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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Transmitter and receiver antenna gain analysis for laser radar and communication systems

A comprehensive and fairly self-contained study of centrally obscured optical transmitting and receiving antennas is presented and is intended for use by the laser radar and communication systems designer. The material is presented in a format which allows the rapid and accurate evaluation of antenna gain. The Fresnel approximation to scalar wave theory is reviewed and the antenna analysis proceeds in terms of the power gain. Conventional range equations may then be used to calculate the power budget. The transmitter calculations, resulting in near and far field antenna gain patterns, assumes the antenna is illuminated by a laser operating in the fundamental cavity mode. A simple equation is derived for matching the incident source distribution to a general antenna configuration for maximum on-axis gain. An interpretation of the resultant gain curves allows a number of auxiliary design curves to be drawn which display the losses in antenna gain due to pointing errors and the cone angle of the outgoing beam as a function of antenna size and central obscuration. The use of telescope defocusing as an approach to spreading the beam for target acquisition is compared to some alternate methods.

Klein, B. J.↗
NASA NTRS1973

Zero-gravity cloud physics laboratory: Candidate experiments definition and preliminary concept studies

The candidate definition studies on the zero-g cloud physics laboratory are covered. This laboratory will be an independent self-contained shuttle sortie payload. Several critical technology areas have been identified and studied to assure proper consideration in terms of engineering requirements for the final design. Areas include chambers, gas and particle generators, environmental controls, motion controls, change controls, observational techniques, and composition controls. This unique laboratory will allow studies to be performed without mechanical, aerodynamics, electrical, or other type techniques to support the object under study. This report also covers the candidate experiment definitions, chambers and experiment classes, laboratory concepts and plans, special supporting studies, early flight opportunities and payload planning data for overall shuttle payload requirements assessments.

Eaton, L. R.↗
NASA NTRS1972

Stability of large-scale systems.

The purpose of this paper is to present the results obtained in stability study of large-scale systems based upon the comparison principle and vector Liapunov functions. The exposition is essentially self-contained, with emphasis on recent innovations which utilize explicit information about the system structure. This provides a natural foundation for the stability theory of dynamic systems under structural perturbations.

Siljak, D. D.↗
NASA NTRS1972

An integrated radiation physics computer code system.

An integrated computer code system for the semi-automatic and rapid analysis of experimental and analytic problems in gamma photon and fast neutron radiation physics is presented. Such problems as the design of optimum radiation shields and radioisotope power source configurations may be studied. The system codes allow for the unfolding of complex neutron and gamma photon experimental spectra. Monte Carlo and analytic techniques are used for the theoretical prediction of radiation transport. The system includes a multichannel pulse-height analyzer scintillation and semiconductor spectrometer coupled to an on-line digital computer with appropriate peripheral equipment. The system is geometry generalized as well as self-contained with respect to material nuclear cross sections and the determination of the spectrometer response functions. Input data may be either analytic or experimental.

Steyn, J. J.↗
NASA NTRS1972

A modular Space Station/Base electrical power system - Requirements and design study.

The requirements and procedures necessary for definition and specification of an electrical power system (EPS) for the future space station are discussed herein. The considered space station EPS consists of a replaceable main power module with self-contained auxiliary power, guidance, control, and communication subsystems. This independent power source may 'plug into' a space station module which has its own electrical distribution, control, power conditioning, and auxiliary power subsystems. Integration problems are discussed, and a transmission system selected with local floor-by-floor power conditioning and distribution in the station module. This technique eliminates the need for an immediate long range decision on the ultimate space base power sources by providing capability for almost any currently considered option.

Eliason, J. T.↗
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

SIRU utilization. Volume 2: Software description and program documentation

A complete description of the additional analysis, development and evaluation provided for the SIRU system as identified in the requirements for the SIRU utilization program is presented. The SIRU configuration is a modular inertial subsystem with hardware and software features that achieve fault tolerant operational capabilities. The SIRU redundant hardware design is formulated about a six gyro and six accelerometer instrument module package. The modules are mounted in this package so that their measurement input axes form a unique symmetrical pattern that corresponds to the array of perpendiculars to the faces of a regular dodecahedron. This six axes array provides redundant independent sensing and the symmetry enables the formulation of an optimal software redundant data processing structure with self-contained fault detection and isolation (FDI) capabilities. Documentation of the additional software and software modifications required to implement the utilization capabilities includes assembly listings and flow charts

Oehrle, J.↗
NASA NTRS1973

NASTRAN multipartitioning and one-shot substructuring

For intermediate size problems where all the data is accessible, the present method of substructuring in three separate phases (for static analysis) is unneccessarily cumbersome. The versatility of NASTRAN's DMAP and internal logic lends itself to finding a practical alternative to these procedures whereby self-contained special-purpose ALTER packages can be written to be run in one pass. Two examples are presented here under the titles of multipartitioning and one-shot substructuring. The flow of multipartitioning resembles that of the present three-phase substructuring. The basic effect is to partition the structure into substructures and operate on each substructure separately. This can be used to reduce the bandwidth of a given problem as well as to store information which will allow a change to be made in one of the substructures in a later run. This latter procedure is carried out in a second program titled one-shot substructuring.

Levy, A.↗
NASA NTRS1973

Wind power systems for individual applications

A small windpower system is described which is suitable for electrifying a house. The self-contained unit consists of a two kilowatt wind driven generator, a set of 19 storage batteries, a small dc to ac inverter, and a gasoline generator for use as an emergency backup system in case of prolonged calm periods. Cost effectiveness of the electricity generated by this windmill system comes out to about 15 cents per kilowatt hour - assuming a 10 year life for the batteries and a 20 year life for the other components. Some other small windpower systems are also described, and it is shown that a windpowered generator in the 15- to 25-kilowatt output range coupled to a direct heated water storage system is able to heat a typical New England home.

Clews, H. M.↗
NASA NTRS1973

A 30-cm thruster power processor test console

The development of a high performance ion propulsion system composed of an ion thruster and its associated power processing equipment, dictates the establishment of a mutually compatible set of electrical characteristics. A 30-cm thruster power processing console has been developed which utilizes power and control circuitry applicable to flight hardware designs, incorporates interface circuitry for optional direct computer control, and has self-contained instrumentation for assessing steady-state and dynamic system behavior. This paper discusses the console's design, utility, performance, and the potential impact of this development effort on future hardware designs.

Herron, B. G.↗
NASA NTRS1973

Safety considerations involved in testing, checkout and launch operations at Cape Kennedy

This paper concerns itself with identifying safety problems associated with launch operations conducted during preparations for manned space flights at Cape Kennedy. This includes transportation and assembly of large space vehicles in the Vehicle Assembly Building, rollout to Launch Pad 39, test, checkout, and the launch countdown. Under these broad categories, the risks of fuel and oxidizer loading, installation of pyrotechnics, and similar hazardous operations are discussed. The many aspects for fire and rescue requirements are examined. These encompass the water deluge systems on the Mobile Service Structure and the Mobile Launcher, the insulated fire and rescue tractor, slide wire escape system, fire proximity suits, self-contained breathing apparatus and emergency cutting tools. In addition, written procedures for tests, emergencies, rescue and backout, as well as certification of personnel and TV monitoring of the launch system are detailed.-

Bolger, P. H.↗
NASA NTRS1974

Development status of solid polymer electrolyte water electrolysis for manned spacecraft life support systems

Details of the design and system verification test results are presented for a six-man-rated oxygen generation system. The system configuration incorporates components and instrumentation for computer-controlled operation with automatic start-up/shutdown sequencing, fault detection and isolation, and with self-contained sensors and controls for automatic safe emergency shutdown. All fluid and electrical components, sensors, and electronic controls are designed to be easily maintainable under zero-gravity conditions. On-board component spares are utilized in the system concept to sustain long-term operation (six months minimum) in a manned spacecraft application. The system is centered on a 27-cell solid polymer electrolyte water electrolysis module which, combined with the associated system components and controls, forms a total system envelope 40 in. high, 40 in. wide, and 30 in. deep.

Nuttall, L. J.↗
NASA NTRS1972

An Adaptive Technique for a Redundant-Sensor Navigation System

An on-line adaptive technique is developed to provide a self-contained redundant-sensor navigation system with a capability to utilize its full potentiality in reliability and performance. The gyro navigation system is modeled as a Gauss-Markov process, with degradation modes defined as changes in characteristics specified by parameters associated with the model. The adaptive system is formulated as a multistage stochastic process: (1) a detection system, (2) an identification system and (3) a compensation system. It is shown that the sufficient statistics for the partially observable process in the detection and identification system is the posterior measure of the state of degradation, conditioned on the measurement history.

Chien, T. T.↗
NASA NTRS1974

Electrochemical carbon dioxide concentrator subsystem math model

A steady state computer simulation model has been developed to describe the performance of a total six man, self-contained electrochemical carbon dioxide concentrator subsystem built for the space station prototype. The math model combines expressions describing the performance of the electrochemical depolarized carbon dioxide concentrator cells and modules previously developed with expressions describing the performance of the other major CS-6 components. The model is capable of accurately predicting CS-6 performance over EDC operating ranges and the computer simulation results agree with experimental data obtained over the prediction range.

Marshall, R. D.↗
NASA NTRS1974

Prototype color field sequential television lens assembly

The design, development, and evaluation of a prototype modular lens assembly with a self-contained field sequential color wheel is presented. The design of a color wheel of maximum efficiency, the selection of spectral filters, and the design of a quiet, efficient wheel drive system are included. Design tradeoffs considered for each aspect of the modular assembly are discussed. Emphasis is placed on achieving a design which can be attached directly to an unmodified camera, thus permitting use of the assembly in evaluating various candidate camera and sensor designs. A technique is described which permits maintaining high optical efficiency with an unmodified camera. A motor synchronization system is developed which requires only the vertical synchronization signal as a reference frequency input. Equations and tradeoff curves are developed to permit optimizing the filter wheel aperture shapes for a variety of different design conditions.

Source record↗
NASA NTRS1974

Engineering report: Oxygen boost compressor study

An oxygen boost compressor is described which supports a self-contained life support system. A preliminary analysis of the compressor is presented along with performance test results, and recommendations for follow-on efforts.

Tera, L. S.↗
NASA NTRS1974

The prologue - A look at Apollo and Apollo/Soyuz

The importance of man to the success of the Apollo missions is considered, giving attention to man's capabilities to provide rapid response to emergencies, the ability to carry out self-contained operations in the absence of communication with the ground, and the ability for rapid sensing, reaction, and vehicle control. In the upcoming Shuttle era the capabilities possessed by man are to be further utilized. The concern for the safety of men in space is one of the major reasons for the flight of the Apollo/Soyuz test project. Details regarding this project are discussed, taking into account the mission profile, hardware, program organization, mission communication modes, tracking, the participating astronauts and cosmonauts, and scientific studies.

Lee, C. M.↗