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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 937 records · Page 52
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Diagnostic evaluations of a beam-shielded 8-cm mercury ion thruster

An engineering model thruster fitted with a remotely actuated graphite fiber polyimide composite beam shield was tested in a 3- by 6.5-meter vacuum facility for in-situ assessment of beam shield effects on thruster performance. Accelerator drain current neutralizer floating potential and ion beam floating potential increased slightly when the shield was moved into position. A target exposed to the low density regions of the ion beam was used to map the boundaries of energetic fringe ions capable of sputtering. The particle efflux was evaluated by measurement of film deposits on cold, heated, bare, and enclosed glass slides.

Nakanishi, S.↗
NASA NTRS1977

Hierarchy of simulation models for a turbofan gas engine

Steady-state and transient performance of an F-100-like turbofan gas engine are modeled by a computer program, DYNGEN, developed by NASA. The model employs block data maps and includes about 25 states. Low-order nonlinear analytical and linear techniques are described in terms of their application to the model. Experimental comparisons illustrating the accuracy of each model are presented.

Longenbaker, W. E.↗
NASA NTRS1979

Solar Power Satellite (SPS) pilot beam and communication link subsystem investigation study, phase 1

A preliminary engineering model of ionospheric interactions with the pilot beam was established and used to demonstrate that the dual frequency baseline pilot beam system might not be viable in the presence of an unstable transmission path. Alternate approaches to remove this difficulty are described. Although ionospheric fluctuations will not significantly degrade beam pointing or raise the sidelobe levels, they will reduce transmission efficiency by upwards of 25%. Mitigating strategies to substantially reduce this effect are proposed. Based on the Klystron noise spectrum, the pilot beam transmitter power was determined as a function of frequency offset from the power beam carrier frequency. The RFI from the pilot beam, on the ground and at geosynchronous orbit is shown. Noise levels on the earth's surface due to the SPS are presented as a function of frequency and the number of SPS systems. Analysis of the communication subsystem indicates that a standard telemetry line of 1.544 MB/s would satisfy both voice and data link requirements. Additional links would be required for TV and radio transmissions.

Source record↗
NASA NTRS1977

Outer planets probe testing

An atmospheric entry Probe is being developed by NASA Ames Research Center (ARC) to conduct in situ scientific investigations of the outer planets' atmospheres. A full scale engineering model of an MDAC-E Probe configuration, was fabricated by NASA ARC. Proof-of-concept test validation of the structural and thermal design is being obtained at NASA ARC. The model was successfully tested for shock and dynamic loading and is currently in thermal vacuum testing.

Smittkamp, J. A.↗
NASA NTRS1979

Automated biowaste sampling system feces monitoring system

The Feces Monitoring System (FMS) Program designed, fabricated, assembled and tested an engineering model waste collector system (WCS) to be used in support of life science and medical experiments related to Shuttle missions. The FMS design was patterned closely after the Shuttle WCS, including: interface provisions; mounting; configuration; and operating procedures. These similarities make it possible to eventually substitute an FMS for the Shuttle WCS of Orbiter. In addition, several advanced waste collection features, including the capability of real-time inertial fecal separation and fecal mass measurement and sampling were incorporated into the FMS design.

Hunt, S. R.↗
NASA NTRS1979

An ultraviolet polarimeter for the Solar Maximum Mission

The Solar Maximum Mission experiment contingency will include one instrument originally designed and built for OSO-8. The engineering model of the OSO-8 High Resolution Spectrometer has been rebuilt to make it lightworthy and to encompass several new functions, including solar ultraviolet polarimetry. The rebuilt package is designated as the High Resolution Ultraviolet Spectrometer/Polarimeter. The device that enables polarimetry is a dual channel rotating waveplate system. The waveplates are magnesium fluoride and will allow measurements to be made ranging from the Lyman alpha line to near visible ultraviolet. One wavelength channel will use the polarization characteristics of the spectrometer diffraction grating as the analyzer. The second channel has a built-in four-mirror polarizer. This paper describes the polarimeter design, operation, and calibration.

Calvert, J.↗
NASA NTRS1979

Primary Electric Propulsion Technology Study

An investigation of the 30-cm engineering-model-thruster technology with emphasis placed on the development of models for understanding and predicting the operational characteristics and wear-out mechanisms of the thruster as a function of operating or design parameters is presented. The task studies include: (1) the wear mechanisms and wear rates that determine the useful lifetime of the thruster discharge chamber; (2) cathode lifetime as determined by the depletion of barium from the barium-aluminate-impregnated-porous-tungsten insert that serves as a barium reservoir; (3) accelerator-grid-system technology; (4) a verification of the high-voltage propellant-flow-electrical-isolator design developed under NASA contract NAS3-20395 for operation at 10-kV applied voltage and 10-A equivalent propellant flow with mercury and argon propellants. A model was formulated for predicting performance.

Poeschel, R. L.↗
NASA NTRS1980

A new controller for battery-powered electric vehicles

This paper describes the development, under a NASA/DOE contract, of a new concept for efficient and reliable control of battery-powered vehicles. It avoids the detrimental effects of pulsed-power controllers like the SCR 'chopper' by using rotating machines to meter continuous currents to the traction motor. The concept is validated in a proof-of-principle demonstration system and a complete vehicle is simulated on an analog computer. Test results show exceptional promise for a full-scale system. Optimum control strategies to minimize controller weight are developed by means of the simulated vehicle. The design for an Engineering Model is then prepared in the form of a practical, compact two-bearing package with forced air cooling. Predicted performance is outstanding, with controller efficiency of over 90% at high speed.

Belsterling, C. A.↗
NASA NTRS1980

Thematic Mapper - An interim report on anticipated performance

The requirements and design concept of the Thematic Mapper are briefly reviewed. Emphasis is placed on the anticipated on-orbit performance based on subsystem and system level test results obtained from Engineering Model and Protoflight Model hardware. The anticipated performance of the Thematic Mapper is discussed in four key areas: spectral response, radiometric sensitivity, square-wave response, and band-to-band registration.

Engel, J. L.↗
NASA NTRS1981

Payload carrier systems for conducting sortie mode science

The capabilities and characteristics of the payload carriers developed to provide structural and operational interfaces between the Space Shuttle and the various types of experiments designed to operate in the sortie mode are discussed. The Spacelab is a flexible laboratory system composed of interchangeable elements that can be put together in eight different combinations of pallets and pressurized modules, and provides considerable standard services to users in such areas as equipment installation, power distribution, thermal control, command and data management, software, pointing systems and crew participation. A modular three-axis pointing control system designated the Annular Suspension and Pointing System, is being developed to provide additional pointing capabilities to those payloads that require capabilities not provided by the Spacelab instrument pointing system. Two engineering models of the Spacelab pallet have been designated Orbital Flight Test Pallets which, together with a special experiment support structure, are intended for initial and operational payloads that do not constitute a complete Spacelab mission. The simplest and smallest payload carriers are the Getaway Special cans, intended for small, self-contained, self-sufficient payloads, and the orbiter middeck lockers. In this way, most of the user requirements for Shuttle sortie missions identified to date can be fulfilled.

Jean, O. C.↗
NASA NTRS1980

A J-band space-fed phased array

A J-band, space-fed transmissive array suitable to the constraints of space platform applications has been designed and an engineering model array has been fabricated and tested. Attention is given to the design of the aperture, radiating element, phase shifter module, and flatplate feed. Test results and performance are discussed with reference to gain, sidelobe level, and beamwidth as functions of frequency and scan angle.

Orr, C. L.↗
NASA NTRS1981

Annual survey of spaceflight safety systems: 11th supplement. Survey period - July 1980-June 1981

Reports in the field of space flight safety applicable to current and future operational space activities which appeared between July 1980 and June 1981 are surveyed. Subjects in the area of flight rescue and safety during launch, on-orbit, reentry and landing phases include the major activities and findings of the first Shuttle test flight, a slidewire system for emergency egress from the Space Shuttle on the launch pad, and the testing of the Spacelab engineering model. In the area of human capabilities and crew roles, attention is given to reports of repairs to the Salyut 6 space station made by a Soyuz crew, and an assessment of weightlessness effects on space worker health and safety. Safety requirements for STS payloads including pressure vessels, and the Orbiter window system and for spacecraft testing are also presented, along with those for a television system to aid in monitoring astronaut extravehicular activities. For the operation of large space structures, reports include EVA equipment for satellite servicing and the safety aspects of connectors used in construction. Finally, attention is given to safety-related criteria in a study of Shuttle interactions with the proposed Space Operations Center.

Brown, N. E.↗
NASA NTRS1980

Meteosat spacecraft charging investigation

A number of phenomena observed on the first orbiting Meteosat satellite attributed to spacecraft charging effects are considered. Design analysis, correlation of anomalies with space environmental data, on ground tests with an engineering model spacecraft, tests on the validity of improvements, and installation of suitable monitors for the second improved flight satellite are discussed.

Hoge, D. G.↗
NASA NTRS1980

Electron irradiation tests on European meteorological satellite

The observation of in orbit anomalies on Meteosat resulted in a test being performed to establish the charging and discharging characteristics of a flight configured engineering model when irradiated with electrons. Surface potentials were measured together with discharge rates and amplitudes. Results indicate that a large number of discharges are possible on the satellite whether or not the external surfaces are grounded. Initial measurements show that there are very high potential gradients around the satellite which obviously contribute largely to the discharging behavior. The time constant for charging is very small, indicating also that equilibrium conditions are achieved very quickly as the local ambient changes in orbit. A.R.H.

Reddy, J.↗
NASA NTRS1982

Escalator design features evaluation

Escalators are available with design features such as dual speed (90 and 120 fpm), mat operation and flat steps. These design features were evaluated based on the impact of each on capital and operating costs, traffic flow, and safety. A human factors engineering model was developed to analyze the need for flat steps at various speeds. Mat operation of escalators was found to be cost effective in terms of energy savings. Dual speed operation of escalators with the higher speed used during peak hours allows for efficient operation. A minimum number of flat steps required as a function of escalator speed was developed to ensure safety for the elderly.

Zimmerman, W. F.↗
NASA NTRS1981

V/STOL propulsion control technology

Results of a NASA sponsored study of V/STOL Propulsion Control Analysis are presented. The study involved propulsion control requirements, design concepts and procedures, and control designs for supersonic V/STOL. A variable cycle engine with a remote augmented lift system was used as a basis for establishing typical operating requirements and control concepts, and a nonlinear engine model was developed for control development as a precursor to a real-time simulation capability. A simplified aircraft model was also used to investigate transition requirements, and a long-range technology plan was developed to define subsequent program requirements for achieving a real-time piloted simulation capability.

Brown, H.↗
NASA NTRS1983

The design and development of a mounting and jettison assembly for the shuttle orbiter advanced gimbal system

This paper describes the requirements, design development, and qualification of the mounting and jettison assembly (MJA) which serves as the base structure for the advanced gimbal system (AGS) developed for NASA, Marshall Space Flight Center, for use during shuttle missions. An engineering model of the MJA has been built and subjected to the following testing: stiffness and modal characterization, sine and random vibration, and a jettison function and energy release. A qualitative summary of the results and the problems encountered during testing, together with the design solutions, is presented.

Korzeniowski, E. S.↗
NASA NTRS1982

Software and system level tests of a test flight mercury ion thruster subsystem

A U.S. Air Force technology spacecraft flight is scheduled to carry an Ion Auxiliary Propulsion System (IAPS) as part of its experimental payload. This paper presents the results of the successful flight-software qualification and system-level tests which were performed on IAPS. The software tests were performed with an operating engineering model ion thruster and power processing unit, and failure/off-normal recovery modes, operation with and without temperature telemetry from the thruster vaporizers, and with closed-loop control or fixed setpoint operation of the thruster vaporizers. The system-level tests cover a wide range of thermal and operating conditions with the entire system exposed to a simulated space environment.

Robson, R. R.↗