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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 865 records · Page 48

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NASA NTRS1985

Orbital transfer vehicle concept definition and system analysis study, 1985. Volume 2: OTV concept definition and evaluation. Book 4: Operations

The benefits of the reusable Space Shuttle and the advent of the new Space Station hold promise for increasingly effective utilization of space by the scientific and commercial as well as military communities. A high energy reusable oribital transfer vehicle (OTV) represents an additional capability which also exhibits potential for enhancing space access by allowing more ambitious missions and at the same time reducing launch costs when compared to existing upper stages. This section, Vol. 2: Book 4, covers launch operations and flight operations. The launch operations section covers analyses of ground based and space based vehicles, launch site facilities, logistics requirements, propellant loading, space based maintenance and aft cargo carrier access options. The flight operations sections contain summary descriptions of ground based and space based OTV missions, operations and support requirements, and a discussion of fleet implications.

Mitchell, Jack C.↗

NASA NTRS1988

Successful expert systems for space shuttle payload integration

Expert systems are successfully applied to solve recurring NASA Space Shuttle orbiter payload integration problems. Recurrence of these problems is the result of each Space Shuttle mission being unique. The NASA Space Shuttle orbiter was designed to be extremely flexible in its ability to handle many types and combinations of satellites and experiments. This flexibility results in different and unique engineering resource requirements for each of the payload satellites and experiments. The first successful expert system to be applied to these problems was the Orbiter Payload Bay Cabling Expert System (EXCABL), developed at Rockwell International Space Transportation Systems Division. The operational version of EXCABL was delivered in 1986 and successfully solved the payload electrical support services cabling layout problem. As a result of this success, a second expert system, Expert Drawing Matching System (EXMATCH), was developed to generate a list of the reusable installation drawings available for each EXCABL solution. EXMATCH went operational in 1987. As a result of these initial successes, the need for a third expert system was defined and is awaiting development. This new Expert System, called Technical Order Listing Expert System (EXTOL), will generate a list of all the applicable reusable installation drawings available to support the total payload bay mission provisioning and installation effort. This paper describes these expert systems, the individual problems that they were designed to solve, their individual solutions, and the degree of success achieved. These expert systems' instantiate the applicability of this technology to the solution of real-world Space Shuttle payload integration problems.

Morris, Keith↗

NASA NTRS1988

Booster propulsion/vehicle impact study

The use of hydrogen RP-1, propane, and methane as fuels for booster engines of launch vehicles is discussed. An automated procedure for integrated launch vehicle, engine sizing, and design optimization was used to define two stage and single stage concepts for minimum dry weight. The two stage vehicles were unmanned and used a flyback booster and partially reusable orbiter. The single stage designs were fully reusable, manned flyback vehicles. Comparisons of these vehicle designs, showing the effects of using different fuels, as well as sensitivity and trending data, are presented. In addition, the automated design technique utilized for the study is described.

Weldon, Vincent↗

NASA NTRS1989

Design, fabrication and test of the RL10 derivative II chamber/primary nozzle

The design, fabrication and test of the RL10-II chamber/primary nozzle was accomplished as part of the RL10 Product Improvement Program (PIP). The overall goal of the RL10 PIP was to gain the knowledge and experience necessary to develop new cryogenic upper stage engines to fulfill future NASA requirements. The goal would be reached by producing an RL10 engine designed to be reusable, operate at several thrust levels, and have increased performance. The goals for the chamber/primary nozzle task were: (1) to design a reusable assembly capable of operation at increased mixture ratio and low thrust; (2) to fabricate three assemblies using new or updated techniques where possible; and (3) to test one assembly to verify the design and construction. The design and fabrication phases produced an assembly having improved features such as single piece reinforcing band segments (i.e., Mae West segments) and relocated tube exit braze joints (i.e., hooked tube exit). In addition, a computer program was developed to design the chamber tubes to meet both performance and heat transfer requirements. The test phase showed the specific impulse of the test bed engine system to be as predicted. These results, along with the heat transfer data obtained, sufficiently proved the overall design of the RL10-II recontoured and shortened chamber/primary nozzle assembly.

Marable, R. W.↗

NASA NTRS1989

Flight motor set 360L001 (STS-26R). Volume 5: Nozzle component

A review of the performance and post-flight condition of the STS-26 Redesigned Solid Rocket Motor (RSRM) nozzles is presented. The nozzle assemblies, flown on the Space Shuttle Discovery on 29 September 1988, were tested to demonstrate flex bearing system reusability. The evaluation indicated no condition that would adversely affect the reusability of the flex bearing system. Inspection showed that the flex bearings did not leak, were not damaged by water impact, had the expected erosion profiles, and that the remaining ablative liner thicknesses met the performance margin of safety. Applicable Discrepancy Reports and Process Departures, the Nozzle Component Program Team performance evaluation, and the Redesign Program Review Board assessment are included.

George, Russell J.↗

NASA NTRS1989

Advanced manned launch systems

Advanced Manned Launch Systems (AMLS) studies underway at the NASA Langley Research Center are described. The AMLS studies have focused on investigating mission needs and identifying technologies, operational requirements, and life-cycle costs. Two-stage vertical take off rocket vehicles with significant levels of reusability are shown to be cost effective for moderate to high flight rates. All-hydrogen fuel vehicles are preferred over methane boosted systems for both operational and cost considerations. Drawings of possible AMLS design solutions are presented. Fully reusable, partially resusable, expendable stage and horizontal take off airbreather/rocket solutions are compared.

Talay, Theodore A.↗

NASA NTRS1988

Development of an Ada programming support environment database SEAD (Software Engineering and Ada Database) administration manual

Software Engineering and Ada Database (SEAD) was developed to provide an information resource to NASA and NASA contractors with respect to Ada-based resources and activities which are available or underway either in NASA or elsewhere in the worldwide Ada community. The sharing of such information will reduce duplication of effort while improving quality in the development of future software systems. SEAD data is organized into five major areas: information regarding education and training resources which are relevant to the life cycle of Ada-based software engineering projects such as those in the Space Station program; research publications relevant to NASA projects such as the Space Station Program and conferences relating to Ada technology; the latest progress reports on Ada projects completed or in progress both within NASA and throughout the free world; Ada compilers and other commercial products that support Ada software development; and reusable Ada components generated both within NASA and from elsewhere in the free world. This classified listing of reusable components shall include descriptions of tools, libraries, and other components of interest to NASA. Sources for the data include technical newletters and periodicals, conference proceedings, the Ada Information Clearinghouse, product vendors, and project sponsors and contractors.

Liaw, Morris↗

NASA NTRS1990

A real time neural net estimator of fatigue life

A neural net architecture is proposed to estimate, in real-time, the fatigue life of mechanical components, as part of the Intelligent Control System for Reusable Rocket Engines. Arbitrary component loading values were used as input to train a two hidden-layer feedforward neural net to estimate component fatigue damage. The ability of the net to learn, based on a local strain approach, the mapping between load sequence and fatigue damage has been demonstrated for a uniaxial specimen. Because of its demonstrated performance, the neural computation may be extended to complex cases where the loads are biaxial or triaxial, and the geometry of the component is complex (e.g., turbopump blades). The generality of the approach is such that load/damage mappings can be directly extracted from experimental data without requiring any knowledge of the stress/strain profile of the component. In addition, the parallel network architecture allows real-time life calculations even for high frequency vibrations. Owing to its distributed nature, the neural implementation will be robust and reliable, enabling its use in hostile environments such as rocket engines. This neural net estimator of fatigue life is seen as the enabling technology to achieve component life prognosis, and therefore would be an important part of life extending control for reusable rocket engines.

Troudet, T.↗

NASA NTRS1989

Operations and support cost modeling using Markov chains

Systems for future missions will be selected with life cycle costs (LCC) as a primary evaluation criterion. This reflects the current realization that only systems which are considered affordable will be built in the future due to the national budget constaints. Such an environment calls for innovative cost modeling techniques which address all of the phases a space system goes through during its life cycle, namely: design and development, fabrication, operations and support; and retirement. A significant portion of the LCC for reusable systems are generated during the operations and support phase (OS). Typically, OS costs can account for 60 to 80 percent of the total LCC. Clearly, OS costs are wholly determined or at least strongly influenced by decisions made during the design and development phases of the project. As a result OS costs need to be considered and estimated early in the conceptual phase. To be effective, an OS cost estimating model needs to account for actual instead of ideal processes by associating cost elements with probabilities. One approach that may be suitable for OS cost modeling is the use of the Markov Chain Process. Markov chains are an important method of probabilistic analysis for operations research analysts but they are rarely used for life cycle cost analysis. This research effort evaluates the use of Markov Chains in LCC analysis by developing OS cost model for a hypothetical reusable space transportation vehicle (HSTV) and suggests further uses of the Markov Chain process as a design-aid tool.

Unal, Resit↗

NASA NTRS1990

Advanced tube-bundle rocket thrust chamber

An advanced rocket thrust chamber for future space application is described along with an improved method of fabrication. Potential benefits of the concept are improved cyclic life, reusability, and performance. Performance improvements are anticipated because of the enhanced heat transfer into the coolant which will enable higher chamber pressure in expander cycle engines. Cyclic life, reusability and reliability improvements are anticipated because of the enhanced structural compliance inherent in the construction. The method of construction involves the forming of the combustion chamber with a tube-bundle of high conductivity copper or copper alloy tubes, and the bonding of these tubes by an electroforming operation. Further, the method of fabrication reduces chamber complexity by incorporating manifolds, jackets, and structural stiffeners while having the potential for thrust chamber cost and weight reduction.

Kazaroff, John M.↗

NASA NTRS1988

Summary of booster propulsion/vehicle impact study results

Hydrogen, RP-1, propane, and methane were identified by propulsion technology studies as the most probable fuel candidates for the boost phase of future launch vehicles. The objective of this study was to determine the effects of booster engines using these fuels and coolant variations on representative future launch vehicles. An automated procedure for integrated launch vehicle, engine sizing, and design optimization was used to optimize two stage and single stage concepts for minimum dry weight. The two stage vehicles were unmanned and used a flyback booster and partially reusable orbiter. The single stage designs were fully reusable, manned flyback vehicles. Comparisons of these vehicle designs, showing the effects of using different fuels, as well as sensitivity and trending data, are presented. In addition, the automated design technique is described.

Weldon, Vincent A.↗

NASA NTRS1990

Space transportation systems supporting a lunar base

Results are presented on preliminary design studies conducted by NASA and its contractors to define the transportation vehicle for the support of a human return to the moon mission. Attention is given to the transportation needs and requirements, the design solutions to meet these requirements, the rationale for the selection of the designs, and the ground/orbital support facilities for placing these systems into routine earth-moon transportation service. The reference system includes a partially reusable lunar transfer vehicle that operates between the earth and lunar orbits and a fully reusable lunar excursion vehicle that operates between the lunar orbit and the lunar surface. The system can deliver 27 metric tons of cargo to the lunar surface in an automated flight mode, and can transport a crew of four and deliver 15 tons of cargo in a piloted mode.

Priest, C. C.↗

NASA NTRS1990

Advanced tube-bundle rocket thrust chamber

Kazaroff, John M.↗

NASA NTRS1988

Filament wound metal lined propellant tanks for future Earth-to-orbit transports

For future Earth-to-orbit transport vehicles, reusability and lighter weights are sought for the main propellant tanks. To achieve this, a filament wound tank with a metal liner and an intermediate layer of foam-filled honeycomb is proposed. A hydrogen tank is used as an example. To accommodate mismatches in the expansion of liner and overwrap a design is proposed wherin the liner is configured so that the extension of the liner under pressure matches the expected contraction of the same liner due to the presence of a cryogen. In operation, the liner is pressurized at a rate such that the pressure strain matches the contraction due to decrease in temperature. As an alternate approach, compressive pre-stress is placed in the liner such that it will not separate from the overwrap. A finite element program is used to show stresses in the liner and overwrap for various tank pressures for the pre-stressed liner concept. A fracture mechanics analysis is made of the liners to determine tank life. The tank concept shown has a similar weight to the Shuttle external hydrogen tank, but the filament wound tank is expected to be reusable. Integration of the propellant tanks into a future transport vehicle is discussed.

Macconochie, Ian O.↗

NASA NTRS1988

Evolving impact of Ada on a production software environment

Many aspects of software development with Ada have evolved as our Ada development environment has matured and personnel have become more experienced in the use of Ada. The Software Engineering Laboratory (SEL) has seen differences in the areas of cost, reliability, reuse, size, and use of Ada features. A first Ada project can be expected to cost about 30 percent more than an equivalent FORTRAN project. However, the SEL has observed significant improvements over time as a development environment progresses to second and third uses of Ada. The reliability of Ada projects is initially similar to what is expected in a mature FORTRAN environment. However, with time, one can expect to gain improvements as experience with the language increases. Reuse is one of the most promising aspects of Ada. The proportion of reusable Ada software on our Ada projects exceeds the proportion of reusable FORTRAN software on our FORTRAN projects. This result was noted fairly early in our Ada projects, and experience shows an increasing trend over time.

Mcgarry, F.↗

NASA NTRS1990

Flight motor set 36OH005 (STS-28R). Volume 5: (Nozzle component)

A review of the performance and post flight condition of the STS-28 redesigned solid rocket motor (RSRM) nozzles is presented in this document. Applicable discrepancy reports (DR's) and process departures (PD's) are presented in section 5.0. The nozzle component program team (NCPT) performance evaluation and the redesign program review board (RPRB) assessment is included in section 6.0. The STS-28 nozzle assemblies were flown on the RSRM fifth flight (Space Shuttle Columbia). The nozzles were a partially submerged convergent/divergent movable design with an aft pivot point flexible bearing. The nozzle assemblies incorporated the following features: (1) RSRM forward exit cone with snubber assembly; (2) RSRM fixed housing; (3) structural backup outer boot ring (OBR); (4) RSRM cowl ring; (5) RSRM nose inlet assembly; (6) RSRM throat assembly; (7) RSRM forward nose and aft inlet ring; (8) RSRM aft exit cone assembly with linear-shaped charge (LSC); (9) RTV backfill in joints 1, 3, and 4; (10) use of EA913 NA adhesive in place of EA913; (11) redesigned nozzle plug; and (12) carbon cloth phenolic (CCP) with 750 ppm sodium content. The RSRM fifth flight test objectives are as follows: (1) verify that flexible bearing seals operate within the specified temperature range; (2) verify that flexible bearing maintained a positive gas seal between its internal components; (3) inspect flexible bearing for damage due to water impact; (4) verify performance of the nozzle liner; (5) verify that nozzle parts are reusable; (6) verify through flight demonstration and a postflight inspection that the flexible bearing is reusable; (7) verify by inspection the remaining nozzle ablative thicknesses; and (8) verify the nozzle performance margins of safety.

Smith, Dan M., Jr.↗

NASA NTRS1989

AdaNET prototype library administration manual

The functions of the AdaNET Prototype Library of Reusable Software Parts is described. Adopted from the Navy Research Laboratory's Reusability Guidebook (V.5.0), this is a working document, customized for use the the AdaNET Project. Within this document, the term part is used to denote the smallest unit controlled by a library and retrievable from it. A part may have several constituents, which may not be individually tracked. Presented are the types of parts which may be stored in the library and the relationships among those parts; a concept of trust indicators which provide measures of confidence that a user of a previously developed part may reasonably apply to a part for a new application; search and retrieval, configuration management, and communications among those who interact with the AdaNET Prototype Library; and the AdaNET Prototype, described from the perspective of its three major users: the part reuser and retriever, the part submitter, and the librarian and/or administrator.

Hanley, Lionel↗

NASA NTRS1990

New method of making advanced tube-bundle rocket thrust chambers

An improved method of fabrication rocket chambers for future space applications is described. Included are fabrication demonstrator and test chambers produced by this method. This concept offers the promise of improved cyclic life, reusability, and performance. The performance is improved because of the enhanced enthalpy extraction. The improved cyclic life, reusability, and reliability is improved because of the structural compliance inherent in the construction. The method of construction involves the forming of the combustion chamber by a tube-bundle of high conductivity copper or copper alloy tubes and the bonding of these tubes by a unique electroforming operation. Furthermore, the method of fabrication reduces chamber complexity by incorporating manifolds, and structural stiffeners while having the potential for thrust chamber cost and weight reduction.

Kazaroff, John M.↗