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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 991 records · Page 55
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Noncontacting Inspection Heads For Robots

Compact assembly for hand of robot includes group of sensors to monitor internal conditions of such complex equipment as turbines, pumps, motors, and generators. Inspection head includes sensors; for example, pyrometers, isotope wear analyzers, spectrometers, and interferometers. Conditions as overheating of turbines, wear of ball bearings and seals, erosion of blades and impellers, leakage of joints, and deformations of housings, monitored without disassembly or shutdown. Used in typical robot applications.

Barkhoudarian, Sarkis↗
NASA NTRS1988

Fast Detection Of Breaks In Ducts

Breaks in optical fibers reveal failures in duct walls. Group of optical fibers wrapped around duct carries light beams from lasers to photodiodes. Break in duct breaks fiber bonded to it, interrupting path of light between laser and photodetector. Interruption used to command shutdown of engine or other system to minimize damage.

Smith, Matthew A.↗
NASA NTRS1987

Analysis of internal flows relative to the space shuttle main engine

Cooperative efforts between the Lockheed-Huntsville Computational Mechanics Group and the NASA-MSFC Computational Fluid Dynamics staff has resulted in improved capabilities for numerically simulating incompressible flows generic to the Space Shuttle Main Engine (SSME). A well established and documented CFD code was obtained, modified, and applied to laminar and turbulent flows of the type occurring in the SSME Hot Gas Manifold. The INS3D code was installed on the NASA-MSFC CRAY-XMP computer system and is currently being used by NASA engineers. Studies to perform a transient analysis of the FPB were conducted. The COBRA/TRAC code is recommended for simulating the transient flow of oxygen into the LOX manifold. Property data for modifying the code to represent LOX/GOX flow was collected. The ALFA code was developed and recommended for representing the transient combustion in the preburner. These two codes will couple through the transient boundary conditions to simulate the startup and/or shutdown of the fuel preburner. A study, NAS8-37461, is currently being conducted to implement this modeling effort.

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NASA NTRS1987

RB-ARD: A proof of concept rule-based abort

The Abort Region Determinator (ARD) is a console program in the space shuttle mission control center. During shuttle ascent, the Flight Dynamics Officer (FDO) uses the ARD to determine the possible abort modes and make abort calls for the crew. The goal of the Rule-based Abort region Determinator (RB/ARD) project was to test the concept of providing an onboard ARD for the shuttle or an automated ARD for the mission control center (MCC). A proof of concept rule-based system was developed on a LMI Lambda computer using PICON, a knowdedge-based system shell. Knowdedge derived from documented flight rules and ARD operation procedures was coded in PICON rules. These rules, in conjunction with modules of conventional code, enable the RB-ARD to carry out key parts of the ARD task. Current capabilities of the RB-ARD include: continuous updating of the available abort mode, recognition of a limited number of main engine faults and recommendation of safing actions. Safing actions recommended by the RB-ARD concern the Space Shuttle Main Engine (SSME) limit shutdown system and powerdown of the SSME Ac buses.

Smith, Richard↗
NASA NTRS1987

Reactor instrumentation and control design and performance simulation for SP-100

The SP-100 flight system will be launched with all primary and secondary lithium in the solid state. Once in orbit, the reactor will be brought critical and maintained at a low power level while the lithium is thawed out. Once the system is thawed out, the reactor power will be controlled to provide the energy source required by the power conversion system to meet the payload electrical power requirements. The Reactor Instrumentation and Control subsystem which includes the reactor control drives, instrumentation and the digital controller provides for the control of the nuclear subsystem to perform these operating maneuvers as well as providing for automatic shutdown and restart under certain off-normal conditions. The design and performance of this system are described.

Meyer, R. A.↗
NASA NTRS1988

ARGES: an Expert System for Fault Diagnosis Within Space-Based ECLS Systems

ARGES (Atmospheric Revitalization Group Expert System) is a demonstration prototype expert system for fault management for the Solid Amine, Water Desorbed (SAWD) CO2 removal assembly, associated with the Environmental Control and Life Support (ECLS) System. ARGES monitors and reduces data in real time from either the SAWD controller or a simulation of the SAWD assembly. It can detect gradual degradations or predict failures. This allows graceful shutdown and scheduled maintenance, which reduces crew maintenance overhead. Status and fault information is presented in a user interface that simulates what would be seen by a crewperson. The user interface employs animated color graphics and an object oriented approach to provide detailed status information, fault identification, and explanation of reasoning in a rapidly assimulated manner. In addition, ARGES recommends possible courses of action for predicted and actual faults. ARGES is seen as a forerunner of AI-based fault management systems for manned space systems.

Pachura, David W.↗
NASA NTRS1987

Performance evaluation of SPE electrolyzer for Space Station life support

An static water-vapor feed electrolyzer has been developed as a candidate for Space Station life-support oxygen generation. The five-cell electrolysis module has eliminated the need for phase separation devices, pumps, and deionizers by transporting only water vapor to the solid polymer electrolyte cells. The introduction of an innovative electrochemical hydrogen pump allows the use of low-pressure reclaimed water to generate gas pressures of up to 230 psia. The electrolyzer has been tested in a computer-controlled test stand featuring continuous, cyclic, and standby operation (including automatic shutdown with fault detection).

Erickson, A. C.↗
NASA NTRS1987

User interface and operational issues with thermionic space power systems

Thermionic space power systems have unique features which facilitate predeployment operations, provide operational flexibility and simplify the interface with the user. These were studied in some detail during the SP-100 program from 1983 to 1985. Three examples are reviewed in this paper: (1) system readiness verification in the prelaunch phase; (2) startup, shutdown, and dormancy in the operations phase; (3) part-load operation in the operations phase.

Dahlberg, R. C.↗
NASA NTRS1987

Visual display and alarm system for wind tunnel static and dynamic loads

A wind tunnel balance monitor and alarm system developed at NASA Ames Research Center will produce several beneficial results. The costs of wind tunnel delays because of inadvertent balance damage and the costs of balance repair or replacement can be greatly reduced or eliminated with better real-time information on the balance static and dynamic loading. The wind tunnel itself will have enhanced utility with the elimination of overly cautious limits on test conditions. The microprocessor-based system features automatic scaling and 16 multicolored LED bargraphs to indicate both static and dynamic components of the signals from eight individual channels. Five individually programmable alarm levels are available with relay closures for internal or external visual and audible warning devices and other functions such as automatic activation of external recording devices, model positioning mechanism, or tunnel shutdown.

Hanly, Richard D.↗
NASA NTRS1989

Computer Control For Ion Engines

Computer system controls start-up, steady-state operation, throttling, and shutdown of pair of xenon-ion propulsion engines. Controls direction of thrust of each engine through operation of gimbal stepping motors. Controls valves in propellant-storage and propellant-distribution system. Control software establishes and maintains efficient, stable operation over entire range of operating variables, and throttles engines to any point within range. Computer operates power supplies, valves, and flow controllers of two ion engines, ion-neutralizer subsystem, and other equipment. Designed for use in interplanetary flight, system adaptable to industrial use in ion-beam deposition of thin films.

Brophy, John R.↗
NASA NTRS1988

High pressure water electrolysis for space station EMU recharge

A high pressure oxygen recharge system (HPORS), is being developed for application on board the Space Station. This electrolytic system can provide oxygen at up to 6000 psia without a mechanical compressor. The Hamilton standard HPORS based on a solid polymer electrolyte system is an extension of the much larger and succesful 3000 psia system of the U.S. Navy. Cell modules have been successfully tested under conditions beyond which spacecraft may encounter during launch. The control system with double redundancy and mechanical backups for all electronically controlled components is designed to ensure a safe shutdown.

Lance, Nick↗
NASA NTRS1990

System Detects Vibrational Instabilities

Sustained vibrations at two critical frequencies trigger diagnostic response or shutdown. Vibration-analyzing electronic system detects instabilities of combustion in rocket engine. Controls pulse-mode firing of engine and identifies vibrations above threshold amplitude at 5.9 and/or 12kHz. Adapted to other detection and/or control schemes involving simultaneous real-time detection of signals above or below preset amplitudes at two or more specified frequencies. Potential applications include rotating machinery and encoders and decoders in security systems.

Bozeman, Richard J., Jr.↗
NASA NTRS1987

Independent Orbiter Assessment (IOA): Analysis of the orbiter main propulsion system

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items (PCIs). To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The independent analysis results for the Orbiter Main Propulsion System (MPS) hardware are documented. The Orbiter MPS consists of two subsystems: the Propellant Management Subsystem (PMS) and the Helium Subsystem. The PMS is a system of manifolds, distribution lines and valves by which the liquid propellants pass from the External Tank (ET) to the Space Shuttle Main Engines (SSMEs) and gaseous propellants pass from the SSMEs to the ET. The Helium Subsystem consists of a series of helium supply tanks and their associated regulators, check valves, distribution lines, and control valves. The Helium Subsystem supplies helium that is used within the SSMEs for inflight purges and provides pressure for actuation of SSME valves during emergency pneumatic shutdowns. The balance of the helium is used to provide pressure to operate the pneumatically actuated valves within the PMS. Each component was evaluated and analyzed for possible failure modes and effects. Criticalities were assigned based on the worst possible effect of each failure mode. Of the 690 failure modes analyzed, 349 were determined to be PCIs.

Mcnicoll, W. J.↗
NASA NTRS1989

Software development for avionics SSME control and diagnostics

A study was made of software to integrate data from about 500 sensors that monitor the Space Shuttle Main Engine (SSME) and to make decisions for real-time control. Such software is expected to be applicable to other distributed systems as well. This study investigated the use of pattern recognition and other techniques to detect trends that could lead to major damage to the SSME and which would allow an orderly shutdown of the SSME before such damage could occur.

Choudry, A.↗
NASA NTRS1990

A radiological assessment of nuclear power and propulsion operations near Space Station Freedom

Scenarios were identified which involve the use of nuclear power systems in the vicinity of Space Station Freedom (SSF) and their radiological impact on the SSF crew was quantified. Several of the developed scenarios relate to the use of SSF as an evolutionary transportation node for lunar and Mars missions. In particular, radiation doses delivered to SSF crew were calculated for both the launch and subsequent return of a Nuclear Electric Propulsion (NEP) cargo vehicle and a Nuclear Thermal Rocket (NTR) personnel vehicle to low earth orbit. The use of nuclear power on co-orbiting platforms and the storage and handling issues associated with radioisotope power systems were also explored as they relate to SSF. A central philosophy in these analyses was the utilization of a radiation dose budget, defined as the difference between recommended dose limits from all radiation sources and estimated doses received by crew members from natural space radiations. Consequently, for each scenario examined, the dose budget concept was used to identify and quantify constraints on operational parameters such as launch separation distances, returned vehicle parking distances, and reactor shutdown times prior to vehicle approach. The results indicate that realistic scenarios do not exist which would preclude the use of nuclear power sources in the vicinity of SSF. The radiation dose to the SSF crew can be maintained at safe levels solely by implementing proper and reasonable operating procedures.

Bolch, Wesley E.↗
NASA NTRS1990

Hubble space telescope six-battery test bed

A test bed for a large space power system breadboard for the Hubble Space Telescope (HST) was designed and built to test the system under simulated orbital conditions. A discussion of the data acquisition and control subsystems designed to provide for continuous 24 hr per day operation and a general overview of the test bed is presented. The data acquisition and control subsystems provided the necessary monitoring and protection to assure safe shutdown with protection of test articles in case of loss of power or equipment failure over the life of the test (up to 5 years).

Pajak, J. A.↗
NASA NTRS1990

Evaluation of abort capabilities of rocket-powered single-stage-to-orbit launch vehicles

Application of advanced technologies to future launch vehicle designs would allow the introduction of a rocket-powered, single-stage-to-orbit (SSTO) launch system early in the next century. A fully reusable SSTO vehicle would be quite desirable from an operational standpoint; however, such a vehicle cannot be designed without accompanying technological advances in structure, propulsion, and subsystems. The conceptual design of such a vehicle has recently been completed. This paper examines the abort capabilities of an advanced SSTO launch vehicle which has five main engines. In the event of a single or dual main engine shutdown it was determined when the vehicle could execute return-to-launch-site, abort-to-orbit, or down-range abort maneuvers. Throughout each abort maneuver, vehicle loads are kept within nominal ascent and entry design values.

Stanley, Douglas O.↗
NASA NTRS1990

Fluid Phase Separation (FPS) experiment for flight on the shuttle in a Get Away Special (GAS) canister: Design and fabrication

The separation of fluid phases in microgravity environments is of importance to environmental control and life support systems (ECLSS) and materials processing in space. A successful fluid phase separation experiment will demonstrate a proof of concept for the separation technique and add to the knowledge base of material behavior. The phase separation experiment will contain a premixed fluid that will be exposed to a microgravity environment. After the phase separation of the compound has occurred, small samples of each of the species will be taken for analysis on Earth. By correlating the time of separation and the temperature history of the fluid, it will be possible to characterize the process. The phase separation experiment is totally self-contained, with three levels of containment on all fluids, and provides all necessary electrical power and control. The controller regulates the temperature of the fluid and controls data logging and sampling. An astronaut-activated switch will initiate the experiment and an unmaskable interrupt is provided for shutdown. The experiment has been integrated into space available on a manifested Get Away Special (GAS) experiment, CONCAP 2, part of the Consortium for Materials Complex Autonomous Payload (CAP) Program, scheduled for STS 42 in April 1991. Presented here are the design and the production of a fluid phase separation experiment for rapid implementation at low cost.

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