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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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Circuit protects technical personnel and test equipment from hazardous currents conducted through safety barriers and into data acquisition equipment. Network isolates energy source, restricts arcing to remote area, and dissipates harmlessly residual energy transient.
The development of the alpha and X-ray spectrometers which were used on the Apollo 15 and 16 flights is discussed. Specific subjects presented are: (1) lunar program management, (2) scientific and technical approach, (3) major test programs, (4) reliability, quality assurance, and safety, and (5) subcontract management.
A study was carried out of 112 impact survivable jet transport aircraft accidents (world wide) of 27,700 kg (60,000 lb.) aircraft and up extending over the last 20 years. This study centered on the effect of impact and the follow-on events on aircraft structures and was confined to the approach, landing and takeoff segments of the flight. The significant characteristics, frequency of occurrence and the effect on the occupants of the above data base were studied and categorized with a view to establishing typical impact scenarios for use as a basis of verifying the effectiveness of potential safety concepts. Studies were also carried out of related subjects such as: (1) assessment of advanced materials; (2) human tolerance to impact; (3) merit functions for safety concepts; and (4) impact analysis and test methods.
A high temperature silicon production process using existing electric arc heater technology is discussed. Silicon tetrachloride and a reductant, liquid sodium, were injected into an arc heated mixture of hydrogen and argon. Under these high temperature conditions, a very rapid reaction occurred, yielding silicon and gaseous sodium chloride. Techniques for high temperature separation and collection of the molten silicon were developed. The desired degree of separation was not achieved. The electrical, control and instrumentation, cooling water, gas, SiCl4, and sodium systems are discussed. The plasma reactor, silicon collection, effluent disposal, the gas burnoff stack, and decontamination and safety are also discussed. Procedure manuals, shakedown testing, data acquisition and analysis, product characterization, disassembly and decontamination, and component evaluation are reviewed.
This report collects, documents, and models data relating the expected accuracies of tracking variables to be obtained from the FAA's Mode S Secondary Surveillance Radar system. The data include measured range and azimuth to the tracked aircraft plus the encoded altitude transmitted via the Mode S data link. A brief summary is made of the Mode S system status and its potential applications for aircraft safety improvement including accident analysis. FAA flight test results are presented demonstrating Mode S range and azimuth accuracy and error characteristics and comparing Mode S to the current ATCRBS radar tracking system. Data are also presented that describe the expected accuracy and error characteristics of encoded altitude. These data are used to formulate mathematical error models of the Mode S variables and encoded altitude. A brief analytical assessment is made of the real-time tracking accuracy available from using Mode S and how it could be improved with down-linked velocity.
The development of a model for the cost-effective management of space venture risks is discussed. The risk assessment and control program of insurance companies is examined. A simplified system development cycle which consists of a conceptual design phase, a preliminary design phase, a final design phase, a construction phase, and a system operations and maintenance phase is described. The model incorporates insurance safety risk methods and reliability engineering, and testing practices used in the development of large aerospace and defense systems.
The test bed fabricated to demonstrate hydrogen/oxygen propulsion technology readiness for the IOC Space Station application is described and test results are presented. The reliability and safety of the O2/H2 system was demonstrated with blowdowns and thruster firings. The flexibility of the system was demonstrated through the addition of an electrolysis supply module.
The Task 2.0 Engine Throat/Nozzle Optics for Plume Spectroscopy, effort was performed under the NASA LeRC Development of Life Prediction Capabilities for Liquid Propellant Rocket Engines program. This Task produced the engineering design of an optical probe to enable spectroscopic measurements within the SSME main chamber. The probe mounts on the SSME nozzle aft manifold and collects light emitted from the throat plane and chamber. Light collected by the probe is transferred to a spectrometer through a fiber optic cable. The design analyses indicate that the probe will function throughout the engine operating cycle and is suitable for both test stand and flight operations. By detecting metallic emissions that are indicative of component degradation or incipient failure, engine shutdown can be initiated before catastrophic failure. This capability will protect valuable test stand hardware and provide enhanced mission safety.
Aircraft models and other aerodynamic tests are conducted at the NASA Ames Research Center National Full Scale Aerodynamics Complex (NFAC). The models, tested in NFAC's wind tunnels, are sometimes heavily instrumented and are connected to a data acquisition system. Besides recording data for evaluation, certain critical information must be monitored to be sure the model is within operational limits. The signals for these parameters are for the most part low-level signals that require good instrumentation amplification. These amplifiers need to be grounded and shielded for common mode rejection and noise reduction. The instrumentation also needs to be grounded to prevent electrical shock hazards. The purpose of this paper is to present an understanding of the principles and purpose of grounding, bonding, and shielding.
A 250 Ah lithium thionyl chloride battery is being developed for a booster rocket engine. Extensive cell testing is running to evaluate functional and safety performances. Some results are presented. The lithium/thionyl chloride batteries were selected for their high energy density (low weight) as compared to other sources. The temperature of a lower weight item will be more sensitive to variations of internal and external heat fluxes than a heavier one. The use of high energy density L/TC batteries is subjected to stringent thermal environments to have benefit of energy density and to stay safe in any conditions. The battery thermal environment and discharge rate have to be adjusted to obtain the right temperature range at cell level, to have the maximum performances. Voltage and capacity are very sensitive to temperature. This temperature is the cell internal actual temperature during discharge. This temperature is directed by external thermal environment and by cell internal heat dissipation, i.e., cell actual voltage.
The NaSTEC program focuses on developing currently available sodium sulfur cells for use in space applications and investigating the operational parameters of the cells. The specific goals of the program are to determine the operational parameters and verify safety limits of Na/S technology battery cells; test long term zero-g operation; and create a life test database. The program approach and ground and flight test objectives are described in textual and graphic form.
Safety and productivity of the initial flight test phase of a new vehicle have been enhanced by developing the ability to measure the stability margins of the combined control system and vehicle in flight. One shortcoming of performing this analysis is the long duration of the excitation signal required to provide results over a wide frequency range. For flight regimes such as high angle of attack or hypersonic flight, the ability to maintain flight condition for this time duration is difficult. Significantly reducing the required duration of the excitation input is possible by tailoring the input to excite only the frequency range where the lowest stability margin is expected. For a multiple-input/multiple-output system, the inputs can be simultaneously applied to the control effectors by creating each excitation input with a unique set of frequency components. Chirp-Z transformation algorithms can be used to match the analysis of the results to the specific frequencies used in the excitation input. This report discusses the application of a tailored excitation input to a high-fidelity X-31A linear model and nonlinear simulation. Depending on the frequency range, the results indicate the potential to significantly reduce the time required for stability measurement.
The use of Electric Auxiliary Power Unit (EAPU) in commercial, and military aviation, and in commercial electric automobiles, is reviewed. The specifications of the battery to be used in the space shuttle are reviewed, and the possible vendors discussed. The testing activity and the reliability and the safety features are presented.
The Mars Observer Propulsion and Pyrotechnic Corrective Actions Test Program has been in progress at the NASA White Sands Test Facility since 1995. This program has developed capabilities to accurately characterize pyrovalve hazards and has established corrective actions that arc helping to preclude loss of spacecraft due to pyrovalve and propellant interaction. Rather than wait for conclusion of the test program, significant rest results, findings, and safety recommendations have been and will continue to be released soon after they became available to meet needs of near-term NASA and commercial space programs. This release will cover approximately three to five papers per year until program end.
The goals of the project described in this viewgraph presentation are the following: (1) Increase safety by understanding operating conditions and component capabilities; and (2) Reduce development and operating costs by reducing testing and design cycle times and reducing engine weight and increasing component life. The objectives are to determine cooling system effectiveness and structural loads.
Topics covered include: Small-cell EAPU work done by NASA-JSC & COM DEV; Looking at safety features (short circuit protection - PTCs); Early tests showed that long strings do not withstand short circuit; a) Some PTCs experience large negative voltages; b) Destructive results. Solution: group cells into shorter substrings, with bypass diodes Work included: a) Tests with single cells shorted; b) Tests with single cells with imposed-negative voltages; c) 6s, 7s and 8s string shorts; and d) Tests with protection scheme in place, on 12s and 41s x 5p.
Military test ranges containing unexploded ordnance due to live-fire testing and training exercises are a significant safety problem in many locations.
This paper describes the concept of a potential test vehicle for the National Highway Traffic Safety Administration (NHTSA) that is designed to evaluate the dynamics, human factors, and safety aspects of advanced technologies in passenger class automobiles expected to be introduced as a result of the Intelligent Vehicle/Highway System (IVHS) Program. The Variable Dynamic Testbed Vehicle (VDTV) requirements were determined from the inputs of anticipated users and possible research needs of NHTSA. Design and implementation approaches are described, the benefits of the vehicle are discussed and costs for several options presented.