"Not So Pristine" Samples
Useful
By Judy Allton
The wisdom of carefully curating all lunar
samples, even those crumbs from equipment and dust from spacesuits, is
paying off. Among the lunar collection are samples useful for distinguishing
contamination resulting from surface sample collection from curatorial
sample handling. Ranging from the very clean to the “not so clean,”
are the following kinds of samples:
1) A clean sample, uncontaminated
by astronauts and uncontaminated by curation: Samples extracted from the
chemically pure dissection pass of a 4-cm diameter core meet this requirement.
The ideal core sample is one which was returned to Earth in a sealed ALSRC
and from a sample vial not further allocated or handled since dissection.
2) Sample exposed to minimal contamination
by astronauts: SESC (Space Environment Sample Containers – indium-sealed
cans). One SESC sample was opened and subdivided in the University
of California at Berkeley organically clean cabinet.
3) A sample exposed to contamination
during collection, but little handled during curation: Fines from
ALSRCs (rock boxes) and from Tote Bags or Sample Collection Bags (which
were returned outside of an ALSRC) are candidates, if samples are selected
based on minimal subsequent handling in laboratory.
4) Lunar material expected to be
heavily contaminated by surface activities and LRL processing: samples
from vacuuming of space suits and freon rinsing of flight hardware.
5) Material expected to be heavily
contaminated from curation handling: cabinet sweepings.
6) Sample especially handled for
organic cleanliness: organic reserve or University of California
at Berkeley prepared samples.
7) Sample uncontaminated by astronauts
and with limited exposure to laboratory handling: band saw fines.
8) Sample stored frozen.
9) Sample stored in air for extensive
time (returned sample vault). A band saw fines sample from category
7 may meet this requirement, if stored for 20+ years.
The Curators of the lunar sample collection
are working to establish a reference suite of samples for organic and bioanalyses.
Complementary data obtained with an appropriate suite of analytical methods
on the same samples will be informative. Firm sample numbers are
not currently available.
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