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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 1,207 records · Page 67
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Supportability evaluation of thermoplastic and thermoset composites

Nearly 300 advanced composite components manufactured by Northrop Corporation are flying on U.S. Air Force and U.S. Navy supersonic aircraft as part of a three-year Air Force/Navy/Northrop supportability evaluation. Both thermoplastic and high-temperature thermoset composites were evaluated for their in-service performance on 48 USAF and Navy F-5E fighter and USAFT-38 trainer aircraft in the first large-scale, long-term maintenance evaluation of these advanced materials. Northrop manufactured four types of doors for the project-avionics bay access, oil fill, inlet duct inspection, and a main landing gear door. The doors are made of PEEK (polyetheretherketone) thermoplastic, which is tougher and potentially less expensive to manufacture than conventional composites; and 5250-3 BMI (bismaleimide) thermoset, which is manufactured like a conventional epoxy composite but can withstand higher service temperatures. Results obtained so far indicate that both the BMI and PEEK are durable with PEEK being somewhat better than BMI.

Chanani, G. R.↗
NASA NTRS1992

Third SEI Technical Interchange: Proceedings

Given here are the proceedings of the 3rd Space Exploration Initiative (SEI) Technical Interchange. Topics covered include the First Lunar Outpost (FLO), the Lunar Resource Mapper, lunar rovers, lunar habitat concepts, lunar shelter construction analysis, thermoelectric nuclear power systems for SEI, cryogenic storage, a space network for lunar communications, the moon as a solar power satellite, and off-the-shelf avionics for future SEI missions.

Douglas R Cooke↗
NASA NTRS1992

SATWG networked quality function deployment

The initiative of this work is to develop a cooperative process for continual evolution of an integrated, time phased avionics technology plan that involves customers, technologists, developers, and managers. This will be accomplished by demonstrating a computer network technology to augment the Quality Function Deployment (QFD). All results are presented in viewgraph format.

Brown, Don↗
NASA NTRS1991

Design and flight test of a differential GPS/inertial navigation system for approach/landing guidance

NASA-Langley has conducted a flight test program evaluating a differential GPS/inertial navigation system's (DGPS/INS) utility as an approach/landing aid. The DGPS/INS airborne and ground components are based on off-the-shelf transport aircraft avionics, namely a global positioning/inertial reference unit (GPIRU) and two GPS sensor units (GPSSUs). Systematic GPS errors are measured by the ground GPSSU and transmitted to the aircraft GPIRU, allowing the errors to be eliminated or greatly reduced in the airborne equipment. Over 120 landings were flown; 36 of these were fully automatic DGPS/INS landings.

Vallot, Lawrence↗
NASA NTRS1991

Formal specification and verification of Ada software

The use of formal methods in software development achieves levels of quality assurance unobtainable by other means. The Larch approach to specification is described, and the specification of avionics software designed to implement the logic of a flight control system is given as an example. Penelope is described which is an Ada-verification environment. The Penelope user inputs mathematical definitions, Larch-style specifications and Ada code and performs machine-assisted proofs that the code obeys its specifications. As an example, the verification of a binary search function is considered. Emphasis is given to techniques assisting the reuse of a verification effort on modified code.

Hird, Geoffrey R.↗
NASA NTRS1991

Integrated energy balance analysis for Space Station Freedom

An integrated simulation model is described which characterizes the dynamic interaction of the energy transport subsystems of Space Station Freedom for given orbital conditions and for a given set of power and thermal loads. Subsystems included in the model are the Electric Power System (EPS), the Internal Thermal Control System (ITCS), the External Thermal Control System (ETCS), and the cabin Temperature and Humidity Control System (THC) (which includes the avionics air cooling, cabin air cooling, and intermodule ventilation systems). Models of the subsystems were developed in a number of system-specific modeling tools and validated. The subsystem models are then combined into integrated models to address a number of integrated performance issues involving the ability of the integrated energy transport system of Space Station Freedom to provide power, controlled cabin temperature and humidity, and equipment thermal control to support operations.

Tandler, John↗
NASA NTRS1992

Tools and techniques for estimating high intensity RF effects

Tools and techniques for estimating and measuring coupling and component disturbance for avionics and electronic controls are described. A finite-difference-time-domain (FD-TD) modeling code, TSAR, used to predict coupling is described. This code can quickly generate a mesh model to represent the test object. Some recent applications as well as the advantages and limitations of using such a code are described. Facilities and techniques for making low-power coupling measurements and for making direct injection test measurements of device disturbance are also described. Some scaling laws for coupling and device effects are presented. A method for extrapolating these low-power test results to high-power full-system effects are presented.

Zacharias, Richard L.↗
NASA NTRS1992

Design for validation

An approach is outlined for the development of ultrareliable avionics for civil air transports using a design-for-validation philosophy that includes rigorous application of formal methods. The basic concept of the methodology is introduced, and the role of formal methods is explored. The impact of the design-for-validation philosophy on the system design process is then demonstrated by two simple examples. More details about the design-for-validation methodology are then given.

Johnson, Sally C.↗
NASA NTRS1990

Space Congress, 27th, Cocoa Beach, FL, Apr. 24-27, 1990, Proceedings

The present symposium on aeronautics and space encompasses DOD research and development, science payloads, small microgravity carriers, the Space Station, technology payloads and robotics, commercial initiatives, STS derivatives, space exploration, and DOD space operations. Specific issues addressed include the use of AI to meet space requirements, the Astronauts Laboratory Smart Structures/Skins Program, the Advanced Liquid Feed Experiment, an overview of the Spacelab program, the Autonomous Microgravity Industrial Carrier Initiative, and the Space Station requirements and transportation options for a lunar outpost. Also addressed are a sensor-data display for telerobotic systems, the Pegasus and Taurus launch vehicles, evolutionary transportation concepts, the upgrade of the Space Shuttle avionics, space education, orbiting security sentinels, and technologies for improving launch-vehicle responsiveness.

Source record↗
NASA NTRS1992

A low cost/low complexity concept for the Mars Sample Return mission

Earlier concepts for the Mars Sample Return mission were complex and costly, and had little chance of being funded. This paper summarizes the evolution of a concept that permitted cost to be reduced by a factor of six, and the number of spacecraft elements to be halved. The primary feature of this low cost/low complexity concept is the application of advanced lightweight propulsion, materials, power, and avionics technology to the Mars Ascent Vehicle to make a direct return from Mars feasible. Mission parameters, launch mass breakdowns, spacecraft configuration drawings, technology requirements, and cost estimates are presented.

Gamber, R. T.↗
NASA NTRS1992

Design and testing of the U.S. Space Station Freedom primary propulsion system

The primary propulsion system (PPS) for the Space Station Freedom is discussed in terms of salient design characteristics and key testing procedures. The rocket engine modules contain reboost and attitude control thrusters, and their designs are illustrated showing the mounting structures, thruster solenoid valves, and thrust chambers. The propellant tank assembly for storing gaseous N pressurant and hydrazine propellant is described as are the system avionics, thruster solenoid valves, and latching isolation valves. PPS testing conducted on the development systems includes the use of a propulsion-module development unit, a development test article, and system qualification testing. Specific test articles include functional heaters, mass/thermal simulated components, flight-quality structures, and software control operations.

Morano, Joseph S.↗
NASA NTRS1992

HiRel - Reliability/availability integrated workstation tool

The HiRel software tool is described and demonstrated by application to the mission avionics subsystem of the Advanced System Integration Demonstrations (ASID) system that utilizes the PAVE PILLAR approach. HiRel marks another accomplishment toward the goal of producing a totally integrated computer-aided design (CAD) workstation design capability. Since a reliability engineer generally represents a reliability model graphically before it can be solved, the use of a graphical input description language increases productivity and decreases the incidence of error. The graphical postprocessor module HARPO makes it possible for reliability engineers to quickly analyze huge amounts of reliability/availability data to observe trends due to exploratory design changes. The addition of several powerful HARP modeling engines provides the user with a reliability/availability modeling capability for a wide range of system applications all integrated under a common interactive graphical input-output capability.

Bavuso, Salvatore J.↗
NASA NTRS1992

Health management and controls for earth to orbit propulsion systems

Fault detection and isolation for advanced rocket engine controllers are discussed focusing on advanced sensing systems and software which significantly improve component failure detection for engine safety and health management. Aerojet's Space Transportation Main Engine controller for the National Launch System is the state of the art in fault tolerant engine avionics. Health management systems provide high levels of automated fault coverage and significantly improve vehicle delivered reliability and lower preflight operations costs. Key technologies, including the sensor data validation algorithms and flight capable spectrometers, have been demonstrated in ground applications and are found to be suitable for bridging programs into flight applications.

Bickford, R. L.↗
NASA NTRS1992

Reusable ultralight personnel carrier (RUPC)

Attention is given to a personnel-carrying space vehicle concept developed to minimize the cost of access to LEO. The RUPC could provide alternate access to Space Station Freedom (SSF) for six passengers per flight. It can also bring and return small amounts of cargo, up to and including one SSF double rack. These capabilities are ideal for utilization flights during man-tended operations at SSF and for crew rotation during permanently manned periods. The RUPC is a reusable conical reentry vehicle and disposable adapter with propulsion and power subsystems. Avionics subsystem benefit from advanced low-power high-performance microelectronics developed for both the civilian and military space sectors. The RUPC core cabin concept has growth potential for other applications, including assured crew return, ground-launched crew rescue, delivery and retrieval of SSF cargo, and crew cabin for flights to the moon.

Clark, B. C., III↗
NASA NTRS1992

Aeronautical technologies for the twenty-first century

This study gives an overview of the future technologies in aeronautics. This collaborative effort relies upon the input of numerous experts from around the country. Specific issues covered include subsonic transport aircraft, high-speed civil transport aircraft short-haul aircraft, environmental issues, operational issues, aerodynamics, propulsion, materials and structures, avionics and control, and cognitive engineering. The appendices include bibliography, abbreviations and acronyms, and NASA fiscal year 1992 aeronautics funding (table) and participants. The forward states that over the last decade, foreign aircraft manufacturers have made significant inroads into the global aircraft market, to the detriment of U.S. interests. Recommendations are made to counter that trend.

Source record↗
NASA NTRS1992

Appraisal of digital terrain elevation data for low-altitude flight

The use of terrain elevation databases in advanced guidance and navigation systems has greatly expanded. However, the limitations and accuracies of these databases must be considered and established prior to safe system flight evaluation. A simple approach to quantify reasonable flight limits is presented and evaluated for a helicopter guidance system dependent on a terrain database. The flight test evaluated involved a helicopter equipped with a Global Positioning System (GPS) receiver and radar altimeter, and a ground station GPS receiver which provided improved helicopter positioning. The precision navigation and radar altimeter data was acquired while flying low-altitude missions in south-central Pennsylvania. The aircraft-determined terrain elevations were compared with the terrain predicted by the Defense Mapping Agency (DMA) Level 1 terrain elevation data for the same area. The results suggest a safe set clearance altitude of 220 ft for flight testing of a DMA-based guidance avionic in the same area.

Zelenka, Richard E.↗
NASA NTRS1992

Integration of radar altimeter, precision navigation, and digital terrain data for low-altitude flight

Avionic systems that depend on digitized terrain elevation data for guidance generation or navigational reference require accurate absolute and relative distance measurements to the terrain, especially as they approach lower altitudes. This is particularly exacting in low-altitude helicopter missions, where aggressive terrain hugging maneuvers create minimal horizontal and vertical clearances and demand precise terrain positioning. Sole reliance on airborne precision navigation and stored terrain elevation data for above-ground-level (AGL) positioning severely limits the operational altitude of such systems. A Kalman filter is presented which blends radar altimeter returns, precision navigation, and stored terrain elevation data for AGL positioning. The filter is evaluated using low-altitude helicopter flight test data acquired over moderately rugged terrain. The proposed Kalman filter is found to remove large disparities in predicted AGL altitude (i.e., from airborne navigation and terrain elevation data) in the presence of measurement anomalies and dropouts. Previous work suggested a minimum clearance altitude of 220 ft AGL for a near-terrain guidance system; integration of a radar altimeter allows for operation of that system below 50 ft, subject to obstacle-avoidance limitations.

Zelenka, Richard E.↗
NASA NTRS1992

Formal design specification of a Processor Interface Unit

This report describes work to formally specify the requirements and design of a processor interface unit (PIU), a single-chip subsystem providing memory-interface bus-interface, and additional support services for a commercial microprocessor within a fault-tolerant computer system. This system, the Fault-Tolerant Embedded Processor (FTEP), is targeted towards applications in avionics and space requiring extremely high levels of mission reliability, extended maintenance-free operation, or both. The need for high-quality design assurance in such applications is an undisputed fact, given the disastrous consequences that even a single design flaw can produce. Thus, the further development and application of formal methods to fault-tolerant systems is of critical importance as these systems see increasing use in modern society.

Fura, David A.↗