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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 109 records · Page 6

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NASA NTRS1986

Considerations for the design of Ada reusable packages

Two important considerations that precede the design of Ada reusable packages (commonality and programming standards) are discuessed. First, the importance of designing packages to yield widespread commonality is expressed. A means of measuring the degree of applicability of packages both within and across applications areas is presented. Design consideration that will improve commonality are also discussed. Second, considerations for the development of programming standards are set forth. These considerations will lead to standards that will improve the reusability of Ada packages.

Nise, Norman S.↗

NASA NTRS1988

A reusable rocket engine intelligent control

An intelligent control system for reusable space propulsion systems for future launch vehicles is described. The system description includes a framework for the design. The framework consists of an execution level with high-speed control and diagnostics, and a coordination level which marries expert system concepts with traditional control. A comparison is made between air breathing and rocket engine control concepts to assess the relative levels of development and to determine the applicability of air breathing control concepts ot future reusable rocket engine systems.

Merrill, Walter C.↗

NASA NTRS1989

Expendable vs reusable propulsion systems cost sensitivity

One of the key trade studies that must be considered when studying any new space transportation hardware is whether to go reusable or expendable. An analysis is presented here for such a trade relative to a proposed Liquid Rocket Booster which is being studied at MSFC. The assumptions or inputs to the trade were developed and integrated into a model that compares the Life-Cycle Costs of both a reusable LRB and an expendable LRB. Sensitivities were run by varying the input variables to see their effect on total cost. In addition a Monte-Carlo simulation was run to determine the amount of cost risk that may be involved in a decision to reuse or expend.

Hamaker, Joseph W.↗

NASA NTRS1990

Advanced Reusable Foam Cryogenic Insulation

Lightweight, reusable cryogenic containers reduce costs of operation of advanced hypersonic airplanes and space launch vehicles. Specimens demonstrated in temperature range of negative 420 to positive 400 degrees F (negative 251 to positive 204 degrees C). Prototype reusable cryogenic foam insulation developed. Consists of two discrete layers of closed-cell polymethacrylimide foam of density 6.9 lb/ft to the 3rd power (111 kg/m to the 3rd power) bonded together with epoxy adhesive. Additionally reinforced with 0.003-in. (0.08-mm)-thick layer of fiberglass cloth. Wrapped with precut and preformed vapor-barrier cover. Such containers useful on Earth in laboratories, factories, and transportation systems.

Taylor, Allan H.↗

NASA NTRS1991

Systems integration and demonstration of advanced reusable structure for ALS

The objective was to investigate the potential of advanced material to achieve life cycle cost (LCC) benefits for reusable structure on the advanced launch system. Three structural elements were investigated - all components of an Advanced Launch System reusable propulsion/avionics module. Leading aeroshell configurations included sandwich structure using titanium, graphite/polyimide (Gr/PI), or high-temperature aluminum (HTA) face sheets. Thrust structure truss concepts used titanium, graphite/epoxy, or silicon carbide/aluminum struts. Leading aft bulkhead concepts employed graphite epoxy and aluminum. The technical effort focused on the aeroshell because the greatest benefits were expected there. Thermal analyses show the structural temperature profiles during operation. Finite element analyses show stresses during splash-down. Weight statements and manufacturing cost estimates were prepared for calculation of LCC for each design. The Gr/PI aeroshell showed the lowest potential LCC, but the HTA aeroshell was judged to be lower risk. A technology development plan was prepared to validate the applicable structural technology.

Gibbins, Martin N.↗

NASA NTRS1991

Reusable rocket engine intelligent control system framework design, phase 2

Elements of an advanced functional framework for reusable rocket engine propulsion system control are presented for the Space Shuttle Main Engine (SSME) demonstration case. Functional elements of the baseline functional framework are defined in detail. The SSME failure modes are evaluated and specific failure modes identified for inclusion in the advanced functional framework diagnostic system. Active control of the SSME start transient is investigated, leading to the identification of a promising approach to mitigating start transient excursions. Key elements of the functional framework are simulated and demonstration cases are provided. Finally, the advanced function framework for control of reusable rocket engines is presented.

Nemeth, ED↗

NASA NTRS1991

Reusable cryogenic foam insulation for advanced aerospace vehicles

Future high-speed aircraft and aerospace vehicles using cryogenic propellants will require an advanced reusable insulation system for the propellant tank structure. This cryogenic insulation system must be lightweight, structurally and thermally efficient, and capable of multiple reuse without cracking or degraded performance. This paper presents recent progress in the development of a reusable cryogenic foam insulation system having a maximum service temperature of 400 F. The system consists of preshaped, precut blocks of rigid polymethacrylimide foam insulation, wrapped with a high-temperature Kapton and aluminum foil vapor barrier which is adhesively bonded to the propellant tank wall.

Mcauliffe, Patrick S.↗

NASA NTRS1991

Linear quadratic servo control of a reusable rocket engine

A design method for a servo compensator is developed in the frequency domain using singular values. The method is applied to a reusable rocket engine. An intelligent control system for reusable rocket engines was proposed which includes a diagnostic system, a control system, and an intelligent coordinator which determines engine control strategies based on the identified failure modes. The method provides a means of generating various linear multivariable controllers capable of meeting performance and robustness specifications and accommodating failure modes identified by the diagnostic system. Command following with set point control is necessary for engine operation. A Kalman filter reconstructs the state while loop transfer recovery recovers the required degree of robustness while maintaining satisfactory rejection of sensor noise from the command error. The approach is applied to the design of a controller for a rocket engine satisfying performance constraints in the frequency domain. Simulation results demonstrate the performance of the linear design on a nonlinear engine model over all power levels during mainstage operation.

Musgrave, Jeffrey L.↗

NASA NTRS1990

Design of an unmanned, reusable vehicle to de-orbit debris in Earth orbit

The space debris problem is becoming more important because as orbital missions increase, the amount of debris increases. It was the design team's objective to present alternative designs and a problem solution for a deorbiting vehicle that will alleviate the problem by reducing the amount of large debris in earth orbit. The design team was asked to design a reusable, unmanned vehicle to de-orbit debris in earth orbit. The design team will also construct a model to demonstrate the system configuration and key operating features. The alternative designs for the unmanned, reusable vehicle were developed in three stages: selection of project requirements and success criteria, formulation of a specification list, and the creation of alternatives that would satisfy the standards set forth by the design team and their sponsor. The design team selected a Chain and Bar Shot method for deorbiting debris in earth orbit. The De-orbiting Vehicle (DOV) uses the NASA Orbital Maneuvering Vehicle (OMV) as the propulsion and command modules with the deorbiting module attached to the front.

Aziz, Shahed↗

NASA NTRS1992

A demonstration of an intelligent control system for a reusable rocket engine

An Intelligent Control System for reusable rocket engines is under development at NASA Lewis Research Center. The primary objective is to extend the useful life of a reusable rocket propulsion system while minimizing between flight maintenance and maximizing engine life and performance through improved control and monitoring algorithms and additional sensing and actuation. This paper describes current progress towards proof-of-concept of an Intelligent Control System for the Space Shuttle Main Engine. A subset of identifiable and accommodatable engine failure modes is selected for preliminary demonstration. Failure models are developed retaining only first order effects and included in a simplified nonlinear simulation of the rocket engine for analysis under closed loop control. The engine level coordinator acts as an interface between the diagnostic and control systems, and translates thrust and mixture ratio commands dictated by mission requirements, and engine status (health) into engine operational strategies carried out by a multivariable control. Control reconfiguration achieves fault tolerance if the nominal (healthy engine) control cannot. Each of the aforementioned functionalities is discussed in the context of an example to illustrate the operation of the system in the context of a representative failure. A graphical user interface allows the researcher to monitor the Intelligent Control System and engine performance under various failure modes selected for demonstration.

Musgrave, Jeffrey L.↗

NASA NTRS1993

System For Retrieving Reusable Software

Encyclopedia of Software Components (ESC) is information-retrieval system of computer hardware and software providing access to generic reusable software tools and parts. Core of ESC is central tool base, which is repository of reusable software. It receives queries and submissions from user through local browser subsystem and receives authorized updates from maintenance subsystem. Sends retrievals to local browser subsystem and user's submissions to maintenance subsystem. Future versions will provide for advanced media, including voice and video, and will link system to database-management system. Programmers will not only retrieve software, but also modify, execute, and cross-link with other software.

Van Warren, Lloyd↗

NASA NTRS1992

Reusable thermal protection system development: A prospective

The state of the art in passive reusable thermal protection system materials is described. Development of the Space Shuttle Orbiter, which was the first reusable vehicle, is discussed. The thermal protection materials and given concepts and some of the shuttle development and manufacturing problems are described. Evolution of a family of grid and flexible ceramic external insulation materials from the initial shuttle concept in the early 1970's to the present time is described. The important properties and their evolution are documented. Application of these materials to vehicles currently being developed and plans for research to meet the space programs future needs are summarized.

Goldstein, Howard↗

NASA NTRS1991

Reusable Reentry Satellite (RRS) system design study: System cost estimates document

The Reusable Reentry Satellite (RRS) program was initiated to provide life science investigators relatively inexpensive, frequent access to space for extended periods of time with eventual satellite recovery on earth. The RRS will provide an on-orbit laboratory for research on biological and material processes, be launched from a number of expendable launch vehicles, and operate in Low-Altitude Earth Orbit (LEO) as a free-flying unmanned laboratory. SAIC's design will provide independent atmospheric reentry and soft landing in the continental U.S., orbit for a maximum of 60 days, and will sustain three flights per year for 10 years. The Reusable Reentry Vehicle (RRV) will be 3-axis stabilized with artificial gravity up to 1.5g's, be rugged and easily maintainable, and have a modular design to accommodate a satellite bus and separate modular payloads (e.g., rodent module, general biological module, ESA microgravity botany facility, general botany module). The purpose of this System Cost Estimate Document is to provide a Life Cycle Cost Estimate (LCCE) for a NASA RRS Program using SAIC's RRS design. The estimate includes development, procurement, and 10 years of operations and support (O&S) costs for NASA's RRS program. The estimate does not include costs for other agencies which may track or interface with the RRS program (e.g., Air Force tracking agencies or individual RRS experimenters involved with special payload modules (PM's)). The life cycle cost estimate extends over the 10 year operation and support period FY99-2008.

Source record↗

NASA NTRS1991

Vehicle/payload interface specification for the reusable reentry satellite

This document describes the common interface requirements between the Vehicle Segment and the Payload Segment of the Reusable Reentry Satellite (RRS) system. The system consists of a single transport vehicle design that provides a uniform, unidirectional payload gravitational environment which is selectable during on-orbit operations over the range of 10(exp -5) (microgravity) to 1.5 g's. The initial Reusable Reentry Vehicle/Payload Module (RRV/PM) integration and checkout will occur at the launch base unless otherwise agreed to in a mission-unique addendum to this specification. Pre-integration interface qualification shall be done using emulators as described.

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NASA NTRS1992

Towards automated support for extraction of reusable components

A cost effective introduction of software reuse techniques requires the reuse of existing software developed in many cases without aiming at reusability. This paper discusses the problems related to the analysis and reengineering of existing software in order to reuse it. We introduce a process model for component extraction and focus on the problem of analyzing and qualifying software components which are candidates for reuse. A prototype tool for supporting the extraction of reusable components is presented. One of the components of this tool aids in understanding programs and is based on the functional model of correctness. It can assist software engineers in the process of finding correct formal specifications for programs. A detailed description of this component and an example to demonstrate a possible operational scenario are given.

Abd-El-hafiz, S. K.↗

NASA NTRS1991

Design of a reusable kinetic energy absorber for an astronaut safety tether to be used during extravehicular activities on the Space Station

The goal of this project is to design a reusable safety device for a waist tether which will absorb the kinetic energy of an astronaut drifting away from the Space Station. The safety device must limit the tension of the tether line in order to prevent damage to the astronaut's space suit or to the structure of the spacecraft. The tether currently used on shuttle missions must be replaced after the safety feature has been developed. A reusable tether for the Space Station would eliminate the need for replacement tethers, conserving space and mass. This report presents background information, scope and limitations, methods of research and development, alternative designs, a final design solution and its evaluation, and recommendations for further work.

Borthwick, Dawn E.↗

NASA NTRS1992

Structural and loads analysis of a two-stage fully reusable Advanced Manned Launch System

The conceptual design of a rocket-powered, two-stage fully reusable launch vehicle has been performed as a part of NASA's Advanced Manned Launch System (AMLS) study. This paper summarizes the structural design and loads analysis of this two-stage fully reusable launch vehicle. The method used to determine the structural weights consists of generating a finite-element model for each vehicle, selecting a set of critical loading conditions, determining the loads on the model caused by those conditions, determining the model response and changing the sizes of individual elements to obtain a safe structure. The integrated loads on the two-stage vehicle were obtained from a three-degrees-of-freedom trajectory analysis.

Robinson, James C.↗

NASA NTRS1991

Towards automated support for extraction of reusable components

Abd-El-hafiz, S. K.↗