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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 NTRS1984

The Design and Use of Subtasks in Part Training and Their Relationship to the Whole Task

The part versus whole training is discussed. Common sense dictates that a massive body of knowledge should not be taught as a whole. For the same reason, if a part of the task is very difficult, one should not go over the task in its entirety. Repetitive training on the difficult part should lead to better results. Several part training methods were developed, including: pure part, progressive part, repetitive part, retrogressive and isolated parts. The question was posited whether training on parts of a task is a beneficial enterprise. The way the task will be disassembled for the part training needs to be determined. It is argued that the effectiveness of part training depends on the degree to which a task is decomposable.

Mane, A. M.↗
NASA NTRS1985

Solid rocket booster retrieval operations

Solid Rocket Booster Retrieval operations are discussed in detail. The recovery of expended boosters and associated hardware without damage attributable to retrieval procedures is the main goal. The retrieval force consists tof ship's personnel and retrieval team members, each of whom has been trained and is highly skilled in multi-faceted operations. The retrieval force is equipped with two specially-built, highly maneuverable ships outfitted with parachute reels, retrieval cranes, towing winches, large volume-low pressure air compressors, SCUBA diving gear, inflatable boats with outboard motors and diver-operated SRB dewatering devices. The two ships are deployed in sufficient time to conduct an electronic and visual search of the impact area prior to launch. Upon search completeion, each ship takes station a safe distance from the predetermined impact point initiating both visual and electronic search in the direction of flight path, ensuring SRB acquisition at splashdown. When safe, the ships enter the impact area and commence recovery of all floating flight hardware which is subsequently returned to the Disassembly Facility for refurbishment and reuse. Retrieval techniques have evolved in parallel with equipment and flight hardware configuration changes. Additional changes have been initiated to improve personnel safety.

Rasmussen, A. M.↗
NASA NTRS1985

Reusable rocket engine turbopump condition monitoring

Significant improvements in engine readiness with attendant reductions in maintenance costs and turnaround times can be achieved with an engine condition monitoring system (CMS). The CMS provides real time health status of critical engine components, without disassembly, through component monitoring with advanced sensor technologies. Three technologies were selected to monitor the rotor bearings and turbine blades: the isotope wear detector and fiber optic deflectometer (bearings), and the fiber optic pyrometer (blades). Signal processing algorithms were evaluated and ranked for their utility in providing useful component health data to unskilled maintenance personnel. Design modifications to current configuration Space Shuttle Main Engine (SSME) high pressure turbopumps and the MK48-F turbopump were developed to incorporate the sensors.

Hampson, M. E.↗
NASA NTRS1985

Nickel-hydrogen Cell Test Program Summary

Three prototype 50 ampere-hour (Ah) nickel-hydrogen cells of the Air Force Wright Aeronautical Laboratories (AWFAL) design were cycled to failure. A summary of the life cycling tests and failure analyses of the cells are presented. The cells were cycled in a simulated low earth orbit regime at depths of discharge ranging from 25 to 80 percent. Trend data, such as end of discharge voltage and cell capacity, was recorded during test. Cells 1, 2, and 3 completed 17167, 2473, and 10080 charge/discharge cycles, respectively, prior to failure. All failed due to internal shorts, and were disassembled to determine cause of failure.

Mueller, V. C.↗
NASA NTRS1985

Voyager 0.2-lbf thruster valve assembly short pulse test report

The short pulse width testing completed on the Voyager 0.2-lbf thruster value assemblies (T/VA's) and the disassembly and inspection of T/VA S/N 020 is reported. The purpose for performing the short pulse width testing on Voyager 0.2-lbf thruster valve assemblies (T/VA's) was to determine: (1) impulse bit versus electrical pulse width; (2) impulse bit variations versus electrical pulse width; and (3) whether the short pulses decrease thruster life.

Johnson, D. R.↗
NASA NTRS1985

A strategy planner for NASA robotics applications

Automatic strategy or task planning is an important element of robotics systems. A strategy planner under development at Goddard Space Flight Center automatically produces robot plans for assembly, disassembly, or repair of NASA spacecraft from computer aided design descriptions of the individual parts of the spacecraft.

Brodd, S. S.↗
NASA NTRS1985

Observation of super high energy big family with large scale Fe emulsion chambers

In order to get higher efficiencies for detecting hadrons and to make technical improvements in the chamber structure, the Mt. Kambala Emulsion Chamber Collaboration constructed 57 sq. m. of Fe chamber, with thickness 29 c.u.(1c.u.=17.6 mm Fe), using 300 tons of Fe plates and made the first exposure from Sept., 1982 to May, 1984. The photosensitive layers consist of X-ray films of Sakura N type, Fuji No. 100 type and Tianjin III type, some of them contain also emulsion plates of Fuji ET7B type. They are inserted between the Fe plates at 2 c.u., beginning at 5 c.u. from the chamber top. In a number of blocks, 3 mm spacings are provided at every 2 c.u. of Fe plates to facilitate the replacement of photosensitive layers, without disassembling the chamber. On the bottom of the chamber Fe plates of thickness 9 mm are placed in order to shield the chamber from the radioactivities of the ground. An event, numbered K2 58 of visible energy sigma E sub gamma = 7345 TeV was found in this exposure. No obvious halo is seen in the event and all the showers are clearly separated and easy to measure. A brief report of the preliminary results is presented.

Source record↗
NASA NTRS1984

Technique for the efficient and reproducible fabrication of electromagnetic levitation coils

A technique has been developed for fabricating electromagnetic induction coils in a reproducible manner. The process utilizes a split mandrel that can be disassembled to remove the mandrel from the coil. The technique has increased coil production rates by a factor of 8 over the freehand winding method. The success rate for producing a functional levitation coil has been increased from 50 percent to 95 percent. The levitation coil designed during this work has successfully levitated and melted a variety of alloys including Cu, Ag, Ag-Ni, Cu-Fe, Fe-C, and Nb-Ge. W was also levitated but not melted at temperatures as high as 2700 C. The highest sample melt temperature achieved was 2400 C for the Nb-Ge samples.

Ethridge, E. C.↗
NASA NTRS1984

Reusable rocket engine turbopump condition monitoring

Significant improvements in engine readiness with reductions in maintenance costs and turn-around times can be achieved with an engine condition monitoring systems (CMS). The CMS provides health status of critical engine components, without disassembly, through monitoring with advanced sensors. Engine failure reports over 35 years were categorized into 20 different modes of failure. Rotor bearings and turbine blades were determined to be the most critical in limiting turbopump life. Measurement technologies were matched to each of the failure modes identified. Three were selected to monitor the rotor bearings and turbine blades: the isotope wear detector and fiberoptic deflectometer (bearings), and the fiberoptic pyrometer (blades). Signal processing algorithms were evaluated for their ability to provide useful health data to maintenance personnel. Design modifications to the Space Shuttle Main Engine (SSME) high pressure turbopumps were developed to incorporate the sensors. Laboratory test fixtures have been designed for monitoring the rotor bearings and turbine blades in simulated turbopump operating conditions.

Hampson, M. E.↗
NASA NTRS1984

Space Shuttle Main Engine overhaul program

The Space Shuttle Main Engine first flight set from the Orbiter Columbia was returned to Rockwell International/Rocketdyne Division in Canoga Park, California for overhaul after five successful development flights. The three main engines have been completely disassembled and the hardware assessed for space flight effects. Schedules to overhaul subsequent flight engines have been established based on operational requirements of the Space Transportation System. To support these requirements, a dedicated Space Shuttle Main Engine Overhaul Center is being built at the Canoga Park Rocketdyne Facility incorporating the latest in manufacturing, inspection, and data processing equipment.

Stohler, S.↗
NASA NTRS1984

Activity of calcium activated protease in skeletal muscles and its changes in atrophy and stretch

The reduction of protein content in skeletal muscle undergoing disuse-induced atrophy is correlated with accelerated rates of protein degradation and reduced rates of protein synthesis (Goldspink, 1977). It is not known in what manner myofibers are partially disassembled during disuse atrophy to fibers of smaller diameter; nor is it known which proteases are responsible for this morphological change in contractile protein mass. Dayton and colleagues (1975) have suggested that the Ca(2+)-activated protease (CaP) may initiate myofibril degradation. The discovery of a form of CaP that is activatable by nano-molar concentrations of Ca(2+) indicates that CaP activity may be regulated by physiological concentrations of Ca(2+) (Mellgren, 1980). The enhancement of proteolysis by the Ca(2+) ionophore A23187, reported by Etlinger (1979), is consistent with a significant role for CaP in protein degradation. It was of interest, therefore, to measure the levels of CaP activity and the CaP inhibitor in extracts obtained from skeletal muscles of rat and chicken limbs undergoing disuse atrophy or stretch hypertrophy, respectively.

Ellis, S.↗
NASA NTRS1986

Detecting Contaminant Particles Acoustically

Apparatus "listens" for particles in interior of complex turbomachinery. Contact microphones are attached at several points on pump housing. Acoustic transducer also attached to housing to excite entire pump with sound. Frequency of sound is slowly raised until pump resonates. Microphones detect noise of loose particles scraping against pump parts. Such as machining chips in turbopumps or other machinery without disassembly.

Wyett, L. M.↗
NASA NTRS1986

Ultrasonic Inspection Near Small Bores

Portable ultrasonic probe makes it possible to inspect for hidden cracks near insides of narrow tubes. Using pulse-echo technique, instrument detects cracks as small as 0.015-in. (0.38-mm) deep. Used for nondestructive inspection of other hard-to-reach places where conventional large transducers will not fit or where difficult to apply coupling liquid for contact ultrasonic testing. Inspects bore of tubelike fitting. Instrument makes it unnecessary to disassemble fitting to check for cracks. Precise orientation of transducer with respect to part not necessary for detecting cracks.

Parent, R. G.↗
NASA NTRS1986

Hydraulic-Leak Detector for Hidden Joints

Slow leakage of fluid made obvious. Indicator consists of wick wrapped at one end around joint to be monitored. Wick absorbs hydraulic fluid leaking from joint and transmits to opposite end, located outside cover plate and visible to inspector. Leakage manifested as discoloration of outside end of wick. Indicator reveals leaks in hidden fittings on hydraulic lines. Fast inspection of joints without disassembly. Used in aerospace, petroleum, chemical, nuclear, and other industries where removing covers for inspection impossible, difficult, or time-consuming.

Anderson, G. E.↗
NASA NTRS1984

Telescoping space station modules

A design concept is described wherein telescoping space station modules would be utilized to nearly double the useful volume onboard a station. Methods for utilizing the concept to obtain enchanced protection from space debris and radiation are described. The amenability of the concept to variation in station configuration, assembly, and disassembly is discussed. A modification of the concept which could provide flexibility in the manner in which the Shuttle Orbiter is docked with the station and enhance collision avoidance during such maneuvers is described.

Witcofski, R. D.↗
NASA NTRS1986

Optical multiple sample vacuum integrating sphere

An integrating sphere comprised of a uniform difusely reflecting spherical cavity, having mutually transverse input and output ports, and a linear sample transport mechanism is described. The sample transport mechanism is secured so that the multiple samples can be brought into registration with the input port, one at a time, without having to open or disassemble the apparatus when a change of sample is desired. A vacuum tight seal is provided between the cavity and the transport mechanism. This maintains the integrity of a vacuum generated with the sphere when attached to the source of optical energy. The device is utilized to test emissive characteristics such as the relative fluorescence quantum efficiency of a dye sample placed in the path of a monochromatic optical energy source coupled to the input port while having a light detector coupled to the output port.

Butner, C. L.↗
NASA NTRS1987

Increasing Maintainability of a Wastewater-Recovery Unit

Modified system leaks less and easier to disassemble for maintenance. Redesign of wastewater-recovery system separates water from urine: improved operation and system easier to maintain. Details of redesign, chiefly affected hollow-fiber-membrane evaporator, described in report.

Dehner, G. F.↗
NASA NTRS1985

Analysis of DRIRU bearings and lubricant from solar max repair mission

The Solar Maximum Repair Mission (SMRM) by the shuttle astronauts in April 1984, returned to Earth the Delta Redundant Inertial Reference Unit 2 (DRIRU 2) from the Solar Maximum satellite. The DRIRU 2 included three gyroscopes. The gyroscope, S/N 094, in position 2 was disassembled by Teledyne Systems personnel of Northridge, California, and the bearings were returned to Goddard Space Flight Center for examination. The Solar Max Satellite was in orbit for 4 years with the bearings running continuously at 6000 rpm. The ball bearings, had sufficient remaining lubrication and had runs successfully for over the last 4 years. As a result of these findings, the bearings should have lasted their predicted life of 5 years with no problems.

Uber, J. M.↗