Curatorial statistics on apollo regolith fragments applicable to sample collection by raking

Abstract The technological and science risk for robotic sample return missions to the Moon is lowered because of lessons learned from the effectiveness of Apollo sampling devices in recovering the specimens desired. Apollo lunar sample curatorial statistics of the specimens collected by the astronauts, and the sub-samples allocated for scientific research, have useful information applicable to future lunar robotic sample return missions. Because regolith processes are global, the best broad-based predictors of numbers of fragments to be expected from sieving lunar regolith are the results of sieving 144 Apollo soil samples from 4 sites comprising 46 kg of material.Weight percents are: 1–2 mm (4%), 2–4 mm (3%), 4–10 mm (3%). We assume that future sample return missions will focus on recovery of igneous crystalline material or crystalline melt sheet material, untainted by regolith processing. Therefore we assigned 474 rocks, 665 rake samples and 3376 fragments (4–10 mm) as either “crystalline” or “regolith-derived”, based on existing lithologic characterizations developed by the Preliminary Examination Teams. For rocks statistically gathered with 1-cm -spaced tines (the rake samples), an increase in relative abundance of regolith-derived specimens occurs among lower weight rocks.The weight at which the number of regolith-derived samples exceed crystalline samples occurs at 18g for Apollo 16, 10 g for Apollo 17 and 6 g for Apollo 15. When the crystalline fraction for rocks, rakes and 4–10 rum fragments is compared for each sampling station, the relative abundance of crystalline material is consistent in all sizes, but differences between sampling stations within a landing site are distinct.