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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 91 records · Page 5

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NASA NTRS1974

Bone mineral computation with a rectilinear scanner

A portable rectilinear transmission scanner and associated computerized data reduction techniques for estimating bone mineral content are described. This unit can be easily disassembled for transport to various measurement sites and has been used to estimate the bone mineral content of the os calcis, radius, and ulna in the Apollo and Skylab astronauts. The scanner is used to obtain multiple rows of data from which a bone profile is derived. Bone edges are determined with the aid of a digital computer program which employs an algorithm that determines the greatest rate of change of the counting rate.

Ullman, J.↗

NASA NTRS1974

A rack-mounted precision waveguide-below-cutoff attenuator with an absolute electronic readout

A coaxial precision waveguide-below-cutoff attenuator is described which uses an absolute (unambiguous) electronic digital readout of displacement in inches in addition to the usual gear driven mechanical counter-dial readout in decibels. The attenuator is rack-mountable and has the input and output RF connectors in a fixed position. The attenuation rate for 55, 50, and 30 MHz operation is given along with a discussion of sources of errors. In addition, information is included to aid the user in making adjustments on the attenuator should it be damaged or disassembled for any reason.

Cook, C. C.↗

NASA NTRS1975

Space shuttle solid rocket booster processing and recovery operations at Kennedy Space Center

This paper describes the processing and recovery operations at Kennedy Space Center as applied to the Space Shuttle Solid Rocket Booster. The introductory portion covers the overall Space Shuttle launch vehicle with a description of the Solid Rocket Boosters and explanations of their functions. Processing operations begin with the arrival of the new or refurbished Solid Rocket Motor segments by rail cars from the manufacturer. Segment buildup is performed on the Mobile Launch Platform, and the completed major booster elements are functionally tested prior to their integration with other prime elements that comprise a complete Shuttle launch vehicle. The recovery operations following launch include Solid Rocket Booster separation, parachute deployment, splashdown, and the activities associated with retrieval of the reusable components of the Solid Rocket Boosters. Subsequently, the paper describes the processing required to thoroughly clean the retrieved items, the disassembly activities, and refurbishment steps planned for restoration of the hardware components to usable condition.

Dickinson, W. J.↗

NASA NTRS1975

Operations analysis (study 2.1): Program manual and users guide for the LOVES computer code

Information is provided necessary to use the LOVES Computer Program in its existing state, or to modify the program to include studies not properly handled by the basic model. The Users Guide defines the basic elements assembled together to form the model for servicing satellites in orbit. As the program is a simulation, the method of attack is to disassemble the problem into a sequence of events, each occurring instantaneously and each creating one or more other events in the future. The main driving force of the simulation is the deterministic launch schedule of satellites and the subsequent failure of the various modules which make up the satellites. The LOVES Computer Program uses a random number generator to simulate the failure of module elements and therefore operates over a long span of time typically 10 to 15 years. The sequence of events is varied by making several runs in succession with different random numbers resulting in a Monte Carlo technique to determine statistical parameters of minimum value, average value, and maximum value.

Wray, S. T., Jr.↗

NASA NTRS1975

Data management system CIU and DIU. Appendix A: CIU and DIU schematics

The Computer Interface Unit (CIU) and the Data Interface Unit (DIU) of the Data Management System (DMS) were described as to their functional location, purpose and function. This describes the CIU and DIU at the unit level illustrating their interface thru the Data Bus (DBUS) and to other DMS units. All unit level interfaces are defined as to function and characteristics. The controls, indicators, test points and connectors are listed and function, location and application are described for each. The mechanical configuration is defined and illustrated to provide card and component location for modification or repair purposes. Unique disassembly and assembly requirements are outlined where applicable. A unit internal functional block diagram level description is provided.

Source record↗

NASA NTRS1976

Inspection of two Brayton rotating units after extensive endurance testing

A system was designed to produce 2-10 kW net continuous electric power for at least 5 years. The turbine-alternator-compressor power conversion unit in the system is designated Brayton Rotating Unit (BRU). Four BRU's were fabricated and extensively tested. One BRU has accumulated 11,000 hours of operation, and another has accumulated in excess of 21,000 hours. Testing has demonstrated that the BRU's have met or exceeded performance objectives. Two BRU's were disassembled and given a thorough post-test inspection. The inspection results show that after 21,000 hours of operation there is no apparent wear or failure mode that will prevent the attainment of the 5-year life objective.

Dunn, J. H.↗

NASA NTRS1977

Design study of superconducting magnets for a combustion magnetohydrodynamic (MHD) generator

Design trade off studies for 13 different superconducting magnet systems were carried out. Based on these results, preliminary design characteristics were prepared for several superconducting magnet systems suitable for use with a combustion driven MHD generator. Each magnet generates a field level of 8 T in a volume 1.524 m (60 in.) long with a cross section 0.254 m x 0.254 m (10 in. x 10 in.) at the inlet and 0.406 m x .406 m (16 in. x 16 in.) at the outlet. The first design involves a racetrack coil geometry intended for operation at 4.2 K; the second design uses a racetrack geometry at 2.0 K; and the third design utilizes a rectangular saddle geometry at 4.2 K. Each case was oriented differently in terms of MHD channel axis and main field direction relative to gravity in order to evaluate fabrication ease. All cases were designed such that the system could be disassembled to allow for alteration of field gradient in the MHD channel by changing the angle between coils. Preliminary design characteristics and assembly drawings were generated for each case.

Thome, R. J.↗

NASA NTRS1976

Aerospike thrust chamber program

An existing, but damaged, 25,000-pound thrust, flightweight, oxygen/hydrogen aerospike rocket thrust chamber was disassembled and partially repaired. A description is presented of the aerospike chamber configuration and of the damage it had suffered. Techniques for aerospike thrust chamber repair were developed, and are described, covering repair procedures for lightweight tubular nozzles, titanium thrust structures, and copper channel combustors. Effort was terminated prior to completion of the repairs and conduct of a planned hot fire test program when it was found that the copper alloy walls of many of the thrust chamber's 24 combustors had been degraded in strength and ductility during the initial fabrication of the thrust chamber. The degradation is discussed and traced to a reaction between oxygen and/or oxides diffused into the copper alloy during fabrication processes and the hydrogen utilized as a brazing furnace atmosphere during the initial assembly operation on many of the combustors. The effects of the H2/O2 reaction within the copper alloy are described.

Campbell, J., Jr.↗

NASA NTRS1979

Easily-wired toggle switch

Crimp-type connectors reduce assembly and disassembly time. With design, no switch preparation is necessary and socket contracts are crimped to wires inserted in module attached to back of toggle switch engaging pins inside module to make electrical connections. Wires are easily removed with standard detachment tool. Design can accommodate wires of any gage and as many terminals can be placed on switch as wire gage and switch dimensions will allow.

Dean, W. T.↗

NASA NTRS1977

Mechanical characteristics of stability-bleed valves for a supersonic inlet

Mechanical characteristics of a set of direct-operated relief valves used in a throat-bypass stability-bleed system designed for the YF-12 aircraft inlet are described. A comparison of data taken before and after the windtunnel tests (at room temperature) showed that both the effective spring rate and the piston friction had decreased during the wind tunnel tests. In neither the effective spring rate nor the piston friction was the magnitude of change great enough to cause significant impairment of overall system effectiveness. No major valve mechanical problems were encountered in any of the tests. During high temperature bench tests, piston frictional drag increased. The friction returned to its initial room temperature value when the stability-bleed valve was disassembled and reassembled. The problem might be solved by using a different material for the piston sleeve bearing and the piston rings.

Neiner, G. H.↗

NASA NTRS1978

Long-term CF6 engine performance deterioration: Evaluation of engine S/N 451-479

The performance testing and analytical teardown of CF6-6D engine is summarized. This engine had completed its initial installation on DC-10 aircraft. The investigative test program was conducted inbound prior to normal overhaul/refurbishment. The performance testing included an inbound test, a test following cleaning of the low pressure turbine airfoils, and a final test after leading edge rework and cleaning the stage one fan blades. The analytical teardown consisted of detailed disassembly inspection measurements and airfoil surface finish checks of the as received deteriorated hardware. Included in this report is a detailed analysis of the test cell performance data, a complete analytical teardown report with a detailed description of all observed hardware distress, and an analytical assessment of the performance loss (deterioration) relating measured hardware conditions to losses in both SFC (specific fuel consumption) and EGT (exhaust gas temperature).

Kramer, W. H.↗

NASA NTRS1978

Long-term CF6 engine performance deterioration: Evaluation of engine S/N 451-380

The performance testing and analytical teardown of CF6-6D engine serial number 451-380 which was recently removed from a DC-10 aircraft is summarized. The investigative test program was conducted inbound prior to normal overhaul/refurbishment. The performance testing included an inbound test, a test following cleaning of the low pressure turbine airfoils, and a final test after leading edge rework and cleaning the stage one fan blades. The analytical teardown consisted of detailed disassembly inspection measurements and airfoil surface finish checks of the as-received deteriorated hardware. Aspects discussed include the analysis of the test cell performance data, a complete analytical teardown report with a detailed description of all observed hardware distress, and an analytical assessment of the performance loss (deterioration) relating measured hardware conditions to losses in both specific fuel comsumption and exhaust gas temperature.

Kramer, W. H.↗

NASA NTRS1979

Troubleshooting plated-wire memories

Faults in plated wire memories are identified and located from outside of system by applying electrical impulses and analyzing their reflectance in technique of Time-Domain Reflectometry (TDR). Intermittent faults are easier to find because memory system is not disturbed by probing or disassembly.

Baker, C. M.↗

NASA NTRS1979

Fixture for limited-access welding

Fixture consisting of screw-on expansion clamps and backup bar aligns edges of plates for precision butt welding. Tool holds plates securely, without offset, and allows welding and clamp disassembly to be completed when there is access from only one side of structure.

Tryon, J. R.↗

NASA NTRS1979

Retainers for threaded parts

Retaining ring and fine wire secure nuts or screws reliably. Retainer is easy to assemble and to disassemble, even in confined areas.

Davis, N. M.↗

NASA NTRS1978

Design considerations for large space antennas

Performance requirements and costs for transportation, fabrication, and orbital assembly are the drivers in the design of large space antennas will range in size from approximately 30 m to 1 km in diameter and include radiometers, multibeam lens antennas, and microwave power transmission systems. Research and development is required to define comprehensive structural criteria for specific missions, to determine optimized geometries for truss elements and truss configurations and to establish requirements for joint design with consideration of tolerances, load transfer, thermal compatibility, and assembly and disassembly. Candidate structural elements, materials systems for the low pressure rapid cure of advanced composite materials, and various on orbit assembly and fabrication techniques must also be developed.

Johnson, R., Jr.↗

NASA NTRS1979

Space Shuttle Orbiter AFT heat shield seal

The evolution of the orbiter aft heat shield seal (AHSS) design, which involved advancing mechanical seal technology in severe thermal environment is discussed. The baseline design, various improvements for engine access, and technical problem solution are presented. It is a structure and mechanism at the three main propulsion system (MPS) engine interfaces to the aft compartment structure. Access to each MPS engine requires disassembly and removal of the AHSS. Each AHSS accommodates the engine movement, is exposed to an extremely high temperature environment, and is part of the venting control of the aft compartment.

Walkover, L. J.↗

NASA NTRS1981

Anatomy of a short

The plate stocks of nickel cadmium batteries were disassembled to locate shorts. Through testing, the cause of the shorts was discovered to be a growth of cadmium coming through the separator.

Scott, W. R.↗