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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 883 records · Page 49

All sources NASA NTRS DOE OSTI

NASA NTRS1975

Payload/orbiter contamination control requirement study

The results of a contamination impact analysis upon the spacelab carrier and the spacelab carrier upon some of its potential payloads are presented. These results are based upon contamination computer modeling techniques developed to predict the induced environment for spacelab and to provide the basis for evaluation of the predicted environment against the current on orbit contamination control criteria as specified for payloads. Those spacelab carrier contamination sources evaluated against the stated contamination control criteria were outgassing/offgassing of the major nonmetallic thermal control coating of the spacelab carriers, spacelab core and experiment module and tunnel cabin atmosphere leakage, avionics bay vent, spacelab condensate vent, random particulate sloughing, and the return flux of the molecular content of these sources from the gas-gas interactions with the ambient orbital environment. It is indicated that the spacelab carrier can meet the intent of the contamination control criteria through incorporating known contamination control practices.

Bareiss, L. E.↗

NASA NTRS1975

Impact of coverage on the reliability of a fault tolerant computer

A mathematical reliability model is established for a reconfigurable fault tolerant avionic computer system utilizing state-of-the-art computers. System reliability is studied in light of the coverage probabilities associated with the first and second independent hardware failures. Coverage models are presented as a function of detection, isolation, and recovery probabilities. Upper and lower bonds are established for the coverage probabilities and the method for computing values for the coverage probabilities is investigated. Further, an architectural variation is proposed which is shown to enhance coverage.

Bavuso, S. J.↗

NASA NTRS1974

Flight management - Pilot procedures and system interfaces for the 1980-1990's

In the air transportation system of the 1980-1990's, aircraft must perform with greater precision in time and position than is possible today. Rapid development in electronics technology makes renovation in airborne-system concepts feasible. The Ames Research Center is conducting research on pilot procedures and pilot-system interfaces for such systems. Research on various pilot-system interface devices and manned simulations was conducted to study rules of distributed decision making authority among pilots and controllers with various airborne display concepts, and a pilot-oriented command logic for the control of avionic systems was studied. Results are summarized, and ongoing work and future research plans described.

Wempe, T. E.↗

NASA NTRS1974

A flight research program to develop airborne systems for improved terminal area operations

The research program considered is concerned with the solution of operational problems for the approximate time period from 1980 to 2000. The problems are related to safety, weather effects, congestion, energy conservation, noise, atmospheric pollution, and the loss in productivity caused by delays, diversions, and schedule stretchouts. The terminal configured vehicle (TCV) program is to develop advanced flight-control capability. The various aspects of the TCV program are discussed, giving attention to avionics equipment, the piloted simulator, terminal-area environment simulation, the Wallops research facility, flight procedures, displays and human factors, flight activities, and questions of vortex-wake reduction and tracking.

Reeder, J. P.↗

NASA NTRS1975

SEPS guidance and navigation autonomy selection via mission analysis

A systematic rationale for selecting a cost-effective guidance and navigation (G & N) autonomy level for the solar electric propulsion stage (SEPS) vehicle is developed. After a definition of autonomy levels, a mission analysis is performed for representative SEPS missions using realistic G & N sensor hardware. Cost data for fabricating, integrating and refurbishing onboard avionics hardware and the ground costs corresponding to each autonomy level are generated. Results are presented that indicate performance of various G & N sensor hardware sets and the dominating factors which influence G & N autonomy level selection.

Causey, W.↗

NASA NTRS1975

Radioactive waste disposal via electric propulsion

It is shown that space transportation is a feasible method of removal of radioactive wastes from the biosphere. The high decay heat of the isotopes powers a thermionic generator which provides electrical power for ion thrust engines. The massive shields (used to protect ground and flight personnel) are removed in orbit for subsequent reuse; the metallic fuel provides a shield for the avionics that guides the orbital stage to solar system escape. Performance calculations indicate that 4000 kg. of actinides may be removed per Shuttle flight. Subsidiary problems - such as cooling during ascent - are discussed.

Burns, R. E.↗

NASA NTRS1975

Software engineering of a navigation and guidance system for commercial aircraft

The avionics experimental configuration of the considered system is briefly reviewed, taking into account the concept of an advanced air traffic management system, flight critical and noncritical functions, and display system characteristics. Cockpit displays and the navigation computer are examined. Attention is given to the functions performed in the navigation computer, major programs in the navigation computer, and questions of software development.

Lachmann, S. G.↗

NASA NTRS1975

Status report on NASA two-segment approach program

NASA, in cooperation with the FAA, is evaluating the two-segment approach as a routine procedure for reducing aircraft noise. The program calls for separate flight evaluations using a 727 and a DC-8, and an extrapolation of these results to determine the adaptability of the technique to the rest of the fleet. After a review of the total program, this paper presents (1) the profile and procedures developed and the noise reduction achievable, (2) the vortex characteristics behind an aircraft on a two-segment path, and (3) cost estimates for retrofitting aircraft with two-segment avionics.

Denery, D. G.↗

NASA NTRS1975

Flight experience with time-of-arrival control for STOL aircraft in the terminal area

A research program on STOL operating systems is underway at the Ames Research Center. One investigation is concerned with design, analysis, and flight test of promising four-dimensional RNAV systems. One promising system generates a capture flight path from the present aircraft position to a waypoint on a selected fixed STOL approach route. It predicts arrival time at the runway and controls time and position along the path. The system was flight tested using a digital avionics system on a Convair 340 and on an experimental powered-lift STOL airplane. Flight tests in the flight director mode show that the pilot can choose and change the desired time of arrival, and meet this time within a few seconds, in spite of navigation errors and varying winds. Initial tests of the automatic mode using a flight simulator and the NASA Augmentor Wing Jet STOL Research Aircraft (AWJSRA) show that good time control was achieved at the cost of excess throttle activity. This fault was later corrected.

Neuman, F.↗

NASA NTRS1975

Sensor equipment of the German earth scientific airplane program

The German airplane program for earth scientific research supports the work of a vast staff of earth scientists from universities and federal agencies. Due to their fields of interest, which are in oceanography, hydrology, geology, ecology, and forestry, five test areas were selected which are spread all over Germany. The sensor package, which was designed in accordance with the requirements of this group of scientists, will be installed in a DO 28 D2 type airplane. The sensor equipment consists of a series of 70-mm cameras having different film/filter combinations, a photogrammetric camera, an infrared radiometer, an 11-channel multispectral line scanner, a LANDSAT-compatible radiometer, and a complex avionic system. Along with the airplane, a truck will be equipped with a set of radiometers and other sensor devices for extensive ground-truth measurement; this also includes a cherry picker.

Seige, P.↗

NASA NTRS1976

General aviation technology program

The research and technology program of the civil air transportation system is reported. Research is discussed for stall/spin, crashworthiness, pilot operations, flight efficiency, propulsion, and avionics.

Source record↗

NASA NTRS1976

Acceptance test procedure for shuttle actuators simulator (elevon subsystem)

The acceptance test procedure is described for the Lockheed Electronics Elevon Servoactuator Simulator to be used in the Shuttle Avionics Integration Laboratory (SAIL). The intent of this acceptance test procedure is to comply with the technical Shuttle Actuators Simulator Requirements. Acceptance tests will be performed on each Elevon Servoactuator Simulator.

Barr, J.↗

NASA NTRS1976

Computer technology forecast study for general aviation

A multi-year, multi-faceted program is underway to investigate and develop potential improvements in airframes, engines, and avionics for general aviation aircraft. The objective of this study was to assemble information that will allow the government to assess the trends in computer and computer/operator interface technology that may have application to general aviation in the 1980's and beyond. The current state of the art of computer hardware is assessed, technical developments in computer hardware are predicted, and nonaviation large volume users of computer hardware are identified.

Seacord, C. L.↗

NASA NTRS1976

NASA advanced control technology: An overview

NASA's current and projected advanced control technology programs for future transport aircraft include the design and verification of full flight envelope autopilots, the development and flight test of all-digital fly by wire systems, the evolution of low cost innovative avionics concepts such as split surface stability augmentation systems, the evaluation of integrated propulsion control and cooperative autopilot/propulsion control systems, the application of active control systems to short haul and long haul transports, and the demonstration of reconfigured active control aircraft. Key technical features and anticipated contributions of these technologies are outlined.

Peter R Kurzhals↗

NASA NTRS1976

Space shuttle digital flight control system

The space shuttle digital, fly by wire, flight control system presents an interesting challenge in avionics system design. In residence in each of four redundant general purpose computers at lift off are the guidance, navigation, and control algorithms for the entire flight. The mission is divided into several flight segments: first stage ascent, second stage ascent; abort to launch site, abort once around; on orbit operations, entry, terminal area energy management; and approach and landing. The FCS is complicated in that it must perform the functions to fly the shuttle as a boost vehicle, as a spacecraft, as a reentry vehicle, and as a conventional aircraft. The crew is provided with both manual and automatic modes of operations in all flight phases including touchdown and rollout.

Minott, G. M.↗

NASA NTRS1976

A flight investigation of a terminal area navigation and guidance concept for STOL aircraft

A digital avionics system was installed in the CV-340 transport aircraft. Flight tests were made to obtain preliminary performance data in the manual flight director mode using time controlled guidance. These tests provide a basis for selection of terminal area guidance, navigation, and control system concepts for short haul aircraft and for investigating operational procedures.

Smith, D. W.↗

NASA NTRS1976

General Purpose Computer (GPC) to GPC systems interface description

The General Purpose Computer (GPC) 'subsystem' of the Orbiter Data Processing System was described. Two interface areas are discussed. One is the area of GPC intraconnections and intracommunications involving the hardware/software interface between the Central Processing Unit (CPU) and the Input/Output Processor (IOP). The other is the area of GPC interconnections and intercommunications and involves the hardware/software interface between the five Orbiter GPC's. Based on the detailed GPC interface given, it is felt that the basic CPU to IOP interface and the GPC to GPC interface have the potential for trouble free operation. However, due to the complexity of the interface and the criticality of GPC synchronization to overall avionics performance, the GPC to GPC interface should be carefully evaluated when attempting to resolve test anomalies that may involve GPC timing and synchronization errors.

Breyer, B. C.↗

NASA NTRS1976

Information and display requirements for independent landing monitors

The ways an Independent Landing Monitor (ILM) may be used to complement the automatic landing function were studied. In particular, a systematic procedure was devised to establish the information and display requirements of an ILM during the landing phase of the flight. Functionally, the ILM system is designed to aid the crew in assessing whether the total system (e.g., avionics, aircraft, ground navigation aids, external disturbances) performance is acceptable, and, in case of anomaly, to provide adequate information to the crew to select the least unsafe of the available alternatives. Economically, this concept raises the possibility of reducing the primary autoland system redundancy and associated equipment and maintenance costs. The required level of safety for the overall system would in these cases be maintained by upgrading the backup manual system capability via the ILM. A safety budget analysis was used to establish the reliability requirements for the ILM. These requirements were used as constraints in devising the fault detection scheme. Covariance propagation methods were used with a linearized system model to establish the time required to correct manually perturbed states due to the fault. Time-to-detect and time-to-correct requirements were combined to devise appropriate altitudes and strategies for fault recovery.

Karmarker, J. S.↗