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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Space nuclear power applied to electric propulsion

Space reactor power systems with characteristics ideal for advanced spacecraft systems applications are discussed. These characteristics are: high power-to-weight ratio (15 to 33 W/kg); high volume density (high ballistic coefficient); no preferential orientation in orbit; long operational life; high reliability; and total launch and operational safety. These characteristics allow the use of electric propulsion to raise spacecraft from low earth parking orbits to operational orbits, greatly increasing the useful orbit payload for a given launch vehicle by eliminating the need for a separation injection stage. A proposed demonstration mission is described.

Vicente, F. A.↗
NASA NTRS2005

Power monitoring in space nuclear reactors using silicon carbide radiation detectors

Space reactor power monitors based on silicon carbide (SiC) semiconductor neutron detectors are proposed. Detection of fast leakage neutrons using SiC detectors in ex-core locations could be used to determine reactor power: Neutron fluxes, gamma-ray dose rates and ambient temperatures have been calculated as a function of distance from the reactor core, and the feasibility of power monitoring with SiC detectors has been evaluated at several ex-core locations. Arrays of SiC diodes can be configured to provide the required count rates to monitor reactor power from startup to full power Due to their resistance to temperature and the effects of neutron and gamma-ray exposure, SiC detectors can be expected to provide power monitoring information for the fill mission of a space reactor.

silicon carbide detectors↗
NASA NTRS1991

An interagency space nuclear propulsion safety policy for SEI - Issues and discussion

An interagency Nuclear Safety Policy Working Group (NSPWG) was chartered to recommend nuclear safety policy, requirements, and guidelines for the Space Exploration Initiative nuclear propulsion program to facilitate the implementation of mission planning and conceptual design studies. The NSPWG developed a top level policy to provide the guiding principles for the development and implementation of the nuclear propulsion safety program and the development of Safety Functional Requirements. In addition, the NSPWG reviewed safety issues for nuclear propulsion and recommended top level safety requirements and guidelines to address these issues. Safety topics include reactor start-up, inadvertent criticality, radiological release and exposure, disposal, entry, safeguards, risk/reliability, operational safety, ground testing, and other considerations. In this paper the emphasis is placed on the safety policy and the issues and considerations that are addressed by the NSPWG recommendations.

Marshall, A. C.↗
NASA NTRS1985

Thermionic reactors for space nuclear power

Thermionic reactor designs for a variety of space power applications spanning the range from 5 kWe to 3 MWe are described. In all of these reactors, nuclear heat is converted directly to electrical energy in thermionic fuel elements (TFEs). A circulating reactor coolant carries heat from the core of TFEs directly to a heat rejection radiator system. The recent design of a thermionic reactor to meet the SP-100 requirements is emphasized. Design studies of reactors at other power levels show that the same TFE can be used over a broad range in power, and that design modifications can extend the range to many megawatts. The design of the SP-100 TFE is similar to that of TFEs operated successfully in test reactors, but with design improvements to extend the operating lifetime to seven years.

Homeyer, W. G.↗
NASA NTRS2005

Closed Cycle Magnetohydrodynamic Nuclear Space Power Generation Using Helium/Xenon Working Plasma

A multimegawatt-class nuclear fission powered closed cycle magnetohydrodynamic space power plant using a helium/xenon working gas has been studied, to include a comprehensive system analysis. Total plant efficiency was expected to be 55.2 percent including pre-ionization power. The effects of compressor stage number, regenerator efficiency, and radiation cooler temperature on plant efficiency were investigated. The specific mass of the power generation plant was also examined. System specific mass was estimated to be 3 kg/kWe for a net electrical output power of 1 MWe, 2-3 kg/kWe at 2 MWe, and approx.2 kg/KWe at >3 MWe. Three phases of research and development plan were proposed: (1) Phase I-proof of principle, (2) Phase II-demonstration of power generation, and (3) Phase III-prototypical closed loop test.

Litchford, R. J.↗
NASA NTRS1987

Benefits of 20 kHz PMAD in a nuclear space station

Compared to existing systems, high frequency ac power provides higher efficiency, lower cost, and improved safety benefits. The 20 kHz power system has exceptional flexibility, is inherently user friendly, and is compatible with all types of energy sources; photovoltaic, solar dynamic, rotating machines and nuclear. A 25 kW, 20 kHz ac power distribution system testbed was recently (1986) developed. The testbed possesses maximum flexibility, versatility, and transparency to user technology while maintaining high efficiency, low mass, and reduced volume. Several aspects of the 20 kHz power management and distribution (PMAD) system that have particular benefits for a nuclear power Space Station are discussed.

Sundberg, Gale R.↗
NASA NTRS1991

NASA mission planning for space nuclear power

An evaluation is conducted of those aspects of the Space Exploration Initiative which stand to gain from the use of nuclear powerplants. Low-power, less than 10 kW(e) missions in question encompass the Comet Rendezvous Asteroid Flyby, the Cassini mission to Saturn, the Mars Network mission, a solar probe, the Mars Rover Sample Return mission, the Rosetta comet nucleus sample return mission, and an outer planets orbiter/probe. Reactor power yielding 10-100 kW(e) can be used by advanced rovers and initial lunar and Martian outposts, as well as Jovian and Saturnian grand tours and sample-return missions.

Bennett, Gary L.↗
NASA NTRS1985

Technology status of tantalum alloys for space nuclear power applications

Tantalum alloys have a variety of properties which make them attractive candidates for application in nuclear power systems required to operate in space at elevated temperatures (1200 to 1600 K) for extended time periods. Most of the technology development on this class of alloys which is pertinent to space system application occurred during the 1960 to 1972 time period under NASA sponsorship. The most extensive data bases resulting from this earlier work were obtained on the alloys T-111 (Ta-8W-2Hf) and ASTAR 811C (Ta-8W-1Re-0.7Hf-0.025C). Emphasis in this paper is directed at the following technical factors: producibility, creep strength, weldability and compatibility. These factors are considered to be the most important elements in the selection of alloys for this application. Review of the available information indicates that alloys of this type are appropriate for application in many systems, particularly those utilizing alkali metals as the working fluid.

Hoffman, E. E.↗
NASA NTRS2008

Space Nuclear Power and Propulsion: Materials Challenges for the 21st Century

The current focus of NASA s space fission effort is Fission Surface Power (FSP). FSP systems could be used to provide power anytime, anywhere on the surface of the Moon or Mars. FSP systems could be used at locations away from the lunar poles or in permanently shaded regions, with no performance penalty. A potential reference 40 kWe option has been devised that is cost-competitive with alternatives while providing more power for less mass. The potential reference system is readily extensible for use on Mars. At Mars the system could be capable of operating through global dust storms and providing year-round power at any Martian latitude. To ensure affordability, the potential near-term, 40 kWe reference concept is designed to use only well established materials and fuels. However, if various materials challenges could be overcome, extremely high performance fission systems could be devised. These include high power, low mass fission surface power systems; in-space systems with high specific power; and high performance nuclear thermal propulsion systems. This tutorial will provide a brief overview of space fission systems and will focus on materials challenges that, if overcome, could help enable advanced exploration and utilization of the solar system.

Houts, Mike↗
NASA NTRS2012

Space Nuclear Power Systems

Fission power and propulsion systems can enable exciting space exploration missions. These include bases on the moon and Mars; and the exploration, development, and utilization of the solar system. In the near-term, fission surface power systems could provide abundant, constant, cost-effective power anywhere on the surface of the Moon or Mars, independent of available sunlight. Affordable access to Mars, the asteroid belt, or other destinations could be provided by nuclear thermal rockets. In the further term, high performance fission power supplies could enable both extremely high power levels on planetary surfaces and fission electric propulsion vehicles for rapid, efficient cargo and crew transfer. Advanced fission propulsion systems could eventually allow routine access to the entire solar system. Fission systems could also enable the utilization of resources within the solar system.

Houts, Michael G.↗
NASA NTRS1972

Design, performance, and evaluation of a direct-current contactor for space nuclear electrical systems

A direct-current contactor for use in large space power systems was designed, built, and tested. It was developed to be operational in an environment of 540 C and at a pressure of 0.0001 N/sq m or lower. The contactor is rated to pass 10 A continuously and to interrupt a 20-A current at 10,000 V. It was tested to determine the corona threshold level and the leakage current at different temperatures. Also, it was tested for its closing and interruption ability.

Mueller, L. A.↗