Michael B. Duke

A Prototype Bucket Wheel Excavator for the Moon, Mars and Phobos

Excavation of surface regolith material is the first step in processes to extract volatile materials from planetary surface regolith for the production of propellant and life support consumables. Typically, concentrations of volatiles are low, so relatively large amounts of material must be excavated. A bucket wheel excavator is proposed, which has the capability of continuous excavation, which is readily adapted to granular regolith materials as found on the Moon, in drift deposits on Mars, and probably on the surface of asteroids and satellites, such as Phobos. The bucket wheel excavator is relatively simple, compared to machines such as front end loaders. It also has the advantage that excavation forces are principally horizontal rather than vertical, which minimizes the need for excavator mass and suits it to operations in reduced gravity fields. A prototype small bucket wheel excavator has been built at approximately the scale of the rovers that are carried to Mars on the Mars Exploration Rover Missi...

Lunar resource utilization: Implications for commerce and exploration

Abstract Propellant derived from ice located in permanently shadowed craters near the Moons poles has been proposed as a commercial venture for the Moon. A detailed analysis of the possibilities associated with lunar propellants has been carried out with an integrated technical-financial tool. The analysis shows that, with current understanding of the available technology for propellant production, transportation systems, and the market for launch of vehicles between LEO-GEO, it is difficult to demonstrate that a viable commercial opportunity exists to serve that market with lunar propellant. Improvements in technology, the location of higher concentrations of ice on the Moon, the availability of a space infrastructure, and a larger market each could significantly improve the prospects for commercial viability. A government-sponsored human exploration program, using the Earth-Moon L-1 point as a hub, could address many of these issues while avoiding program costs and could open commercial opportunities in space transportation.

Manufacture of solar cells on the moon

In support of the space exploration initiative a new architecture for the production of solar cells on the lunar surface is devised. The paper discusses experimental data on the fabrication and properties of lunar glass substrates, evaporated lunar regolith thin films (antireflect coatings and insulators), and preliminary attempts in the fabrication of thin film (silicon/II-Vl) photovoltaic materials on lunar regolith substrates. A conceptual design for a solar powered robotic rover capable of fabricating solar cells directly on the lunar surface is provided. Technical challenges in the development of such a facility and strategies to alleviate perceived difficulties are discussed. Finally, preliminary cost benefit ratio analysis for different in situ solar cell production scenarios (using exclusively in-situ planetary resources or hybrid) are discussed.

Sample return from the lunar South Pole-Aitken Basin

Abstract Automated sample return missions to the South Pole — Aitken Basin on the lunar far side are proposed as the best means of addressing major problems concerning the early impact history of the inner solar system, the nature of very large impact events, and the early differentiation of rocky planets. The opportunity to propose such missions has been opened by the recommendations of the U. S. National Research Councils Decadal Study of Solar System Exploration and the creation by NASA of the New Frontiers Program, which will support missions of intermediate cost, between the Discovery Program and large missions. A proposal for a South Pole — Aitken Basin Sample Return Mission was submitted to the Discovery Program in 2000, but not fimded. The New Frontiers Program, with a somewhat less stringent budget constraint, should allow several of the potential risks associated with the Discovery proposal to be addressed, including scientific and programmatic risks. A principal goal of current mission studies is to determine whether, within the New Frontiers Programs cost constraints, two separate samples could be collected from areas of different post-Basin geological history. If accepted by the New Frontiers Program, a South Pole — Aitken Basin sample return mission could be flown as early as 2008–2009.

Architecture Studies for Commercial Production of Propellants From the Lunar Poles

Two architectures are developed that could be used to convert water held in regolith deposits within permanently shadowed lunar craters into propellant for use in near‐Earth space. In particular, the model has been applied to an analysis of the commercial feasibility of using lunar derived propellant to convey payloads from low Earth orbit to geosynchronous Earth orbit. Production and transportation system masses were estimated for each architecture and cost analysis was made using the NAFCOM cost model. Data from the cost model were analyzed using a financial analysis tool reported in a companion paper (Lamassoure et al., 2002) to determine under what conditions the architectures might be commercially viable. Analysis of the architectural assumptions is used to identify the principal areas for further research, which include technological development of lunar mining and water extraction systems, power systems, reusable space transportation systems, and orbital propellant depots. The architectures and com...

Silicon PV cell production on the Moon as the basis for a new architecture for space exploration

A method is described by which silicon photovoltaic (PV) devices can be directly deposited onto the lunar regolith using primarily lunar materials. In sequence, a robotic “crawler” moving at slow speed sequentially melts the top layer of regolith and deposits a conducting layer, a doped silicon, a top conducting grid, and an antireflective coating by vacuum evaporation techniques. Concentrated solar energy is utilized as the energy source. Development of this capability would significantly lower the cost of electrical energy on the Moon and would enable a range of other activities, including lower cost propellant production, human outposts with complete food-growth capabilities, and advanced materials production. Low cost energy could affect the economics of propellants in space by allowing the extraction of solar wind hydrogen from the lunar regolith. This would allow the economical export of propellants and other materials to space, first to an Earth-Moon Lagrangian Point and potentially to low Earth orbit.

An Interplanetary Rapid Transit System Between Earth and Mars

A revolutionary interplanetary rapid transit concept for transporting scientists and explorers between Earth and Mars is presented by Global Aerospace Corporation under funding from the NASA Institute for Advanced Concepts (NIAC) with support from the Colorado School of Mines (CSM), Science Applications International Corporation (SAIC), and others. We describe an innovative architecture that uses highly autonomous, solar‐powered, xenon ion‐propelled spaceships, dubbed Astrotels; small Taxis for trips between Astrotels and planetary Spaceports; Shuttles that transport crews to and from orbital space stations and planetary surfaces; and low‐thrust cargo freighters that deliver hardware, fuels and consumables to Astrotels and Spaceports. Astrotels can orbit the Sun in cyclic orbits between Earth and Mars and Taxis fly hyperbolic planetary trajectories between Astrotel and Spaceport rendezvous. Together these vehicles transport replacement crews of 10 people on frequent, short trips between Earth and Mars. Tw...

Is Extraction of Methane, Hydrogen and Oxygen from the Lunar Regolith Economically Feasible?

The extraction of oxygen from the lunar regolith is relatively straightforward and has been studied extensively. Extraction of hydrogen is also straightforward, but because the concentration of hydrogen is so low (∼50 ppm), the economics is problematical. However, a process for extracting hydrogen may also extract carbon, which is typically present at the 100 ppm level. A small amount of available oxygen can be extracted in the same process, through the hydrogen or carbon reduction of iron oxide in the regolith. Thus, a combined process is possible in which methane and oxygen are the end products. Methane has advantages over hydrogen in terms of storage and liquefaction energy requirements. We show that the combined hydrogen and carbon content of a given quantity of lunar regolith, if converted to methane and used in a methane/oxygen engine, can lift more payload off of the Moon than a hydrogen/oxygen engine utilizing hydrogen and oxygen extracted from the same amount of regolith. We examine the conditions under which it might become economically feasible to utilize these minor constituents of the lunar regolith. It is concluded that improved excavator, extractor, and power technologies could make the extraction economically feasible. This would open practically any place on the Moon as a source of rocket propellant.The extraction of oxygen from the lunar regolith is relatively straightforward and has been studied extensively. Extraction of hydrogen is also straightforward, but because the concentration of hydrogen is so low (∼50 ppm), the economics is problematical. However, a process for extracting hydrogen may also extract carbon, which is typically present at the 100 ppm level. A small amount of available oxygen can be extracted in the same process, through the hydrogen or carbon reduction of iron oxide in the regolith. Thus, a combined process is possible in which methane and oxygen are the end products. Methane has advantages over hydrogen in terms of storage and liquefaction energy requirements. We show that the combined hydrogen and carbon content of a given quantity of lunar regolith, if converted to methane and used in a methane/oxygen engine, can lift more payload off of the Moon than a hydrogen/oxygen engine utilizing hydrogen and oxygen extracted from the same amount of regolith. We examine the condition...

Lunar and Mars Missions, Challenges for Advanced Life Support

The development of a suite of scenarios is a prerequisite to the studies that will enable an informed decision by the United States on a program to meet the recently announced space policy goal to expand human presence beyond earth orbit. NASAs Office of Exploration is currently studying a range of initiative options that would extend the sphere of human activity in space to Mars and include permanent bases or outposts on the moon and on Mars. This paper describes the evolutionary lunar base and the Mars expedition scenarios in some detail so that an evaluation can be made from the point of view of human support and opportunities. Alternative approaches in the development of lunar outposts are outlined along with Mars expeditionary scenarios. Human environmental issues are discussed, including: closed loop life support systems; EVA systems; mobility systems; and medical support, physiological deconditioning, and psychological effects associated with long-duration missions.

PISCES: Developing New Design, Materials, and Technologies for Sustained Human Presence on the Moon and Mars

PISCES, the Pacific International Space Center for Exploration Systems, is being developed on the Big Island of Hawaii as an integrated research facility and simulated lunar settlement for the purpose of developing new technologies needed for a sustained human presence on the Moon and Mars. PISCES was created by the University of Hawaii under the auspices of the Japan-US Science, Technology and Space Applications Program (JUSTSAP), and has recently been funded by the State of Hawaii through the Department of Business, Economic Development and Tourism (DBEDT). This new center will be built on partnerships between industry, academia and the governments of spacefaring nations, adopting a model that has seen wide success in such programs as the NASA Research Partnership Centers (RPCs), the NASA Robotic Engineering Consortium at Carnegie Mellon University, and numerous programs within NIST, the Department of Commerce and the National Science Foundation. In addition to its research and development mission, PISCES will function as an education, research and technology development center; a training center for astronauts, scientists, K-12 and university students; and a public outreach resource for local residents and tourists to experience the multitude of scientific, educational and economic benefits that space exploration could bring to Hawaii. New technologies developed in PISCES and at universities and industries around the world will require testing in an environment simulating as closely as possible that found on the Moon. Several nations plan robotic exploration missions to the Moon in the next few years, and PISCES will be an important proving ground for hardware developed through collaborative projects in science and technology. To validate space operations, new system architectures, designs, materials and mechanisms had to be developed, such as a robotic vehicle called ATHLETE (the All-Terrain Hex-Limbed, Extra-Terrestrial Explorer), and materials had to be utilized from space. This ATHLETE vehicle concept is capable of efficient rolling mobility on moderate terrain and walking mobility on extreme terrain. Each limb has a quick-disconnect tool adapter and associated tools so that it can perform general-purpose handling, drilling, scooping, assembly, maintenance and servicing tasks using any or all of the limbs. Each of ATHLETEs 6-degree freedom limbs is equipped with non-pneumatic, lunarappropriate, compliant wheels to enable rolling mobility in soft soil. Also, new ISRU materials and designs had to be developed to accommodate the space environment to sustain human settlements, deal with moon dust, and ensure very long-duration operations. Astronauts embarking on exploration missions and long stays on the Moon will need training in the use of these new technologies to free themselves from the drudgery of routine chores and to increase their time for scientific and technological achievements. This paper describes the PISCES development plans, particularly in the areas of In-Situ Resource Utilization, Robotics and Education and Outreach.