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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 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Application of hybrid propulsion systems to planetary missions

The feasibility and application of hybrid rocket propulsion to outer-planet orbiter missions is assessed in this study and guidelines regarding future development are provided. A Jupiter Orbiter Mission was selected for evaluation because it is the earliest planetary mission which may require advanced chemical propulsion. Mission and spacecraft characteristics which affect the selection and design of propulsion subsystems are presented. Alternative propulsion subsystems, including space-storable bipropellant liquids, a solid/monopropellant vernier, and a hybrid, are compared on the basis of performance, reliability, and cost. Cost-effectiveness comparisons are made for a range of assumptions including variation in (1) the level of need for spacecraft performance (determined in part by launch vehicle injected mass capability), and (2) achievable reliability at corresponding costs. The results indicated that the hybrid and space-storable bipropellant mechanizations are competitive.

Don, J. P.↗
NASA NTRS1971

Technology of nuclear-Brayton space power systems

The present technology of Brayton power systems is reviewed. The potential for even higher system efficiency at the 10 KWe level is assessed as well as the potential for comparable efficiency with an output of 1 or 2 KWe. Systems accommodation of isotope decay is briefly discussed. The salient features are described for a Brayton power system based on this technology and employing the ZrH reactor. Reactor lives for this and competitive systems are compared. Growth capability with an advanced reactor is assessed. A concept for application of this technology to driving a gas-dynamic laser is described.

English, R. E.↗
NASA NTRS1971

Comparison of a discrete steepest ascent method with the continuous steepest ascent method for optimal programing

A discrete steepest ascent method which allows controls which are not piecewise constant (for example, it allows all continuous piecewise linear controls) was derived for the solution of optimal programming problems. This method is based on the continuous steepest ascent method of Bryson and Denham and new concepts introduced by Kelley and Denham in their development of compatible adjoints for taking into account the effects of numerical integration. The method is a generalization of the algorithm suggested by Canon, Cullum, and Polak with the details of the gradient computation given. The discrete method was compared with the continuous method for an aerodynamics problem for which an analytic solution is given by Pontryagin's maximum principle, and numerical results are presented. The discrete method converges more rapidly than the continuous method at first, but then for some undetermined reason, loses its exponential convergence rate. A comparsion was also made for the algorithm of Canon, Cullum, and Polak using piecewise constant controls. This algorithm is very competitive with the continuous algorithm.

Childs, A. G.↗
NASA NTRS1971

Organizational stress and individual strain: A social-psychological study of risk factors in coronary heart disease among administrators, engineers, and scientists

It is hypothesized that organizational stresses, such as high quantitative work load, responsibility for persons, poor relations with role senders, and contact with alien organizational territories, may be associated with high levels of psychological and physiological strain which are risk factors in coronary heart disease. It is further hypothesized that persons with coronary-prone Type A personality characteristics are most likely to exhibit strain under conditions of organizational stress. Measures of these stresses, personality traits, and strains were obtained from 205 male NASA administrators, engineers, and scientists. Type A personality measures included sense of time urgency, persistence, involved striving, leadership, and preference for competitive and environmentally overburdening situations.

Caplan, R. D.↗
NASA NTRS1971

Superconducting magnets and devices for space vehicles and experiments

Superconductivity research has been oriented toward those problems that tend to restrict the greater application of superconducting devices in space research and technology. These include magnetic problems of high field magnets, increasing operating temperatures, and development of useful competitive superconducting instruments.

Urban, E. W.↗
NASA NTRS1971

Long term cryogenic storage system integration

Investigations have revealed significant increases in performance when a reliquefier and solar shield in conjunction with a zero-gravity vapor vent system are utilized. Application of a reliquefier and solar shield in long term deep space missions may effect a 60% reduction in propellant loss, compared to that associated with the vapor vent system only. Significant improvements in storage system performance are possible for low earth orbit applicatons; for the typical system that was evaluated, system performance gains were realized for mission durations exceeding 7 days. Spherical solar shields are generally not competitive for low earth orbit applications.

Stonemetz, R. E.↗
NASA NTRS1972

Study of the techniques feasible for food synthesis aboard a spacecraft

Synthesis of sugars by Ca(OH)2 catalyzed formaldehyde condensation (the formose reaction) has produced branched carbohydrates that do not occur in nature. The kinetics and mechanisms of the homogeneously catalyzed autocatalytic condensation were studied and analogies between homogeneous and heterogeneous rate laws have been found. Aldol condensations proceed simultaneously with Cannizzaro and crossed-Cannizzaro reactions and Lobry de Bruyn-Van Eckenstein rearrangements. The separate steps as well as the interactions of this highly complex reaction system were elucidated. The system exhibits instabilities, competitive catalytic, mass action, and equilibrium phenomena, complexing, and parallel and consecutive reactions. Specific finding that have been made on the problem will be of interest for synthesizing sugars, both for sustained space flight and for large scale food manufacture. A contribution to methodology for studying complex catalyzed reactions and to understanding control of reaction selectivity was a broad goal of the project.

Weiss, A. H.↗
NASA NTRS1972

The NAS-PAK Logic System

The design and fabrication of telemetry ground data processing equipment using commercial logic cards or modules are discussed. A microelectronics program was initiated to evaluate circuitry, packaging methods, and fabrication approaches necessary to produce a competitively procured logic system. The NAS-PAK logic system covering all phases of implementation is considered.

Billingsley, J.↗
NASA NTRS1972

Transonic transport study, summary

The effects of possible increases in cruise speed over present-day transport aircraft were investigated. Increased cruise speed is desirable not only because of a possible competitive market advantage, but also because of the resulting increase in aircraft productivity. Aircraft designed to cruise at Mach numbers greater than those of present-day transports but less than those which produce a sonic boom on the ground were studied. The purpose of the study was three-fold: (1) to compare, on an equal basis, the performance and economics of advanced commercial transport aircraft designed to cruise at Mach numbers 0.90, 0.98, and 1.15; (2) to determine the sensitive technical areas affecting the performance and economics of the aircraft; and (3) to assess the impact of advanced technology, particularly the supercritical wing and advanced composite materials on the performance and economics of the aircraft.

Williams, L. J.↗
NASA NTRS1972

Effect of jet convergence angle on the performance of annular nozzles with semitoroidal concave plugs at Mach numbers up to 1.82

Results of an investigation at static conditions and at Mach numbers up to 1.82 are presented for 12 nozzle configurations which have jet convergence angle and jet throat area as geometric parameters. The variation of jet convergence angle from 15 to 40 deg had little effect on the performance of the nozzles having the large value of primary throat area; however, increasing jet convergence angle generally had an adverse effect on performance of the nozzles having the smaller value of primary throat area. The performance of the nozzle configurations with the larger primary throat area is competitive with nozzles designed for operation over the Mach number range.

Mercer, C. E.↗
NASA NTRS1971

Characteristics of the continuous wave neutral argon laser.

Study of the characteristics of the CW neutral argon IR laser, using a variety of techniques. The output power enhancement effects of helium and chlorine gases are measured, and the reasons for the enhancement are determined. The gain is measured for the 2.397-, 2.208-, 2.062-, and 1.792-micron laser lines, using an internal cavity-loss method and a single-pass amplifier method. In addition, the saturation intensity is measured, and competition effects are studied. It is concluded that helium aids excitation of the upper laser levels by producing a significant increase in the electron temperature. Chlorine is shown to aid deexcitation of the lower laser levels by partially depopulating the metastable argon 4s levels that lie just below them.

Dauger, A. B.↗
NASA NTRS1971

Technology of nuclear-Brayton space power systems.

The present technology of Brayton power systems is reviewed. The potential for even higher system efficiency at the 10 kWe level is assessed as well as the potential for comparable efficiency with an output of 1 or 2 kWe. System accommodation of isotope decay is briefly discussed. The salient features are described for a Brayton power system based on this technology and employing the ZrH reactor. Reactor lives for this and competitive systems are compared. Growth capability with an advanced reactor is assessed. A concept for application of this technology to driving a gas-dynamic laser is described.

English, R. E.↗
NASA NTRS1972

Positive ion chemistry of the D and E regions.

A comparison of ion-molecule reaction rates implied by E- and F-region chemistry and measured in the laboratory shows on the whole good agreement except that the ionospheric analysis demands stronger temperature dependences. In the daytime D region, it is claimed that the reconciliation of positive ion densities with production rates and laboratory rate constants would best be achieved if (1) ionization of O2(1 delta g) and hydration of O4(+) in competition with the reduction of O4(+) to O2(+) by O were the dominant source of hydrates between 85 and 77 km, (2) ionization of NO by solar Lyman alpha followed by hydration was the dominant source of hydrates below 77 km, and (3) for some reason, Lyman alpha did not ionize NO effectively at pressures below those prevailing at 75 km.

Donahue, T. M.↗
NASA NTRS1972

Diffusion bonded columbium panels for the shuttle heat shield.

Work at North American Rockwell in the development of a satisfactory panel diffusion bonding method for Nb shuttle orbiter heat shield panel designs is reviewed. The topics include the diffusion bonding process, panel fabrication and quality control. A practicable Nb alloy diffusion bonding method, using a Ti foil interleaf, is described and is characterized as one providing a production basis at competitive cost.

Korb, L. J.↗
NASA NTRS1970

An experiment with interactive planning models

Experiments on decision making in planning problems are described. Executives were tested in dealing with capital investments and competitive pricing decisions under conditions of uncertainty. A software package, the interactive risk analysis model system, was developed, and two controlled experiments were conducted. It is concluded that planning models can aid management, and predicted uses of the models are as a central tool, as an educational tool, to improve consistency in decision making, to improve communications, and as a tool for consensus decision making.

Beville, J.↗
NASA NTRS1972

Comparative performance of several SST configurations powered by noise limited turbojet engines

A simplified study was made in which the mission performances of three Mach 2.7 airplane configurations were compared. Both wing loading and size of the unaugmented turbojet engines were varied at different levels of suppressor technology. The lowest gross weight and the best return on investment were obtained with an advanced arrow wing configuration when a mission range of 4200 nautical miles was specified. This comparison was made for the takeoff noise levels specified in F.A.R. 36 using retractable jet noise suppressors assumed to be capable of 15 PNdb of suppression with only a 7.5-percent thrust loss. With less advanced suppressor technology, a modified delta configuration is a close competitor of the arrow wing. Despite its good takeoff characteristics, a swing-wing configuration was too structurally heavy to be competitive at F.A.R. 36 noise levels. Engine performance and weight commensurate with engine definition in 1975 were postulated.

Whitlow, J. B., Jr.↗
NASA NTRS1973

Northwest passage: Trade route for large air cushion vehicles

A conceptual vehicle and powerplant (10,000-ton) nuclear-powered air-cushion vehicle (ACV) that could open the Northwest Passage and other Arctic passages to commercial traffic is identified. The report contains a description of the conceptual vehicle, including the powerplant and operations, an assessment of technical feasibility, estimates of capital and operating costs, and identification of eligible cargo and markets. A comparison of the nuclear ACV freighter with nuclear container ships shows that for containerized or roll-on/roll-off cargo the ACV would provide greatly reduced transit time between North Atlantic and North Pacific ports at a competitive cost.

Anderson, J. L.↗
NASA NTRS1973

Evaluation of an electrochemical N2/H2 gas separator

A program was successfully completed to evaluate an electrochemical nitrogen/hydrogen (N2/H2) separator for use in a spacecraft nitrogen (N2) generator. Based on the technical data obtained a N2/H2 separator subsystem consisting of an organic polymer gas permeator first stage and an electrochemical second and third stage was estimated to have the lowest total spared equivalent weight, 257 kg (566 lb), for a 15 lb/day N2 generation rate. A pre-design analysis of the electrochemical N2/H2 separator revealed that its use as a first stage resulted in too high a power requirement to be competitive with the organic polymer membrane and the palladium-silver membrane separation methods. As a result, program emphasis was placed on evaluating the electrochemical. A parametric test program characterized cell performance and established second- and third-stage electrochemical N2/H2 separator operating conditions. A design verification test was completed on the second and third stages. The second stage was then successfully endurance tested for 200 hours.

Marshall, R. D.↗