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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 91 records · Page 5

A Qualitative Piloted Evaluation of the Tupolev Tu-144 Supersonic Transport

Two U.S. research pilots evaluated the Tupolev Tu-144 supersonic transport aircraft on three dedicated flights: one subsonic and two supersonic profiles. The flight profiles and maneuvers were developed jointly by Tupolev and U.S. engineers. The vehicle was found to have unique operational and flight characteristics that serve as lessons for designers of future supersonic transport aircraft. Vehicle subsystems and observed characteristics are described as are flight test planning and ground monitoring facilities. Maneuver descriptions and extended pilot narratives for each flight are included as appendices.

Rivers, Robert A.↗

Electric propulsion system design and development for primary propulsion applications

An electric thrust subsystem technology development program to demonstrate the readiness of primary electric propulsion for flight applications is described. The development program is based on a subsystem design sufficiently flexible to be applicable to a broad range of mission requirements with minimum impact on the subsystem elements or interface designs. The effort includes development and qualification testing of new subsystem elements, the assembly and test of subsystem models to verify the physical and functional interfaces of the subsystem with other spacecraft subsystems, and the investigation of the effects of thrust subsystem operation on all aspects of spacecraft performance. The present status of this effort and some of the results so far obtained are presented.

Kerrisk, D. J.↗

Initial Flight Testing of an eXternal Vision System (XVS) for the Low Boom Flight Demonstrator (LBFD)

NASA will design an eXternal Vision System (XVS) that, with other aircraft systems and subsystems, will ensure safe and efficient operations in all phases of flight for its Low Boom Flight Demonstrator vehicle. XVS is a combination of display, sensor, and computing technologies, creating an electronic means of forward visibility for the pilot. A flight test was performed evaluating a preliminary design of an XVS to quantify, by direct comparison, the ability of a pilot using an XVS to see and recognize airborne traffic compared to that of a pilot using forward-facing windows during challenging see-and-avoid scenarios. The data showed that the XVS and forward-facing windows were essentially equivalent in detecting and recognizing incurring traffic aircraft. The data also showed that the pilot using the XVS could see and recognize the incurring traffic at no less than 0.7 nm prior to the pilot using the forward-facing windows. The performance of the XVS was dependent upon the application of image contrast enhancement. Recommendations for future improvements were captured from evaluation pilot commentary.

Kramer, Lynda J↗

The Space Station Prototype Program - The development of a regenerative life support system for extended-duration missions.

Design concepts and test philosophies which may contribute to the development of a low-cost maintainable environmental control/life support system are examined. It is shown that the concept of producing flight prototype equipment during a developmental program can reduce the eventual cost of a flight system by incorporating realistic flight-type design requirements without imposing exacting design features and stringent controls. A flight prototype design is one that can be converted readily into an actual flight design without any conceptual change. Modularity of subsystems provides the system and the program a degree of flexibility relative to the eventual vehicle configuration and technological improvements.

Willis, N. C., Jr.↗

The IRIS-GUS Shuttle Borne Upper Stage System

This paper describes the Italian Research Interim Stage - Gyroscopic Upper Stage (IRIS-GUS) upper stage system that will be used to launch NASA's Triana Observatory from the Space Shuttle. Triana is a pathfinder earth science mission being executed on rapid schedule and small budget, therefore the mission's upper stage solution had to be a system that could be fielded quickly at relatively low cost and risk. The building of the IRIS-GUS system wa necessary because NASA lost the capability to launch moderately sized upper stage missions fro the Space Shuttle when the PAM-D system was retired. The IRIS-GUS system restores this capability. The resulting system is a hybrid which mates the existing, flight proven IRIS (Italian Research Interim Stage) airborne support equipment to a new upper stage, the Gyroscopic Upper Stage (GUS) built by the GSFC for Triana. Although a new system, the GUS exploits flight proven hardware and design approaches in most subsystems, in some cases implementing proven design approaches with state-of-the-art electronics. This paper describes the IRIS-GUS upper stage system elements, performance capabilities, and payload interfaces.

Tooley, Craig↗

Improving Safety and Reliability of Space Auxiliary Power Units

Auxiliary Power Units (APU's) play a critical role in space vehicles. On the space shuttle, APU's provide the hydraulic power for the aerodynamic control surfaces, rocket engine gimballing, landing gear, and brakes. Future space vehicles, such as the Reusable Launch Vehicle, will also need APU's to provide electrical power for flight control actuators and other vehicle subsystems. Vehicle designers and mission managers have identified safety, reliability, and maintenance as the primary concerns for space APU's. In 1997, the NASA Lewis Research Center initiated an advanced technology development program to address these concerns.

Viterna, Larry A.↗

Astrobee Systems Engineering Design Overview

The Astrobee preliminary design documents include subsystem design overview slides and a 3D model of the preliminary design of the Astrobee system including: mechanical, electrical, flight software, network, and ground subsystems.

Smith, Marion F.↗

Space station prototype Sabatier reactor design verification testing

A six-man, flight prototype carbon dioxide reduction subsystem for the SSP ETC/LSS (Space Station Prototype Environmental/Thermal Control and Life Support System) was developed and fabricated for the NASA-Johnson Space Center between February 1971 and October 1973. Component design verification testing was conducted on the Sabatier reactor covering design and off-design conditions as part of this development program. The reactor was designed to convert a minimum of 98 per cent hydrogen to water and methane for both six-man and two-man reactant flow conditions. Important design features of the reactor and test conditions are described. Reactor test results are presented that show design goals were achieved and off-design performance was stable.

Cusick, R. J.↗

Apollo experience report: Lunar module environmental control subsystem

A functional description of the environmental control subsystem is presented. Development, tests, checkout, and flight experiences of the subsystem are discussed; and the design fabrication, and operational difficulties associated with the various components and subassemblies are recorded. Detailed information is related concerning design changes made to, and problems encountered with, the various elements of the subsystem, such as the thermal control water sublimator, the carbon dioxide sensing and control units, and the water section. The problems associated with water sterilization, water/glycol formulation, and materials compatibility are discussed. The corrective actions taken are described with the expection that this information may be of value for future subsystems. Although the main experiences described are problem oriented, the subsystem has generally performed satisfactorily in flight.

Gillen, R. J.↗

Thermal Management Tools for Propulsion System Trade Studies and Analysis

Energy-related subsystems in modern aircraft are more tightly coupled with less design margin. These subsystems include thermal management subsystems, vehicle electric power generation and distribution, aircraft engines, and flight control. Tighter coupling, lower design margins, and higher system complexity all make preliminary trade studies difficult. A suite of thermal management analysis tools has been developed to facilitate trade studies during preliminary design of air-vehicle propulsion systems. Simulink blocksets (from MathWorks) for developing quasi-steady-state and transient system models of aircraft thermal management systems and related energy systems have been developed. These blocksets extend the Simulink modeling environment in the thermal sciences and aircraft systems disciplines. The blocksets include blocks for modeling aircraft system heat loads, heat exchangers, pumps, reservoirs, fuel tanks, and other components at varying levels of model fidelity. The blocksets have been applied in a first-principles, physics-based modeling and simulation architecture for rapid prototyping of aircraft thermal management and related systems. They have been applied in representative modern aircraft thermal management system studies. The modeling and simulation architecture has also been used to conduct trade studies in a vehicle level model that incorporates coupling effects among the aircraft mission, engine cycle, fuel, and multi-phase heat-transfer materials.

McCarthy, Kevin↗

Conceptual Design of a Hypervelocity Asteroid Intercept Vehicle (HAIV) Flight Validation Mission

In this paper we present a detailed overview of the MDL study results and subsequent advances in the design of GNC algorithms for accurate terminal guidance during hypervelocity NEO intercept. The MDL study produced a conceptual con guration of the two-body HAIV and its subsystems; a mission scenario and trajectory design for a notional flight validation mission to a selected candidate target NEO; GNC results regarding the ability of the HAIV to reliably intercept small (50 m) NEOs at hypervelocity (typically greater than 10 km/s); candidate launch vehicle selection; a notional operations concept and cost estimate for the flight validation mission; and a list of topics to address during the remainder of our NIAC Phase II study.

Barbee, Brent W.↗

A software engineering approach to expert system design and verification

Software engineering design and verification methods for developing expert systems are not yet well defined. Integration of expert system technology into software production environments will require effective software engineering methodologies to support the entire life cycle of expert systems. The software engineering methods used to design and verify an expert system, RENEX, is discussed. RENEX demonstrates autonomous rendezvous and proximity operations, including replanning trajectory events and subsystem fault detection, onboard a space vehicle during flight. The RENEX designers utilized a number of software engineering methodologies to deal with the complex problems inherent in this system. An overview is presented of the methods utilized. Details of the verification process receive special emphasis. The benefits and weaknesses of the methods for supporting the development life cycle of expert systems are evaluated, and recommendations are made based on the overall experiences with the methods.

Bochsler, Daniel C.↗

CID-720 aircraft high-environment flight instrumentation system

The high-environment flight instrumentation system was designed to acquire Langley's structural response data during the full scale transport-controlled impact demonstration test. There was only one opportunity for data acquisition. Thus, a high reliability and crashworthy design approach was implemented. The approach featured multi-level redundancy and a vigorous quality assurance testing program. Complying with an accelerated schedule, the instrumentation system was developed, tested and shipped within 18 months to Dryden Flight Research Facility. The flight instrumentation system consists of two autonomous data systems, DAS #1 and #2, and an excellent checkout subsystem. Each data system is partitioned into four pallets. The system was designed to operate on manned and unmanned flights. There are 176 data channels per data system. These channels are sequentially sampled and encoded into 1 megabit/sec pulse code modulation (PCM) data signal. To increase the probability of success, a special PCM distribution subsystem was developed. This subsystem distributes the PCM signal to two transmitters, one delay memory, and eight recorder tracks. The data on four of these trackes was digitally delayed approximately 300 msec to maximize data acquisition during impact. Therefore each data system's data is redundantly recorded onboard and on the ground. There are two time code generators. Parallel time from each is encoded into both data systems. Serial time from each is redundantly recorded on both onboard recorders. Instrumentation power is independent of aircraft power and self-contained.

Calloway, R. S.↗

Orbiting Geophysical Observatory Attitude Control Subsystem Design Survey. NASA/ERC Design Criteria Program, Guidance and Control

This design survey summarizes the history of the Orbiting Geophysical Observatories' (OGO) Attitude Control Subsystem (ACS) from the proposal phase through current flight experience. Problems encountered in design, fabrication, test, and on orbit are discussed. It is hoped that the experiences of the OGO program related here will aid future designers.

Mc Kenna, K. J.↗

Thermal re-design of the Galileo spacecraft for a Venus-earth-earth-gravity assist (VEEGA) trajectory

The cancellation of the Centaur upper stage program in the aftermath of the Challenger tragedy forced a redesign of the flight trajectory of the Galileo spacecraft to Jupiter, i.e., from a direct trajectory to the Venus-earth-earth-gravity-assist (VEEGA) trajectory on the lower energy two-stage inertial upper stage (IUS), with the result that the spacecraft would be exposed to more than twofold increase in peak solar irradiance. This paper describes the general system-level thermal redesign effort for the Galileo spacecraft, from the start of feasibility studies to its final implementation. Results indicate that the addition of sunshades and the generous utilization of second-surface aluminized Kapton surface material for reflecting high percentages of incident solar irradiation would 'harden' the spacecraft's existing thermal protection system adequately, provided that sun-pointing at the relatively higher solar irradiance levels could be maintained. The final miximum flight temperature predictions for the spacecraft's subsystem thermal designs are given.

Reeve, R.↗

Key Reliability Drivers of Liquid Propulsion Engines and A Reliability Model for Sensitivity Analysis

This paper is to address the in-flight reliability of a liquid propulsion engine system for a launch vehicle. We first establish a comprehensive list of system and sub-system reliability drivers for any liquid propulsion engine system. We then build a reliability model to parametrically analyze the impact of some reliability parameters. We present sensitivity analysis results for a selected subset of the key reliability drivers using the model. Reliability drivers identified include: number of engines for the liquid propulsion stage, single engine total reliability, engine operation duration, engine thrust size, reusability, engine de-rating or up-rating, engine-out design (including engine-out switching reliability, catastrophic fraction, preventable failure fraction, unnecessary shutdown fraction), propellant specific hazards, engine start and cutoff transient hazards, engine combustion cycles, vehicle and engine interface and interaction hazards, engine health management system, engine modification, engine ground start hold down with launch commit criteria, engine altitude start (1 in. start), Multiple altitude restart (less than 1 restart), component, subsystem and system design, manufacturing/ground operation support/pre and post flight check outs and inspection, extensiveness of the development program. We present some sensitivity analysis results for the following subset of the drivers: number of engines for the propulsion stage, single engine total reliability, engine operation duration, engine de-rating or up-rating requirements, engine-out design, catastrophic fraction, preventable failure fraction, unnecessary shutdown fraction, and engine health management system implementation (basic redlines and more advanced health management systems).

Huang, Zhao-Feng↗