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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Megawatt solar power systems for lunar surface operations

Lunar surface operations require habitation, transportation, life support, scientific, and manufacturing systems, all of which require some form of power. As an alternative to nuclear power, the development of a modular one megawatt solar power system is studied, examining both photovoltaic and dynamic cycle conversion methods, along with energy storage, heat rejection, and power backup subsystems. For photovoltaic power conversion, two systems are examined. First, a substantial increase in photovoltaic conversion efficiency is realized with the use of new GaAs/GaSb tandem photovoltaic cells, offering an impressive overall array efficiency of 23.5 percent. Since these new cells are still in the experimental phase of development, a currently available GaAs cell providing 18 percent efficiency is examined as an alternate to the experimental cells. Both Brayton and Stirling cycles, powered by linear parabolic solar concentrators, are examined for dynamic cycle power conversion. The Brayton cycle is studied in depth since it is already well developed and can provide high power levels fairly efficiently in a compact, low mass system. The dynamic conversion system requires large scale waste heat rejection capability. To provide this heat rejection, a comparison is made between a heat pipe/radiative fin system using advanced composites, and a potentially less massive liquid droplet radiator system. To supply power through the lunar night, both a low temperature alkaline fuel cell system and an experimental high temperature monolithic solid-oxide fuel cell system are considered. The reactants for the fuel cells are stored cryogenically in order to avoid the high tankage mass required by conventional gaseous storage. In addition, it is proposed that the propellant tanks from a spent, prototype lunar excursion vehicle be used for this purpose, therefore resulting in a significant overall reduction in effective storage system mass.

Adams, Brian↗
NASA NTRS2004

Technology Development and Demonstration Concepts for the Space Elevator

During the 1990s several discoveries and advances in the development of carbon nano-tube (CNT) materials indicated that material strengths many times greater than common high-strength composite materials might be possible. Progress in the development of this material led to renewed interest in the space elevator concept for construction of a tether structure from the surface of the Earth through a geostationary orbit (GEO) and thus creating a new approach to Earth-to-orbit transportation infrastructures. To investigate this possibility the author, in 1999, managed for NASA a space elevator work:hop at the Marshall Space Flight Center to explore the potential feasibility of space elevators in the 21 century, and to identify the critical technologies and demonstration missions needed to make development of space elevators feasible. Since that time, a NASA Institute for Advanced Concepts (NIAC) funded study of the Space Elevator proposed a concept for a simpler first space elevator system using more near-term technologies. This paper will review some of the latest ideas for space elevator development, the critical technologies required, and some of the ideas proposed for demonstrating the feasibility for full-scale development of an Earth to GEO space elevator. Critical technologies include CNT composite materials, wireless power transmission, orbital object avoidance, and large-scale tether deployment and control systems. Numerous paths for technology demonstrations have been proposed utilizing ground experiments, air structures. LEO missions, the space shuttle, the international Space Station, GEO demonstration missions, demonstrations at the lunar L1 or L2 points, and other locations. In conclusion, this paper finds that the most critical technologies for an Earth to GEO space elevator include CNT composite materials development and object avoidance technologies; that lack of successful development of these technologies need not preclude continued development of space elevator systems in general; and that the critical technologies required for the Earth to GEO space elevator are not required for similar systems at the Moon, Mars, Europa, or for orbital tether systems at GEO, Luna, and other locations.

Smitherman, David V., Jr.↗
NASA NTRS2014

Controllable Multi-Functional Heat Exchanger for Space Applications

Team Spacering will design SpaceRing, a cooling and waste heat recycling system that addresses NASA’s interest for a cooling and power-generating unit in its prototype deep space habitat[1]. The merits of this system are as follows: - Controllable cooling is critical in maintaining a habitable environment and in the functionality of life support systems, powering electronics and other devices in a spacecraft. - Power is expensive to produce in a space environment. Converting wasted thermal energy into electricity will save energy and money for the space station. Space habitation is a highly complex endeavor. Consequently, the SpaceRing must adhere to additional constraints, which include: - Lack of natural fluid or gas convection due to micro-gravity environment - Limited range for heat source and cold sink temperature - Subject to high fluctuations of incoming thermal energy - Minimal weight due to the high cost of transporting items into space After consulting with NASA and experts in thermal studies, several design objectives were identified and are listed below in order of importance: - High cooling capacity - Reliable safety control and alert system - Maximization of energy generation from wasted heat - Optimization of cooling capability and power generation - Long operational life and minimization of maintenance In space, conventional cooling systems utilize passive heat pipe systems for small-scale heat rejection and pumped pipes with heat exchangers for large-scale heat rejection. Thermal power generation in space is mainly achieved by using thermoelectric material that produces electric energy from temperature differentials. We propose a design that combines cooling and thermoelectric power generation. Using a hot pipe connected to a heat source, a cold pipe connected to a radiator, a heat exchanger in contact with both pipes, and a pump in each pipe to move the fluid, we make an active cooling system. The thermoelectric material is inserted in the heat exchanger between the hot and cold pipes to extract energy from the maximum temperature difference coming from the two pipes. It also provides controllable cooling capacity through the use of the thermoelectric material as cooling modules. We have tested our system under target heat source and sink conditions and measured the temperatures and flow rates. Our preliminary results are promising, demonstrating the output of 25 Watts of power on average. We are in the process of running control tests to compare the heat transfer performance without the thermoelectric generators, which is vital in determining whether or not the generators introduce an unacceptable amount of thermal resistance. While some control tests have been run already, the results have been noisy. We have modified our testing environment and data acquisition methods to allow for simple comparison between the control test results and thermoelectric performance results. Lastly, we have modified the heat exchanger design slightly to include acrylic baffles. This will allow the heat to flow through the heat exchanger more efficiently. We have presented our preliminary results to NASA and will deliver the final product by the end of May 2014.

Lee Xiong↗
NASA NTRS2017

Evaluation of a Variable Thickness Hybrid Composite Bull Gear

For several years, NASA Glenn Research Center and the U.S. Army Research Laboratory have been investigating hybrid (composite/steel) gear technology for use in vertical lift drive systems. The hybrid gear concept replaces the structural portion of a gear between the shaft and the gear rim with a lightweight carbon fiber composite, in an effort to reduce the overall weight of a gear and increase the drive system power density. Past research includes both small-scale and large-scale hybrid gear concepts, all of which have a constant composite thickness throughout. The design described in this paper is of a variable thickness, such that the composite is thickest at the inner diameter and this thickness is gradually reduced toward the outer diameter. The resulting "stair stepped" design stems from dropping plies of the braided carbon fiber prepreg composite fabric gradually with increased radius. Additionally, the interlock pattern at the inner metallic adapter was adjusted slightly from previous designs to obtain a better stress distribution on the inner metallic adapter. The manufactured variable thickness web was tested both in static torsion tests and operationally in a relevant gearbox environment. The results of these experiments will be presented and compared to a baseline steel configuration.

Gears; Drive Systems; Rotorcraft Propulsion;↗
NASA NTRS1980

An assessment of inductive coupling roadway powered vehicles

The technical concept underlying the roadway powered vehicle system is the combination of an electrical power source embedded in the roadway and a vehicle-mounted power pickup that is inductively coupled to the roadway power source. The feasibility of such a system, implemented on a large scale was investigated. Factors considered included current and potential transportation modes and requirements, economics, energy, technology, social and institutional issues. These factors interrelate in highly complex ways, and a firm understanding of each of them does not yet exist. The study therefore was structured to manipulate known data in equally complex ways to produce a schema of options and useful questions that can form a basis for further, harder research. A dialectical inquiry technique was used in which two adversary teams, mediated by a third-party team, debated each factor and its interrelationship with the whole of the known information on the topic.

Leschly, K. O.↗
NASA NTRSDate not supplied

Automated Reconfigurable Mission Adaptive Digital Assembly Systems (ARMADAS)

To meet the needs of future deep space exploration, NASA is interested in large-scale hardware systems in the agency’s thrust areas of solar power, communications, habitats and science interests. Scalable in-space assembly of physical systems is critical to massless exploration and in-space reliance goals. The ARMADAS project demonstrates the autonomous assembly of digital materials and structures. This provides automation technologies with potential for meeting long duration and deep space infrastructure needs, such as construction and maintenance of long duration spaceport, surface infrastructure, and habitat scale systems. Project demonstrations to date include a system that can fit into a small satellite-sized payload, which automatically assembles into primary structures, such as a small habitat module or array/antenna, using onboard robotic assemblers.

In Space Assembly↗
NASA NTRS1991

ASPEC: Solar power satellite

The solar power satellite (SPS) will provide a clean, reliable source of energy for large-scale consumption. The system will use satellites in geostationary orbits around the Earth to capture the Sun's energy. The intercepted sunlight will be converted to laser beam energy that can be transmitted to the Earth's surface. Ground systems on the Earth will convert the transmissions from space into electric power. The preliminary design for the SPS consists of one satellite in orbit around the Earth transmitting energy to a single ground station. The SPS design uses multilayer solar cell technology arranged on a 20 km squared planar array to intercept sunlight and convert it to an electric voltage. Power conditioning devices then send the electricity to a laser, which transmits the power to the surface of the Earth. A ground station will convert the beam into electricity. Typically, a single SPS will supply 5 GW of power to the ground station. Due to the large mass of the SPS, about 41 million kg, construction in space is needed in order to keep the structural mass low. The orbit configuration for this design is to operate a single satellite in geosynchronous orbit (GEO). The GEO allows the system to be positioned above a single receiving station and remain in sunlight 99 percent of the time. Construction will take place in low Earth orbit (LEO); array sections, 20 in total, will be sailed on solar wind out to the GEO location in 150 days. These individual transportation sections are referred to as solar sailing array panels (SSAP's). The primary truss elements used to support the array are composed of composite tubular members in a pentahedral arrangement. Smart segments consisting of passive and active damping devices will increase the control of dynamic SPS modes.

Source record↗
NASA NTRS1978

Large scale static tests of a tilt-nacelle V/STOL propulsion/attitude control system

The concept of a combined V/STOL propulsion and aircraft attitude control system was subjected to large scale engine tests. The tilt nacelle/attitude control vane package consisted of the T55 powered Hamilton Standard Q-Fan demonstrator. Vane forces, moments, thermal and acoustic characteristics as well as the effects on propulsion system performance were measured under conditions simulating hover in and out of ground effect.

Source record↗
NASA NTRS2015

Space-to-Space Power Beaming Enabling High Performance Rapid Geocentric Orbit Transfer

The use of electric propulsion is more prevalent than ever, with industry pursuing all electric orbit transfers. Electric propulsion provides high mass utilization through efficient propellant transfer. However, the transfer times become detrimental as the delta V transitions from near-impulsive to low-thrust. Increasing power and therefore thrust has diminishing returns as the increasing mass of the power system limits the potential acceleration of the spacecraft. By using space-to-space power beaming, the power system can be decoupled from the spacecraft and allow significantly higher spacecraft alpha (W/kg) and therefore enable significantly higher accelerations while maintaining high performance. This project assesses the efficacy of space-to-space power beaming to enable rapid orbit transfer while maintaining high mass utilization. Concept assessment requires integrated techniques for low-thrust orbit transfer steering laws, efficient large-scale rectenna systems, and satellite constellation configuration optimization. This project includes the development of an integrated tool with implementation of IPOPT, Q-Law, and power-beaming models. The results highlight the viability of the concept, limits and paths to infusion, and comparison to state-of-the-art capabilities. The results indicate the viability of power beaming for what may be the only approach for achieving the desired transit times with high specific impulse.

Dankanich, John W.↗
NASA NTRSDate not supplied

Large-Scale Computational Fluid Dynamics Simulations of Aerospace Configurations on the Frontier Exascale System

Over the past fifteen years, the high performance computing landscape has undergone a seismic shift in both hardware and software paradigms, which has been necessary to realize a 1000× leap in computational performance while meeting stringent constraints on power consumption. A historical overview of a long-term research effort aimed at addressing these challenges within the context of a commonly-used aerospace computational fluid dynamics (CFD) application is presented. Details of the current implementation as they relate to the new era of exascale-relevant hardware architectures and programming models are described. Two large-scale simulations of aerospace configurations are performed using the entire Frontier exascale system, currently ranked as the most powerful supercomputing system in the world. The effort serves to address a 2024 milestone posed a decade ago by the seminal CFD Vision 2030 Study.

Eric J Nielsen↗
NASA NTRS1968

Large superconducting magnets for M.H.D.

Large superconducting magnets for MHD power plants, discussing scale-up requirements, cryogenic system, stable operation margin and emergency system shutdown

Stekly, Z. J. J.↗
NASA NTRS1990

Potential vorticity index

Using standard data analysis techniques, researchers explore the links between disturbance growth and quasi-geostrophic potential vorticity (PV) gradients; appearance and disappearance of cutoff lows and blocking highs and their relation to a zonal index (properly defined in terms of PV); and teleconnections between different flow patterns and their relation to the zonal index. It was found that the PV index and the eddy index correlate better than a zonal index (defined by zonal wind) and the eddy index. In the frequency domain there are three frequencies (.03, .07 and .17 cpd (cycle per day) corresponding to periods of 33, 14 and 6 days) at which PV index and the eddy index exhibit local maxima. The high correlation found at periods of 33 days is mainly due to eddy activity at high latitudes while the local correlation maxima found at the shorter periods are mainly due mid-latitude eddy activity. The correlation between the PV index and the geopotential height anomaly at 500 mb, at each grid point in the Northern Hemisphere, shows the existence of most of the teleconnection patterns summarized by Wallace and Gutzler (1981): the North Atlantic Oscillation, the North Pacific Oscillation, and the Pacific/North American patterns. Results show that the Isentropic Potential Vorticity (IPV) analysis can be a very useful and powerful tool when used to understand the dynamics of several large scale atmospheric systems. Although the data are limited to only one winter, and it is difficult to assess the statistical significance of the correlation coefficients presented here, the results are encouraging from physical viewpoint.

Barcilon, Albert↗
NASA NTRS1983

Proceedings of the Flat-Plate Solar Array Project Research Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Stations

The Flat Plate Solar Array Project, focuses on advancing technologies relevant to the design and construction of megawatt level central station systems. Photovoltaic modules and arrays for flat plate central station or other large scale electric power production facilities require the establishment of a technical base that resolves design issues and results in practical and cost effective configurations. Design, qualification and maintenance issues related to central station arrays derived from the engineering and operating experiences of early applications and parallel laboratory reserch activities are investigated. Technical issues are examined from the viewpoint of the utility engineer, architect/engineer and laboratory researcher. Topics on optimum source circuit designs, module insulation design for high system voltages, array safety, structural interface design, measurements, and array operation and maintenance are discussed.

Source record↗
NASA NTRS2019

Sub-Kelvin Cooling Systems for Quantum Computers

Future large-scale quantum processors (i.e. 100s of qubits), especially those based on superconducting circuits, will require large cooling powers (~10s of microW) at very low temperatures (<50 mK) with stringent temperature stabilities to avoid quantum decoherence and thus guarantee successful operation of such systems. One attractive option for providing this cooling is through Continuous Adiabatic Demagnetization Refrigerators (CADR). Scalable state-of-the-art CADRs at NASA's Goddard Space Flight Center have successfully shown to lift 6 W of heat at 50 mK with a 1 K temperature stability while rejecting its heat to a cryocooler at 4K. Carefully planned and proper heat sinking of cables, attenuators, and microwave components at various temperature stages (between 4K and base temperature) is critical in the cooling architecture of quantum computers and can be provided through proper staging of each unit within the CADR system. As an alternative method of cooling, dilution refrigerators with the potential to meet cooling requirements of emerging large-scale quantum processors are also discussed.

quantum cooling↗
NASA NTRSDate not supplied

Development Status of Powered Descent for High-Mass Mars Entry, Descent, and Landing Systems

Retropropulsion, initiated at supersonic conditions, provides both deceleration and control authority as an enabling capability for the delivery of human-scale payloads to the surface of Mars. There are no other presently viable approaches to the descent phase of flight for vehicles of such scales. NASA continues to dedicate investment in the maturation of powered descent in atmospheric environments, for the express application to large-scale entry, descent, and landing systems. Efforts focus on parametric, subscale, inert gas ground testing, rigorous validation of computational modeling approaches against these data, and the implementation of highly efficient, scalable simulation tools. This paper summarizes the current maturity of retropropulsion in a free-flight, atmospheric environment for vehicles with significant aerodynamic surface area, as well as the current status of efforts within NASA for ground testing, computational simulation, and flight testing.

Mars↗
NASA NTRSDate not supplied

Development Status of Powered Descent for High-Mass Mars Entry, Descent, and Landing Systems

Retropropulsion, initiated at supersonic conditions, provides both deceleration and control authority as an enabling capability for the delivery of human-scale payloads to the surface of Mars. There are no other presently viable approaches to the descent phase of flight for vehicles of such scales. NASA continues to dedicate investment in the maturation of powered descent in atmospheric environments, for the express application to large-scale entry, descent, and landing systems. Efforts focus on parametric, subscale, inert gas ground testing, rigorous validation of computational modeling approaches against these data, and the implementation of highly efficient, scalable simulation tools. This paper summarizes the current maturity of retropropulsion in a free-flight, atmospheric environment for vehicles with significant aerodynamic surface area, as well as the current status of efforts within NASA for ground testing, computational simulation, and flight testing.

Ashley Korzun↗
NASA NTRS1985

Solar-Power System Produces High-Pressure Steam

Combination of three multistaged solar collectors produces highpressure steam for large-scale continuously operating turbines for generating mechanical or electrical energy. Superheated water vapor drives turbines, attaining an overall system efficiency about 22 percent.

Lansing, F. L.↗