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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 199 records · Page 11

All sources NASA NTRS DOE OSTI

NASA NTRS1973

System design of the Pioneer Venus spacecraft. Volume 10: Propulsion/orbit insertion subsystem studies

The Pioneer Venus orbiter and multiprobe missions require spacecraft maneuvers for successful accomplishment. This report presents the results of studies performed to define the propulsion subsystems required to perform those maneuvers. Primary goals were to define low mass subsystems capable of performing the required missions with a high degree of reliability for low cost. A review was performed of all applicable propellants and thruster types, as well as propellant management techniques. Based on this review, a liquid monopropellant hydrazine propulsion subsystem was selected for all multiprobe mission maneuvers, and for all orbiter mission maneuvers except orbit insertion. A pressure blowdown operating mode was selected using helium as the pressurizing gas. The forces associated with spacecraft rotations were used to control the liquid-gas interface and resulting propellant orientation within the tank.

Rosenstein, B. J.↗

NASA NTRS1973

Hollow cathodes with BaO impregnated, porous tungsten inserts and tips

The technology of impregnated materials is described and some inherently advantageous characteristics of impregnated cathodes are discussed. Thermionic emission measurements are presented for oxide coated and impregnated cathodes. Five cathode configurations with barium oxide impregnated porous tungsten inserts and/or tips have been fabricated and tested. Reliability, durability, and stability of operation are characterized. One of the cathodes has accumulated over 9000 operational hours, another has been cycled on and off more than 900 times.

Hudson, W. R.↗

NASA NTRS1976

Viking 1 planetary phase tracking operations: Mars orbit insertion through landing

This article describes tracking operations during the Viking 1 planetary phase. Particular attention is paid to special planning for critical phase tracking operations, and to the degree of success subsequently achieved by these special plans during the actual operations. In-depth coverage is provided for Mars orbit insertion (MOI), periapsis passage tracking, and Lander direct links. The article concludes that on balance, tracking operations during the Viking 1 planetary phase have been effectively implemented and quite successful.

Berman, A. L.↗

NASA NTRS1978

TACT1, a computer program for the transient thermal analysis of a cooled turbine blade or vane equipped with a coolant insert. 1. Users manual

A computer program to calculate transient and steady state temperatures, pressures, and coolant flows in a cooled, axial flow turbine blade or vane with an impingement insert is described. Coolant side heat transfer coefficients are calculated internally in the program, with the user specifying either impingement or convection heat transfer at each internal flow station. Spent impingement air flows in a chordwise direction and is discharged through the trailing edge and through film cooling holes. The ability of the program to handle film cooling is limited by the internal flow model. Sample problems, with tables of input and output, are included in the report. Input to the program includes a description of the blade geometry, coolant supply conditions, outside thermal boundary conditions, and wheel speed. The blade wall can have two layers of different materials, such as a ceramic thermal barrier coating over a metallic substrate. Program output includes the temperature at each node, the coolant pressures and flow rates, and the inside heat-transfer coefficients.

Gaugler, R. E.↗

NASA NTRS1979

TACT 1: A computer program for the transient thermal analysis of a cooled turbine blade or vane equipped with a coolant insert. 2. Programmers manual

A computer program to calculate transient and steady state temperatures, pressures, and coolant flows in a cooled axial flow turbine blade or vane with an impingement insert is described. Coolant-side heat transfer coefficients are calculated internally in the program, with the user specifying either impingement or convection heat transfer at each internal flow station. Spent impingement air flows in a chordwise direction and is discharged through the trailing edge and through film cooling holes. The ability of the program to handle film cooling is limited by the internal flow model. Input to the program includes a description of the blade geometry, coolant-supply conditions, outside thermal boundary conditions, and wheel speed. The blade wall can have two layers of different materials, such as a ceramic thermal barrier coating over a metallic substrate. Program output includes the temperature at each node, the coolant pressures and flow rates, and the coolant-side heat transfer coefficients.

Gaugler, R. E.↗

NASA NTRS1981

Analysis of a cooled, turbine blade or vane with an insert

Computer program, TACTI, has been developed to calculate transient and steady-state temperatures, pressures, and flow in cooled turbine blade or vane with impingement insert. Coolant-side heat-transfer coefficients are calculated internally in program, with user specifying 1 of 3 modes of heat transfer at each station: impingement (including effect of crossflow); or forced convection over pin fins.

Saugler, R. E.↗

NASA NTRS1980

A study on various methods of supplying propellant to an orbit insertion rocket engine

Various types of pumps and pump drives were evaluated to determine the lightest weight system for supplying propellants to a planetary orbit insertion rocket engine. From these analyses four candidate propellant feed systems were identified. Systems Nos. 1 and 2 were both battery powered (lithium-thionyl-chloride or silver-zinc) motor driven pumps. System 3 was a monopropellant gas generator powered turbopump. System 4 was a bipropellant gas generator powered turbopump. Parameters considered were pump break horsepower, weight, reliability, transient response and system stability. Figures of merit were established and the ranking of the candidate systems was determined. Conceptual designs were prepared for typical motor driven pumps and turbopump configurations for a 1000 lbf thrust rocket engine.

Boretz, J. E.↗

NASA NTRS1982

Studies with sample conductivity, insertion rates, and particle deflection in a continuous flow electrophoresis system

The continuous flow electrophoresis system makes electrophoresis possible in a free-flowing film of aqueous electrolyte medium. The sample continuously enters the electrolyte at the top of the chamber and is subjected to the action of a lateral dc field. This divides the sample into fractions since each component has a distinctive electrophoretic mobility. Tests were made using monodisperse polystyrene latex microspheres to determine optimum sample conductivity, insertion rates and optimum electric field applications as baseline data for future STS flight experiments. Optimum sample flow rates for the selected samples were determined to be approximately 26 micro-liters/min. Experiments with samples in deionized water yielded best results and voltages in the 20 V/cm to 30 V/cm range were optimum. Deflections of formaldehyde fixed turkey and bovine erythrocytes were determined using the continuous flow electrophoresis system. The effects of particle interactions on sample resolution and migration in the chamber was also evaluated.

Williams, G., Jr.↗

NASA NTRS1985

Tool for Inserting and Removing Tube Plugs

Simple handtool used with both straight and bent tubes. Plug consisting of two expandable O-rings pushed into or pulled out of tube with this flexible tool. Flexible shaft of tool threaded at inner (plug) end to engage or disengage plug when knurled handle turned. Results exceptionally low friction between shaft and tube. Allows insertion and removal of plug carefully controlled.

Molina, O. G.↗

NASA NTRS1986

Precise-Conductance Valve Insert

Valve modification provides two operating modes fully open and small, precise leak. Copper insert with radially oriented holes allows small, controllable, precise effusion rate when valve closed or nearly unobstructed flow when valve open. Numerous applications in surface physics, vacuum physics, materials science, gas kinetics, thin films, and other areas of research requiring measured flows of gas into or out of system.

Outlaw, R. A.↗

NASA NTRS1987

Pressure-Localizing Inserts for Bagging Laminations

Devices compress composite laminates to conform to tight inside corners of molds. Proposed use of pressure-localizing insert allows composite laminates to be compacted into tight corners by conventional pressure or vacuum-bagging techniques. Because of manufacturing technique, larger selection of part shapes becomes amenable to lamination.

Schmaling, Dave↗

NASA NTRS1987

Hardware fault insertion and instrumentation system: Mechanization and validation

Automated test capability for extensive low-level hardware fault insertion testing is developed. The test capability is used to calibrate fault detection coverage and associated latency times as relevant to projecting overall system reliability. Described are modifications made to the NASA Ames Reconfigurable Flight Control System (RDFCS) Facility to fully automate the total test loop involving the Draper Laboratories' Fault Injector Unit. The automated capability provided included the application of sequences of simulated low-level hardware faults, the precise measurement of fault latency times, the identification of fault symptoms, and bulk storage of test case results. A PDP-11/60 served as a test coordinator, and a PDP-11/04 as an instrumentation device. The fault injector was controlled by applications test software in the PDP-11/60, rather than by manual commands from a terminal keyboard. The time base was especially developed for this application to use a variety of signal sources in the system simulator.

Benson, J. W.↗

NASA NTRS1989

Closed loop navigation and guidance for gravity probe B orbit insertion

This paper addresses the problem of guiding the Gravity Probe B (GP-B) spacecraft from its location after initial insertion to a very precise low earth orbit. Specifically, the satellite orbit is required to be circular to within 0.001 eccentricity, polar to within 0.001 deg inclination, and aligned with the direction of the star Rigel to within 0.001 deg. Navigation data supplied by an on-board GPS receiver is used as feedback to a control algorithm designed to minimize the time to achieve the desired orbit. Translational control is provided by the proportional helium thrusters, which are used for drag-free and attitude control during the remainder of the science mission. Simulations of the guidance system are presented which give an indication of performance characteristics for several types of orbit injection errors. This research is the first reported effort to use GPS as a sensor for a closed loop space guidance system.

Axelrad, P.↗

NASA NTRS1989

Using multiple sensors for printed circuit board insertion

As more and more activities are performed in space, there will be a greater demand placed on the information handling capacity of people who are to direct and accomplish these tasks. A promising alternative to full-time human involvement is the use of semi-autonomous, intelligent robot systems. To automate tasks such as assembly, disassembly, repair and maintenance, the issues presented by environmental uncertainties need to be addressed. These uncertainties are introduced by variations in the computed position of the robot at different locations in its work envelope, variations in part positioning, and tolerances of part dimensions. As a result, the robot system may not be able to accomplish the desired task without the help of sensor feedback. Measurements on the environment allow real time corrections to be made to the process. A design and implementation of an intelligent robot system which inserts printed circuit boards into a card cage are presented. Intelligent behavior is accomplished by coupling the task execution sequence with information derived from three different sensors: an overhead three-dimensional vision system, a fingertip infrared sensor, and a six degree of freedom wrist-mounted force/torque sensor.

Sood, Deepak↗

NASA NTRS1990

Saturn orbit insertion mission plan for Cassini

The Cassini mission will be launched in April 1996 and will arrive at Saturn in December 2002. Upon arrival, a large maneuver near Saturn periapsis called Saturn Orbit Insertion (SOI) will reduce the energy of the spacecraft and result in capture into Saturn orbit. SOI is one of the most critical events of the entire mission. Therefore it is prudent to determine what resources must be dedicated to assure successful execution of SOI and what operational resources can be provided to satisfy SOI science objective. To prolong undisturbed science observations near the periapsis, a delayed SOI burn strategy has been developed. To examine potential resource conflicts between science and engineering activities, key considerations such as power and data storage capability have been evaluated. Other constraints such as turning the spacecraft to burn attitude and slewing platforms for science have also been examined. Although there are many constraints and the spacecraft resources are limited, a reasonable amount of science can still be carried out prior to and during the SOI burn.

Chang, Ya-Pei Holden↗

NASA NTRS1990

Probe insertion apparatus with inflatable seal

A sealing apparatus is disclosed for inserting a probe into a pressure vessel having an elongated opening includes a pair of resiliently deformable seals opposingly disposed in sealing engagement with each other. A retainer is connected to the pressure vessel around the elongated opening and holds the pair of seals rigidly to the pressure vessel. A wedge is engageable with the pair of seals and carries the probe, for longitudinally translating the probe in pressure vessel.

Trimarchi, Paul A.↗

NASA NTRS1991

Simulation of brush insert for leading-edge-passage convective heat transfer

Current and proposed high speed aircraft have high leading edge heat transfer (to 160 MW/sq m, 100 Btu/sq in/sec) and surface temperatures to 1370 K (2000 F). Without cooling, these surfaces could not survive. In one proposal the coolant hydrogen is circulated to the leading edge through a passage and returned to be consumed by the propulsion system. Simulated flow studies and visualizations have shown flow separation within the passage with a stagnation locus that isolates a zone of recirculation at the most critical portion of the passage, namely the leading edge itself. A novel method is described for mitigating the flow separation and the isolated recirculation zones by using a brush insert in the flow passage near the leading edge zone, thus providing a significant increase in heat transfer.

Hendricks, R. C.↗

NASA NTRS1992

Thermally Activated Retainers For Insertion In Gaps

Mechanical retainers of new type for use with gap filler easy to install and to attach themselves securely. Concept based on shape-memory properties of metal alloy Nitinol, alloy of nickel and titanium. Retainers conceived for use with Space Shuttle insulating tiles but used on other assemblies of blocks or tiles configured similarly. Tabs bent outward made flush by cooling below memory transition temperature. After insertion in gap and reheating, tabs spring outward.

Grimaldi, Margaret E.↗