THE MOST UNUSUAL SOIL SAMPLE COLLECTED ON THE MOON

The Apollo 17 mission went to the Taurus Littrow Valley, a mare basalt region situated between highland massifs located to the north and south. During extraction of the Lunar Rover (LR) from the Lunar Module (LM), the right rear fender was broken off, requiring a make-shift repair with duct tape and a geologic map. Because of the damaged fender, the lunar soil was thrown up in a ‘rooster tail' that deposited soil onto the back of the LR. After the third EVA when Commander Schmitt was storing rocks and soil samples in the LM, he noticed this accumulation of soil near the “Buddy System for Life Support.” The sample was collected and labeled as the “B-SLiS” soil sample. Because the sample had no known provenance, it was set aside in the Lunar Curatorial Vault, untouched since 1972.

Being a soil randomly collected along the path of the Apollo 17 EVA, it represents the only lunar soil to be collected from a large source area and therefore has important applications for science. For example, 70051 can be used as a ground truth for remote sensing data of the Apollo 17 site. This soil is also useful for In-Situ Resource Utilization (ISRU) studies for Return-to-the-Moon endeavors, including microwaveability, dust toxicity properties, etc.

This unique soil is a sampling of various high and low-Ti basalt fragments, mineral fragments of plagioclase, volcanic orange glass, and typical agglutinates. When looking at large size fractions (<1mm), a large proportion is composed of highland plagioclase fragments. The agglutinitic glass is generated by the melting of soil due to meteoritic impacts. Pyroclastic glass is present in lesser amounts. It tends to be spherical and lacks nanophase Fe particles. The composition of the pyroxenes within the basalt fragments range from low-Ca pigeonite, augite and ferrohedenbergite. These fragments are classified as low titanium basalts based on the analyses of pyroxenes, plagioclase content, and wt% FeO in the sample. It is clear from this study that the sample is a composite of both highland and maria soils and it is likely to provide important information on the average soil composition at the Apollo 17 site.