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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

The origin of the moon.

Recent studies of the dynamics and thermodynamics of the early solar nebula have provided a basis for a theory of the origin of the moon which is consistent with presently developed views of the origin of the solar system. The hypothesis of inhomogeneous planetary accretion is extended. It is suggested that the anomalous properties of the moon, such as its enrichment in Ca, Al, Ti, and other refractories and its depletion in iron and volatiles can be explained if the bulk of the moon represents a high temperature condensate. It is proposed that the moon is composed chiefly of compounds that condense before iron and that the volatile content of the moon was brought in as a thin veneer after the solar nebula dissipated.

Anderson, D. L.↗
NASA NTRS1972

Regenerative fuel cell study

The completion of the study is reported for the regenerative fuel cell subsystem (RFCS) as an energy storage process for use aboard the space shuttle launched modular space station (MSS). The MSS mission requirements, and RFCS are discussed, and a comparison between RFCS and a nickel cadmium battery subsystem is presented. Development costs are also discussed.

Wynveen, R. A.↗
NASA NTRS1974

An approximate inviscid radiating flow-field analysis for sphere-cone Venusian entry vehicles

A computational method based on the earlier work of one of the authors has been improved and modified to provide an accurate and rapid prediction of the radiating flow about blunt conical probes entering the atmosphere of Venus. Special features include a more general approximate equation of state, a more rapidly converging iteration scheme, a 38-step absorption coefficient model for a Venus atmosphere gas mixture model, and a shock-shape formula which yields a computed body shape in excellent agreement with the desired body. The method was used to calculate distributions of radiative heating for a large spherically blunted conical probe vehicle (1.219 m base diameter) and for three small spherically blunted conical probe vehicles (0.724 m base diameter). Solutions obtained with the presently developed approximate method required short computing times of the order of 1 to 3 minutes for each complete solution and gave agreements of 10% to 15% with the more exact predictions.

Falanga, R. A.↗
NASA NTRS1974

MSFC Skylab structures and mechanical systems mission evaluation

A performance analysis for structural and mechanical major hardware systems and components is presented. Development background testing, modifications, and requirement adjustments are included. Functional narratives are provided for comparison purposes as are predicted design performance criterion. Each item is evaluated on an individual basis: that is, (1) history (requirements, design, manufacture, and test); (2) in-orbit performance (description and analysis); and (3) conclusions and recommendations regarding future space hardware application. Overall, the structural and mechanical performance of the Skylab hardware was outstanding.

Source record↗
NASA NTRS1976

Fluctuating pressures in flow fields of jets

The powered lift configurations under present development for STOL aircraft are the externally blown flap (EBF), involving direct jet impingement on the aircraft flaps, and the upper surface blown (USB), where the jet flow is attached on the upper surface of the wing and directed downwards. Towards the goal of developing scaling laws to predict unsteady loads imposed on the structural components of these STOL aircraft from small model tests, the near field fluctuating pressure behavior for the simplified cases of a round free cold jet and the same jet impinging on a flat plate was investigated. Examples are given of coherences, phase lags (giving convection velocities), and overall fluctuating pressure levels measured. The fluctuating pressure levels measured on the flat plate are compared to surface fluctuating pressure levels measured on full-scale powered-lift configuration models.

Schroeder, J. C.↗
NASA NTRS1975

Numerical solution of quadratic matrix equations for free vibration analysis of structures

This paper is concerned with the efficient and accurate solution of the eigenvalue problem represented by quadratic matrix equations. Such matrix forms are obtained in connection with the free vibration analysis of structures, discretized by finite 'dynamic' elements, resulting in frequency-dependent stiffness and inertia matrices. The paper presents a new numerical solution procedure of the quadratic matrix equations, based on a combined Sturm sequence and inverse iteration technique enabling economical and accurate determination of a few required eigenvalues and associated vectors. An alternative procedure based on a simultaneous iteration procedure is also described when only the first few modes are the usual requirement. The employment of finite dynamic elements in conjunction with the presently developed eigenvalue routines results in a most significant economy in the dynamic analysis of structures.

Gupta, K. K.↗
NASA NTRS1977

Visible and infrared imaging radiometers for ocean observations

The current status of visible and infrared sensors designed for the remote monitoring of the oceans is reviewed. Emphasis is placed on multichannel scanning radiometers that are either operational or under development. Present design practices and parameter constraints are discussed. Airborne sensor systems examined include the ocean color scanner and the ocean temperature scanner. The costal zone color scanner and advanced very high resolution radiometer are reviewed with emphasis on design specifications. Recent technological advances and their impact on sensor design are examined.

Barnes, W. L.↗
NASA NTRS1977

Visible and infrared imaging radiometers for ocean observations

The technology of visible and infrared imaging sensors designed for the remote monitoring of the oceans is assessed. Emphasis is placed on multichannel scanning radiometers that are either operational or under development. Present design practices and parameter constraints are discussed. Airborne sensor systems examined include the Ocean Color Scanner (OCS) and the Ocean Temperature Scanner (OTS). The Coastal Zone Color Scanner (CZCS) and Advanced Very High Resolution Radiometer (AVHRR), are reviewed with emphasis on design specifications, expected completion, and anticipated performance. Finally, recent technology advances and their probable impact on sensor design are examined.

Barnes, W. L.↗
NASA NTRS1979

Near-field noise prediction for aircraft in cruising flight: Methods manual

Methods for predicting noise at any point on an aircraft while the aircraft is in a cruise flight regime are presented. Developed for use in laminar flow control (LFC) noise effects analyses, they can be used in any case where aircraft generated noise needs to be evaluated at a location on an aircraft while under high altitude, high speed conditions. For each noise source applicable to the LFC problem, a noise computational procedure is given in algorithm format, suitable for computerization. Three categories of noise sources are covered: (1) propulsion system, (2) airframe, and (3) LFC suction system. In addition, procedures are given for noise modifications due to source soundproofing and the shielding effects of the aircraft structure wherever needed. Sample cases, for each of the individual noise source procedures, are provided to familiarize the user with typical input and computed data.

Tibbetts, J. G.↗
NASA NTRS1979

HEAO Science Symposium

Scientific results from the early analysis of data from the HEAO 1 mission are presented. Development of astronomical catalogs and maps, X-ray variability, extragalactic astronomy, X-ray iron line emission, and optical identification and spectroscopy of X-ray sources are among the topics discussed. Results from HEAO 2 imaging and nonimaging instruments are included.

Dailey, C.↗
NASA NTRS1980

Lubrication of rolling-element bearings

The lubrication of rolling element bearings is surveyed. Emphasis is on the critical design aspects related to speed, temperature, and ambient pressure environment. Types of lubrication including grease, jets, mist, wick, and through the race are discussed. The historical development, present state of technology, and the future problems of rolling element bearing lubrication are discussed.

Parker, R. J.↗
NASA NTRS1980

Lubrication of rolling element bearings

This paper is a broad survey of the lubrication of rolling-element bearings. Emphasis is on the critical design aspects related to speed, temperature, and ambient pressure environment. Types of lubrication including grease, jets, mist, wick, and through-the-race are discussed. The paper covers the historical development, present state of technology, and the future problems of rolling-element bearing lubrication.

Parker, R. J.↗
NASA NTRS1981

Coherent optical determination of the leaf angle distribution of corn

A coherent optical technique for the diffraction analysis of an image is presented. Developments in radar remote sensing shows a need to understand plant geometry and its relationship to plant moisture, soil moisture, and the radar backscattering coefficient. A corn plant changes its leaf angle distribution, as a function of time, from a uniform distribution to one that is strongly vertical. It is shown that plant and soil moisture may have an effect on plant geometry.

Ulaby, F. T.↗
NASA NTRS1983

Bending waves in Saturn's rings

Saturn A ring brightness variations are investigated and noted to be caused by vertical corrugations of the local ring plane due to a spiral bending wave, resonantly excited by Mimas, which propagates inwardly by way of the ring particle collective gravity. Some aspects of the presently developed theory of forced bending waves have been previously treated in the galactic context. It is noted that the theory is generally in good agreement with observations, and in particular may resolve the conflict between ground-based estimates of 1-2 km for the global ring thickness and Voyager stellar occultation measurements of less than 200 m for the local ring thickness.

Shu, F. H.↗
NASA NTRS1983

Solid-state laser sources for remote sensing

Recent progress in slab-geometry and conventional rod Nd:YAG solid-state lasers for applications in remote sensing is presented. Developments in slab geometry lasers, which were aimed at improving pulse energy and tuning range, have been based on the use of a Nd:glass substrate with a zig-zag optical path, with selective Raman shifting in gases and harmonic generation in LiNbO3 and KDP to extend the tuning range into the UV and visible regions. The theoretically predicted advantages of the elimination of birefringence and thermal and stress-induced focusing in the slab-geometry laser have been confirmed in measurements on a test-bed Nd:glass system, and a CW lamp pumped Nd:YAG oscillator, which have also demonstrated an order of magnitude improvement in laser performance. A single axial mode Nd:YAG oscillator has also been designed which, operating in a 3-msec quasi-CW mode, has a chirp rate of 30 kHz/microsec and a free-running stability of + or - 20 MHz. With chirp compensation, this stability is adequate for wind velocity measurements by coherent lidar.

Byer, R. L.↗
NASA NTRS1981

The NASTRAN theoretical manual

Designed to accommodate additions and modifications, this commentary on NASTRAN describes the problem solving capabilities of the program in a narrative fashion and presents developments of the analytical and numerical procedures that underlie the program. Seventeen major sections and numerous subsections cover; the organizational aspects of the program, utility matrix routines, static structural analysis, heat transfer, dynamic structural analysis, computer graphics, special structural modeling techniques, error analysis, interaction between structures and fluids, and aeroelastic analysis.

Source record↗
NASA NTRS1984

Advanced high-power transfer through rotary interfaces

A roll-ring design that is uniquely suited for rotary signal/power transfer in space applications is described. Two high-power configurations of the roll ring were developed. Present lab-proven hardware is available with power transfer capability of 2 kW at 200 amps and higher power units with 100-kW capability are in the design stage. Theoretical analysis indicated that power levels of kW are possible.

Jacobson, P.↗
NASA NTRS1985

Symmetric Composite Laminate Stress Analysis

It is demonstrated that COSMIC/NASTRAN may be used to analyze plate and shell structures made of symmetric composite laminates. Although general composite laminates cannot be analyzed using NASTRAN, the theoretical development presented herein indicates that the integrated constitutive laws of a symmetric composite laminate resemble those of a homogeneous anisotropic plate, which can be analyzed using NASTRAN. A detailed analysis procedure is presented, as well as an illustrative example.

Wang, T.↗