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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

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NASA NTRS1971

Performance of a neutralizer for electron bombardment thruster

Results of the SERT II flight indicate that the hollow cathode neutralizer not only represents a power and propellant weight penalty but can be a contributing cause to accelerator grid erosion. Tests with a 30-cm diameter thruster show that a neutralizer position of approximately 9 cm axially downstream of the accelerator grid and approximately 9 cm radially away from the outer edge of the accelerator grid and pointing parallel to the thruster axis provides the best overall performance. The estimated grid wear rate was less than 0.08 mm in 10,000 hours. The coupling voltage was approximately 17 volts at a neutralizer flow rate of 22 equivalent milliamperes of mercury and a beam current of 1.5 amperes. Neutralizer power was 31 watts and the effect of neutralizer flow on overall propellant utilization efficiency is a 1.2 percentage point reduction at a thruster utilization efficiency of 90 percent. The neutralizer position defined in tests with a 30 cm thruster was tested with a 15 cm SERT II thruster. When the neutralizer was relocated further downstream with this different orientation, accelerator impingement current due to neutralizer operation was reduced by approximately a factor of seven and was nearly independent of neutralizer operation.

Bechtel, R. T.↗

NASA NTRS1971

Environmental impact statement for National Aeronautics and Space Administration Lewis Research Center, Cleveland, Ohio

The probable environmental impact and adverse effects of the Lewis Research Center are assessed. The Cleveland and Plum Brook facilities are briefly described. It is felt that the absence of harmful environmental impact from the Cleveland site is apparent, and the monitoring at the Plum Brook reactor facility shows the effectiveness of effluent controls. The probable adverse effects are considered for air, water, and noise pollution, and radioactive and hazardous waste storage and disposal; it is concluded that all emissions are maintained below Federal, and local standards. There are no appropriate alternatives to the operation of the Center, and no improvement in environmental quality would result from relocation. The relationship between local short-term productivity is briefly discussed. No adverse comment has been received from public agencies or private organizations or individuals.

Source record↗

NASA NTRS1971

New half-range differential approximation for spherically-symmetric radiative transfer.

A new half-range differential approximation for radiative transfer with spherical symmetry is presented. The development is motivated by the various failures of existing differential approximations in determining emissive-power distributions and heat transfer for concentric-spheres problems. The new approach represents a modification of the four-moment double spherical-harmonics method, to which it reduces in the planar limit. The difference is effected by relocating the discontinuity of the assumed directional distribution of radiation intensity. The shift takes the discontinuity from precisely on the division between radially inward and radially outward, to just within the radially-outward directional half range. The method is tested on a variety of concentric spheres problems with and without internal heat sources, reproducing all the important features of the exact results.

Moreno, J. B.↗

NASA NTRS1972

Power processing systems for ion thrusters.

The proposed use of ion thrusters to fulfill various communication satellite propulsion functions such as east-west and north-south stationkeeping, attitude control, station relocation and orbit raising, naturally leads to the requirement for lightweight, efficient and reliable thruster power processing systems. Collectively, the propulsion requirements dictate a wide range of thruster power levels and operational lifetimes, which must be matched by the power processing. This paper will discuss the status of such power processing systems, present system design alternatives and project expected near future power system performance.

Herron, B. G.↗

NASA NTRS1972

Preliminary results of the satellite orbit determination of Mariner Mars 1971.

The preflight planning and real-time experience relating to the navigation of the first artificial satellite placed about a distant planet is presented. Results of determining the orbit of Mariner 9 are presented and contrasted against the preflight simulation test results. It is concluded that the position of Mariner 9 was located to 40 km before coefficients of the gravity field of Mars were estimated. The planet Mars has been found to be 3 to 4 times gravitationally rougher than expected, with the dominant features, the 2nd order tesserals C22 and S22, causing the orbital period of Mariner 9 to oscillate with an amplitude of 40 seconds and a wavelength of 19.5 days. The direction of the Mars spin axis has been relocated from the Camichel-Burton value by 1/2 degree.

Jordan, j. F.↗

NASA NTRS1972

Roll-modulated lifting entry optimization.

Equations of lifting entry are considered for fixed-angle-of-attack vehicular motion with path control for roll modulation of lift. Attention is directed to relocation and its consequences for the fixed-angle-of-attack atmospheric entry problem. Two reduced-order methods for working with the resulting system of equations are briefly examined. The methods are deemed to warrant further study.

Kelley, H. J.↗

NASA NTRS1972

Study of astronaut restraints and mobility aids in a weightless shirtsleeve environment

A study, established to produce needed information about manual performance limits in intravehicular weightlessness such as the motions induced by the astronaut's direct application of force against the body of the vehicle or an object to be moved, is presented. Using both conventional and water immersion techniques, it was possible to develop realistic time estimates for astronaut station-to-station translation in Skylab, to simulate and analyze specific Skylab tasks involving force application and motion dynamics, and to evaluate certain thresholds of force application in weightlessness. The study was divided into three tasks. The first related to locomotion and verification or modification of present Skylab translation timelines. In all cases, translation times were less than the Skylab timelines indicated. The second task studied mass handling and transfer. Specifically, this involved measurement of the astronaut's ability to relocate the Skylab food lockers to stowage levels of three different heights and his ability to transfer the M509 PSS bottles between the OWS and the recharge station. The third task helped define the physical limits of man's ability to perform Skylab translation tasks under weightless conditions.

Loats, H. L., Jr.↗

NASA NTRS1973

Ground station hardware for the ATS-F millimeter wave experiment

The results are presented of a program to design, fabricate, test, and install a primary ATS-F millimeter wave ground receiving station. Propagation parameters at millimeter waves are discussed along with the objective of the overall experiment. A general description is given of the receiving system and its function in the experiment. Typical receiver characteristics are presented which show that the experiment is entirely feasible from a link SNR standpoint. The receiving system hardware designs are discussed with separate treatment given to the propagation and the radiometer receiver designs. The modification and relocation are described of an existing 15-ft antenna to meet the ATS-F requirements. The design of a dual frequency feed subsystem and self calibration equipment is included.

Duffield, T. L.↗

NASA NTRS1974

Finger recording electrode system for electrical impedance plethysmograph

System facilitates location of recording electrodes of impedance plethysmograph that is used for measuring flow of blood in finger segment; electrodes can be relocated accurately and volume of finger segment under study can be determined precisely. System minimizes movement artifacts in plethysmograph trace because finger segment is held firmly.

Montgomery, L. D.↗

NASA NTRS1974

Miniature biaxial strain transducer

Transducer is completely reusable and permits relocation to alternate points to be accomplished quickly. Size permits measurements to be made simultaneously over small areas and yields outputs directly proportional to strains measured. Transducer verifies elastic modulus, Poisson's ratio, and principal strain axes on materials.

Hoffman, I. S.↗

NASA NTRS1974

Apollo experience report: Communications used during recovery operations

Apollo program experience in recovery-support communications is reviewed, and the working relationships among NASA, the Department of Defense, and commercial communications facilities are discussed. The organization, facilities, philosophy, and funding of recovery-support communications are described. The relocation of two recovery control centers is discussed, as are the functions of primary and secondary recovery ships, aircraft, and relay satellities. The possibility of using ships of opportunity for recovery operations is considered. Finally, the means by which money, manpower, and resources have been saved and longlines leased are delineated.

Hoover, J. E.↗

NASA NTRS1975

Thermal control evaluation of a Shuttle Orbiter solar observatory using Skylab ATM backup hardware

A study under the sponsorship of Marshall Space Flight Center (MSFC) established the feasibility to utilize the Skylab Apollo Telescope Mount (ATM) backup hardware for early low cost Shuttle Orbiter solar observation missions. A solar inertial attitude and a seven-day, full sun exposure were baselined. As a portion of the study, a series of thermal control evaluations were performed to resolve the problems caused by the relocation of the ATM to the Shuttle Orbiter bay and resulting configuration changes. Thermal control requirements, problems, the use of solar shields, Spacelab supplied fluid cooling and component placement are discussed.

Class, C. R.↗

NASA NTRS1975

Investigations of lubricant rheology as applied to elastohydrodynamic lubrication

Traction prediction in sliding elastohydrodynamic (EHD) contacts was examined along with an elastohydrodynamic lubrication simulation of the effects of load and speed on temperatures in the EHD contact. An existing shear stress theory and lubricant rheological model were studied and evaluated by applying them to traction prediction. Results obtained using measured film thickness and surface temperature data, were compared with measured traction values. The infrared technique for measuring temperatures in an EHD contact was further developed and ball surface and fluid temperatures are reported for sliding speeds of 0.35 to 5.08 m/s at 0.52 to 2.03 GN/sq m maximum pressure and surface roughnesses of .011 to .381 micrometers c.1.a. The relationship between asperity interaction, as measured by relocation surface profilimetry and high frequency temperature measurements, and the ratio of film thickness to surface roughness was also studied.

Kunz, R. K.↗

NASA NTRS1976

Toward the modeling of land use change: A spatial analysis using remote sensing and historical data

It was hypothesized that the chronological observation of land use change could be shown to follow a predictable pattern and these patterns could be correlated with other statistical data to develop transition probabilities suitable for modeling purposes. A literature review and preliminary research, however, indicated a totally stochastic approach was not practical for simulating land use change and thus a more deterministic approach was adopted. The approach used assumes the determinants of the land use conversion process are found in the market place, where land transactions among buyers and sellers occur. Only one side of the market transaction process is studied, however, namely, the purchaser's desires in securing an ideal or suitable site. The problem was to identify the ideal qualities, quantities or attributes desired in an industrial site (or housing development), and to formulate a general algorithmic statement capable of identifying potential development sites. Research procedures involved developing a list of variables previously noted in the literature to be related to site selection and streamlining the list to a set suitable for statistical testing. A sample of 157 industries which have located (or relocated) in the 16-county Knoxville metropolitan region since 1950 was selected for industrial location analysis. Using NASA color infrared photography and Tennessee Valley Authority historical aerial photography, data were collected on the spatial characteristics of each industrial location event. These data were then subjected to factor analysis to determine the interrelations of variables.

Honea, R. B.↗

NASA NTRS1976

System for imposing directional stability on a rocket-propelled vehicle

An improved system for use in imposing directional stability on a rocket-propelled vehicle is described. The system includes a pivotally supported engine-mounting platform, a gimbal ring mounted on the platform and adapted to pivotally support a rocket engine and an hydraulic actuator connected to the platform for imparting selected pivotal motion. An accelerometer and a signal comparator circuit for providing error intelligence indicative of aberration in vehicle acceleration is included along with an actuator control circuit connected with the actuator and responsive to error intelligence for imparting pivotal motion to the platform. Relocation of the engine's thrust vector is thus achieved for imparting directional stability to the vehicle.

Perkins, H.↗

NASA NTRS1976

Development of a Self-contained Heat Rejection Module (SHRM), phase 1

The laboratory prototype test hardware and testing of the Self-Contained Heat Rejection Module are discussed. The purpose of the test was to provide operational and design experience for application to a flight prototype design. It also provided test evaluation of several of the actual components which were to be used in the flight prototype hardware. Several changes were made in the flight prototype design due to these tests including simpler line routing, relocation of remote operated valves to a position upstream of the expansion valves, and shock mounting of the compressor. The concept of heat rejection control by compressor speed reduction was verified and the liquid receiver, accumulator, remote control valves, oil separator and power source were demonstrated as acceptable. A procedure for mode changes between pumped fluid and vapor compression was developed.

Fleming, M. L.↗

NASA NTRS1976

An onboard deorbit target line computation technique

The design concept and results of a target line generator software package, which was developed to provide the onboard entry interface range, were documented. This generator, which was eventually reduced to one linear equation, was developed to the point that it provides autonomous landing site relocation capability, negligible core storage, and acceptable performance for the cases tested.

Bedford, J. J.↗

NASA NTRS1975

Space colonies and energy supply to the earth

It is pointed out that a space manufacturing facility may be economically more effective than alternative industries on the earth for the construction of products which are to be used in geosynchronous or higher orbits. The suggestion is made to construct solar power stations at a space colony and relocate them in geosynchronous orbit to supply energy to the earth. Attention is given to energy problems and approaches for solving them, taking into account environmental effects and economic factors. Economic aspects of space manufacturing are discussed in some detail.

Oneill, G. K.↗