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The use of metal hydrides as negative electrodes in a hydrogen-air secondary battery seems promising. However, in an unpressurized cell, more stable hydrides that LaNi5H6 must be selected. Partial substitutions of nickel by aluminium or manganese increase the stability of hydrides. Combined with an air reversible electrode, a specific energy close to 100 Wh/kg can be expected.
Alternative mobile power sources for mining applications were assessed. A wide variety of heat engines and energy systems was examined as potential alternatives to presently used power systems. The present mobile power systems are electrical trailing cable, electrical battery, and diesel - with diesel being largely limited in the United States to noncoal mines. Each candidate power source was evaluated for the following requirements: (1) ability to achieve the duty cycle; (2) ability to meet Government regulations; (3) availability (production readiness); (4) market availability; and (5) packaging capability. Screening reduced the list of candidates to the following power sources: diesel, stirling, gas turbine, rankine (steam), advanced electric (batteries), mechanical energy storage (flywheel), and use of hydrogen evolved from metal hydrides. This list of candidates is divided into two classes of alternative power sources for mining applications, heat engines and energy storage systems.
The cooling capacity of a solid hydrogen cooling system is significantly increased by exposing vapor created during evaporation of a solid hydrogen mass to a catalyst and thereby accelerating the endothermic para-to-ortho transition of the vapor to equilibrium hydrogen. Catalyst such as nickel, copper, iron or metal hydride gels of films in a low pressure drop catalytic reactor are suitable for accelerating the endothermic para-to-ortho conversion.
A modified coupled pair functional (CPF) method is presented for the configuration interaction problem that dramatically improves properties for cases where the Hartree-Fock reference configuration is not a good zeroth-order wave function description. It is shown that the tendency for CPF to overestimate the effect of higher excitations arises from the choice of the geometric mean for the partial normalization denominator. The modified method is demonstrated for ground state dipole moment calculations of the NiH, CuH, and ZnH transition metal hydrides, and compared to singles-plus-doubles configuration interaction and the Ahlrichs et al. (1984) CPF method.
Research in the use of FIR and sub-mm lines to provide data relevant to astrochemistry is examined. Spectroscopic features in the FIR and sub-mm are dominated by transitions from species of atoms and atomic ions, metal hydrides, and heavy molecules. The data of Lester et al.(1983) and Dinerstein et al. (1984) on the N/O abundance ratio are discussed. The N/O abundance ratio is analyzed as a function of the galactic radius, and the procedure for determining the N/O abundance ratio from the FIR and sub-mm lines is given. The conditions at the surface of molecular clouds and the chemical profile of molecular clouds are studied in the forbidden lines O I 63.18 and 145.53 microns and the forbidden line C II 157.74 microns. Results of recent FIR/sub-mm observations of post-shocked gas which relate to modeling the chemical processing that occurs in the wake of shock waves are considered.
During this reporting period, the focus of activity in the Materials Science with Muon Spin Rotation (MSMSR) program was muon spin rotation studies of superconducting materials, in particular the high critical temperature and heavy-fermion materials. Apart from these studies, work was continued on the analysis of muon motion in metal hydrides. Results of these experiments are described in six papers included as appendices.
The development of a fuel cell energy storage system for the Space Station Extravehicular Mobility Unit (EMU) is discussed. The ion-exchange membrane fuel cell uses hydrogen stored as a metal hydride. Several features of the hydrogen-oxygen fuel cell are examined, including its construction, hydrogen storage, hydride recharge, water heat, water removal, and operational parameters.
The proceedings from the workshop are presented. The subjects covered include nickel-cadmium, nickel-hydrogen, silver-zinc, and lithium based technologies, as well as advanced technologies including nickel-metal hydride and sodium-sulfur.
The present workshop on cryogenics discusses the anomalous on-orbit behavior of the Cosmic Background Explorer Dewar, the SHOOT orbital operations, cooling options for Astromag, and space IR telescope facility mission and cryogenic design. Attention is given to the design of a spaceworthy adiabatic demagnetization refrigerator, the evaluation of metal hydride compressors for applications in Joule-Thomson cryocoolers, diaphragm Stirling cryocooler developments, and a computer simulation model for Stirling refrigerators. Topics addressed include low-gravity thermal stratification of liquid helium on SHOOT, a screening program to select a resin for gravity probe-B composites, a simplified generic cryostat thermal model for predicting cryogen mass and lifetime, and the effect of gas mass flux on cryogenic liquid jet breakup. Also discussed are damping criteria for thermal acoustic oscillations in slush and liquid hydrogen systems, an STS-based cryogenic fluid management experiment, and the design and testing of a cryogenic mixer pump.
NASA is considering the establishment of a manned lunar base within the next few decades. To house and protect the crew from the harsh lunar environment, a habitat is required. A proposed habitat is an spherical, inflatable module. Heat generated in the module must be rejected to maintain a temperature suitable for human habitation. This report presents a conceptual design of a thermal control system for an inflatable lunar module. The design solution includes heat acquisition, heat transport, and heat rejection subsystems. The report discusses alternative designs and design solutions for each of the three subsystems mentioned above. Alternative subsystems for heat acquisition include a single water-loop, a single air-loop, and a double water-loop. The vapor compression cycle, vapor absorption cycle, and metal hydride absorption cycle are the three alternative transport subsystems. Alternative rejection subsystems include flat plate radiators, the liquid droplet radiator, and reflux boiler radiators. Feasibility studies on alternatives of each subsystem showed that the single water-loop, the vapor compression cycle, and the reflux boiler radiator were the most feasible alternatives. The design team combined the three subsystems to come up with an overall system design. Methods of controlling the system to adapt it for varying conditions within the module and in the environment are presented. Finally, the report gives conclusions and recommendations for further study of thermal control systems for lunar applications.
This document contains the proceedings of the 23rd annual NASA Aerospace Battery Workshop, hosted by the Marshall Space Flight Center on November 15-19, 1992. The workshop was attended by scientists and engineers from various agencies of the U.S. Government, aerospace contractors, and battery manufacturers, as well as international participation in like kind from a number of countries around the world. The subjects covered included nickel-cadmium, nickel-hydrogen, nickel-metal hydride, and lithium based technologies, as well as advanced technologies including sodium-sulfur and various bipolar designs.
The topics covered are presented in viewgraph form and include the following: the Advanced Communications Technology Satellite; the Space Station Freedom (SSF) photovoltaic power module division; Ni/H2 battery and cell design; individual pressure vessel (IPV) nickel-hydrogen cell testing SSF support; the LeRC Electrochemical Technology Branch; improved design IPV nickel-hydrogen cells; advanced technology for IPV nickel-hydrogen flight cells; a lightweight nickel-hydrogen cell; bipolar nickel-hydrogen battery development and technology; aerospace nickel-metal hydride cells; the NASA Sodium-Sulfur Cell Technology Flight Experiment; and the lithium-carbon dioxide battery thermodynamic model.
This document contains the proceedings of the 26th annual NASA Aerospace Battery Workshop, hosted by the Marshall Space Flight Center on 16-18 Nov. 1993. The workshop was attended by scientists and engineers from various agencies of the U.S. Government, aerospace contractors, and battery manufacturers, as well as international participation in like kind from a number of countries around the world. The subjects covered included nickel-cadmium, nickel-hydrogen, nickel-metal hydride, and lithium based technologies, as well as advanced technologies including various bipolar designs.
Eagle-Picher currently has several advanced nickel-hydrogen (NiH2) cell component and battery designs under development including common pressure vessel (CPV), single pressure vessel (SPV), and dependent pressure vessel (DPV) designs. A CPV NiH2 battery, utilizing low-cost 64 mm (2.5 in.) cell diameter technology, has been designed and built for multiple smallsat programs, including the TUBSAT B spacecraft which is currently scheduled (24 Nov. 93) for launch aboard a Russian Proton rocket. An advanced 90 mm (3.5 in.) NiH2 cell design is currently being manufactured for the Space Station Freedom program. Prototype 254 mm (10 in.) diameter SPV batteries are currently under construction and initial boilerplate testing has shown excellent results. NiH2 cycle life testing is being continued at Eagle-Picher and IPV cells have currently completed more than 89,000 accelerated LEO cycles at 15% DOD, 49,000 real-time LEO cycles at 30 percent DOD, 37,800 cycles under a real-time LEO profile, 30 eclipse seasons in accelerated GEO, and 6 eclipse seasons in real-time GEO testing at 75 percent DOD maximum. Nickel-metal hydride battery development is continuing for both aerospace and electric vehicle applications. Eagle-Picher has also developed an extensive range of battery evaluation, test, and analysis (BETA) measurement and control equipment and software, based on Hewlett-Packard computerized data acquisition/control hardware.
Gates Aerospace Batteries is conducting two long term test programs to fully characterize the NiMH cell technology for aerospace applications. The first program analyzes the effects of long term storage upon cell performance. The second program analyzes cycle life testing and preliminary production lot testing. This paper summarizes these approaches to testing the NiMH couple and culminates with initial storage and testing recommendations. Long term storage presents challenges to deter the adverse condition of capacity fade in NiMH cells. Elevated but stabilized pressures and elevated but stabilized end-of-charge voltages also appear to be a characteristic phenomenon of long term storage modes. However, the performance degradation is dependent upon specific characteristics of the metal-hydride alloy. To date, there is no objective evidence with which to recommend the proper method for storage and handling of NiMH cells upon shipment. This is particularly critical due to limited data points that indicate open circuit storage at room temperature for 60 to 90 days will result in irrecoverable capacity loss. Accordingly a test plan was developed to determine what method of mid-term to long-term storage will prevent irrecoverable capacity loss. The explicit assumption is that trickle charging at some rate above the self-discharge rate will prevent the irreversible chemical changes to the negative electrode that result in the irrecoverable capacity loss. Another premise is that lower storage temperatures, typically 0 C for aerospace customers, will impede any negative chemical reactions. Three different trickle charge rates are expected to yield a fairly flat response with respect to recoverable capacity versus baseline cells in two different modes of open circuit. Specific attributes monitored include: end-of-charge voltage, end-of-charge pressure, mid-point discharge voltage, capacity, and end-of-discharge pressure. Cycle life testing and preliminary production lot testing continue to dominate the overall technology development effort at GAB. The cell life test program reflects continuing improvements in baseline cell designs. Performance improvements include lower and more stable charge voltages and pressures. The continuing review of production lot testing assures conformance to the design criteria and expectations. This is especially critical during this period of transferring technology from research and development status to production.
The proceedings of the 27th Annual NASA Aerospace Battery Workshop, hosted by the Marshall Space Flight Center on November 15-17, 1994 are presented. The workshop was attended by representatives from various government agencies, as well as contractors and manufacturers, both U.S. and abroad. The subjects covered included: (1) nickel-cadium; (2) nickel-hydrogen, (3) nickel-metal hydride, and (4) lithium based technologies, as well as flight and ground test data.
Long duration human exploration missions to the Moon will require active thermal control systems which have not previously been used in space. The two technologies which are most promising for long term lunar base thermal control are heat pumps and radiator shades. Recent trade-off studies at the Johnson Space Center have focused development efforts on the most promising heat pump and radiator shade technologies. Since these technologies are in the early stages of development and many parameters used in the study are not well defined, a parametric study was done to test the sensitivity to each assumption. The primary comparison factor in these studies was the total mass system, with power requirements included in the form of a mass penalty for power. Heat pump technologies considered were thermally driven heat pumps such as metal hydride, complex compound, absorption and zeolite. Also considered were electrically driven Stirling and vapor compression heat pumps. Radiator shade concepts considered included step shaped, V-shaped and parabolic (or catenary) shades and ground covers. A further trade study compared the masses of heat pump and radiator shade systems.
SEDSAT-1 is designed to be a low cost scientific satellite which is to be used to perform a minimum of five tasks which include: (1) the acquisition of a number of important parameters associated with the tethering processes from the payloads perspective (such as accelerations incurred and imaging data of the tether during deployment), (2) to act as a remote sensing platform for making measurements of the Earth's Atmosphere (allowing research to be performed in such areas as vertical lightning observation, visible light spectrography, and cloud cover studies, (3) to act as a general purpose amateur radio communication satellite relaying information back to earth, (4) to demonstrate the feasibility of the deployment in low earth orbit of advanced technology such as the Gallium Arsenide Solar Cells, Nickel Metal Hydride batteries, and multi-chip module technology and, (5) to support student's active participation in applying the disciplines of engineering and science to space-based hardware platforms. The project includes the Three-axis Accelerometer System, TAS, Experiment which is designed to report the accelerations that the satellite undergoes during the tethering operations and during the second phase of the mission when the free floating satellite comes in contact with orbit debris. The SEASIS (SEDS Earth, Atmosphere, and Space Imaging System) is another SEDSAT experiment designed to provide images of the tether during its deployment and the earth during the second phase of the mission. To control these experiments and virtually all other satellite operations the Command Data System, CDS is employed. This system utilizes a moderate complexity micro-controller controlled by tasks operating under a real-time operating system to dynamically monitor and control the satellite. The scope of this researchers efforts has been in the general area of coordinating and assisting the student researchers with the development of the CDS and ground station interfaces. This included the low level CDS hardware design and the formulization of a general software plan and schedule for both the CDS and ground station portions of the project.