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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Thermal and structural integration problems associated with primary electric propulsion

A typical solar electric propulsion (SEP) spacecraft design which meets challenges posed by the physical characteristics of SEP and by the operational and environmental requirements associated with missions for which SEP is advantageous is used to develop structural and thermal integration requirements which are important to the successful design of electric propulsion elements. Included are discussions on thruster and power processor thermal and structural integration requirements and the definition of representative environmental requirements. Next, an improved power processor packaging concept, referred to as dual shear plate packaging, is described and shown to meet these requirements. Continued development of a two-axis-gimbal thruster array is also described. This concept demonstrates the successful thermal and structural integration of thrusters, propellant feed system, and thrust-vector-control actuators into a modular thrust assembly which meets the needs of a broad range of missions and possible vehicle configurations. Details of this design concept are presented.

Ross, R. G., Jr.↗
NASA NTRS1977

TVC actuator model

A prototype Space Shuttle Main Engine (SSME) Thrust Vector Control (TVC) Actuator analog model was successfully completed. The prototype, mounted on five printed circuit (PC) boards, was delivered to NASA, checked out and tested using a modular replacement technique on an analog computer. In all cases, the prototype model performed within the recording techniques of the analog computer which is well within the tolerances of the specifications.

Baslock, R. W.↗
NASA NTRS1977

Application of aerial photography to water-related programs in Michigan

The paper describes the use of aerial photography and information system technology in the provision of information required for the effective operation of three water-related programs in Michigan. Potential mosquito breeding sites were identified from specially acquired low altitude 70 mm color photography for the City of Lansing Vector Control Area. A comprehensive inventory of surface water sources and potential access sites was prepared to assist fire departments in Antrim County with fire truck water-recharge operations. Remotely-sensed land cover/use data for Windsor Township, Eaton County were integrated with other resource data into a computer-based information system for regional water quality studies. Eleven thematic maps specifically focussed on landscape features affecting non-point water pollution and waste disposal were generated from analyses of a four-hectare grid-based data file containing land cover/use, soils, topographic and geologic (well-log) data.

Enslin, W. R.↗
NASA NTRS1978

Space Shuttle nozzle review

Two Space Shuttle solid propellant rocket motor (SRM) nozzles have been tested, both successfully. This paper summarizes the results of these tests. The SRM nozzle was designed and fabricated at the Wasatch Division of Thiokol Corporation. It is over 13 ft. long, has a 54.43 in. initial throat diameter, and weighs over 11 tons. A flex bearing is employed for thrust vector control. Design and acceptance testing summaries are presented, along with the post-test results, erosion and actuation data.

Canfield, A.↗
NASA NTRS1979

Multivariable control altitude demonstration on the F100 turbofan engine

The F100 Multivariable control synthesis (MVCS) program, was aimed at demonstrating the benefits of LGR synthesis theory in the design of a multivariable engine control system for operation throughout the flight envelope. The advantages of such procedures include: (1) enhanced performance from cross-coupled controls, (2) maximum use of engine variable geometry, and (3) a systematic design procedure that can be applied efficiently to new engine systems. The control system designed, under the MVCS program, for the Pratt & Whitney F100 turbofan engine is described. Basic components of the control include: (1) a reference value generator for deriving a desired equilibrium state and an approximate control vector, (2) a transition model to produce compatible reference point trajectories during gross transients, (3) gain schedules for producing feedback terms appropriate to the flight condition, and (4) integral switching logic to produce acceptable steady-state performance without engine operating limit exceedance.

Lehtinen, B.↗
NASA NTRS1978

A microwave radiometer spacecraft

A conceptual design for a future microwave-radiometer spacecraft is described. The intended remote-sensing mission is centered around soil moisture measurements and requires all-weather day and night observations at a low microwave frequency (less than 5 GHz) in order to penetrate clouds, haze, and ground covers. The specific mission requirements are summarized in terms of two broad mission objectives, the system design requirements are outlined, and three structural approaches are evaluated at the conceptual design level. The weights, Shuttle flights, and structural member lengths for the three concepts are compared. The dual momentum vector control concept for pointing and slewing control is examined.

Lovelace, U. M.↗
NASA NTRS1979

Multivariable control altitude demonstration on the F100 turbofan engine

The control system designed under the Multivariable Control Synthesis (MVCS) program for the F100 turbofan engine is described. The MVCS program, applied the linear quadratic regulator (LQR) synthesis methods in the design of a multivariable engine control system to obtain enhanced performance from cross-coupled controls, maximum use of engine variable geometry, and a systematic design procedure that can be applied efficiently to new engine systems. Basic components of the control system, a reference value generator for deriving a desired equilibrium state and an approximate control vector, a transition model to produce compatible reference point trajectories during gross transients, gain schedules for producing feedback terms appropriate to the flight condition, and integral switching logic to produce acceptable steady-state performance without engine operating limit exceedance are described and the details of the F100 implementation presented. The engine altitude test phase of the MVCS program, and engine responses in a variety of test operating points and power transitions are presented.

Lehtinen, B.↗
NASA NTRS1979

Space Shuttle solid rocket booster

Details of the design, operation, testing and recovery procedures of the reusable solid rocket boosters (SRB) are given. Using a composite PBAN propellant, they will provide the primary thrust (six million pounds maximum at 20 s after ignition) within a 3 g acceleration constraint, as well as thrust vector control for the Space Shuttle. The drogues were tested to a load of 305,000 pounds, and the main parachutes to 205,000. Insulation in the solid rocket motor (SRM) will be provided by asbestos-silica dioxide filled acrylonitrile butadiene rubber ('asbestos filled NBR') except in high erosion areas (principally in the aft dome), where a carbon-filled ethylene propylene diene monomer-neopreme rubber will be utilized. Furthermore, twenty uses for the SRM nozzle will be allowed by its ablative materials, which are principally carbon cloth and silica cloth phenolics.

Hardy, G. B.↗
NASA NTRS1981

A Jet-diffuser ejector for a V/STOL fighter

A single ejector equipped with only one vector control jet and a diffuser flap was installed close to the leading edge of the strake of a one-fifth scale, semi-span model of the aircraft, without wing, canard, or tail surface. Tests of the system at a nozzle pressure ratio of 1.24 indicated a thrust augmentation of 1.92 and a thrust in the flight direction of about 12% of the total thrust under static conditions. An ejector stall occured at a ratio of tunnel dynamic pressure to nozzle gage pressure of about 0.008. Ejector stall speed can be delayed by using a boundary layer control jet at the front inlet lip of the ejector.

Alperin, M.↗
NASA NTRS1981

Feasibility study of LITVC for shuttle SRB

A liquid injection thrust vector control (LITVC) system for the shuttle solid rocket booster (SRB) was analyzed. The LITVC was compared with the SRB baseline flexible seal. A table of LITVC advantages and disadvantages is presented. It is concluded that the LITVC performs well at low to moderate duty cycles, but not for high duty cycle requirements.

Martin, C. L.↗
NASA NTRS1982

Dynamic scheduling of runway operations

Automated ATM/C decision making is discussed. Runway scheduling and flight plan generator algorithms are considered. Terminal area geometry, ATM/C schematics, vector controller display and simulation work are reported.

Pararas, J.↗
NASA NTRS1981

Have we overlooked the pilot's role in an automated flight deck

Having adopted a philosophy of presenting situation information rather than command type as evidenced in flight directors and of keeping the pilot in a decision-making role, a series of simulation and flight experiments has occurred over a number of years as part of the Langley Terminal Configured Vehicle program. This paper traces the development, refinement, and integration of electronic pictorial displays, and a computer augmented velocity vector control mode. Some benefits and performances derived within the basic philosophy and information usage are brought forth in the discussion as results from the various simulator and flight evaluations are presented.

Steinmetz, G. G.↗
NASA NTRS1987

U.S. Space Shuttle Solid Rocket Booster - Return to flight

The Space Shuttle Solid Rocket Booster (SRB) redesign program instituted in the wake of the Challenger accident encompassed a design requirements review, a failure modes effect analysis/critical items list determination, a hazards analysis, an operational maintenance and requirements specification study, the definition of operational maintenance instructions and launch commit criteria, and design certification and flight readiness reviews. Attention is presently given to the SRB's thrust vector control, separation, and recovery functions, as well as its electrical and instrumentation systems and its case assembly and hardware interfaces.

Coates, K. D.↗
NASA NTRS1989

Algorithm For Optimal Control Of Large Structures

Cost of computation appears competitive with other methods. Problem to compute optimal control of forced response of structure with n degrees of freedom identified in terms of smaller number, r, of vibrational modes. Article begins with Hamilton-Jacobi formulation of mechanics and use of quadratic cost functional. Complexity reduced by alternative approach in which quadratic cost functional expressed in terms of control variables only. Leads to iterative solution of second-order time-integral matrix Volterra equation of second kind containing optimal control vector. Cost of algorithm, measured in terms of number of computations required, is of order of, or less than, cost of prior algoritms applied to similar problems.

Salama, Moktar A.↗
NASA NTRS1988

Liquid rocket booster study. Volume 2, book 4, appendices 6-8: Reports of Rocketdyne, Pratt and Whitney, and TRW

For the pressure fed engines, detailed trade studies were conducted defining engine features such as thrust vector control methods, thrust chamber construction, etc. This was followed by engine design layouts and booster propulsion configuration layouts. For the pump fed engines parametric performance and weight data was generated for both O2/H2 and O2/RP-1 engines. Subsequent studies resulted in the selection of both LOX/RP-1 and O2/H2 propellants for the pump fed engines. More detailed analysis of the selected LOX/RP-1 and O2/H2 engines was conducted during the final phase of the study.

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NASA NTRS1989

Space shuttle Production Verification Motor 1 (PV-1) static fire

All inspection and instrumentation data indicate that the PV-1 static test firing conducted 18 Aug. 1988 was successful. With the exception of the intentionally flawed joints and static test modifications, PV-1 was flight configuration. Fail-safe flaws guaranteeing pressure to test the sealing capability of primary O-rings were included in the aft field joint, case-to-nozzle joint, and nozzle internal Joint 5. The test was conducted at ambient conditions, with the exception of the field joints and case/nozzle joints which were maintained at a minimum of 75 F. Ballistics performance values were within specification requirements. The PV-1 motor exhibited chamber pressure oscillations similar to previously tested Space Shuttle redesigned solid rocket motors, particularly QM-7. The first longitudinal mode oscillations experienced by PV-1 were the strongest ever measured in a Space Shuttle motor. Investigation into this observation is being conducted. Joint insulation performed as designed with no evidence of gas flow within unflawed forward field joints. The intentionally flawed center and aft case field joint insulation performance was excellent. There was no evidence of hot gas past the center field joint capture feature O-ring, the case-to-nozzle joint primary O-ring, or the aft field joint primary O-ring. O-ring seals and barriers with assured pressure at the flaws showed erosion and heat effect, but all sealed against passage of hot gases with the exception of the aft field joint capture feature O-ring. There was no evidence of erosion, heat effect, or blowby on any O-ring seals or barriers at the unflawed joints. Nozzle performance was nominal with typical erosion. Post-test examination revealed that the forward nose ring was of the old high performance motor design configuration with the 150-deg ply angle. All nozzle components remained intact for post-test evaluation. The thrust vector control system operated correctly. The water deluge system, CO2 quench, and other test equipment performed as planned during all required test operations.

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