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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 757 records · Page 42

Temperature averaging thermal probe

A thermal probe to average temperature fluctuations over a prolonged period was formed with a temperature sensor embedded inside a solid object of a thermally conducting material. The solid object is held in a position equidistantly spaced apart from the interior surfaces of a closed housing by a mount made of a thermally insulating material. The housing is sealed to trap a vacuum or mass of air inside and thereby prevent transfer of heat directly between the environment outside of the housing and the solid object. Electrical leads couple the temperature sensor with a connector on the outside of the housing. Other solid objects of different sizes and materials may be substituted for the cylindrically-shaped object to vary the time constant of the probe.

Kalil, L. F.↗

Development of space telescope non-ORU hardware

Since 1979 work has progressed in the development of the Hubble Space Telescope (HST) mockup. Underwater simulations to evaluate proposed on-orbit servicing tasks have also been done. These tasks involve the planned changeout of scientific instruments and the unscheduled changeout of other orbital replacement units (ORUs) such as batteries and computers. The HST components and subsystems that originally were designated ORUs were the items that were mission critical and were designed for easy changeout. Mockups of 14 non-ORU items were designed and fabricated for the purpose of evaluating the EVA changetasks in the MSFC Neutral Buoyancy Simulator (NBS). The objectives of this design/fabrication/test activity were to design and fabricate the potential ORUs so they contained realistic interfaces and were compatible with the NBS environments. The attachment of the mockup hardware to the spacecraft mockup was similar to the flight version. Also, the hardware connectors were flight-like.

Robertson, K. B.↗

MOS integrated circuit fault modeling

Three digital simulation techniques for MOS integrated circuit faults were examined. These techniques embody a hierarchy of complexity bracketing the range of simulation levels. The digital approaches are: transistor-level, connector-switch-attenuator level, and gate level. The advantages and disadvantages are discussed. Failure characteristics are also described.

Sievers, M.↗

Transmission line design for a power distribution system at 20 kHz for aircraft

A low inductance, low characteristic impedance transmission line was designed for a 20 kHz power distribution system. Several different conductor configurations were considered: strip lines, interdigitated metal ribbons, and standard insulated wires in multiwire configurations (circular and rectangular cylindrical arrangements). The final design was a rectangular arrangement of multiple wires of the same gauge with alternating polarities from wire to wire. This offered the lowest inductance per unit length (on the order of several nanohenries/meter) and the lowest characteristic impedance (on the order of one Ohm). Standard multipin connectors with gold-plated elements were recommended with this transmission line, the junction boxes to be internally connected with flat metal ribbons for low inductance, and the line to be constructed in sections of suitable length. Computer programs for the calculation of inductance of multiwire lines and of capacitances of strip lines were developed.

Zelby, L. W.↗

Fiber optics for propulsion control systems

In aircraft systems with digital controls, fiberoptics has advantages over wire systems because of its inherent immunity to electromagnetic noise (EMI) and electromagnetic pulses (EMP). It also offers a weight benefit when metallic conductors are replaced by optical fibers. To take full advantage of the benefits of optical waveguides, passive optical sensors are also being developed to eliminate the need for electrical power to the sensor. Fiberoptics may also be used for controlling actuators on engine and airframe. In this application, the optical fibers, connectors, etc. will be subjected to high temperature and vibrations. This paper discussed the use of fiberoptics in aircraft propulsion systems together with the optical sensors and optically controlled actuators being developed to take full advantage of the benefits which fiberoptics offers. The requirements for sensors and actuators in advanced propulsion systems are identified. The benefits of using fiberoptics in place of conventional wire systems are discussed as well as the environmental conditions under which the optical components must operate.

Baumbick, R. J.↗

Safety considerations in the design of Spacelab refrigerator/freezer

A vapor compression refrigerator/freezer has been designed for Spacelab to conduct life sciences experiments. It is equipped with different safety features to eliminate all probable types of failures. The whole Freon loop is enclosed in a second containment so that any leakage of Freon can be contained. The unit is provided with an 'Emergency On' switch to actuate during backup mode which provides the spacecraft power directly to the compressor and the cooling fans while removing the power supply and all normal control elements from the circuit. During this mode, the compressor runs continuously when operating as a freezer (-22 C) and is controlled by a thermostat to cycle when operating as a refrigerator (4 C). It has a push button switch at the front panel to momentarily power the thermometer by a battery to monitor the inside temperature during an emergency. It has a door switch which shuts off the internal cooling fans when the door is opened. All the important critical performance data will be downlinked through a data connector to monitor during mission.

Hye, A.↗

Duplex Wrench

Special tool enables one worker to do two-worker job. Wrench holds two nuts in place while third nut, coaxial with others, turned. Developed for tightening delicate couplings on gas-supply panel. Single operator restrains coupling pressure cap and connector body nut with one hand. Other hand free to tighten coupling nut with torque wrench.

Canada, C. N.↗

Removing Welding Fumes

Portable exhaust duct for machining and welding shops removes oil mist, dust, smoke, and fumes. Duct used with shop exhaust system, inlets of which placed at various convenient locations in shop floor. Flanged connector on underside of wheeled base links flexible tube to exhaust system under floor. Made especially for welding in room with low ceiling.

Moore, Lloyd J.↗

Mechanism Connects and Disconnects Lines Remotely

Misaligned, widely separated connector halves joined, then separated when necessary, while human operator remains at distance. Remote-connection mechanism accommodates large displacements and misalignments of plug and receptacle.

Strand, Victor↗

Waveguide-Horn-to-Waveguide Transition Assembly

Microstrip-to-waveguide transition integrated with waveguide-horn antenna element. Integrated transition assembly couples electromagnetic energy through horn and transition board to connector.

Davidson, Shayla E.↗

PCACE-Personal-Computer-Aided Cabling Engineering

PCACE computer program developed to provide inexpensive, interactive system for learning and using engineering approach to interconnection systems. Basically database system that stores information as files of individual connectors and handles wiring information in circuit groups stored as records. Directly emulates typical manual engineering methods of handling data, thus making interface between user and program very natural. Apple version written in P-Code Pascal and IBM PC version of PCACE written in TURBO Pascal 3.0

Billitti, Joseph W.↗

Loss-compensation of intensity-modulating fiber-optic sensors

This report describes a new type of intensity-modulating fiber-optic sensor which has high immunity to the effects of variations in the losses of the fiber-link. A variable-splitting-ratio transducer is used to differentially modulate the intensities of the light which it transmits and reflects. Using a four-fiber optical link, light is impinged onto the transducer from either direction, and, in each case, the transmitted and reflected signals are measured. These four signals are then processed to remove the effects of the fiber and connector losses. Loss-compensated sensors of angular position and displacement are described, and their outputs are shown to be highly stable despite considerable variations in the transmissivities of the fiber-link components.

Beheim, G.↗

Four-terminal electrical testing device

The invention relates to a four-terminal electrical connector device for testing and measuring unknown resistances of initiators used for starting pyrotechnic events aboard the space shuttle. The testing device minimizes contact resistance degradation effects and so improves the reliability of resistance measurements taken with the device. Separate and independent voltage sensing and current supply circuits each include a pair of socket contacts for mating engagement with the pins of the initiator. The unknown resistance that is measured by the device is the resistance of the bridgewire of the initiator which is required to be between 0.95 and 1.15 ohms.

Robinson, Robert L.↗

Fiber optics: A research paper

Some basic aspects concerning fiber optics are examined. Some history leading up to the development of optical fibers which are now used in the transmission of data in many areas of the world is discussed. Basic theory of the operation of fiber optics is discussed along with methods for improving performance of the optical fiber through much research and design. Splices and connectors are compared and short haul and long haul fiber optic networks are discussed. Fiber optics plays many roles in the commercial world. The use of fiber optics for communication applications is emphasized.

Drone, Melinda M.↗

Fiber optic data systems

An overview is given of a continuing data system architecture development effort. Accomplishments and states of Office of Aeronautics and Space Technology, NASA efforts are discussed, and possible future directions are briefly commented upon. Some performance data is presented on the access protocol utilized in the Bus Interface Unit (BIU) design effort, and it is compared with other access protocols. The status of the qualification effort is presented showing the successful qualification testing of cables, connectors, light emitting diodes and PIN diodes. Information is given in the form of charts and diagrams.

Hartenstein, R.↗

Knowledge based programming at KSC

Various KSC knowledge-based systems projects are discussed. The objectives of the knowledge-based automatic test equipment and Shuttle connector analysis network projects are described. It is observed that knowledge-based programs must handle factual and expert knowledge; the characteristics of these two types of knowledge are examined. Applications for the knowledge-based programming technique are considered.

Tulley, J. H., Jr.↗

An optical communication link on the Shuttle

A communication link for the transfer of data between the crew cabin and payload bay of the Shuttle is proposed. The configuration of the system, which is to transmit data optically through the Shuttle cabin window, is described. The effects of temperature cycling and cosmic radiation on optical fibers, the cable, connectors, and lenses, and of vibrations during a mission on the alignment of collimating lenses at the window are investigated. Consideration is given to determining the optimum design for the optical fiber and the optimum system operation wavelength for transmission through the aft Orbiter window and the payload environment.

Grady, Jane L.↗

Loss-compensation technique for fiber-optic sensors and its application to displacement measurements

This report describes a new type of intensity-modulating fiber-optic sensor which has high immunity to the effects of variations in the losses of the fiber-link. A variable-splitting-ratio transducer is used to differentially modulate the intensities of the light which it transmits and reflects. Using a four-fiber optical link, light is impinged onto the transducer from either direction, and in each case, the transmitted and reflected signals are measured. These four signals are then processed to remove the effects of the fiber and connector losses. Loss-compensated sensors of angular position and displacement are described, and their outputs are shown to be highly stable despite considerable variations in the transmissivities of the fiber-link components.

Beheim, Glenn↗