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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 1,315 records · Page 73
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

An isotope heat source integrated with a 7 kW/e/ to 25 kW/e/ Brayton cycle space power supply.

The power system described is intended for applications in a manned space mission. The Isotope Reentry Vehicle (IRV) developed is considered together with the Heat Source (HS), the Heat Source Heat Exchanger and the Brayton Cycle Power Conversion Module. Other subjects discussed include the IRV/Brayton cycle spacecraft integration concept, abort and deorbit mechanization, emergency cooling methods, and crew shielding requirements. Mounting and integration for the IRV is to a large degree controlled by nuclear safety requirements. Another major factor in the installation concept is the type of emergency cooling or passive heat dump mode used in rejection of HS energy.

Ryan, R. L.↗
NASA NTRS1973

Space Shuttle flight operations.

The current flight operations concepts for the Space Shuttle are outlined, with emphasis on vehicle and ground support functions in actual missions exclusive of initial tests. The Space Shuttle sortie and delivery-retrieval mission profiles are described along with crew nomenclature and duties, vehicle launch-to-insertion operations, systems operation, correction measures for noncritical malfunctions, management of consumables, payload operations, radiation and contamination monitoring, reentry and landing procedures, and ground support operations.

Carlton, R. L.↗
NASA NTRS1973

Nuclear safety considerations for the design of a shuttle launched 500 to 2000 watt isotope Brayton power system.

An extensive study was conducted to evaluate the safety requirements for the design of a heat source assembly for use in a shuttle launched, isotope Brayton electric power system for the 500-W(e) to 2 kWe range. The assembly is a self-contained package which supplies heat to a power conversion system. A typical mission profile for a shuttle launched, earth orbital mission was assumed. Critical mission accidents were identified and evaluated to determine their impact upon the design of the Heat Source Assembly. Earth-orbital decay reentry analyses were performed to demonstrate survivability of the heat source. Safety design requirements were developed to ensure survivability under credible accident conditions including loss of the power conversion system in orbit.

Garate, J. A.↗
NASA NTRS1973

Unsteady aerodynamic loads on slender cones at free-stream Mach numbers from 0 to 22.

Results of an experimental study to determine the flow-induced unsteady aerodynamic loads on slender cones at very high Mach numbers. Experiments on 8-deg half-angle-cone/flat-base configurations were conducted at free-stream Mach numbers of 6 and 15 and Reynolds numbers corresponding to shuttle reentry conditions. The flow facilities used were the H-3 Hypersonic Facility (Mach 6) and the Longshot Free Piston Tunnel (Mach 15) of the Von Karman Institute for Fluid Dynamics in Rhode-St.-Genese, Belgium. With these test results and pertinent results from other research efforts, data were available at free-stream Mach numbers of 0.67, 2.5, 3, 4, 6, 15, and 22, so that empirical expressions could be developed for the Mach number dependence (1) of the overall fluctuating pressure under an attached turbulence boundary layer and (2) of the overall fluctuating base pressure.

Heller, H. H.↗
NASA NTRS1975

Color-coded area sensitivity maps of photomultipliers

Technique was devised specifically for testing photomultipliers and other photodetectors, but it could also be used to color code any type of mapping data, such as weather or topographical maps, thermal or pressure distributions on reentry surfaces, or any other three-dimensional data to be displayed in two-dimensional form.

Youngbluth, O., Jr.↗
NASA NTRS1973

Space Simulation, 7th

Space simulation facilities and techniques are outlined that encompass thermal scale modeling, computerized simulations, reentry materials, spacecraft contamination, solar simulation, vacuum tests, and heat transfer studies.

Source record↗
NASA NTRS1973

The orbital mechanics of flight mechanics

A reference handbook on modern dynamic orbit theory is presented. Starting from the most basic inverse-square law, the law of gravity for a sphere is developed, and the motion of point masses under the influence of a sphere is considered. The reentry theory and the orbital theory are discussed along with the relative motion between two bodies in orbit about the same planet. Relative-motion equations, rectangular coordinates, and the mechanics of simple rigid bodies under the influence of a gravity gradient field are also discussed.

Dunning, R. S.↗
NASA NTRS1973

Effects of reaction control system jet simulation on the stability and control characteristics of a 0.015-scale space shuttle orbiter model in the Ames Research Center 3.5-foot hypersonic wind tunnel

An experimental investigation was performed in the Ames Research Center 3.5-Foot Hypersonic Wind Tunnel to obtain detailed effects which interactions between the RCS jet flow field and the local orbiter flow field have on orbiter hypersonic stability and control characteristics. Six-component force data were obtained through an angle-of-attack range of 15 to 35 deg with 0 deg angle of sideslip. The test was conducted with yaw, pitch and roll jet simulation at a free-stream Mach number of 10.3. These data simulate two SSV reentry flight conditions at Mach numbers of 28.3 and 10.3. Fuselage base pressures and pressures on the nonmetric RCS pods were obtained in addition to the basic force measurements. Model 42-0 was used for these tests.

Dziubala, T. J.↗
NASA NTRS1974

Effect of chromia doping of thermal stability of silica fibers

Commercial silica fibers of the type being evaluated for reusable surface insulation for reentry vehicles were found to be porous and composed of subfibers. The effect on shrinkage and devitrification of soaking such silica fibers in water, acetic acid, chromium acetate, and chromium nitrate solutions was studied. Felted specimens made of chromia-doped fibers shrunk only about one-half as much as those made of untreated fibers after exposure in air for 4 hours at 1300 C. The devitrification rate of fibers given prolonged soaks in chromium nitrate was as low as that of as-received fibers.

Zaplatynsky, I.↗
NASA NTRS1972

Study of Uncertainties of Predicting Space Shuttle Thermal Environment

Quantitative estimates of the uncertainty in predicting aerodynamic heating rates for a fully reusable space shuttle system are developed and the impact of these uncertainties on Thermal Protection System (TPS) weight are discussed. The study approach consisted of statistical evaluations of the scatter of heating data on shuttle configurations about state-of-the-art heating prediction methods to define the uncertainty in these heating predictions. The uncertainties were then applied as heating rate increments to the nominal predicted heating rate to define the uncertainty in TPS weight. Separate evaluations were made for the booster and orbiter, for trajectories which included boost through reentry and touchdown. For purposes of analysis, the vehicle configuration is divided into areas in which a given prediction method is expected to apply, and separate uncertainty factors and corresponding uncertainty in TPS weight derived for each area.

Fehrman, A. L.↗
NASA NTRS1974

Phase change paint tests on Rockwell orbiter/tank and orbiter alone configurations (OH3A/OH3B)

Wind tunnel tests were conducted on scale models of the space shuttle orbiter and external tank. The tests were designed to determine the basic heating rate and interference effects on the orbiter-tank configuration and to analyze the effectiveness of the thermal protective system on the reentry vehicle. The phase change paint techniques were used to determine areodynamic heating rates. Oil flow and schlieren photographs were used for flow visualization.

Quan, M.↗
NASA NTRS1974

Improved coating for silica fiber based ceramic Reusable Surface Insulation (CRSI)

A series of coatings was developed for the space shuttle type silica fiber insulation system and characterized for optical and physical properties. Reentry simulation tests were run using a radiant panel and also using a hypersonic plasma arc. The coatings produced had improved physical and optical properties as well as greater reuse capability over the GE version of the JSC-0042 coating.

Ormiston, T. J.↗
NASA NTRS1972

Mechanical fasteners for 1800 F and above

The state-of-the-art of mechanical fasteners is reviewed for 1800 F and above. Some of the problems associated with the use of these fasteners are discussed in view of the projected requirements of the space shuttle for metallic heal shields which would be reusable for 100 cycles of orbit and reentry.

Roach, T. A.↗
NASA NTRS1974

Multivariant function model generation

The development of computer programs applicable to space vehicle guidance was conducted. The subjects discussed are as follows: (1) determination of optimum reentry trajectories, (2) development of equations for performance of trajectory computation, (3) vehicle control for fuel optimization, (4) development of equations for performance trajectory computations, (5) applications and solution of Hamilton-Jacobi equation, and (6) stresses in dome shaped shells with discontinuities at the apex.

Source record↗
NASA NTRS1974

A method for determining optimum re-entry trajectories

The Pontryagin Maximum Principle is used to formulate the problem of finding optimum atmospheric vehicular reentry trajectories. The optimization problem is that of minimizing an integral which is a function of the state and control variables. The vehicle's motion is assumed to be influenced by a gravitational force and an aerodynamic force. The problem is formulated and the necessary equations are developed simultaneously for three sets of Euler angles. Computational procedures are suggested so that numerical trajectories may be generated.

Reiter, W. F.↗
NASA NTRS1974

Research on development of equations for performance trajectory computation

A computer program for computing the performance trajectory of spacecraft was developed. An analytical study of a minimum fuel flight for high speed aircraft was conducted. The computer program to compute a minimum time reentry into the atmosphere for an Apollo-type capsule is presented. A technical summary of the minimum fuel problem is provided.

Harmon, G. R.↗
NASA NTRS1974

WAATS: A computer program for Weights Analysis of Advanced Transportation Systems

A historical weight estimating technique for advanced transportation systems is presented. The classical approach to weight estimation is discussed and sufficient data is presented to estimate weights for a large spectrum of flight vehicles including horizontal and vertical takeoff aircraft, boosters and reentry vehicles. A computer program, WAATS (Weights Analysis for Advanced Transportation Systems) embracing the techniques discussed has been written and user instructions are presented. The program was developed for use in the ODIN (Optimal Design Integration System) system.

Glatt, C. R.↗
NASA NTRS1974

A new guidance strategy for unpowered Space Shuttle orbiter flight

A new guidance strategy for use during the TAEM (terminal area energy management) phase of the Shuttle reentry flight has been developed. This guidance system steers the vehicle from initial conditions at about 70,000 ft altitude and Mach 1.5 to the beginning of the final landing maneuver. Explicit control of the vehicle's total energy (potential plus kinetic) via the energy dissipation rate allows this system to effectively control the vehicle's energy in the presence of a head or tail wind without a-priori knowledge of the wind. Furthermore, this is accomplished while maintaining a wings-level attitude during most of the flight.

Elias, A.↗