Progress Made in Lunar In Situ Resource Utilization under NASA's Exploration Technology and Development Program

Abstract

Incorporation of In-Situ Resource Utilization (ISRU) and the production of mission critical consumables for 9 propulsion, power, and life support into mission architectures can greatly reduce the mass, cost, and risk of missions 10 leading to a sustainable and affordable approach to human exploration beyond Earth. ISRU and its products can 11 also greatly affect how other exploration systems are developed, including determining which technologies are 12 important or enabling. While the concept of lunar ISRU has existed for over 40 years, the technologies and systems 13 had not progressed much past simple laboratory proof-of-concept tests. With the release of the Vision for Space 14 Exploration in 2004 with the goal of harnessing the Moon"s resources, NASA initiated the ISRU Project in the 15 Exploration Technology Development Program (ETDP) to develop the technologies and systems needed to meet 16 this goal. In the five years of work in the ISRU Project, significant advancements and accomplishments occurred in 17 several important areas of lunar ISRU. Also, two analog field tests held in Hawaii in 2008 and 2010 demonstrated 18 all the steps in ISRU capabilities required along with the integration of ISRU products and hardware with 19 propulsion, power, and cryogenic storage systems. This paper will review the scope of the ISRU Project in the 20 ETDP, ISRU incorporation and development strategies utilized by the ISRU Project, and ISRU development and 21 test accomplishments over the five years of funded project activity.

Analysis of Lunar Boulder Tracks: Implications for Trafficability of Pyroclastic Deposits

“…Interestingly, the increase of bearing capacity over depth is more significant for LPDs than for mare and highland areas, although reasons for this observation are unknown. The bearing capacity envelope of the three investigated regions down to a depth of ~5 m might support the design and construction of shallow foundations for future infrastructure elements used for long‐term exploration (Sanders & Larson, ) or ISRU purposes such as habitats, radiation shields, storage units, or scientific instruments such as large telescopes. Figures , , and S9 also include measurements that appear to reflect a consolidated type of regolith at depth.…”

Proving the viability of an electrochemical process for the simultaneous extraction of oxygen and production of metal alloys from lunar regolith

“…Sourcing resources locally will likely be essential for sustainable, long-duration activities in space (Anand et al 2012). Such in-situ resource utilisation (ISRU) could significantly reduce the payload mass that would need to be launched from Earth, thus reducing mission cost and the risk to human crews by providing them with the tools to meet their needs from the local environment (Sanders and Larson, 2012).…”

“…Numerous strategies for extracting oxygen from regolith material on the lunar surface have been proposed; summaries of such processes can be found in previous publications (Taylor and Carrier, 1993;Schrunk et al 2007;Schwandt et al 2012a). Some of the more wellresearched processes are the chemical reduction of regolith-derived iron oxides either with hydrogen, followed by the electrolysis of water (Gibson et al, 1994;Allen et al 1996;Li et al 2012;Sanders and Larson, 2012), or alternatively with methane, which would require a further methane-reforming step and the electrolysis of water (Friedlander, 1985). These processes operate at ~900 °C, utilising a low-risk solid-gas interaction, but are low yielding (1-3%) and heavily dependent on feedstock composition and beneficiation.…”

“…'Yield' in this context is defined as weight of oxygen extracted divided by total weight of regolith processed. The carbothermal reduction of molten regolith at ~1600 °C (also requiring subsequent methanereforming and electrolysis steps; Rosenberg et al, 1992;Gustafson et al, 2006;Balasubramaniam, 2010;Sanders and Larson, 2012), and the direct electrolysis of molten regolith at >1600 °C Haskin, 1992, 1993;Vai et al 2010;Sirk 2010;Wang et al 2011;Schreiner 2016), are less feedstock-dependent and higher yielding (theoretically 10-20% and 20-30% respectively), but require the handling of molten regolith at extreme temperatures. Research has also been conducted into the use of molten fluoride salts as a flux to dissolve lunar regolith oxide simulants and related silicate rocks at 960 -1250 °C, and hence to extract a mixed alloy electrochemically; however, these processes rely on the solubility of the various oxides and the efficacy in terms of oxygen yield has not been quantified (Kesterke 1970;Liu et al 2017).…”

Feasibility studies for hydrogen reduction of ilmenite in a static system for use as an ISRU demonstration on the lunar surface

“…Although theoretical ISRU studies have been undertaken from as early as 1979 (Rao et al, 1979), more attention has been paid to laboratory and field studies in the last decade (e.g. Sanders & Larson, 2012) as such technologies could enable future long term exploration missions to the Moon and Mars (ESA, 2015;ISECG, 2018).…”