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Title: Fuel cell systems for first lunar outpost -- Reactant storage options

Abstract

A Lunar Surface Power Working Group was formed to review candidate systems for providing power to the First Lunar Outpost habitat. The working group met for five days in the fall of 1992 and concluded that the most attractive candidate included a photovoltaic unit, a fuel cell, a regenerator to recycle the reactants, and storage of oxygen and hydrogen gases. Most of the volume (97%) and weight (64%) are taken up by the reactants and their storage tanks. The large volume is difficult to accommodate, and therefore, the working group explored ways of reducing the volume. An alternative approach to providing separate high pressure storage tanks is to use two of the descent stage propellant storage tanks, which would have to be wrapped with graphite fibers to increase their pressure capability. This saves 90% of the volume required for storage of fuel cell reactants. Another approach is to use the descent storage propellant tanks for storage of the fuel cell reactants as cryogenic liquids, but this requires a gas liquefaction system, increases the solar array by 40%, and increases the heat rejection rate by 170% compared with storage of reactants as high pressure gases. For a high power system (>20more » kW) the larger energy storage requirement would probably favor the cryogenic storage option.« less

Authors:
 [1]
  1. Argonne National Lab., IL (United States). Chemical Technology Div.
Publication Date:
Research Org.:
Argonne National Lab., IL (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
81025
Report Number(s):
ANL/CMT/CP-85790; CONF-9505226-1
ON: DE95013408; TRN: AHC29520%%92
DOE Contract Number:
W-31109-ENG-38
Resource Type:
Conference
Resource Relation:
Conference: 4. space electrochemical research and technology conference, Cleveland, OH (United States), 2-3 May 1995; Other Information: PBD: [1995]
Country of Publication:
United States
Language:
English
Subject:
30 DIRECT ENERGY CONVERSION; MOON; FUEL CELL POWER PLANTS; HYDROGEN FUELS; STORAGE FACILITIES; OXYGEN; POWER SYSTEMS; HYDROGEN FUEL CELLS; HYDROGEN STORAGE; CRYOGENIC FLUIDS

Citation Formats

Nelson, P.A. Fuel cell systems for first lunar outpost -- Reactant storage options. United States: N. p., 1995. Web.
Nelson, P.A. Fuel cell systems for first lunar outpost -- Reactant storage options. United States.
Nelson, P.A. 1995. "Fuel cell systems for first lunar outpost -- Reactant storage options". United States. doi:. https://www.osti.gov/servlets/purl/81025.
@article{osti_81025,
title = {Fuel cell systems for first lunar outpost -- Reactant storage options},
author = {Nelson, P.A.},
abstractNote = {A Lunar Surface Power Working Group was formed to review candidate systems for providing power to the First Lunar Outpost habitat. The working group met for five days in the fall of 1992 and concluded that the most attractive candidate included a photovoltaic unit, a fuel cell, a regenerator to recycle the reactants, and storage of oxygen and hydrogen gases. Most of the volume (97%) and weight (64%) are taken up by the reactants and their storage tanks. The large volume is difficult to accommodate, and therefore, the working group explored ways of reducing the volume. An alternative approach to providing separate high pressure storage tanks is to use two of the descent stage propellant storage tanks, which would have to be wrapped with graphite fibers to increase their pressure capability. This saves 90% of the volume required for storage of fuel cell reactants. Another approach is to use the descent storage propellant tanks for storage of the fuel cell reactants as cryogenic liquids, but this requires a gas liquefaction system, increases the solar array by 40%, and increases the heat rejection rate by 170% compared with storage of reactants as high pressure gases. For a high power system (>20 kW) the larger energy storage requirement would probably favor the cryogenic storage option.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1995,
month = 6
}

Conference:
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  • A number of different Power system architecture options that include all nuclear, all non-nuclear, and a combination of the two, were defined to satisfy power requirements for the first lunar outpost (FLO). The Life Cycle Costs (LCCs), including development, production, and transportation costs, of these architectures were determined and the sensitivity of the LCC to parameters such as transportation cost and the radioisotope fuel costs was evaluated. The results indicate that the LCC can be very sensitive to the variation in transportation cost and radioiosotope fuel cost. The relative attractiveness of different candidate power system architectures should also be basedmore » on several other evaluation criteria such as safety, performance, risk, commonality, and growth potential. A simple methodology to determine relative ranking of the candidate power system architectures based on these evaluation criteria is suggested.« less
  • Integrated systems and missions studies are presented for an evolutionary lunar-to-Mars space transportion system (STS) based on nuclear thermal rocket (NTR) technology. A standardized'' set of engine and stage components are identified and used in a building block'' fashion to configure a variety of piloted and cargo, lunar and Mars vehicles. The reference NTR characteristics include a thrust of 50 thousand pounds force (klbf), specific impulse (I[sub sp]) of 900 seconds, and an engine thrust-to-weight ratio of 4.3. For the National Aeronautics and Space Administration's (NASA) First Lunar Outpost (FLO) mission, an expendable NTR stage powered by two such enginesmore » can deliver [similar to]96 metric tonnes (t) to trans-lunar injection (TLI) conditions for an initial mass in low Earth orbit (IMLEO) of [similar to]198 t compared to 250 t for a cryogenic chemical system. The stage liquid hydrogen (LH[sub 2]) tank has a diameter, length, and capacity of 10 m, 14.5 m and 66 t, respectively. By extending the stage length and LH[sub 2] capacity to [similar to]20 m and 96 t, a single launch Mars cargo vehicle could deliver to an elliptical Mars parking orbit a 63 t Mars excursion vehicle (MEV) with a 45 t surface payload. Three 50 klbf engines and the two standardized LH[sub 2] tanks developed for the lunar and Mars cargo vehicles are used to configure the vehicles supporting piloted Mars missions as early as 2010. The modular'' NTR vehicle approach forms the basis for an efficient STS able to handle the needs of a wide spectrum of lunar and Mars missions.« less
  • A recent study effort at NASA has developed a preliminary reference mission description for a human return to the Moon by the end of this decade. The First Lunar Outpost (FLO) would provide the framework for establishing a permanent human presence on the Moon and a necessary step toward eventual piloted trips to Mars. The primary objectives of FLO are to sustain a crew of four on the lunar surface for 45 days during which local roving, surface science, and demonstration-level resource extraction would be accomplished. Power systems capable of meeting the diverse requirements of FLO are a significant engineeringmore » challenge. Power requirements range from 10's of watts for small science packages to 10's of kilowatts for the crew habitat. The guidelines imposed on power systems include that they be lightweight, easily deployable, and cost efficient. Nuclear systems such as radioisotope thermoelectric generators (RTGs), dynamic isotope power systems (DIPS), and small reactor power systems offer distinct advantages over solar and electrochemical alternatives. Concepts for modular RTGs and DIPS, and deployable reactor systems relevant to the FLO mission and its evolution are described and compared.« less
  • A study was conducted to examine the characteristics of lunar outpost power systems for the consolidation and utilization phases using closed Brayton cycle (CBC) power conversion and an SP100 nuclear reactor heat source. Three CBC system architectures using the baseline 2400 kWt SP100 reactor were examined: (1) the minimum specific mass CBC power conversion system mated to a single reactor, (2) the minimum mass, 825 kWe CBC power conversion system mated to a single reactor, and (3) an 825 kWe CBC power conversion system, using two SP100 reactors. A reliability assessment was also conducted to verify a minimum reliability ofmore » 0.977 for the power conversion unit for a 15-year mission. The minimum specific mass was found to be 22.0 kg/kW at a total output power level of 550 kWe. This corresponds to a conversion efficiency of 23 percent. The 825 kWe, single reactor case had a specific mass of 27.2 kg/kW. The total mass of the 825 kWe, two reactor system was estimated to be approximately 4000 kg less than the mass of the 825 kWe, single reactor system.« less
  • There are major advantages to be gained by integrating a cryogenic reactant storage system with a hydrogen-oxygen regenerative fuel cell (RFC) to provide on-site electrical power during the lunar night. Although applicable to any power system using hydrogen-oxygen RFC's for energy storage, cryogenic reactant storage offers a significant benefit whenever the sun/shade cycle and energy storage period approach hundreds of hours. For solar power installations on the moon, cryogenic reactant storage reduces overall specific mass and meteoroid vulnerability of the system. In addition, it offers synergistic benefits to on-site users, such as availability of primary fuel cell reactants for surfacemore » rover vehicles and cryogenic propellants for OTV's. The integration involves processing and storing the RFC reactant streams as cryogenic liquids rather than pressurized gases, so that reactant containment (tankage per unit mass of reactants) can be greatly reduced. Hydrogen-oxygen alkaline RFC's, GaAs photovoltaic (PV) arrays, and space cryogenic processing/refrigeration technologies are assumed to be available for the conceptual system design. Advantages are demonstrated by comparing the characteristics of two power system concepts: a conventional lunar surface PV/RFC power system using pressurized gas storage in SOA filament wound pressure vessels and, that same system with gas liquefaction and storage replacing the pressurized storage. Comparisons are made at 20 and 250 kWe. Although cryogenic storage adds a processing plant (drying and liquefaction) to the system plus 30 percent more solar array to provide processing power, the approximate order of magnitude reduction in tankage mass, confirmed by this analysis, results in a reduction in overall total system mass of approximately 50 percent.« less