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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 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Structural considerations in design of lightweight glass-fiber composite pressure vessels

The design concepts used for metal-lined glass-fiber composite pressure vessels are described, comparing the structural characteristics of the composite designs with each other and with homogeneous metal pressure vessels. Specific design techniques and available design data are identified. The discussion centers around two distinctly different design concepts, which provide the basis for defining metal lined composite vessels as either (1) thin-metal lined, or (2) glass fiber reinforced (GFR). Both concepts are described and associated development problems are identified and discussed. Relevant fabrication and testing experience from a series of NASA-Lewis Research Center development efforts is presented.

Faddoul, J. R.↗
NASA NTRS1978

Structural/thermal considerations for design of large space platform structures

A method is described for placing a large, STS-compatible platform on orbit utilizing a construction method employing both deployable and erectable structures. A multifunctional mechanism is used for deployable structures and an on-orbit assembly is used for erectable structures. Also analyses are discussed which assess the thermal distortion of a simple open truss and a more complex truss.

Barclay, D. L.↗
NASA NTRS1978

Statistical considerations in design of spacelab experiments

After making an analysis of experimental error sources, statistical models were developed for the design and analysis of potential Space Shuttle experiments. Guidelines for statistical significance and/or confidence limits of expected results were also included. The models were then tested out on the following proposed Space Shuttle biomedical experiments: (1) bone density by computer tomography; (2) basal metabolism; and (3) total body water. Analysis of those results and therefore of the models proved inconclusive due to the lack of previous research data and statistical values. However, the models were seen as possible guides to making some predictions and decisions.

Robinson, J.↗
NASA NTRS1982

ORION downconverter and power supply

The receiver subsystem supplies the front end assembly (downconverter) and power supply for the ORION Mobile Station. These assemblies are designed to withstand severe environmental conditions. The mechanical, electronic, environmental and maintenance design considerations encountered during the design phase of this project are discussed. The two channel S/X downconverter has a 400 MHz bandwidth channel. Phase stability of 2 and 7 deg at S- and X-bands, respectively, is achieved with a temperature stabilized first local oscillator.

Nishimura, H. G.↗
NASA NTRS1982

Design guidelines for the testability of microprocessor based logic designs

This paper deals with the issue of designing microprocessor based systems with testability in mind. The ease of eventual testability should be a design consideration from the earliest design stage. Design guidelines with explicit examples for ease of testability are given. The issue of testing microprocessors as contrasted with testing random logic design is addressed, and procedures are delineated for the testability of microprocessors. Microprocessor testability design guidelines are discussed both at the design stage of the microprocessor itself as well as at the stage where the processor is imbedded as a component in a larger system. Specific instances and examples of a collection of design do's and don'ts are provided.

Mathur, F. P.↗
NASA NTRS1984

The 406 MHz ELT/EPIRBs

Specifications for the COSPAS/SARSAT beacons are presented and related design considerations are discussed. Critical design aspects having significant impact on cost and performance are highlighted. Among these is the oscillator, whose frequency drift specifications require stabilization by ovens or digital control. Design options are presented and their impact on cost and performance assessed. Beacon designs developed to meet COSPAS/SARSAT specifications are shown.

Flatow, F. S.↗
NASA NTRS1987

Theoretical considerations in designing operator interfaces for automated systems

The domains most amenable to techniques based on artificial intelligence (AI) are those that are systematic or for which a systematic domain can be generated. In aerospace systems, many operational tasks are systematic owing to the highly procedural nature of the applications. However, aerospace applications can also be nonprocedural, particularly in the event of a failure or an unexpected event. Several techniques are discussed for designing automated systems for real-time, dynamic environments, particularly when a 'breakdown' occurs. A breakdown is defined as operation of an automated system outside its predetermined, conceptual domain.

Norman, Susan D.↗
NASA NTRS1988

Loads and low frequency dynamics - An ENVIRONET data base

The loads and low frequency dynamics data base, part of Environet, is described with particular attention given to its development and contents. The objective of the data base is to provide the payload designer with design approaches and design data to meet STS safety requirements. Currently the data base consists of the following sections: abstract, scope, glossary, requirements, interaction with other environments, summary of the loads analysis process, design considerations, guidelines for payload design loads, information data base, and references.

Garba, John A.↗
NASA NTRS1989

Rotor blade aerodynamic design

Aerodynamic performance aspects of rotor blade design are presented. Design considerations, aerodynamic constraints and design variables are described.

Walsh, Joanne L.↗
NASA NTRS1992

Nacelle and forebody considerations in design for reduced sonic boom

Several aspects of designing for reduced sonic boom were investigated to assess the adequacy of the conventional modified linear theory. For a simple test case of a nacelle with a small forecowl angle (2 degrees) mounted below a flat plate, the linear theory compared favorably for a case with simulated nacelle lift and for a computational fluid dynamics (CFD) analysis. In a second study, several methods of analyzing the area distribution due to volume were examined. And finally, in a preliminary study, the effect of forebody shape on the rise time of the bow shock was investigated, indicating a significant increase (several msec) can be obtained by proper forebody shaping.

Haglund, George T.↗
NASA NTRS2000

Operational Considerations when Designing New Ground Systems

The Hubble Space Telescope (HST) launched in April of 1991 with a nominal 15-year old mission. Since then, the HST mission life has been extended to 2010. As is true for all NASA missions, HST is being asked to decrease its operational costs for the remainder of its mission life. Various techniques are being incorporated for cost reductions, with one of the core means being the design of a new and more efficient ground system for HST operations. This new ground system, "Vision 2000", will reduce operational and maintenance costs and also provide the HST Project with added flexibility to react to future changes. Vision 2000 began supporting HST Operations in January of 1999 and will support the mission for the remainder of the mission life. Upgrading a satellite's ground system is a popular approach for reducing costs, but it is also inherently risky. Validating a new ground system can be a severe distraction to a flight team while operating a satellite. Mission data collection and health and safety requirements are rarely, if ever, relaxed during this validation period, forcing flight teams to undertake an additional task while operating the satellite. Additionally, flight teams must usually undergo extensive training to effectively utilize the new system. Once again, this training usually occurs as an additional task, in addition to the nominal satellite operations. While operating the spacecraft, the Flight Team typically assists in the design, validation, and verification of a new ground system. This is a distraction and strain on the Flight Team, but the benefit of using the Flight Team in all phases of ground system development far outweigh the negative aspects. Finally, above the cost of the new system, the integration into the facility with the current control center system are resources and costs not normally taken into account in the design phase of the new system. In addition to the standard issues faced by a Project when upgrading its ground system, the HST Project also must continue to support Space Shuttle servicing missions, which occur approximately every two to three years. This paper will address many of the issues common to all missions when re-hosting ground systems, and those faced by the HST Project in particular.

Walyus, Keith↗
NASA NTRS2007

Thermal Considerations for Designing the Next Lunar Lander

The Vision for Space Exploration calls for NASA to develop a lunar lander that is capable of delivering humans anywhere on the moon's surface at any time. This presents a significant challenge for thermal engineers, as the lander must be able to survive both the freezing 14-day long lunar night as well as the harsh lunar noon. These problems and potential solutions are presented for each stage of the proposed mission that will return American astronauts to the moon.

Garrison, Matthew B.↗
NASA NTRS2007

Compatibility Condition in Theory of Solid Mechanics (Elasticity, Structures, and Design Optimization)

The strain formulation in elasticity and the compatibility condition in structural mechanics have neither been understood nor have they been utilized. This shortcoming prevented the formulation of a direct method to calculate stress. We have researched and understood the compatibility condition for linear problems in elasticity and in finite element analysis. This has lead to the completion of the method of force with stress (or stress resultant) as the primary unknown. The method in elasticity is referred to as the completed Beltrami-Michell formulation (CBMF), and it is the integrated force method (IFM) in structures. The dual integrated force method (IFMD) with displacement as the primary unknown has been formulated. IFM and IFMD produce identical responses. The variational derivation of the CBMF yielded the new boundary compatibility conditions. The CBMF can be used to solve stress, displacement, and mixed boundary value problems. The IFM in structures produced high-fidelity response even with a modest finite element model. The IFM has influenced structural design considerably. A fully utilized design method for strength and stiffness limitation has been developed. The singularity condition in optimization has been identified. The CBMF and IFM tensorial approaches are robust formulations because of simultaneous emphasis on the equilibrium equation and the compatibility condition.

Patnaik, Surya N.↗
NASA NTRS2010

Development of a Contingency Capillary Wastewater Management Device

The Personal Body .Attached Liquid Liquidator (PBALL) is conceived as a passive, capillary driven contingency wastewater disposal device. In this contingency scenario, the airflow system on the NASA Crew Exploration Vehicle (CEV) is assumed to have failed, leaving only passive hardware and vacuum vent to dispose of the wastewater. To meet these needs, the PBALL was conceived to rely on capillary action and urine wetting design considerations. The PBALL is designed to accommodate a range of wetting conditions, from 0deg < (theta)adv approx. 90deg, be adaptable for both male and female use, collect and retain up to a liter of urine, minimize splash-back, and allow continuous drain of the wastewater to vacuum while minimizing cabin air loss. A sub-scale PBALL test article was demonstrated on NASA's reduced gravity aircraft in April, 2010.

Thomas, Evan A.↗