Status of the 2- to 15-kWe Brayton power system and potential gains from component improvements
Brayton cycle 2-15 kW power system for space application and potential gains from component improvements, discussing current status
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Brayton cycle 2-15 kW power system for space application and potential gains from component improvements, discussing current status
A preliminary cost estimate for a small reactor in Brayton space power systems with (u-233)n or (pu-239)n as the fuel in the T-111 fuel elements totaled to about four million dollars; considered is a 22.8 in. diameter reactor with 247 fuel elements.
The design, development, and operation of the Skylab electrical power system are discussed. The electrical systems for the airlock module of the orbital workshop and the Apollo telescope mount are described. Skylab is considered an integral laboratory, however, both cluster and module hardware distinct sections are included. Significant concept and requirement evolution, testing, and modifications resulting from tests are briefly summarized to aid in understanding the launch configuration description and the procedures and performance discussed for in-orbit operation. Specific problems encountered during Skylab orbital missions are analyzed.
The political and legal aspects of a satellite power system focusing on the international jurisprudence are presented.
A picture of Space Power Systems space transportation costs at the present time is given with respect to accuracy as stated, reasonableness of the methods used, assumptions made, and uncertainty associated with the estimates. The approach used consists of examining space transportation costs from several perspectives to perform a variety of sensitivity analyses or reviews and examine the findings in terms of internal consistency and external comparison with analogous systems. These approaches are summarized as a theoretical and historical review including a review of stated and unstated assumptions used to derive the costs, and a performance or technical review. These reviews cover the overall transportation program as well as the individual vehicles proposed. The review of overall cost assumptions is the principal means used for estimating the cost uncertainty derived. The cost estimates used as the best current estimate are included.
A baseline design concept for a 100 kWe nuclear reactor space power system is described. The concept was developed under contract from JPL as part of a joint program of the DOE, DOD, and NASA. The major technical and safety constraints influencing the selection of reactor operating parameters are discussed. A lithium-cooled compact fast reactor was selected as the best candidate system. The material selected for the thermoelectric conversion system was silicon germanium (SiGe) with gallium phosphide doping. Attention is given to the improved safety of the seven in-core control rod configuration.
Space Station Freedom's (SSF's) electric power system (EPS) hardware and software verification is performed at all levels of integration, from components to assembly and system level tests. Careful planning is essential to ensure the EPS is tested properly on the ground prior to launch. The results of the test performed on breadboard model hardware and analyses completed to date have been evaluated and used to plan for design qualification and flight acceptance test phases. These results and plans indicate the verification program for SSF's 75-kW EPS would have been successful and completed in time to support the scheduled first element launch.
Thermophotovoltaic (RTV) energy conversion, coupled to the radioisotope powered General Purpose Heat Source (GPHS) is currently being developed by NASA. The goal of the program is to develop a 100 watt electrical power system with an efficient of 20%. Special control is the key element in obtaining an efficient system. Results presented show that excellent spectral control can be achieved so that reaching the goal of 20% efficiency is possible. Excellent spectral control is achieved by using a combination of selective emitters and optical filters and by eliminating radiation leakage from the optical cavity.
The function of the proposed manned Space Construction Base (SCB) is to provide a permanent manned orbital facility for the construction and operation of a variety of space experiments, ranging from a space-processing development to on-orbit-constructed microwave radiometers and antennas. A typical SCB system might reach initial operational capability in low earth orbit in 1985, have a 10-year mission duration, and have an initial power requirement of 50 kWe. A summary of the requirements imposed by the SCB on the electrical power system (EPS) is presented in a table. Attention is given to EPS options, baseline power platform system operations, an energy storage system evaluation, advanced-technology NiCd batteries and lifetime, and orbital buildup operations.
A preliminary assessment of a potential Satellite Power System (SPS) is provided. The assessment includes discussion of technical and economic feasibility; the effects of microwave power transmission beams on biological, ecological, and electromagnetic systems; the impact of SPS construction, deployment, and operations on the biosphere and on society; and the merits of SPS compared to other future energy alternatives.
Space power system material compatibility tests of selected refractory metal alloys with boiling potassium
The problems in applying standard electric utility models, analyses, and algorithms to the study of the stability of spacecraft power conditioning and distribution systems are discussed. Both single-phase and three-phase systems are considered. Of particular concern are the load and generator models that are used in terrestrial power system studies, as well as the standard assumptions of load and topological balance that lead to the use of the positive sequence network. The standard assumptions regarding relative speeds of subsystem dynamic responses that are made in the classical transient stability algorithm, which forms the backbone of utility-based studies, are examined. The applicability of these assumptions to a spacecraft power system stability study is discussed in detail. In addition to the classical indirect method, the applicability of Liapunov's direct methods to the stability determination of spacecraft power systems is discussed. It is pointed out that while the proposed method uses a solution process similar to the classical algorithm, the models used for the sources, loads, and networks are, in general, more accurate. Some preliminary results are given for a linear-graph, state-variable-based modeling approach to the study of the stability of space-based power distribution networks.
Turbine-coolant flow effects on thermodynamic performance of Brayton cycle space power system
High voltage solid state remote power controllers (RPC's) and the required semiconductor power switches to provide baseline technology for large, high power distribution systems in the space station, all electric airplane and other advanced aerospace applications were developed. The RPC's were developed for dc voltages from 28 to 1200 V and ac voltages of 115, 230, and 440 V at frequencies of 400 Hz to 20 kHz. The benefits and operation of solid state RPC's and highlights of several developments to bring the RPC to technology readiness for future aerospace needs are examined. The 28 V dc Space Shuttle units, three RPC types at 120 V dc, two at 270/300 V dc, two at 230 V ac and several high power RPC models at voltages up to 1200 V dc with current ratings up to 100 A are reviewed. New technology programs to develop a new family of (DI)2 semiconductor switches and 20 kHz, 440 V ac RPC's are described.
High voltage solid state remote power controllers (RPC's) and the required semiconductor power switches to provide baseline technology for large, high power distribution systems in the Space Station, all electric airplane and other advanced aerospace applications were developed. The RPC's were developed for dc voltages from 28 to 1200 V and ac voltages of 115, 230, and 440 V at frequencies of 400 Hz to 20 kHz. The benefits and operation of solid state RPC's and highlights of several developments to bring the RPC to technology readiness for future aerospace needs are examined. The 28 V dc Space Shuttle units, three RPC types at 120 V dc, two at 270/300 V dc, two at 230 V ac and several high power RPC models at voltages up to 1200 V dc with current ratings up to 100 A are reviewed. New technology programs to develop a new family of (DI)2 semiconductor switches and 20 kHz, 440 V ac RPC's are described.
The Marshall Space Flight Center (MSFC) owns and operates a space station module power management and distribution (SSM-PMAD) testbed. This system, managed by expert systems, is used to analyze and develop power system automation techniques for Space Station Freedom. The Lewis Research Center (LeRC), Cleveland, Ohio, has developed and implemented a space station electrical power system (EPS) testbed. This system and its power management controller are representative of the overall Space Station Freedom power system. A virtual link is being implemented between the testbeds at MSFC and LeRC. This link would enable configuration of SSM-PMAD as a load center for the EPS testbed at LeRC. This connection will add to the versatility of both systems, and provide an environment of enhanced realism for operation of both testbeds.
Design of a multihundred-watt Dynamic Isotope Power System (DIPS) based on the U.S. Department of Energy (DOE) General Purpose Heat Source (GPHS) and small (multihundred-watt) free-piston Stirling engine (FPSE) technology is being pursued as a potential lower cost alternative to radioisotope thermoelectric generators (RTG's). The design is targeted at the power needs of future unmanned deep space and planetary surface exploration missions ranging from scientific probes to Space Exploration Initiative precursor missions. Power level for these missions is less than a kilowatt. Unlike previous DIPS designs which were based on turbomachinery conversion (e.g. Brayton), this small Stirling DIPS can be advantageously scaled down to multihundred-watt unit size while preserving size and mass competitiveness with RTG's. Preliminary characterization of units in the output power ranges 200-600 We indicate that on an electrical watt basis the GPHS/small Stirling DIPS will be roughly equivalent to an advanced RTG in size and mass but require less than a third of the isotope inventory.
A technical assessment of a program to develop photovoltaic power system technology for large-scale national energy applications was made by analyzing and judging the alternative candidate photovoltaic systems and development tasks. A program plan was constructed based on achieving the 10 year objective of a program to establish the practicability of large-scale terrestrial power installations using photovoltaic conversion arrays costing less than $0.50/peak W. Guidelines for the tasks of a 5 year program were derived from a set of 5 year objectives deduced from the 10 year objective. This report indicates the need for an early emphasis on the development of the single-crystal Si photovoltaic system for commercial utilization; a production goal of 5 x 10 to the 8th power peak W/year of $0.50 cells was projected for the year 1985. The developments of other photovoltaic conversion systems were assigned to longer range development roles. The status of the technology developments and the applicability of solar arrays in particular power installations, ranging from houses to central power plants, was scheduled to be verified in a series of demonstration projects. The budget recommended for the first 5 year phase of the program is $268.5M.