"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.