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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2005

Debris/Ice/TPS Assessment and Integrated Photographic Analysis of Shuttle Mission STS-108

The Debris Team has developed and implemented measures to control damage from debris in the Shuttle operational environment and to make the control measures a part of routine launch flows. These measures include engineering surveillance during vehicle processing and closeout operations, facility and flight hardware inspections before and after launch, and photographic analysis of mission events. Photographic analyses of mission imagery from launch, on-orbit, and landing provide significant data in verifying proper operation of systems and evaluating anomalies. In addition to the Kennedy Space Center Photo/Video Analysis, reports from Johnson Space Center and Marshall Space Flight Center are also included in this document to provide an integrated assessment of the mission.

Oliu, Armando↗
NASA NTRS2005

Debris/Ice/TPS Assessment and Integrated Photographic Analysis of Shuttle Mission STS-109

The Debris Team has developed and implemented measures to control damage from debris in the Shuttle operational environment and to make the control measures a part of routine launch flows. These measures include engineering surveillance during vehicle processing and closeout operations, facility and flight hardware inspections before and after launch, and photographic analysis of mission events. Photographic analyses of mission imagery from launch, on-orbit, and landing provide significant data in verifying proper operation of systems and evaluating anomalies. In addition to the Kennedy Space Center Photo/Video Analysis, reports from Johnson Space Center and Marshall Space Flight Center are also included in this document to provide an integrated assessment of the mission.

Oliu, Armando↗
NASA NTRS2005

Debris/Ice/TPS Assessment and Integrated Photographic Analysis of Shuttle Mission STS-110

The Debris Team has developed and implemented measures to control damage from debris in the Shuttle operational environment and to make the control measures a part of routine launch flows. These measures include engineering surveillance during vehicle processing and closeout operations, facility and flight hardware inspections before and after launch, and photographic analysis of mission events. Photographic analyses of mission imagery from launch, on-orbit, and landing provide significant data in verifying proper operation of systems and evaluating anomalies. In addition to the Kennedy Space Center Photo/Video Analysis, reports from Johnson Space Center and Marshall Space Flight Center are also included in this document to provide an integrated assessment of the mission.

Oliu, Armando↗
NASA NTRS1937

Maximum Forces Applied by Pilots to Wheel-type Controls

Measurements were made of the maximum push, pull, and tangential forces that could be applied to airplane wheel-type controls for a wide range of fore-and-aft positions of the wheel. The measurements were conducted with several sizes of wheels and several heights of the center of the wheel above the seat. Various one and two-hand grips with pilots both secure and free were studied for each of the two pilots used in the investigation.

Mcavoy, William H↗
NASA NTRS1973

Control point measurements on Mariner 9 pictures

Measurements are given of the control points on the Mariner 9 pictures which were used in the computation of the June 1973 control net of Mars. The method of making the measurements is discussed along with the picture coordinate system and the removal of distortions. Table are presented of the 9804 measurements of 1645 points on 660 pictures.

Davies, M. E.↗
NASA NTRS1982

A dynamic measure of controllability and observability for the placement of actuators and sensors on large space structures

The degree of controllability of a large space structure is found by a four step procedure: (1) finding the minimum control energy for driving the system from a given initial state to the origin in the prescribed time; (2) finding the region of initial state which can be driven to the origin with constrained control energy and time using optimal control strategy; (3) scaling the axes so that a unit displacement in every direction is equally important to control; and (4) finding the linear measurement of the weighted "volume" of the ellipsoid in the equicontrol space. For observability, the error covariance must be reduced toward zero using measurements optimally, and the criterion must be standardized by the magnitude of tolerable errors. The results obtained using these methods are applied to the vibration modes of a free-free beam.

Vandervelde, W. E.↗
NASA NTRS1989

Installation effects on propeller wake/vortex induced structure-borne noise transmission

A laboratory-based test apparatus was employed to investigate the effects of power-plant placement, engine/nacelle mass installation, and wing-to-fuselage attachment methods on propeller-induced structure-borne noise (SBN) transmission levels and their effects on noise-control measures. Data are presented showing SBN transmission is insensitive to propeller spanwise placement, however some sensitivity is seen in propeller-to-wing spacing. Installation of an engine/nacelle mass and variation in wing-to-fuselage attachments have measurable influences on SBN transmission and control measures.

Unruh, J. F.↗
NASA NTRS1982

Thermal monitoring, measurement, and control system for a Volatile Condensable Materials (VCM) test apparatus

A thermal monitoring and control concept is described for a volatile condensable materials (VCM) test apparatus where electric resistance heaters are employed. The technique is computer based, but requires only proportioning ON/OFF relay control signals supplied through a programmable scanner and simple quadrac power controllers. System uniqueness is derived from automatic temperature measurements and the averaging of these measurements in discrete overlapping temperature zones. Overall control tolerance proves to be better than + or - 0.5 C from room ambient temperature to 150 C. Using precisely calibrated thermocouples, the method provides excellent temperature control of a small copper VCM heating plate at 125 + or - 0.2 C over a 24 hr test period. For purposes of unattended operation, the programmable computer/controller provides a continual data printout of system operation. Real time operator command is also provided for, as is automatic shutdown of the system and operator alarm in the event of malfunction.

Ives, R. E.↗
NASA NTRS1993

Controllability and observability measures for Craig-Bampton substructure representations

Measures of controllability and observability are derived for a Craig-Bampton substructure representation for which fixed interface modes and constraint modes are computed relative to control actuator locations. The measures facilitate modal ordering and act as an index of dynamic completeness for modal truncation. Example problems are given to demonstrate that the controllable and observable reduced substructure models have a greater accuracy in predicting closed loop pole locations, transfer functions and actuation commands than conventional normal mode models.

Triller, Michael J.↗
NASA NTRS1988

Insitu measurement and control of processing properties of composite resins in a production tool

An in situ measuring technique for use in automated composite processing and quality control is discussed. Frequency dependent electromagnetic sensors are used to measure processing parameters at four ply positions inside a thick section 192-ply graphite-epoxy composite during cure in an 8 x 4 in. autoclave. Viscosity measurements obtained using the sensors are compared with the viscosities calculated using the Loos-Springer cure process model. Good overall agreement is obtained. In a subsequent autoclave run, the output from the four sensors was used to control the autoclave temperature. Using the 'closed loop' sensor controlled autoclave temperature resulted in a more uniform and more rapid cure cycle.

Kranbuehl, D.↗
NASA NTRS1987

The measurement and control of helicopter blade modal response using blade-mounted accelerometers

The measurement of helicopter blade flapping, bending, and lag modal acceleration and displacement response using blade-mounted accelerometers is described. It is shown that knowledge of the blade mode shapes is sufficient to permit separation of the modal contributions to the accelerometer signals using matrix inversion. The application of the Mckillip (1985) filter to the identification of modal rate response is described. Finally, the design of flapping, bending, and lag mode controllers utilizing the conventional mesh plate is presented. The measurement technique is illustrated using flight test results obtained using a Black Hawk helicopter.

Ham, Norman D.↗
NASA NTRS1987

Structure-borne noise control for propeller aircraft

A laboratory test apparatus was developed which would allow the study and development of propeller wake/vortex-induced structure-borne interior noise control measures. Various methods of wing structural modification, including blocking masses, surface damping treatments, and tuned mechanical absorbers, were evaluated relative to reduced interior noise levels. Inboard wing fuel was found to act as an effective blocking mass. Wing panel add-on damping treatment in the form of a single, constrained layer was not an effective control measure, except in the area of the propeller wake. However, highly damped, tuned mechanical absorbers were found to be the most efficient structure-borne noise (SBN) control measure.

Unruh, James F.↗
NASA NTRS1971

On stochastic control and optimal measurement strategies

The control of stochastic dynamic systems is studied with particular emphasis on those which influence the quality or nature of the measurements which are made to effect control. Four main areas are discussed: (1) the meaning of stochastic optimality and the means by which dynamic programming may be applied to solve a combined control/measurement problem; (2) a technique by which it is possible to apply deterministic methods, specifically the minimum principle, to the study of stochastic problems; (3) the methods described are applied to linear systems with Gaussian disturbances to study the structure of the resulting control system; and (4) several applications are considered.

Kramer, L. C.↗
NASA NTRS1983

Measurement and Control of Free Calcium Inside Small Intact Cells

The use of dye to measure intracellular free calcium concentration was discussed. Difficulty in measuring the calcium is caused by two problems: the small amount of calcium available for testing, and the selectivity to bind calcium at 100 nanomolar excludes substances from entering the cell.

Tsien, R. Y.↗
NASA NTRS1980

Modular instrumentation system for real-time measurements and control on reciprocating engines

An instrumentation system was developed for reciprocating engines. Among the parameters measured are the indicated mean effective pressure, or theoretical work per cycle, and the mass fraction burn rate, a measure of the combustion rate in the cylinder. These computations are performed from measured cylinder pressure and crankshaft angle and are available in real time for the experimenter. A 100 or 200 consecutive-cycle sample is analyzed to reduce the effect of cyclic variations in the engine. Data are displayed in bargraph form, and the mean and standard deviation are computed. Other instruments are also described.

Rice, W. J.↗
NASA NTRS1983

General aviation fuel quality control

Quality control measures for aviation gasoline, and some of the differences between quality control on avgas and mogas are discussed. One thing to keep in mind is that with motor gasoline you can always pull off to the side of the road. It's not so easy to do in an airplane. Consequently, there are reasons for having the tight specifications and the tight quality control measures on avgas as compared to motor gasoline.

Poitz, H.↗