cavity would
have a smell to it, I presume? Just because of it's electrical charge.
There is mention of sunlight charging the lunar dust strongly enough to
cause it to levitate and form a fine mist that marks the moon's day/night
zone.
Residual electrostatic charge might be the smelly agent (said the dirty cop
;-)))

Best regards

Axel Emmermann
Lobbesplein 12
B-2640 Mortsel
URL: http://users.pandora.be/axel.emmerman/home/index.htm
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-----Oorspronkelijk bericht-----
Van: meteorite-list-bounces_at_meteoritecentral.com
[mailto:meteorite-list-bounces_at_meteoritecentral.com]Namens Ron Baalke
Verzonden: dinsdag 31 januari 2006 21:49
Aan: Meteorite Mailing List
Onderwerp: [meteorite-list] The Smell of Moondust



http://science.nasa.gov/headlines/y2006/30jan_smellofmoondust.htm

The Smell of Moondust
NASA Science News
January 30, 2006

This is the third installment of Science_at_NASA's Apollo Chronicles

January 30, 2006: Moondust. "I wish I could send you some," says Apollo
17 astronaut Gene Cernan. Just a thimbleful scooped fresh off the lunar
surface. "It's amazing stuff."

Feel it - it's soft like snow, yet strangely abrasive.

Taste it - "not half bad," according to Apollo 16 astronaut John Young.

Sniff it - it smells like spent gunpowder," says Cernan.

How do you sniff moondust?

Every Apollo astronaut did it. They couldn't touch their noses to the
lunar surface. But, after every moonwalk (or "EVA"), they would tramp
the stuff back inside the lander. Moondust was incredibly clingy, sticking
to boots, gloves and other exposed surfaces. No matter how hard they tried
to brush their suits before re-entering the cabin, some dust (and sometimes
a lot of dust) made its way inside.

Once their helmets and gloves were off, the astronauts could feel, smell
and even taste the moon.

The experience gave Apollo 17 astronaut Jack Schmitt history's first
recorded case of extraterrestrial hay fever. "It's come on pretty fast,"
he radioed Houston with a congested voice. Years later he recalls, "When
I took my helmet off after the first EVA, I had a significant reaction
to the dust. My turbinates (cartilage plates in the walls of the nasal
chambers) became swollen."

Hours later, the sensation faded. "It was there again after the second
and third EVAs, but at much lower levels. I think I was developing some
immunity to it."

Other astronauts didn't get the hay fever. Or, at least, "they didn't
admit it," laughs Schmitt. "Pilots think if they confess their symptoms,
they'll be grounded." Unlike the other astronauts, Schmitt didn't have a
test pilot background. He was a geologist and readily admitted to sniffles.

Schmitt says he has sensitive turbinates: "The petrochemicals in Houston
used to drive me crazy, and I have to watch out for cigarette smoke."
That's why, he believes, other astronauts reacted much less than he did.

But they did react: "It is really a strong smell," radioed Apollo 16
pilot Charlie Duke. "It has that taste -- to me, [of] gunpowder -- and
the smell of gunpowder, too." On the next mission, Apollo 17, Gene
Cernan remarked, "smells like someone just fired a carbine in here."

Schmitt says, "All of the Apollo astronauts were used to handling guns."
So when they said 'moondust smells like burnt gunpowder,' they knew what
they were talking about.

To be clear, moondust and gunpowder are not the same thing. Modern
smokeless gunpowder is a mixture of nitrocellulose (C6H8(NO2)2O5) and
nitroglycerin (C3H5N3O9). These are flammable organic molecules "not
found in lunar soil," says Gary Lofgren of the Lunar Sample Laboratory
at NASA's Johnson Space Center. Hold a match to moondust--nothing
happens, at least, nothing explosive.

What is moondust made of? Almost half is silicon dioxide glass created
by meteoroids hitting the moon. These impacts, which have been going on
for billions of years, fuse topsoil into glass and shatter the same into
tiny pieces. Moondust is also rich in iron, calcium and magnesium bound
up in minerals such as olivine and pyroxene. It's nothing like gunpowder.

So why the smell? No one knows.

ISS astronaut Don Pettit, who has never been to the moon but has an
interest in space smells, offers one possibility:

"Picture yourself in a desert on Earth," he says. "What do you smell?
Nothing, until it rains. The air is suddenly filled with sweet, peaty
odors." Water evaporating from the ground carries molecules to your nose
that have been trapped in dry soil for months.

Maybe something similar happens on the moon.

"The moon is like a 4-billion-year-old desert," he says. "It's
incredibly dry. When moondust comes in contact with moist air in a lunar
module, you get the 'desert rain' effect--and some lovely odors." (For
the record, he counts gunpowder as a lovely odor.)

Gary Lofgren has a related idea: "The gases 'evaporating' from the
moondust might come from the solar wind." Unlike Earth, he explains, the
moon is exposed to the hot wind of hydrogen, helium and other ions
blowing away from the sun. These ions hit the moon's surface and get
caught in the dust.

It's a fragile situation. "The ions are easily dislodged by footsteps or
dustbrushes, and they would be evaporated by contact with warm air
inside the lunar module. Solar wind ions mingling with the cabin's
atmosphere would produce who-knows-what odors."

Want to smell the solar wind? Go to the moon.

Schmitt offers yet another idea: The smell, and his reaction to it,
could be a sign that moondust is chemically active.

"Consider how moondust is formed," he says. "Meteoroids hit the moon,
reducing rocks to jagged dust. It's a process of hammering and
smashing." Broken molecules in the dust have "dangling
bonds"--unsatisfied electrical connections that need atomic partners.

Inhale some moondust and what happens? The dangling bonds seek partners
in the membranes of your nose. You get congested. You report strange
odors. Later, when the all the bonds are partnered-up, these sensations
fade.

Another possibility is that moondust "burns" in the lunar lander's
oxygen atmosphere. "Oxygen is very reactive," notes Lofgren, "and would
readily combine with the dangling chemical bonds of the moondust." The
process, called oxidation, is akin to burning. Although it happens too
slowly for smoke or flames, the oxidation of moondust might produce an
aroma like burnt gunpowder. (Note: Burnt and unburnt gunpowder do not
smell the same. Apollo astronauts were specific. Moondust smells like
burnt gunpowder.)

Curiously, back on Earth, moondust has no smell. There are hundreds of
pounds of moondust at the Lunar Sample Lab in Houston. There, Lofgren
has held dusty moon rocks with his own hands. He's sniffed the rocks,
sniffed the air, sniffed his hands. "It does not smell like gunpowder,"
he says.

Were the Apollo crews imagining things? No. Lofgren and others have a
better explanation:

Moondust on Earth has been "pacified." All of the samples brought back
by Apollo astronauts have been in contact with moist, oxygen-rich air.
Any smelly chemical reactions (or evaporations) ended long ago.

This wasn't supposed to happen.

Astronauts took special "thermos" containers to the moon to hold the
samples in vacuum. But the jagged edges of the dust unexpectedly cut the
seals of the containers, allowing oxygen and water vapor to sneak in
during the 3-day trip back to Earth. No one can say how much the dust
was altered by that exposure.

Schmitt believes "we need to study the dust in situ--on the moon." Only
there can we fully discover its properties: Why does it smell? How does
it react with landers, rovers and habitats? What surprises await?

NASA plans to send people back to the moon in 2018, and they'll stay
much longer than Apollo astronauts did. The next generation will have
more time and better tools to tackle the mystery.

We've only just begun to smell the moondust.

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Received on Tue 31 Jan 2006 05:36:45 PM PST