Utilization of X-Ray Computed Tomography During the Preliminary Examination of Unopened Apollo Drive Tube Samples 73001 and 73002

Abstract

Double drive tube 73001/2 was collected on the Light Mantle Deposit in the Taurus-Littrow Valley by Apollo 17 astronauts. It is a 4-cm diameter core that sampled up to 70 cm deep in a lunar landslide at the base of the North Massif. NASA kept these samples pristine and untouched in anticipation of advanced future analytical techniques, such as high-resolution X-ray computed tomography (XCT). Double drive tube 73001/2 was selected to be studied as part of the Apollo Next Generation Sample Analysis (ANGSA) program and was opened in November 2019 (73002) and February 2022 (73001). We discuss how XCT was utilized during the preliminary examination of these samples. This technique, which was unavailable the last time an Apollo drive tube was opened (1993), provides a three-dimensional (3-D) image of the interior of opaque objects. Prior to opening, high-resolution scans were collected of the full length of both cores, providing a novel 3-D archive of the intact lunar regolith. After opening, 352 > 4 mm particles were individually bagged and scanned, allowing for their lithological classification. We provide an example of the robustness of the individual particle data by analyzing ilmenite crystals (n = 350) in fourteen high-Ti basalt particles. Our results show that ilmenite generally has highly anisotropic shapes and can take on various external morphologies, indicating that 73001/2 likely sampled several lunar basalt flows. This paper illustrates the utility of XCT for curatorial and scientific purposes during ANGSA and demonstrates its value for future sample return missions.