National Aeronautics and Space Administration plans to deploy astronauts to the Moon and construct sustainable habitat modules in collaboration with private companies and national space agencies worldwide. In situ resource utilization (ISRU) is indispensable for large-scale, long-term human lunar exploration. Water ice, which is one of the most precious resources, is believed to exist in the Moon's polar regions. Future plans include using it to maintain life support for astronauts and provide raw materials (H2 and O2) for rocket engines and fuel cells. Because the capture and delivery of ice are required to utilize water on the Moon, the following potentially reliable and efficient capture and delivery technologies for water ice, which are based on electrodynamic, electromagnetic, and mechanical vibration forces, are being developed. (1) The first is a capture and delivery system based on electrodynamic standing waves. When a high alternating voltage is applied to parallel screen electrodes, the alternating electrodynamic force is exerted on ice and regolith particles in contact with the lower electrode, and some agitated particles are captured after they pass through the openings of the upper screen electrode. The captured particles are transported between an array of zigzag electrodes activated by the application of high alternating voltage. (2) The second is a delivery system that utilizes an electrodynamic traveling wave. Three- or four-phase high voltage is applied to parallel line or ring electrodes to form an electrodynamic traveling wave. Meanwhile, regolith and ice particles are conveyed by traveling waves. Horizontal, curved, inclined, and vertical deliveries are realizable using this system. (3) The third is an electromagnetic delivery system based on the coil-gun principle, which considers the fact that lunar regolith particles are magnetic. A multistage coil-gun mechanism powered by a charged inductor-capacitor-resistor (LCR) circuit is used to deliver the regolith particles over long distances. (4) The fourth is a vibration delivery system. The vibration-conveyance mechanism, which is widely applied in terrestrial industries, is used to deliver regolith and ice particles. When the particles are on a plate or in a tube vibrated diagonally by actuators, the vibrating plate or tube is repeatedly propelled and conveys the particles diagonally in the forward direction. When the lower end of an inclined or vertically supported vibrating tube is immersed in a layer of regolith or ice particles, particles are introduced into the tube, and the friction force between the particles and the inner wall of the tube is used to convey the particles upward. This paper provides an overview of the recent progress of these unique technologies for efficient and reliable ISRU on the Moon.

Bio-inspired strategies for robotic sensing are essential for in situ manufactured sensors on the Moon. Sensors are one crucial component of robots that should be manufactured from lunar resources to industrialize the Moon at low cost. We are concerned with two classes of sensor: (a) position sensors and derivatives thereof are the most elementary of measurements; and (b) light sensing arrays provide for distance measurement within the visible waveband. Terrestrial approaches to sensor design cannot be accommodated within the severe limitations imposed by the material resources and expected manufacturing competences on the Moon. Displacement and strain sensors may be constructed as potentiometers with aluminium extracted from anorthite. Anorthite is also a source of silica from which quartz may be manufactured. Thus, piezoelectric sensors may be constructed. Silicone plastic (siloxane) is an elastomer that may be derived from lunar volatiles. This offers the prospect for tactile sensing arrays. All components of photomultiplier tubes may be constructed from lunar resources. However, the spatial resolution of photomultiplier tubes is limited so only modest array sizes can be constructed. This requires us to exploit biomimetic strategies: (i) optical flow provides the visual navigation competences of insects implemented through modest circuitry, and (ii) foveated vision trades the visual resolution deficiencies with higher resolution of pan-tilt motors enabled by micro-stepping. Thus, basic sensors may be manufactured from lunar resources. They are elementary components of robotic machines that are crucial for constructing a sustainable lunar infrastructure. Constraints imposed by the Moon may be compensated for using biomimetic strategies which are adaptable to non-Earth environments.

Water resources are essential to human exploration in deep space or the establishment of long-term lunar habitation. Ice discovered on the Moon may be useful in future missions to the lunar surface, necessitating the consideration of in situ resource utilization if it is present in sufficient amounts. Extraction of ice can cause the regolith to settle, which can lead to unintended structural damage. Therefore, any settlement resulting from ice extraction should be understood from a geotechnical perspective. This work reports on experimental investigation of the potential settlement caused by the extraction of ice from lunar regolith simulant containing different textures of ice. The KLS-1 simulant was prepared with different water contents and ice textures. Significant settlement occurred in simulant-ice mixtures with initial water contents of 5-10%.

Water resources are essential to human exploration in deep space or the establishment of long-term lunar habitation. Ice discovered on the Moon may be useful in future missions to the lunar surface, necessitating the consideration of in situ resource utilization if it is present in sufficient amounts. Extraction of ice can cause the regolith to settle, which can lead to unintended structural damage. Therefore, any settlement resulting from ice extraction should be understood from a geotechnical perspective. This work reports on experimental investigation of the potential settlement caused by the extraction of ice from lunar regolith simulant containing different textures of ice. The KLS-1 simulant was prepared with different water contents and ice textures. Significant settlement occurred in simulant-ice mixtures with initial water contents of 5-10%.

Lunar regolith is the preferred material for lunar base construction using in situ resource utilization technology. The TiO2 variations in lunar regolith collected from different locations significantly impact its suitability as a construction material. Therefore, it is crucial to investigate the effects of TiO2 on the properties of lunar regolith. This study aims to evaluate the influence of TiO2 content and sintering temperature on phase transformation, microstructure, and macroscopic properties (e.g., the shrinkage rate, mechanical properties, and relative density) of lunar regolith simulant samples (CUG-1A). The flexural strength and relative density of the sample with a TiO2 content of 6 wt% sintered at 1100 C-degrees reached 136.66 +/- 4.92 MPa and 91.06%, which were 65% and 12.28% higher than those of the sample not doped with TiO2, respectively. The experiment demonstrated that the doped TiO2 not only reacted with Fe to form pseudobrookite (Fe2TiO5) but also effectively reduced the viscosity of the glass phase during heat treatment. As the sintering temperature increased, the particles underwent a gradual melting process, leading to a higher proportion of the liquid phase. The higher liquid-phase content had a positive impact on the diffusion of mass transfer, causing the voids and gaps between particles to shrink. This shrinkage resulted in greater density and, ultimately, improved the mechanical properties of the material.

Ever since the Lunar Crater Observation and Sensing Satellite (LCROSS) data helped confirm the presence of water in the permanently shadowed regions (PSRs) of the lunar polar area, interest in developing systems for the production of water on the Moon has peaked. Considering the extremely cold environment on the lunar surface, geotechnical properties of icy lunar regolith could have notable variance depending on water content and cryogenic environment. It is essential to have an in-depth understanding of the geotechnical properties of icy lunar regolith under varying conditions such as different water contents and cryogenic temperatures. Previous studies have shown that icy regolith behaves similarly to rock, depending on the water content and degree of compaction. Characterizing icy regolith is critical for any drilling and excavation operations for the development of the bases or for mining activities. This study estimated geotechnical behaviors of icy lunar regolith in cryogenic environments. Geotechnical tests such as unconfined compressive strength (UCS), Brazilian tensile strength (BTS), and punch penetration tests were conducted in simulated lunar cryogenic environments on samples of basaltic lunar simulant with changing water content. The results indicate that geotechnical properties of icy lunar regolith vary substantially in simulated moon environments. Icy lunar regolith tends to behave like rock with soft to medium strengths but has nonbrittle (or ductile) properties. Correlations between strength properties and water content as well as between strength properties and cryogenic temperature are offered. The results of this paper could provide valuable suggestions for future mining and civil activities and other exploration purposes on the moon. The results of mechanical characterization of icy regolith provided in this paper, such as UCS, BTS, and punch penetration tests to determine ductility and brittleness, are among the novel aspect of the study to offer better understanding of the behavior of such materials in future mining and construction activities on the moon.

The Japan Aerospace Exploration Agency is planning to operate an uncrewed rover on the Moon to search for water ice, which exists at the polar regions of the Moon. The rover's 1.5-m-long drill will penetrate the regolith layer of the lunar surface and capture ice particles mixed with the regolith. A transportation system for crushed ice particles mixed with the lunar regolith has been developed utilizing a vibration transportation mechanism that realizes the lifting of particles to physical and chemical analyzers installed on the rover. In this mechanism, the friction force between the inner wall of the tube and particles mainly plays the role of conveying particles upward while the tube inserted vertically into the bulk of the regolith is oscillating up and down. A parametric experiment was conducted to deduce the optimal configuration and operational conditions, and it was achieved that simulant particles and crushed ice particles mixed with lunar regolith are transported through the long tube. In addition, it was predicted by numerical calculations based on the discrete element method that the transportation performance in the lunar environment is better than that on Earth owing to low gravitational acceleration on the Moon.

The existence of water (ice) has been discovered in the polar regions of the Moon, and it is expected to be used to support life for astronauts and to provide the raw material of hydrogen and oxygen. Because the exact location of ice, including the depth from the lunar surface, chemical and physical forms, and the amount of water, is unclear, the Japan Aerospace Exploration Agency (JAXA) is planning to search for ice directly by operating an uncrewed rover on the Moon. A long drill, approximately 1.5 m long, will be screwed in the regolith layer, and regolith mixed with ice will be captured and transported from the lower deep portion of the regolith layer to chemical and physical analyzers mounted on the rover. A long-range technology for vertical ice transport is indispensable for ice exploration. To this end an electrodynamic sampling system that can transport crushed ice particles vertically up to the 1.5-m height is developed. Parallel ring electrodes were attached to a collection tube, and four-phase rectangular wave high voltage was applied to the electrodes to form an electrodynamic traveling wave. Ice particles were transported upward synchronized to the traveling wave. It was demonstrated that this system could be used to capture and transport crushed ice particles, as well as regolith particles. Performance in the lunar environment (1/6-G and absence of air drag) was evaluated by the numerical calculation based on the modified discrete-element method.

The recent evidence of water in the lunar crater Cabeus from the LCROSS mission (Colaprete et al., 2010) provides confirmation of a valuable resource on the lunar surface. To understand this resource and the impact it can have on future exploration, further information is needed on the distribution and availability of the water ice. The Lunar Advanced Volatile Analysis (LAVA) subsystem is a part of the Regolith & Environment Science and Oxygen & Lunar Volatile Extraction (RESOLVE) payload, designed to provide ground truth to the volatile distribution near the permanently shadowed regions on the lunar surface. The payload is designed to drill and extract a regolith core sample, heat the regolith to drive off the volatiles, and identify and quantify the volatile resources. The LAVA subsystem is specifically responsible for processing and analyzing the volatile gas sample from the lunar regolith sample. The main objective of this paper is to provide insight into the operations and hardware for volatile analysis developed and deployed at the 2012 RESOLVE Field Test on the slopes of Mauna Kea. The vision of employing Commercial Off the Shelf (COTS) and modified COTS hardware to lower the cost for mission-enabling field tests will be highlighted. This paper will discuss how the LAVA subsystem hardware supported several high level RESOLVE mission objectives to demonstrate the challenging lunar mission concept proposed. Published by Elsevier Ltd. on behalf of COSPAR.

Incorporation of in situ resource utilization (ISRU) and the production of mission-critical consumables for propulsion, power, and life support into mission architectures can greatly reduce the mass, cost, and risk of missions, leading to a sustainable and affordable approach to human exploration beyond Earth. ISRU and its products can also greatly affect how other exploration systems are developed, including determining which technologies are important or enabling. Although the concept of lunar ISRU has existed for more than 40 years, the technologies and systems had not progressed much past simple laboratory proof-of-concept tests. With the release of the Vision for Space Exploration in 2004 with the goal of harnessing the Moon's resources, the National Aeronautics and Space Administration (NASA) initiated the ISRU project in the Exploration Technology Development Program (ETDP) to develop the technologies and systems needed to meet this goal. In the 5 years of work in the ISRU Project, significant advancements and accomplishments occurred in several important areas of lunar ISRU. Also, two analog field tests held in Hawaii in 2008 and 2010 demonstrated all the steps in ISRU capabilities required, along with the integration of ISRU products and hardware with propulsion, power, and cryogenic storage systems. This paper will review the scope of the ISRU Project in the ETDP, ISRU incorporation, development strategies used by the ISRU project, and ISRU development and test accomplishments over the 5 years of funded project activity. DOI: 10.1061/(ASCE)AS.1943-5525.0000208. (C) 2013 American Society of Civil Engineers.