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Enabling Universal Access to Power on the Lunar Surface
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Megawatt solar power systems for lunar surface operations
The work presented here shows that a solar power system can provide power on the order of one megawatt to a lunar base with a fairly high specific power. The main drawback to using solar power is still the high mass, and therefore, cost of supplying energy storage through the solar night. The use of cryogenic reactant storage in a fuel cell system, however, greatly reduces the total system mass over conventional energy storage schemes.
Distillation and Air Stripping Designs for the Lunar Surface
Air stripping and distillation are two different gravity-based methods, which may be applied to the purification of wastewater on the lunar base. These gravity-based solutions to water processing are robust physical separation techniques, which may be advantageous to many other techniques for their simplicity in design and operation. The two techniques can be used in conjunction with each other to obtain high purity water. The components and feed compositions for modeling waste water streams are presented in conjunction with the Aspen property system for traditional stage distillation models and air stripping models. While the individual components for each of the waste streams will vary naturally within certain bounds, an analog model for waste water processing is suggested based on typical concentration ranges for these components. Target purity levels for the for recycled water are determined for each individual component based on NASA s required maximum contaminant levels for potable water Distillation processes are modeled separately and in tandem with air stripping to demonstrate the potential effectiveness and utility of these methods in recycling wastewater on the Moon. Optimum parameters such as reflux ratio, feed stage location, and processing rates are determined with respect to the power consumption of the process. Multistage distillation is evaluated for components in wastewater to determine the minimum number of stages necessary for each of 65 components in humidity condensate and urine wastewater mixed streams. Components of the wastewater streams are ranked by Henry s Law Constant and the suitability of air stripping in the purification of wastewater in terms of component removal is evaluated. Scaling factors for distillation and air stripping columns are presented to account for the difference in the lunar gravitation environment. Commercially available distillation and air stripping units which are considered suitable for Exploration Life Support are presented. The advantages to the various designs are summarized with respect to water purity levels, power consumption, and processing rates.
NASA lunar surface habitat and remote exploration demonstration project
The Human Exploration Demonstration Project (HEDP) conducted by the NASA Ames Research Center to develop technological integration and demonstration capabilities for lunar and Mars space missions is described. The development of safe, effective, and reliable systems requires that independently engineered subsystems be fully integrated and tested under realistic conditions. The primary objective of the HEDP is demonstration of various aspects of human exploration and habitation on extraterrestrial surfaces. Some of the technologies to be demonstrated are also applicable to unmanned precursor mission functions. It is concluded that the HEDP will provide a unique opportunity to address a broad spectrum of advanced mission operations by bridging between the early requirements for robotic systems with control at earth-based workstations.
Directed Illumination of Sunlight Collimated and Observed Beneath A Lunar Lander (DISCOBaLL): Structured Illumination for a Lunar Surface Photogrammetry System
A lighting system has been developed to provide structured illumination allowing photogrammetry to be performed during and after landing on extraterrestrial bodies. The system, known as Directed Illumination of Sunlight Collimated and Observed Beneath a Lunar Lander (DISCOBaLL), provides patterned lighting suitable for two- and multiple-camera photogrammetry, allowing several different measurements to be obtained including pre-landing terrain shape, visualization and localization of the ejecta sheet during landing, and post-landing terrain shape enabling quantitative measurement of plume-induced cratering. The paper explains the methodology of designing the DISCOBaLL, describes multiple prototypes, and shows the performance of these prototypes using actual solar radiation in a laboratory setting.
Fuel cell technology for lunar surface operations
Hydrogen-oxygen fuel cells have been shown, in several NASA and contractor studies, to be an enabling technology for providing electrical power for lunar bases, outposts, and vehicles. The fuel cell, in conjunction with similar electrolysis cells, comprises a closed regenerative energy storage system, commonly referred to as a regenerative fuel cell (RFC). For stationary applications, energy densities of 1,000 watt-hours per kilograms an order of magnitude over the best rechargeable batteries, have been projected. In this RFC, the coupled fuel cell and electrolyzer act as an ultra-light battery. Electrical energy from solar arrays 'charges' the system by electrolyzing water into hydrogen and oxygen. When an electrical load is applied, the fuel cell reacts the hydrogen and oxygen to 'discharge' usable power. Several concepts for utilizing RFC's, with varying degrees of integration, have been proposed, including both primary and backup roles. For mobile power needs, such as rovers, an effective configuration may be to have only the fuel cell located on the vehicle, and to use a central electrolysis 'gas station'. Two fuel cell technologies are prime candidates for lunar power system concepts: alkaline electrolyte and proton exchange membrane. Alkaline fuel cells have been developed to a mature production power unit in NASA's Space Shuttle Orbiter. Recent advances in materials offer to significantly improve durability to the level needed for extended lunar operations. Proton exchange membrane fuel cells are receiving considerable support for hydrospace and terrestrial transportation applications. This technology promises durability, simplicity, and flexibility.
Measurement on the lunar surface of impact-produced plasma clouds.
Simultaneous enhancements of low-energy ions and negative-particle fluxes due to the impact of the Apollo 14 lunar module were observed by the lunar-based charged-particle lunar-environment experiment (CPLEE). The impact occurred 66 km away from CPLEE, and the time delay between impact and flux onset was approximately 1 min. It is argued that the observed charged particles could not have energized at the instant of impact but rather that the impact produced expanding gas clouds and that constituents of these clouds were ionized and accelerated by some continuously active acceleration mechanism. It is further shown that the acceleration mechanism could not have been a static electric field but rather is possibly a consequence of interaction between the solar wind and the gas cloud.
Transportation of detrital materials on the lunar surface - Evidence from Apollo 15
The thickness frequency distribution of stratigraphic layers intersected by the Apollo 15 deep core suggests that the majority of impact events reworking the lunar soil are small and produce ejecta blankets with an average thickness of less than 1.5 cm. The energy frequency distribution of the meteorites producing the layers may be bimodal. The impacting meteorites produce both normal and reverse graded beds which appear to be the end products of two depositional mechanisms. First, the normally graded beds appear to be produced in base surges as escaping gases fluidize the flowing debris and larger particles move downward in response to Stokes Law. Second, if the gas loss from the base surge is excessive, the fluidization may cease and inertial grain flow dominates. In this situation, the beds are reverse graded as larger particles move under dispersive pressure to the region of minimum shear stress at the upper boundary of the base surge.
Directed Illumination of Sunlight Collimated and Observed Beneath a Lunar Lander (DISCOBaLL): Structured Illumination For a Lunar Surface Photogrammetry System
A lighting system has been developed to provide structured illumination allowing photogrammetry to be performed during and after landing on extraterrestrial bodies. The system, known as Directed Illumination of Sunlight Collimated and Observed Beneath a Lunar Lander (DISCOBaLL), provides patterned lighting suitable for two- and multiple-camera photogrammetry, allowing several different measurements to be obtained including pre-landing terrain shape, visualization and localization of the ejecta sheet during landing, and post-landing terrain shape enabling quantitative measurement of plume-induced cratering. The paper explains the methodology of designing the DISCOBaLL, describes multiple prototypes, and shows the performance of these prototypes using actual solar radiation in a laboratory setting.
Coronagraphic Observations of the Lunar Sodium Exosphere Near the Lunar Surface
The sodium exosphere of the Moon was observed using a solar coronagraph to occult the illuminated surface of the Moon. Exceptionally dust-free atmospheric conditions were required to allow the faint emission from sunlight scattered by lunar sodium atoms to be distinguished from moonlight scattered from atmospheric dust. At 0300 UT on April 22, 1994, ideal conditions prevailed for a few hours, and one excellent image of the sodium exosphere was measured, with the Moon at a phase angle of 51 deg, 81 % illuminated. Analysis of the image data showed that the weighted mean temperature of the exosphere was 1280 K and that the sodium column density varied approximately as cosine-cubed of the latitude. A cosine-cubed variation is an unexpected result, since the flux per unit area of solar photons and solar particles varies as the cosine of latitude. It is suggested that this can be explained by a temperature dependence for the sputtering of sodium atoms from the surface. This is a characteristic feature of chemical sputtering, which has been previously proposed to explain the sodium exosphere of Mercury. A possible interaction between chemical sputtering and solar photons is suggested.
Apollo lunar surface experiments package
Progress in the ALSEP program is reported. Test results are presented for the following areas: Apollo 17 (array E), data subsystem, structural/thermal and crew engineering, and lunar experiments.
PILS – Photovoltaic Investigation on the Lunar Surface
Presentation on the PILS project to the Electrical Power Technology Discipline Team
A Conceptual Study for the Autonomous Direct Forming of Lunar Regolith into Flexlock (Trademark) Geomats for Lunar Surface Operations
We describe the conceptual method of an autonomously operable Direct Forming machine that would consume regolith or regolith slag to mold intimately, interlinked elements in a continuous process. The resulting product, one to three meter wide geomats, would be deployed over commonly traversed areas to isolate the astronauts and equipment from underlying dust. The porous geotextile would provide areas for dust settling, thereby mitigating dust impingement on astronaut suits or surface structures. Because of their self-supporting yet flexible structure, these geomats could be assembled into shields and buttresses to protect lunar habitants from radiation, forming a "flexoskeleton" from in situ materials.
A Versatile Lifting Device for Lunar Surface Payload Handling, Inspection and Regolith Transport Operations
Devices for lifting and transporting payloads and material are critical for efficient Earth-based construction operations. Devices with similar functionality will be needed to support lunar-outpost construction, servicing, inspection, regolith excavation, grading and payload placement. Past studies have proposed that only a few carefully selected devices are required for a lunar outpost. One particular set of operations involves lifting and manipulating payloads in the 100 kg to 3,000 kg range, which are too large or massive to be handled by unassisted astronauts. This paper will review historical devices used for payload handling in space and on earth to derive a set of desirable features for a device that can be used on planetary surfaces. Next, an innovative concept for a lifting device is introduced, which includes many of the desirable features. The versatility of the device is discussed, including its application to lander unloading, servicing, inspection, regolith excavation and site preparation. Approximate rules, which can be used to size the device for specific payload mass and reach requirements, are provided. Finally, details of a test-bed implementation of the innovative concept, which will be used to validate the structural design and develop operational procedures, is provided.
Mapping of lunar surface from side-looking orbital radar images
Side-looking spacecraft radar imagery has thus far been produced only from an orbit around the moon. This was a part of the Apollo Lunar Sounder Experiment (ALSE) of the Apollo 17 mission in December 1972. This paper reports results of a radargrammetric evaluation of overlapping Apollo 17 synthetic-aperture radar images (wavelength 2 m). The potential to map from single images and to reconstruct three-dimensional stereoscopic models is studied. The relative height accuracy achieved is about + or - 100 m and is thus competitive with that obtained with the vidicon camera presently used for planetary exploration.
Thermal control on the lunar surface
For a mission to the Moon which lasts more than a few days, thermal control is a challenging problem because of the Moon's wide temperature swings and long day and night periods. During the lunar day it is difficult to reject heat temperatures low enough to be comfortable for either humans or electronic components, while excessive heat loss can damage unprotected equipment at night. Fluid systems can readily be designed to operate at either the hot or cold temperature extreme but it is more difficult to accomodate both extermes within the same system. Special consideration should be given to sensitive systems, such as optics and humans, and systems that generate large amounts of waste heat, such as lunar bases or manufacturing facilities. Passive thermal control systems such as covers, shades and optical coatings can be used to mitigate the temperature swings experienced by components. For more precise thermal control active systems such as heaters or heat pumps are required although they require more power than passive systems.
Exploration Medical Capability, (ExMC), Human Research Program Medical System Foundation for Level of Care IV Long-Duration Lunar Orbit and Lunar Surface: Context, Process, and Project History
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