[meteorite-list] True Fakes: Scientists Make Simulated Lunar Soil

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 28 Dec 2006 16:05:53 -0800 (PST)
Message-ID: <200612290005.QAA20209_at_zagami.jpl.nasa.gov>

http://science.nasa.gov/headlines/y2006/28dec_truefake.htm

True Fakes: Scientists make simulated lunar soil
NASA Science News
December 28, 2006

Dec. 28 , 2006: Life is tough for a humble grain of dirt on the surface
of the Moon. It's peppered with cosmic rays, exposed to solar flares,
and battered by micrometeorites--shattered, vaporized and re-condensed
countless times over the billions of years. Adding insult to injury,
Earthlings want to strip it down to oxygen and other elements for "in
situ resource utilization," or ISRU, the process of living off the land
when NASA returns to the Moon in the not-so-distant future.

But, as Robert Heinlein famously observed, "the Moon is a harsh
mistress." Living with moondust and striping it down may be trickier
than anyone supposes.

To find out how tricky, researchers would like to test their ideas for
ISRU and their designs for lunar rovers on real lunar soil before
astronauts return to the Moon. But there's a problem:

"We don't have enough real moondust to go around," says Larry Taylor,
director of Planetary Geosciences Institute at the University of
Tennessee in Knoxville. To run all the tests, "we need to make a
well-qualified lunar simulant." And not just a few bags will do. "We
need tons of it, mainly for working on technologies for diggers and
wheels and machinery on the surface," adds David S. McKay, chief
scientist for astrobiology at the Johnson Space Center (JSC).

Taylor and McKay are lead members of a small group of self-styled
"lunatics" whose careers have focused on lunar soil and rocks. They are
among several consultants to NASA's Marshall Space Flight Center (MSFC),
which manages the Lunar Regolith Simulant Development Program.

Carole McLemore is the program manager at Marshall. Back in the 1990s,
she explains, researchers used a lunar simulant called JSC-1 developed
at JSC. But "there is no more JSC-1 available." So, to get started,
researchers at Marshall are working with the Astromaterials Research and
Exploration Science office at Johnson to create a replica of the JSC-1
simulant: JSC-1A. It comes in three types based on grain size (fine,
medium and coarse). MSFC has also begun work on more demanding simulants
representing various locations on the Moon.

Until the Apollo astronauts brought lunar soil samples to Earth during
1969-72, the belief was that the Moon's dry, airless environment left
the soil largely undisturbed. Reality is much harsher.

Micrometeorites, many smaller than a pencil point, constantly rain onto
the surface at up to 100,000 km/hr (about 62,000 mph), chipping off
materials or forming microscopic impact craters. Some melt the soil and
vaporize and re-condense as glassy coats on other specks of dust.
Impacts weld debris into "agglutinates." Complicated interactions with
the solar wind convert iron in the soil into myriads of "nano-phase"
metallic iron grains just a few nanometers wide.

These processes form the "regolith" -- Greek for stone blanket (litho +
rhegos) -- covering the Moon's surface. What greets astronauts and
spaceships is a complex material comprising "sharp, abrasive,
interlocking fragile glass shards and fragments," Taylor says. It grinds
machinery and seals, and damages human lungs.

"Some of the stuff that got into the Apollo spacecraft was very finely
ground," McKay said. Dust was everywhere and impossible to brush off.
All the lunar astronauts had lung reactions to this dust, some more than
others, like Harrison H. (Jack) Schmitt's "lunar dust hay fever."

The Apollo specimens are America's Crown Jewels and are doled out in
ultra-small samples to scientists who can demonstrate that nothing else
will do for high-value experiments. Renewed interest in lunar
exploration in the late 1980s meant that lunar simulants were needed to
test schemes for building structures on the Moon or for extracting
oxygen and other materials.

That led to JSC-1 in 1993, made of basaltic volcanic cinder cone
deposits from a quarry near Flagstaff, AZ. The 25-ton lot -- distributed
in 50-pound bags -- proved popular.

"We're totally out, but that's soon to be corrected," said McKay. MSFC
has a Small Business Innovative Research (SBIR) contract with Orbitec of
Madison, WI, to manufacture about 16 metric tonnes of three types of
JSC-1A: 1 tonne of fines (delivered); 14 tonnes of moderate grains
(being delivered); and 1 tonne of coarse grains (coming soon). The U.S.
Geological Survey in Denver and the University of Colorado at Boulder --
key partners -- are checking the chemical, mineralogical, and
geotechnical properties.

MSFC is developing three new simulants. Two will represent mare and
polar highlands regions. A third will represent the glassy, sharp,
jagged edges of regolith that test the best of hardware and humans.
But matching every location on the Moon would require large numbers of
small, unique, expensive batches.

"Instead, we will develop root simulants and manufacture specific
simulants from these, but also enable investigators to enhance the
products as needed," McLemore added. "I liken this process to baking a
cake: depending on the type of cake you want, you need certain
ingredients for it to come out right and taste right. Getting the recipe
right whether for a cake or lunar simulants is critical."

For example, the new mare simulant will be enriched with ilmenite, a
crystalline iron-titanium oxide. Source materials used to produce the
three simulants will potentially come from locations as diverse as
Montana, Arizona, Virginia, Florida, Hawaii, and even some international
sites.

Initial lots will weigh just tens of pounds to ensure that the simulant
is made correctly. "Eventually we will scale up to larger quantities
when we can make sure that there is little variation from batch to
batch," McLemore said.

Once NASA understands how to make the various simulants, plans are to
farm the work out to companies to produce larger batches. "We will have
certification procedures in place for vendors to follow so users know
that the simulants meet the NASA standards," McLemore said.

And that will be the best way to tell it's a "true fake." Accept no
substitutes.

Investigators and other potential users should contact Carole A.
McLemore NASA/MSFC -- VP33, Huntsville, AL 35812 (256-544-2314 or
carole.a.mclemore at nasa.gov)
Received on Thu 28 Dec 2006 07:05:53 PM PST