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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Operational status of the space test program P78-2 spacecraft and payloads

Operations of the P78-2 spacecraft and its 12 payloads, which attempt to measure the buildup and breakdown of charge on various spacecraft components and to characterize the natural environment at synchronous altitudes, are summarized. Launch procedures, orbit alignment, and eclipse seasons are reviewed. The spacecraft configuration and subsystems are described. Catastrophic payload failures are reported: the SC6 (AFGL Thermal Plasma Analyzer) failed due to an excessive power draw in the electron step generator. The SC7 (NASA/MSFC Light Ion Mass Spectrometer) internal power supply failed. Lesser payload failures, including SC2 probe biasing, SC4-1 pulsed mode, and SC4-2 neutralizer are discussed.

Osgood, R. N.↗
NASA NTRS1982

Power Systems integration

Power systems integration in large flexible space structures is discussed with emphasis upon body control. A solar array is discussed as a typical example of spacecraft configuration problems. Information on how electric batteries dominate life-cycle costs is presented in chart form. Information is given on liquid metal droplet generators and collectors, hot spot analysis, power dissipation in solar arrays, solar array protection optimization, and electromagnetic compatibility for a power system platform.

Brantley, L. W.↗
NASA NTRS1983

The linear boom actuator designed for the Galileo spacecraft

Because the linear boom actuator is to be used on a flight spacecraft, as opposed to a ground based application, there is a comprehensive set of requirements. First, of course, the actuator must be capable of positioning and holding the load. Initially the load as predicted to be 4448 N (1000 lb) but with subsequent spacecraft configuration changes the load has been greatly reduced to a constant tensile pull of 1477 N (332 lb) due to centrifugal force. Lesser compressive loads of 1317 N (296 centrifugal lb) may be experienced during launch and deployment. This actuator must have the maximum redundancy possible. Life requirements were defined by the 10.16 to 15.24 cm (4 to 6 in.) total liner travel expected during the five-year flight duration. Liner range required of the actuator was set at plus and minus 5.08 cm to accommodate configuration changes.

Koch, E. F.↗
NASA NTRS1982

Development of deployable structures for large space platform systems, volume 1

Generic deployable spacecraft configurations and deployable platform systems concepts were identified. Sizing, building block concepts, orbiter packaging, thermal analysis, cost analysis, and mass properties analysis as related to platform systems integration are considered. Technology needs are examined and the major criteria used in concept selection are delineated. Requirements for deployable habitat modules, tunnels, and OTV hangars are considered.

Source record↗
NASA NTRS1982

Space Schmidt telescope

The complete survey takes in 3627 fields, each 4.87 deg in diameter, arranged in a hexagonal pattern superimposed on the celestial equatorial coordinate system. The declination bands are spaced every 3 deg, 20 min. The optical instrument is a folded all-reflecting Schmidt system with an aperture of 0.74 m, a focal length of 2.0 m (f/2.7), a circlar field with a diameter of 4.87 deg, and a limiting image diameter of less than 2 arcsec over the entire field. The detector is an electrographic camera having a photocathode diameter of 170 mm. In discussing the telescope structure, it is pointed out that the optical support system is to be of graphite-epoxy construction. The focal tolerance (the most critical optical tolerance) is to be + or - 12 microns. Regarding contamination control, it is expected that with appropriate design it will be possible to operate in sunlight for observations in a restricted portion of the sky, at least more than 90 deg from the sun, depending on the geometry and reflectivity of the platform or spacecraft configuration.

Wray, J. D.↗
NASA NTRS1983

LO2/LH2 propulsion for outer planet orbiter spacecraft

Galileo class orbiter missions (750-1500 kg) to the outer planets require a large postinjection delta-V for improved propulsion performance. The present investigation shows that a pump-fed low thrust LO2/LH2 propulsion system can provide a significantly larger net on-orbit mass for a given delta-V than a state-of-the-art earth storable, N2O4/monomethylhydrazine pressure-fed propulsion system. A description is given of a conceptual design for a LO2/LH2 pump-fed propulsion system developed for a Galileo class mission to the outer planets. Attention is given to spacecraft configuration, details regarding the propulsion system, the thermal control of the cryogenic propellants, and aspects of mission performance.

Garrison, P. W.↗
NASA NTRS1983

Aerobraking of a low L/D manned vehicle from Geo return to rendezvous with the Space Shuttle

The results of a study of the airbraking portion of the flight of an Apollo class vehicle designed for a sortie from the Orbiter to Geo and return to Leo for Orbiter retrieval are presented. An ablative heat shield would be used on the vehicle to shed velocity to speeds commensurate with Orbiter rendezvous. A reference design was selected for a spacecraft configuration with an L/D ratio of 0.3 and a weight to lift surface ratio of 236 lb/sq ft. Atmospheric guidance would consist of using the bank angle for altitude and inclination angle control and an equilibrium bank angle was defined. The vehicle would have a maximum temperature, considering a reference sphere, of 4800 F and a peak load of about 2 g. Atmospheric exit parameters were also determined, together with minimum delta-V for rendezvous.

Gamble, J. D.↗
NASA NTRS1983

Subsonic Longitudinal Performance Coefficient Extraction from Shuttle Flight Data: an Accuracy Assessment for Determination of Data Base Updates

Longitudinal performance comparisons between flight derived and predicted values are presented for the first five NASA Space Shuttle Columbia flights. Though subsonic comparisons are emphasized, comparisons during the transonic and low supersonic regions of flight are included. Computed air data information based on the remotely sensed atmospheric measurements as well as in situ Orbiter Air Data System (ADS) measurements were incorporated. Each air data source provides for comparisons versus the predicted values from the LaRC data base. Principally, L/D, C sub L, and C sub D, comparisons are presented, though some pitching moment results are included. Similarities in flight conditions and spacecraft configuration during the first five flights are discussed. Contributions from the various elements of the data base are presented and the overall differences observed between the flight and predicted values are discussed in terms of expected variations. A discussion on potential data base updates is presented based on the results from the five flights to date.

Findlay, J. T.↗
NASA NTRS1983

Excess science accommodation capabilities and excess performance capabilities assessment for Mars Geoscience and Climatology Orbiter: Extended study

The excess science accommodation and excess performance capabilities of a candidate spacecraft bus for the Mars Geoscience and Climatology Orbiter MGCO mission are assessed. The appendices are included to support the conclusions obtained during this contract extension. The appendices address the mission analysis, the attitude determination and control, the propulsion subsystem, and the spacecraft configuration.

Clark, K.↗
NASA NTRS1985

Constellations

Multiple spacecraft configurations which involve tethering are presented. Potential applications of such tethered systems are enumerated. Tethers are thought to provide a way to open up the utility of large masses in orbit, perhaps allowing for the reoptimization of the STS toward greater total mass and volume per launch. Significant materials reserves could also be held in orbit.

Criswell, D. R.↗
NASA NTRS1985

Summary presentation of the Constellations Panel

Tethered multiple spacecraft configurations are discussed relative to low Earth orbit, geosynchronous Earth orbit, and one, two, or three dimensional configurations. Attitude control, pointing, and stabilization of such tethered systems are addressed.

Williams, F.↗
NASA NTRS1985

A study of spacecraft technology and design concepts. Volume 2: Appendices

Electrical, mechanical, and software subsystem needs in the Post 1990 space operations environment are considered as well as the effect of radiation environment on spacecraft configuration. Criteria are given for selecting a specific design or technology concept from among the alternatives available.

Zylius, F. A.↗
NASA NTRS1987

Identifying Vibration Parameters in Large Structures

Analytical method separately examines low-frequency and highfrequency behavior. Report discusses techniques for identifying rigid-body parameters, flexible-body parameters, and quasi-static disturbances in large structures. Techniques developed to aid in planning space station. Though effort directed towards space station dynamic model and environment, proposed methodology for systems identification is generic enough to allow application to arbitrarily large space structures and spacecraft configurations.

Bayard, D. S.↗
NASA NTRS1987

Acoustic fatigue: Overview of activities at NASA Langley

A number of aircraft and spacecraft configurations are being considered for future development. These include high-speed turboprop aircraft, advanced vertical take-off and landing fighter aircraft, and aerospace planes for hypersonic intercontinental cruise or flight to orbit and return. Review of the acoustic environment expected for these vehicles indicates levels high enough that acoustic fatigue must be considered. Unfortunately, the sonic fatique design technology used for current aircraft may not be adequate for these future vehicles. This has resulted in renewed emphasis on acoustic fatigue research at the NASA Langley Research Center. The overall objective of the Langley program is to develop methods and information for design of aerospace vehicles that will resist acoustic fatigue. The program includes definition of the acoustic loads acting on structures due to exhaust jets of boundary layers, and subsequent determination of the stresses within the structure due to these acoustic loads. Material fatigue associated with the high frequency structural stress reversal patterns resulting from acoustic loadings is considered to be an area requiring study, but no activity is currently underway.

Mixson, John S.↗
NASA NTRS1987

An interactive approach to surface-fitting complex geometries for flowfield applications

Numerical flowfield methods require a geometry subprogram which can calculate body coordinates, slopes, and radii of curvature for typical aircraft and spacecraft configurations. The objective of this paper is to develop a new surface-fitting technique which addresses two major problems with existing geometry packages: computer storage requirements and the time required of the user for the initial set-up of the geometry model. In the present method, coordinates of cross sections are fit in a least-squares sense using segments of general conic sections. After fitting each cross section, the next step is to blend the cross-sectional curve-fits in the longitudinal direction using general conics to fit specific meridional half-planes. For the initial setup of the geometry model, an interactive, completely menu-driven computer code has been developed to allow the user to make modifications to the initial fit for a given cross section or meridional cut. Graphic displays are provided to assist the user in the visualization of the effect of each modification. The completed model may be viewed from any angle using the code's three-dimensional graphics package. Geometry results for the modeling of the Space Shuttle and a proposed Aeroassist Flight Experiment (AFE) geometry are presented, in addition to calculated heat-transfer rates based on these models.

Dejarnette, Fred R.↗
NASA NTRS1988

Conceptual Spacecraft-Guidance Algorithm

Required weight of spacecraft minimized. Report describes conceptual algorithm for guidance of spacecraft launched from surface of Mars. Spacecraft to carry canister of specimens from surface to another spacecraft in orbit about Mars; second spacecraft then to carry canister back to Earth. Algorithm sufficiently general to be adaptable to prediction/correction algorithms for other spacecraft configurations.

Mccormick, Bernell R.↗
NASA NTRS1987

Overview of STIP intervals 15-19

Five STIP Intervals for special scientific study of solar and interplanetary phenomena were designated between February 1984 and March 1986. The first two intervals were selected retrospectively after unusual periods of solar activity; the remaining three intervals were selected in advance in conjunction with anticipated spacecraft configurations and measurements. In this overview the historical background of these STIP Intervals and a summary of the rationale in the selection of these particular time periods for concentrated studies are presented.

Shea, M. A.↗
NASA NTRS1988

Evaluation of the communications impact of a low power arcjet thruster

The interaction of a 1 kW arcjet thruster plume with a communications signal is evaluated. A two-parameter, source flow equation has been used to represent the far flow field distribution of the arcjet plume in a realistic spacecraft configuration. Modelling the plume as a plasma slab, the interaction of the plume with a 4 GHz communications signal is then evaluated in terms of signal attenuation and phase shift between transmitting and receiving antennas. Except for propagation paths which pass very near the arcjet source, the impacts to transmission appear to be negligible. The dominant signal loss mechanism is refraction of the beam rather than absorption losses due to collisions. However, significant reflection of the signal at the sharp vacuum-plasma boundary may also occur for propagation paths which pass near the source.

Carney, Lynnette M.↗