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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

In-Space Propulsion Technology Program Solar Electric Propulsion Technologies

NASA's In-space Propulsion (ISP) Technology Project is developing new propulsion technologies that can enable or enhance near and mid-term NASA science missions. The Solar Electric Propulsion (SEP) technology area has been investing in NASA s Evolutionary Xenon Thruster (NEXT), the High Voltage Hall Accelerator (HiVHAC), lightweight reliable feed systems, wear testing, and thruster modeling. These investments are specifically targeted to increase planetary science payload capability, expand the envelope of planetary science destinations, and significantly reduce the travel times, risk, and cost of NASA planetary science missions. Status and expected capabilities of the SEP technologies are reviewed in this presentation. The SEP technology area supports numerous mission studies and architecture analyses to determine which investments will give the greatest benefit to science missions. Both the NEXT and HiVHAC thrusters have modified their nominal throttle tables to better utilize diminished solar array power on outbound missions. A new life extension mechanism has been implemented on HiVHAC to increase the throughput capability on low-power systems to meet the needs of cost-capped missions. Lower complexity, more reliable feed system components common to all electric propulsion (EP) systems are being developed. ISP has also leveraged commercial investments to further validate new ion and hall thruster technologies and to potentially lower EP mission costs.

Dankanich, John W.↗
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 NTRS1975

Comparative assessment of out-of-core nuclear thermionic power systems

The hardware selections available for fabrication of a nuclear electric propulsion stage for planetary exploration were explored. The investigation was centered around a heat-pipe-cooled, fast-spectrum nuclear reactor for an out-of-core power conversion system with sufficient detail for comparison with the in-core system studies completed previously. A survey of competing power conversion systems still indicated that the modular reliability of thermionic converters makes them the desirable choice to provide the 240-kWe end-of-life power for at least 20,000 full power hours. The electrical energy will be used to operate a number of mercury ion bombardment thrusters with a specific impulse in the range of about 4,000-5,000 seconds.

Estabrook, W. C.↗
NASA NTRS1980

Nuclear electro-optic power

Tertiary-nuclear power cell utilizes alpha source from which radiated particles strike phosphore which in turn emits photons that are converted to electricity by solar cell. Experiments indicated that device is capable of providing sufficient power for numerous electronic applications where reliability and long life are important.

Singh, J. J.↗
NASA NTRS1982

Space Operations Center System Analysis: Requirements for a Space Operations Center, revision A

The system and program requirements for a space operations center as defined by systems analysis studies are presented as a guide for future study and systems definition. Topics covered include general requirements for safety, maintainability, and reliability, service and habitat modules, the health maintenance facility; logistics modules; the docking tunnel; and subsystem requirements (structures, electrical power, environmental control/life support; extravehicular activity; data management; communications and tracking; docking/berthing; flight control/propulsion; and crew support). Facilities for flight support, construction, satellite and mission servicing, and fluid storage are included as well as general purpose support equipment.

Woodcock, G. R.↗
NASA NTRS1971

External fuel thermionic reactor system.

Thermionic reactors are prime candidates for nuclear electric propulsion. The national thermionic reactor effort is concentrated on the flashlight concept with the external-fuel concept as the backup. The external-fuel concept is very adaptable to a completely modular power subsystem which is attractive for highly reliable long-life applications. The 20- to 25-cm long, externally-fueled converters have been designed, fabricated, and successfully tested with many thermal cycles by electrical heating. However, difficulties have been encountered during encapsulation for nuclear heated tests and none have been started to date. These nuclear tests are required to demonstrate the concept feasibility.

Mondt, J. F.↗
NASA NTRS2015

Standardized Modular Power Interfaces for Future Space Explorations Missions

Earlier studies show that future human explorations missions are composed of multi-vehicle assemblies with interconnected electric power systems. Some vehicles are often intended to serve as flexible multi-purpose or multi-mission platforms. This drives the need for power architectures that can be reconfigured to support this level of flexibility. Power system developmental costs can be reduced, program wide, by utilizing a common set of modular building blocks. Further, there are mission operational and logistics cost benefits of using a common set of modular spares. These benefits are the goals of the Advanced Exploration Systems (AES) Modular Power System (AMPS) project. A common set of modular blocks requires a substantial level of standardization in terms of the Electrical, Data System, and Mechanical interfaces. The AMPS project is developing a set of proposed interface standards that will provide useful guidance for modular hardware developers but not needlessly constrain technology options, or limit future growth in capability. In 2015 the AMPS project focused on standardizing the interfaces between the elements of spacecraft power distribution and energy storage. The development of the modular power standard starts with establishing mission assumptions and ground rules to define design application space. The standards are defined in terms of AMPS objectives including Commonality, Reliability-Availability, Flexibility-Configurability and Supportability-Reusability. The proposed standards are aimed at assembly and sub-assembly level building blocks. AMPS plans to adopt existing standards for spacecraft command and data, software, network interfaces, and electrical power interfaces where applicable. Other standards including structural encapsulation, heat transfer, and fluid transfer, are governed by launch and spacecraft environments and bound by practical limitations of weight and volume. Developing these mechanical interface standards is more difficult but an essential part of defining physical building blocks of modular power. This presentation describes the AMPS projects progress towards standardized modular power interfaces.

Spacecraft Power↗
NASA NTRS1991

Augmentation of the space station module power management and distribution breadboard

The space station module power management and distribution (SSM/PMAD) breadboard models power distribution and management, including scheduling, load prioritization, and a fault detection, identification, and recovery (FDIR) system within a Space Station Freedom habitation or laboratory module. This 120 VDC system is capable of distributing up to 30 kW of power among more than 25 loads. In addition to the power distribution hardware, the system includes computer control through a hierarchy of processes. The lowest level consists of fast, simple (from a computing standpoint) switchgear that is capable of quickly safing the system. At the next level are local load center processors, (LLP's) which execute load scheduling, perform redundant switching, and shed loads which use more than scheduled power. Above the LLP's are three cooperating artificial intelligence (AI) systems which manage load prioritizations, load scheduling, load shedding, and fault recovery and management. Recent upgrades to hardware and modifications to software at both the LLP and AI system levels promise a drastic increase in speed, a significant increase in functionality and reliability, and potential for further examination of advanced automation techniques. The background, SSM/PMAD, interface to the Lewis Research Center test bed, the large autonomous spacecraft electrical power system, and future plans are discussed.

Walls, Bryan↗
NASA NTRS2009

Benchmarking Diagnostic Algorithms on an Electrical Power System Testbed

Diagnostic algorithms (DAs) are key to enabling automated health management. These algorithms are designed to detect and isolate anomalies of either a component or the whole system based on observations received from sensors. In recent years a wide range of algorithms, both model-based and data-driven, have been developed to increase autonomy and improve system reliability and affordability. However, the lack of support to perform systematic benchmarking of these algorithms continues to create barriers for effective development and deployment of diagnostic technologies. In this paper, we present our efforts to benchmark a set of DAs on a common platform using a framework that was developed to evaluate and compare various performance metrics for diagnostic technologies. The diagnosed system is an electrical power system, namely the Advanced Diagnostics and Prognostics Testbed (ADAPT) developed and located at the NASA Ames Research Center. The paper presents the fundamentals of the benchmarking framework, the ADAPT system, description of faults and data sets, the metrics used for evaluation, and an in-depth analysis of benchmarking results obtained from testing ten diagnostic algorithms on the ADAPT electrical power system testbed.

Kurtoglu, Tolga↗
NASA NTRS1971

A guide to onboard checkout. Volume 3: Electrical power

The baseline electrical power subsystem for a space station is considered. The subsystem was anlayzed in order to define onboard checkout requirements. Reliability, failure effects, and maintenance are discussed.

Source record↗
NASA NTRS1971

Reliability testing and demonstration - Aerospace problems.

Several aerospace problems are solved using various reliability methods. The problems considered are associated with distribution functions, sampling, accelerated life testing, and accept/reject decisions with sequential testing. In addition, two reliability case histories are described in detail. They include the second space Electric Rocket Test (SERT II), and the Microthruster Power Conditioner (MTPC) life test, both conducted by the Lewis Research Center.

Lalli, V. R.↗
NASA NTRS1973

Isotope heat source simulator for testing of space power systems

A reliable isotope heat source simulator was designed for use in a Brayton power system. This simulator is composed of an electrically heated tungsten wire which is wound around a boron nitride core and enclosed in a graphite jacket. Simulator testing was performed at the expected operating temperature of the Brayton power system. Endurance testing for 5012 hours was followed by cycling the simulator temperature. The integrity of this simulator was maintained throughout testing. Alumina beads served as a diffusion barrier to prevent interaction between the tungsten heater and boron nitride core. The simulator was designed to maintain a surface temperature of 1311 to 1366 K (1900 to 2000 F) with a power input of approximately 400 watts. The design concept and the materials used in the simulator make possible man different geometries. This flexibility increases its potential use.

Prok, G. M.↗
NASA NTRS1979

LSA Large Area Silicon Sheet Task Continuous Liquid Feed Czochralski Growth

A process for the continuous growth of crystals by the Czochralski method, suitable for producing single silicon crystals for use in solar cells was studied. Continuous growth is the growth of 100 Kg of single silicon crystals, 10 cm in diameter, from one container. A furnace with continuous liquid replenishment of the growth crucible, accomplished by a melt-down system and a liquid transfer mechanism, with associated automatic feedback controls was developed. Elements of the transfer system were further developed and tested during actual transfer runs. Considerable simplification of the heating element of the transfer tube was achieved. Accuracy and reliability of the temperature sensor, which is part of the power input control system for the transfer tube, was improved. Electrical and thermal effectiveness were increased while assembly of the transfer tube system was further simplified.

Fiegl, G.↗
NASA NTRS1984

Subatmospheric Brayton-cycle Engine Program Review

A solar energy powered electrical generator utilizing a Subatmospheric Brayton cycle engine is examined. The generator consists of a subatmospheric, Brayton-cycle engine and a permanent magnet (PM) alternator. The electrical power is generated by an alternator driven directly by the Brayton-cycle engine rotating group. Features that enhance reliability and performance include air foil bearings on both the Brayton-cycle engine rotating group and the PM alternator, an atmospheric-pressure solar receiver and gas-fired trim heater, and a high temperature recuperator. The subatmospheric Brayton-cycle engine design is based on that of the gas fired heat pump engine.

Johnson, R. L.↗
NASA NTRS1992

Regenerative life support technology challenges for the Space Exploration Initiative

Regenerative life support systems have been identified as one of the critical enabling technologies for future human exploration of space. This discipline encompasses processes and subsystems which regenerate the air, water, solid waste, and food streams typical of human habitation so as to minimize the mass and volume of stored consumables which must accompany the humans on a mission. A number of key technology challenges within this broad discipline are described, ranging from the development of new physical, chemical, and biological processes for regenerating the air, water, solid waste, and food streams to the development of improved techniques for monitoring and controlling microbial and trace constituent contamination. A continuing challenge overarching the development of these new technologies is the need to minimize the mass, volume, and electrical power consumption of the flight hardware. More important for long duration exploration missions, however, is the development of highly reliable, long-lived, self- sufficient systems which absolutely minimize the logistics resupply and operational maintenance requirements of the life support system and which ensure human safety through their robust, reliable operating characteristics.

Bilardo, Vincent J., Jr.↗
NASA NTRS2000

In Space Nuclear Power as an Enabling Technology for Deep Space Exploration

Deep Space Exploration missions, both for scientific and Human Exploration and Development (HEDS), appear to be as weight limited today as they would have been 35 years ago. Right behind the weight constraints is the nearly equally important mission limitation of cost. Launch vehicles, upper stages and in-space propulsion systems also cost about the same today with the same efficiency as they have had for many years (excluding impact of inflation). Both these dual mission constraints combine to force either very expensive, mega systems missions or very light weight, but high risk/low margin planetary spacecraft designs, such as the recent unsuccessful attempts for an extremely low cost mission to Mars during the 1998-99 opportunity (i.e., Mars Climate Orbiter and the Mars Polar Lander). When one considers spacecraft missions to the outer heliopause or even the outer planets, the enormous weight and cost constraints will impose even more daunting concerns for mission cost, risk and the ability to establish adequate mission margins for success. This paper will discuss the benefits of using a safe in-space nuclear reactor as the basis for providing both sufficient electric power and high performance space propulsion that will greatly reduce mission risk and significantly increase weight (IMLEO) and cost margins. Weight and cost margins are increased by enabling much higher payload fractions and redundant design features for a given launch vehicle (higher payload fraction of IMLEO). The paper will also discuss and summarize the recent advances in nuclear reactor technology and safety of modern reactor designs and operating practice and experience, as well as advances in reactor coupled power generation and high performance nuclear thermal and electric propulsion technologies. It will be shown that these nuclear power and propulsion technologies are major enabling capabilities for higher reliability, higher margin and lower cost deep space missions design to reliably reach the outer planets for scientific exploration.

Sackheim, Robert L.↗
NASA NTRS2003

Effects Of Environmental And Operational Stresses On RF MEMS Switch Technologies For Space Applications

Micro Electro Mechanical Systems (MEMS) have been heralded for their ability to provide tremendous advantages in electronic systems through increased electrical performance, reduced power consumption, and higher levels of device integration with a reduction of board real estate. RF MEMS switch technology offers advantages such as low insertion loss (0.1- 0.5 dB), wide bandwidth (1 GHz-100 GHz), and compatibility with many different process technologies (quartz, high resistivity Si, GaAs) which can replace the use of traditional electronic switches, such as GaAs FETS and PIN Diodes, in microwave systems for low signal power (x < 500 mW) applications. Although the electrical characteristics of RF MEMS switches far surpass any existing technologies, the unknown reliability, due to the lack of information concerning failure modes and mechanisms inherent to MEMS devices, create an obstacle to insertion of MEMS technology into high reliability applications. All MEMS devices are sensitive to moisture and contaminants, issues easily resolved by hermetic or near-hermetic packaging. Two well-known failure modes of RF MEMS switches are charging in the dielectric layer of capacitive membrane switches and contact interface stiction of metal-metal switches. Determining the integrity of MEMS devices when subjected to the shock, vibration, temperature extremes, and radiation of the space environment is necessary to facilitate integration into space systems. This paper will explore the effects of different environmental stresses, operational life cycling, temperature, mechanical shock, and vibration on the first commercially available RF MEMS switches to identify relevant failure modes and mechanisms inherent to these device and packaging schemes for space applications. This paper will also describe RF MEMS Switch technology under development at NASA GSFC.

Jah, Muzar↗