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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Optical interstellar lines toward 18 stars of low reddening. III

Photoelectric scans of the interstellar D-line of Na I and the K-line of Ca II are compared with those of H I and H sub 2. Three general conclusions are drawn from the observations: (1) normal Na I/H ratios are found in 14 of the 18 cases studied, most likely due to absorption in cool, dense clouds; (2) low Na I/H ratios are observed in the direction of Gamma-Pegasus and Mu-Scorpio, implying that absorption occurs in clouds of warm (over 100 K) gas, or through extended paths of cool gas with low ionization; and (3) the absence of Na I, H I, and H sub 2 lines toward Nu-Scorpio and Sigma-Sagittarius indicates that little neutral gas is present along these light paths.

Hobbs, L. M.↗
NASA NTRS1981

Conceptual/preliminary design study of subsonic v/stol and stovl aircraft derivatives of the S-3A

A computerized aircraft synthesis program was used to examine the feasibility and capability of a V/STOL aircraft based on the Navy S-3A aircraft. Two major airframe modifications are considered: replacement of the wing, and substitution of deflected thrust turbofan engines similar to the Pegasus engine. Three planform configurations for the all composite wing were investigated: an unconstrained span design, a design with the span constrained to 64 feet, and an unconstrained span oblique wing design. Each design was optimized using the same design variables, and performance and control analyses were performed. The oblique wing configuration was found to have the greatest potential in this application. The mission performance of these V/STOL aircraft compares favorably with that of the CTOL S-3A.

Kidwell, G. H., Jr.↗
NASA NTRS1982

A Piecewise Linear State Variable Technique for Real Time Propulsion System Simulation

The emphasis on increased aircraft and propulsion control system integration and piloted simulation has created a need for higher fidelity real time dynamic propulsion models. A real time propulsion system modeling technique which satisfies this need and which provides the capabilities needed to evaluate propulsion system performance and aircraft system interaction on manned flight simulators was developed and demonstrated using flight simulator facilities at NASA Ames. A piecewise linear state variable technique is used. This technique provides the system accuracy, stability and transient response required for integrated aircraft and propulsion control system studies. The real time dynamic model includes the detail and flexibility required for the evaluation of critical control parameters and propulsion component limits over a limited flight envelope. The model contains approximately 7.0 K bytes of in-line computational code and 14.7 K of block data. It has an 8.9 ms cycle time on a Xerox Sigma 9 computer. A Pegasus-Harrier propulsion system was used as a baseline for developing the mathematical modeling and simulation technique. A hydromechanical and water injection control system was also simulated. The model was programmed for interfacing with a Harrier aircraft simulation at NASA Ames. Descriptions of the real time methodology and model capabilities are presented.

Mihaloew, J. R.↗
NASA NTRS1981

Maintenance problems associated with the operation of the F402 /Pegasus/ engine in the AV-8A /Harrier/ aircraft

The U.S. Marine Corp (USMC) has been operating the only V/STOL attack aircraft in the western world since 1971. Some of the maintenance problems experienced are related to the unique V/STOL design criteria of the Pegasus engine. However, the major part of the required maintenance effort is found to involve the more conventional engine problems. A description of the aircraft engine is provided and the problems resulting from V/STOL design demands are examined. Attention is given to the fuel system control, the engine air bleed, foreign object damage to the hp compressor, and the engine exhaust system.

Stanley, C. W.↗
NASA NTRS1982

Experiences and perspectives with SRI's tools for software design and validation

Development of tools that include the STP theorem poer and its associated Design Verification Systems; PHIL, a meta-programmable context sensitive structured editor; Pegasus, a system for support of graphical programming; and OBJ, an ultra high level programming language based on rewrite rules and abstract data type is reported.

Goguen, J.↗
NASA NTRS1982

A piecewise linear state variable technique for real time propulsion system simulation

The emphasis on increased aircraft and propulsion control system integration and piloted simulation has created a need for higher fidelity real time dynamic propulsion models. A real time propulsion system modeling technique which satisfies this need and which provides the capabilities needed to evaluate propulsion system performance and aircraft system interaction on manned flight simulators was developed and demonstrated using flight simulator facilities at NASA Ames. A piecewise linear state variable technique is used. This technique provides the system accuracy, stability and transient response required for integrated aircraft and propulsion control system studies. The real time dynamic model includes the detail and flexibility required for the evaluation of critical control parameters and propulsion component limits over a limited flight envelope. The model contains approximately 7.0 K bytes of in-line computational code and 14.7 K of block data. It has an 8.9 ms cycle time on a Xerox Sigma 9 computer. A Pegasus-Harrier propulsion system was used as a baseline for developing the mathematical modeling and simulation technique. A hydromechanical and water injection control system was also simulated. The model was programmed for interfacing with a Harrier aircraft simulation at NASA Ames. Descriptions of the real time methodology and model capabilities are presented.

Mihaloew, J. R.↗
NASA NTRS1984

A possible relationship between metal abundance and luminosity for disk galaxies

Near-infrared colors have been measured for a sample of 31 late-type galaxies in the Pegasus I and Pisces clusters; system luminosities in the sample cover the range of M(H) between -19 and -23.5. The color index (J - K) correlates strongly with the absolute H magnitude; lower-luminosity systems have bluer colors. These observations are consistent with the assumption that the mean metal abundance of the old disk population decreases systematically with luminosity. The systematic variation (B - H) with absolute H magnitude reported recently by Tully et al. (1982) derives in part from this proposed systematic change of metallicity with luminosity. However, a relative increase in the number of newly formed stars and/or a systematic smaller age for lower-luminosity disks must still be posited in order to fully explain the observed (B - H), H relation.

Bothun, G. D.↗
NASA NTRS1984

Computer study of a jet flap ASTVOL 'Harrier'

A study of the costs/benefits trade-off was conducted for an Advanced Supersonic Short Takeoff and Vertical Landing (ASTOVL) aircraft incorporating a jet flap. The data used were the theory of jet flaps and high aspect ratio nozzles, experience with a V/STOL aircraft study performed for NASA Ames Research Center in February 1982, and a high performance aircraft-synthesis program (ACSYNT). The methodology was to accurately model the supersonic Harrier V/STOL aircraft design on ACSYNT, and then modify the design by both adding high aspect-ratio nozzles in place of the rear (core-flow) nozzles on the Pegasus-type turbofan engine, and integrating these nozzles on each wing's trailing edge, thus creating a jet flap. The predicted performance advantages (increase in maximum lift coefficient with flap deflection and horizontal thrust recovery) were traded off against the disadvantages (additional weight and thrust loss due to ducting) on two representative missions.

Wilson, S. B., III↗
NASA NTRS1985

Research and technology Fiscal Year 1985 report

A quarter of a century is but a moment on the cosmic calendar. Now that Marshall Space Flight Center has reached its 25th Anniversity, it seems just moments ago that President Dwight D. Eisenhower stood on these grounds and formally dedicated the George C. Marshall Space Flight Center in Huntsville, Alabama. The Fiscal Year 1985 Research and Technology Report reflects the wide spectrum of activities closely linked with the Center's mainstream spaceflight developments. Past accomplishments testify to the success of getting deeply involved in the science and technology of its projects - 32 Saturn launches, Pegasus, the Skylab missions, three High Energy Astronomy Observatory missions, the Apollo - Soyuz mission, and an accelerating schedule of successful Shuttle, Spacelab, and Shuttle payload missions. The Center continues to be involved in engineering development, scientific research, and technology. At the beginning of the second quarter century, the experience and dedication of the engineers and scientists, and the success of the collaboration with industry and academia will now be aimed at the next great endeavor, the Space Station.

Speer, F.↗
NASA NTRS1987

Far-infrared properties of cluster galaxies

Far-infrared properties are derived for a sample of over 200 galaxies in seven clusters: A262, Cancer, A1367, A1656 (Coma), A2147, A2151 (Hercules), and Pegasus. The IR-selected sample consists almost entirely of IR normal galaxies, with Log of L(FIR) = 9.79 solar luminosities, Log of L(FIR)/L(B) = 0,79, and Log of S(100 microns)/S(60 microns) = 0.42. None of the sample galaxies has Log of L(FIR) greater than 11.0 solar luminosities, and only one has a FIR-to-blue luminosity ratio greater than 10. No significant differences are found in the FIR properties of HI-deficient and HI-normal cluster galaxies.

Bicay, M. D.↗
NASA NTRS1987

Far-infrared properties of cluster galaxies

Far-infrared properties are derived for a sample of over 200 galaxies in seven clusters: A262, Cancer, A1367, A1656 (Coma), A2147, A2151 (Hercules), and Pegasus. The IR-selected sample consists almost entirely of IR normal galaxies, with Log of L(FIR) = 9.79 solar luminosities, Log of L(FIR)/L(B) = 0.79, and Log of S(100 microns)/S(60 microns) = 0.42. None of the sample galaxies has Log of L(FIR) greater than 11.0 solar luminosities, and only one has a FIR-to-blue luminosity ratio greater than 10. No significant differences are found in the FIR properties of HI-deficient and HI-normal cluster galaxies.

Bicay, Michael D.↗
NASA NTRS1988

Overview of the US/UK ASTOVL program

An account is given of progress to date in a US/UK advanced, supersonic flight-capable, powered-lift aircraft development collaborative effort formalized in January, 1986 by a memorandum of understanding (MOU). MOU-related work has investigated such ASTOVL propulsion configuration concepts as the remote augmented lift system, using a two-mode powerplant; augmenting ejectors, which generate a more benign ground environment; plenum chamber burning vectored thrust, which elaborates the geometry of the Harrier Pegasus powerplant; and tandem fans, which are also closely related to the Harrier concept but incorporate a truly variable-cycle engine.

Armstrong, Frank W.↗
NASA NTRS1988

Vectoring Single Expansion Ramp Nozzle (VSERN) static model test program

A variable throat-area, side-vectoring single expansion ramp nozzle (VSERN) concept's internal performance characteristics are studied with a view to controlling the bypass flow of an unmixed turbofan engine. Static tests have been conducted on VSERN at NASA-Langley using a variety of parametric models giving attention to the effects of upstream bend angle, ramp geometry, area ratio, and nozzle pressure ratio on static thrust and flow performance. Advantages of VSERN over the conventional vectoring axisymmetric convergent side-nozzles typified by those of the Harrier's Pegasus engine.

Eames, D. J. H.↗
NASA NTRS1989

United States space transportation survey

Different developmental paths for the U.S. space transportation fleet are discussed. Development of a purely cargo, unmanned space shuttle, using many components of the present manned space shuttle system, is presented. Future manned spacecraft solutions are discussed. Launch vehicle programs for unmanned missions are described. The Titan solid rocket motor upgrade is identified as the biggest improvement in this area. A return to a better balance between manned and unmanned launch systems for space transportation is predicted. The Titan, Delta, Scout, and Pegasus families of rockets are described. The need to upgrade this fleet in meeting the space challenges of the future is stressed.

Branscome, Darrel R.↗
NASA NTRS1990

Microspacecraft and Earth observation: Electrical field (ELF) measurement project

The Utah State University space system design project for 1989 to 1990 focuses on the design of a global electrical field sensing system to be deployed in a constellation of microspacecraft. The design includes the selection of the sensor and the design of the spacecraft, the sensor support subsystems, the launch vehicle interface structure, on board data storage and communications subsystems, and associated ground receiving stations. Optimization of satellite orbits and spacecraft attitude are critical to the overall mapping of the electrical field and, thus, are also included in the project. The spacecraft design incorporates a deployable sensor array (5 m booms) into a spinning oblate platform. Data is taken every 0.1 seconds by the electrical field sensors and stored on-board. An omni-directional antenna communicates with a ground station twice per day to down link the stored data. Wrap-around solar cells cover the exterior of the spacecraft to generate power. Nine Pegasus launches may be used to deploy fifty such satellites to orbits with inclinations greater than 45 deg. Piggyback deployment from other launch vehicles such as the DELTA 2 is also examined.

Olsen, Tanya↗
NASA NTRS1990

Long-term orbital lifetime predictions

Long-term orbital lifetime predictions are analyzed. Predictions were made for three satellites: the Solar Max Mission (SMM), the Long Duration Exposure Facility (LDEF), and the Pegasus Boiler Plate (BP). A technique is discussed for determining an appropriate ballistic coefficient to use in the lifetime prediction. The orbital decay rate should be monitored regularly. Ballistic coefficient updates should be done whenever there is a significant change in the actual decay rate or in the solar activity prediction.

Dreher, P. E.↗
NASA NTRS1992

PASP Plus: An experiment to measure space-environment effects on photovoltaic power subsystems

The Photovoltaic Array Space Power Plus Diagnostic experiment (PASP Plus) was accepted as part of the APEX Mission payload aboard a Pegastar satellite to be orbited by a Pegasus launch vehicle in late 1992. The mission's elliptical orbit will allow us to investigate both space plasma and space radiation effects. PASP Plus will have eleven types of solar arrays and a full complement of environmental and interactions diagnostic sensors. Measurements of space-plasma interactions on the various solar arrays will be made at large negative voltages (to investigate arcing parameters) and at large positive voltages (to investigate leakage currents) by biasing the arrays to various levels up to -500 and +500 volts. The long-term deterioration in solar array performance caused by exposure to space radiation will also be investigated; radiation dosage will be measured by an electron/proton dosimeter included in the environmental sensor complement. Experimental results from PASP Plus will help establish cause-and-effect relationships and lead to improved design guidelines and test standards for new-technology solar arrays.

Guidice, Donald A.↗
NASA NTRS1992

Manipulator design and development for the Ranger satellite servicing vehicle

The Ranger program is a planned series of low cost telerobotics flight experiments, based on the use of Pegasus launch vehicles. As the first step towards this goal, the Space Systems Lab was developing a neutral buoyancy version of Ranger for use in design verification and operations testing. The design approach and results of the Ranger manipulator development program is related. Ranger is designed to incorporate four appendages: a pair of dexterous, seven degree of freedom manipulators for general manipulation; a six DOF grappling arm for securing the vehicle to the local work site; and a five DOF positioning manipulator for the stereo camera pair that provide feedback to the remote operator. Each of these manipulators incorporate unique approaches to satisfying design requirements. The numerical and operational requirements are given for Ranger manipulators, and the evolution is discussed of the differing design approaches based on similarities and differences in the requirements. Testing results for individual joints and manipulator assemblies are presented, followed by initial results of operational testing on satellite servicing tasks with the integrated Ranger neutral buoyancy vehicle.

Howard, Russell D.↗