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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 199 records · Page 11

SEI rover solar-electrochemical power system options

A trade study of power system technology for proposed lunar vehicles and services is presented. A variety of solar-based power systems were selected and analyzed for each. The analysis determined the power system mass, volume, and deployed area. A comparison was made between periodic refueling/recharging systems and onboard power systems to determine the most practical system. The trade study concluded that the power system significantly impacts the physical characteristics of the vehicle. The refueling/recharging systems were lighter and more compact, but dependent on availability of established lunar base infrastructure. Onboard power systems pay a mass penalty for being fully developed systems.

Withrow, Colleen A.↗

Early Results from Solar Dynamic Space Power System Testing

A government/industry team designed, built and tested a 2-kWe solar dynamic space power system in a large thermal vacuum facility with a simulated Sun at the NASA Lewis Research Center. The Lewis facility provides an accurate simulation of temperatures, high vacuum and solar flux as encountered in low-Earth orbit. The solar dynamic system includes a Brayton power conversion unit integrated with a solar receiver which is designed to store energy for continuous power operation during the eclipse phase of the orbit. This paper reviews the goals and status of the Solar Dynamic Ground Test Demonstration project and describes the initial testing, including both operational and performance data. System testing to date has accumulated over 365 hours of power operation (ranging from 400 watts to 2.0-W(sub e)), including 187 simulated orbits, 16 ambient starts and 2 hot restarts. Data are shown for an orbital startup, transient and steady-state orbital operation and shutdown. System testing with varying insolation levels and operating speeds is discussed. The solar dynamic ground test demonstration is providing the experience and confidence toward a successful flight demonstration of the solar dynamic technologies on the Space Station Mir in 1997.

Shaltens, Richard K.↗

A Summary Description of a Computer Program Concept for the Design and Simulation of Solar Pond Electric Power Generation Systems

A solar pond electric power generation subsystem, an electric power transformer and switch yard, a large solar pond, a water treatment plant, and numerous storage and evaporation ponds. Because a solar pond stores thermal energy over a long period of time, plant operation at any point in time is dependent upon past operation and future perceived generation plans. This time or past history factor introduces a new dimension in the design process. The design optimization of a plant must go beyond examination of operational state points and consider the seasonal variations in solar, solar pond energy storage, and desired plant annual duty-cycle profile. Models or design tools will be required to optimize a plant design. These models should be developed in order to include a proper but not excessive level of detail. The model should be targeted to a specific objective and not conceived as a do everything analysis tool, i.e., system design and not gradient-zone stability.

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The High Energy Astronomy Observatory X-ray Telescope

The High Energy Astronomy Observatory-Mission B (HEAO-B) is a satellite observatory for the purpose of performing a detailed X-ray survey of the celestial sphere. Measurements will be made of stellar radiation in the range 0.2 through 20 keV. The primary viewing requirement is to provide final aspect solution and internal alignment information to correlate an observed X-ray image with the celestial sphere to within one-and-one-half arc seconds. The Observatory consists of the HEAO Spacecraft together with the X-ray Telescope. The Spacecraft provides the required attitude control and determination system, data telemetry system, space solar power system, and interface with the launch vehicle. The X-ray Telescope includes a high resolution mirror assembly, optical bench metering structure, X-ray detectors, detector positioning system, detector electronics and aspect sensing system.

Miller, R.↗

Contamination

Contamination of spacecraft in the aerospace environment is examined. The optical systems, thermal control systems and solar power systems were deemed to be most vulnerable to particle damage. It was decided that all orbits should be considered. Specific issues concern whether there are changes in transmittance of optics and the radiative properties of protective coatings.

Maag, Carl R.↗

Solar power satellite system definition study. Volume 1, phase 1: Executive summary

A systems definition study of the solar satellite system (SPS) is presented. The technical feasibility of solar power satellites based on forecasts of technical capability in the various applicable technologies is assessed. The performance, cost, operational characteristics, reliability, and the suitability of SPS's as power generators for typical commercial electricity grids are discussed. The uncertainties inherent in the system characteristics forecasts are assessed.

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Solar power satellite system definition study. Volume 5: Space transportation analysis, phase 3

A small Heavy Lift Launch Vehicle (HLLV) for the Solar Power Satellites (SPS) System was analyzed. It is recommended that the small HLLV with a payload of 120 metric tons be adopted as the SPS launch vehicle. The reference HLLV, a shuttle-derived option with a payload of 400 metric tons, should serve as a backup and be examined further after initial flight experience. The electric orbit transfer vehicle should be retained as the reference orbit-to-orbit cargo system.

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Effects off system factors on the economics of and demand for small solar thermal power systems

Market penetration as a function time, SPS performance factors, and market/economic considerations was estimated, and commercialization strategies were formulated. A market analysis task included personal interviews and supplemental mail surveys to acquire statistical data and to identify and measure attitudes, reactions and intentions of prospective SPS users. Interviews encompassed three ownership classes of electric utilities and industrial firms in the SIC codes for energy consumption. A market demand model was developed which utilized the data base developed, and projected energy price and consumption data to perform sensitivity analyses and estimate potential market for SPS.

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Deployable Propulsion and Power Systems for Solar System Exploration

NASA is developing thin-film based, deployable propulsion, power and communication systems for small spacecraft that could provide a revolutionary new capability allowing small spacecraft exploration of the solar system. The Near Earth Asteroid (NEA) Scout reconnaissance mission will demonstrate solar sail propulsion on a 6U CubeSat interplanetary spacecraft and lay the groundwork for their future use in deep space science and exploration missions. Solar sails use sunlight to propel vehicles through space by reflecting solar photons from a large, mirror-like sail made of a lightweight, highly reflective material. This continuous photon pressure provides propellantless thrust, allowing for very high delta V maneuvers on long-duration, deep space exploration. Since reflected light produces thrust, solar sails require no onboard propellant. The Lightweight Integrated Solar Array and Transceiver (LISA-T) is a launch stowed, orbit deployed array on which thin-film photovoltaic and antenna elements are embedded. Inherently, small satellites are limited in surface area, volume, and mass allocation; driving competition between power, communications, and GN&C (guidance navigation and control) subsystems. This restricts payload capability and limits the value of these low-cost satellites. LISA-T is addressing this issue, deploying large-area arrays from a reduced volume and mass envelope - greatly enhancing power generation and communications capabilities of small spacecraft. The NEA Scout mission, funded by NASA's Advanced Exploration Systems Program and managed by NASA MSFC, will use the solar sail as its primary propulsion system, allowing it to survey and image one or more NEA's of interest for possible future human exploration. NEA Scout uses a 6U cubesat (to be provided by NASA's Jet Propulsion Laboratory), an 86 sq m solar sail and will weigh less than 12 kilograms. NEA Scout will be launched on the first flight of the Space Launch System in 2018. Similar in concept to the NEA Scout solar sail, the LISA-T array is designed to fit into a very small volume and provide abundant power and omnidirectional communications in just about any deployment configuration. The technology is being proposed for flight validation as early as 2019 in a low earth orbit demonstration using a 3U cubesat, of which less than 1U will be devoted to the LISA-T power and propulsion system. By leveraging recent advancements in thin films, photovoltaics and miniaturized electronics, new mission-level capabilities will be enabled aboard lower-cost small spacecraft instead of their more expensive, traditional counterparts, enabling a new generation of frequent, inexpensive deep space missions.

Johnson, Les↗

Organic Rankine power conversion subsystem development for the small community solar thermal power system

The development and preliminary test results for an air-cooled, hermetically sealed 20 kW sub E organic Rankine cycle engine/alternator unit for use with point focussing distributed receiver solar thermal power system. A 750 F toluene is the working fluid and the system features a high speed, single-stage axial flow turbine direct-coupled to a permanent magnet alternator. Good performance was achieved with the unit in preliminary tests.

Barber, R. E.↗

A review on the integration of probabilistic solar forecasting in power systems

As one of the fastest growing renewable energy sources, the integration of solar power poses great challenges to power systems due to its variable and uncertain nature. As an effective approach to promote the integration of solar power in power systems, the value of probabilistic forecasts is being increasingly recognized in the recent decade. While the current use of probabilistic forecasts in power systems is limited, enormous amount of research has been conducted to promote the adoption of probabilistic forecasts and many methods have been proposed. This paper gives a comprehensive review on how probabilistic solar forecasts are utilized in power systems to address the challenges. Potential methods to deal with uncertainties in power systems are summarized, such as probabilistic load flow models, stochastic optimization, robust optimization, and chance constraints. Additionally, specific areas where these methods can be applied are discussed and state-of-the-art studies are summarized.

14 SOLAR ENERGY↗

A dish-Stirling solar-thermal power system

This paper presents results of a preliminary design/economic study of a first-generation point focusing distributed receiver solar-thermal electric system optimized for application to industrial and small community power plants at power levels up to 10 MWe. Power conversion is provided by small Stirling cycle engines mounted at the focus of paraboloidal solar concentrators. The output of multiple power modules (concentrator, receiver, engine, and electric generator) is collected by means of a conventional electrical system and interfaced with a utility grid. Based on the United Stirling P-75 engine, a 1 MWe system employing mass-produced components (100,000 modules/year) could produce electricity at costs competitive with those projected for electricity generated by more conventional means, e.g. with fossil fuels.

Pons, R. L.↗

Test results on parabolic dish concentrators for solar thermal power systems

This paper presents results of development testing of various solar thermal parabolic dish concentrators. The concentrators were mostly designed for the production of electric power using dish-mounted Rankine, Brayton or Stirling cycle engines, intended to be produced at low cost. Measured performance for various dishes included optical efficiencies ranging from 0.32 to 0.86 at a geometric concentration ratio of 500, and from about 0.09 to 0.85 at a geometric concentration ratio of 3000. Some malfunctions were observed. The tests should provide operating information of value in developing concentrators with improved performance and reduced maintenance.

Jaffe, Leonard D.↗

Photovoltaic Test and Demonstration Project

The Photovoltaic Test and Demonstration Project was initiated by NASA in June, 1975, to develop economically feasible photovoltaic power systems suitable for a variety of terrestrial applications. Objectives include the determination of operating characteristic and lifetimes of a variety of solar cell systems and components and development of methodology and techniques for accurate measurements of solar cell and array performance and diagnostic measurements for solar power systems. Initial work will be concerned with residential applications, with testing of the first prototype system scheduled for June, 1976. An outdoor 10 kW array for testing solar power systems is under construction.

Forestieri, A. F.↗

Solar power satellite system definition study. Part 1 and part 2, volume 1: Executive summary

The Solar Power Satellite principle is illustrated and it shows that in a geostationary orbit 36,000 km above the earth's equator, each SPS is in sunlight 99% of the time and in continuous line of sight contact with its ground receiving station. Electrical power produced on the satellite by photovoltaic or heat engine conversion of sunlight is then converted to radio frequency energy at high efficiency, and formed into a focused beam precisely aimed at the SP ground stations. The ground station receiving antenna reconverts the energy into electricity for distribution.

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