Search NASA⌕ Search

SEARCH · Search NASA

Results for “Operations and Life Cycle”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4

Status of Regenerative Life Support Research and Technology Program at NASA Ames Research Center

1. Provide Advanced Life Support technologies that significantly reduce life cycle costs, improve operational performance, promote self-sufficiency, and minimize expenditure of resources for missions of long duration. 2. Develop and apply methods of systems analysis and engineering to guide investments in technology, resolve and integrate competing needs, and guide evolution of advanced life support systems. 3. Resolve issues of hypogravity performance through space flight research and evaluation. 4. Ensure timely transfer of new life support technologies to missions. 5. Transfer technologies to private sectors for national benefit.

Kliss, Mark↗

Advanced Manned Launch Systems

Advanced Manned Launch Systems (AMLS) studies underway at the NASA Langley Research Center are part of a broader effort examining options for the next U.S. manned space transportation system. AMLS study phases have focused on investigating mission needs and identifying technologies and technology levels, concepts, systems, operational requirements, and life-cycle costs. For near-term technologies and an operations-oriented approach, two-stage vertical-takeoff rocket vehicles with significant levels of reusability are shown to be cost-effective for moderate to high flight rates. All-hydrogen fuel vehicles are also preferred over methane boosted systems from both operational and cost considerations.

Talay, Theodore A.↗

Advanced Control Considerations for Turbofan Engine Design

This paper covers the application of a model-based engine control (MBEC) methodology featuring a self tuning on-board model for an aircraft turbofan engine simulation. The nonlinear engine model is capable of modeling realistic engine performance, allowing for a verification of the advanced control methodology over a wide range of operating points and life cycle conditions. The on-board model is a piece-wise linear model derived from the nonlinear engine model and updated using an optimal tuner Kalman Filter estimation routine, which enables the on-board model to self-tune to account for engine performance variations. MBEC is used here to show how advanced control architectures can improve efficiency during the design phase of a turbofan engine by reducing conservative operability margins. The operability margins that can be reduced, such as stall margin, can expand the engine design space and offer potential for efficiency improvements. Application of MBEC architecture to a nonlinear engine simulation is shown to reduce the thrust specific fuel consumption by approximately 1% over the baseline design, while maintaining safe operation of the engine across the flight envelope.

control↗

OAO-3 end of mission power subsystem evaluation

End of mission tests were performed on the OAO-3 power subsystem in three component areas: solar array, nickel-cadmium batteries and the On-Board Processor (OBP) power boost operation. Solar array evaluation consisted of analyzing array performance characteristics and comparing them to earlier flight data. Measured solar array degradation of 14.1 to 17.7% after 8 1/3 years is in good agreement with theortical radiation damage losses. Battery discharge characteristics were compared to results of laboratory life cycle tests performed on similar cells. Comparison of cell voltage profils reveals close correlation and confirms the validity of real time life cycle simulation. The successful operation of the system in the OBP/power boost regulation mode demonstrates the excellent life, reliability and greater system utilization of power subsystems using maximum power trackers.

Tasevoli, M.↗

Technical and Economic Assessment of Span-Distributed Loading Cargo Aircraft Concepts

A 700,000 kg (1,540,000-lb) aircraft with a cruise Mach number of 0.75 was found to be optimum for the specified mission parameters of a 272 155-kg (600,000-lb) payload, a 5560-km (3000-n.mi.) range, and an annual productivity of 113 billion revenue-ton km (67 billion revenue-ton n. mi.). The optimum 1990 technology level spanloader aircraft exhibited the minimum 15-year life-cycle costs, direct operating costs, and fuel consumption of all candidate versions. Parametric variations of wing sweep angle, thickness ratio, rows of cargo, and cargo density were investigated. The optimum aircraft had two parallel rows of 2.44 x 2.44-m (8 x 8-ft) containerized cargo with a density of 160 kg/cu m (10 lb/ft 3) carried throughout the entire 101-m (331-ft) span of the constant chord, 22-percent thick, supercritical wing. Additional containers or outsized equipment were carried in the 24.4-m (80-ft) long fuselage compartment preceding the wing. Six 284,000-N (64,000-lb) thrust engines were mounted beneath the 0.7-rad (40-deg) swept wing. Flight control was provided by a 36.6-m (120-ft) span canard surface mounted atop the forward fuselage, by rudders on the wingtip verticals and by outboard wing flaperons.

Johnston, W. M.↗

Preliminary design study of an alternate heat source assembly for a Brayton isotope power system

Results are presented for a study of the preliminary design of an alternate heat source assembly (HSA) intended for use in the Brayton isotope power system (BIPS). The BIPS converts thermal energy emitted by a radioactive heat source into electrical energy by means of a closed Brayton cycle. A heat source heat exchanger configuration was selected and optimized. The design consists of a 10 turn helically wound Hastelloy X tube. Thermal analyses were performed for various operating conditions to ensure that post impact containment shell (PICS) temperatures remain within specified limits. These limits are essentially satisfied for all modes of operation except for the emergency cooling system for which the PICS temperatures are too high. Neon was found to be the best choice for a fill gas for auxiliary cooling system operation. Low cycle fatigue life, natural frequency, and dynamic loading requirements can be met with minor modifications to the existing HSA.

Strumpf, H. J.↗

Improved, low cost inorganic-organic separators for rechargeable silver-zinc batteries

Several flexible, low-cost inorganic-organic separators with performance characteristics and cycle life equal to, or better than, the Lewis Research Center Astropower separator were developed. These new separators can be made on continuous-production equipment at about one-fourth the cost of the Astropower separator produced the same way. In test cells, these new separators demonstrate cycle life improvement, acceptable operating characteristics, and uniform current density. The various separator formulas, test cell construction, and data analysis are described.

Sheibley, D. W.↗

Preliminary study of advanced turboprop and turboshaft engines for light aircraft

The effects of engine configuration, advanced component technology, compressor pressure ratio and turbine rotor-inlet temperature on such figures of merit as vehicle gross weight, mission fuel, aircraft acquisition cost, operating, cost and life cycle cost are determined for three fixed- and two rotary-wing aircraft. Compared with a current production turboprop, an advanced technology (1988) engine results in a 23 percent decrease in specific fuel consumption. Depending on the figure of merit and the mission, turbine engine cost reductions required to achieve aircraft cost parity with a current spark ignition reciprocating (SIR) engine vary from 0 to 60 percent and from 6 to 74 percent with a hypothetical advanced SIR engine. Compared with a hypothetical turboshaft using currently available technology (1978), an advanced technology (1988) engine installed in a light twin-engine helicopter results in a 16 percent reduction in mission fuel and about 11 percent in most of the other figures of merit.

Knip, G.↗

Phase 1 of the near term hybrid passenger vehicle development program. Appendix B: Trade-off studies, volume 1

Tradeoff study activities and the analysis process used are described with emphasis on (1) review of the alternatives; (2) vehicle architecture; and (3) evaluation of the propulsion system alternatives; interim results are presented for the basic hybrid vehicle characterization; vehicle scheme development; propulsion system power and transmission ratios; vehicle weight; energy consumption and emissions; performance; production costs; reliability, availability and maintainability; life cycle costs, and operational quality. The final vehicle conceptual design is examined.

Traversi, M.↗

Cost/benefit analysis of advanced materials technology candidates for the 1980's, part 2

Cost/benefit analyses to evaluate advanced material technologies projects considered for general aviation and turboprop commuter aircraft through estimated life-cycle costs, direct operating costs, and development costs are discussed. Specifically addressed is the selection of technologies to be evaluated; development of property goals; assessment of candidate technologies on typical engines and aircraft; sensitivity analysis of the changes in property goals on performance and economics, cost, and risk analysis for each technology; and ranking of each technology by relative value. The cost/benefit analysis was applied to a domestic, nonrevenue producing, business-type jet aircraft configured with two TFE731-3 turbofan engines, and to a domestic, nonrevenue producing, business type turboprop aircraft configured with two TPE331-10 turboprop engines. In addition, a cost/benefit analysis was applied to a commercial turboprop aircraft configured with a growth version of the TPE331-10.

Dennis, R. E.↗

Catalysts for long-life closed-cycle CO2 lasers

Long-life, closed-cycle operation of pulsed CO2 lasers requires catalytic CO-O2 recombination both to remove O2, which is formed by discharge-induced CO2 decomposition, and to regenerate CO2. Platinum metal on a tin (IV) oxide substrate (Pt/SnO2) has been found to be an effective catalyst for such recombination in the desired temperature range of 25 to 100 C. This paper presents a description of ongoing research at NASA-LaRC on Pt/SnO2 catalyzed CO-O2 recombination. Included are studies with rare-isotope gases since rare-isotope CO2 is desirable as a laser gas for enhanced atmospheric transmission. Results presented include: (1) achievement of 98% to 100% conversion of a stoichiometric mixture of CO and O2 to CO2 for 318 hours (greater than 1 x 10 to the 6th power seconds), continuous, at a catalyst temperature of 60 C, and (2) development of a technique verified in a 30-hour test, to prevent isotopic scrambling when CO-18 and O-18(2) are reacted in the presence of a common-isotope Pt/Sn O-16(2) catalyst.

Schryer, David R.↗

Research on catalysts for long-life closed-cycle CO2 laser oaperation

Long-life, closed-cycle operation of pulsed CO2 lasers requires catalytic CO-O2 recombination both to remove O2, which is formed by discharge-induced CO2 decomposition, and to regenerate CO2. Platinum metal on a tin-oxide substrate (Pt/SnO2) has been found to be an effective catalyst for such recombination in the desired temperature range of 25 to 100 C. This paper presents a description of ongoing research at NASA-Langley on Pt/SnO2 catalyzed CO-O2 recombination. Included are studies with rare-isotope gases since rare-isotope CO2 is desirable as a laser gas for enhanced atmospheric transmission. Results presented include: (1) the effects of various catalyst pretreatment techniques on catalyst efficiency; (2) development of a technique, verified in a 30-hour test, to prevent isotopic scrambling when C(O-18) and (O-18)2 are reacted in the presence of a common-isotope Pt/Sn(O-16)2 catalyst; and (3) development of a mathematical model of a laser discharge prior to catalyst introduction.

Sidney, Barry D.↗

Pretreatment of CO oxidation catalysts

CO oxidation catalysts with high activity in the range of 25 C to 100 C are important for long-life, closed-cycle operation of pulsed carbon dioxide 2 lasers. A reductive pretreatment with either CO or H sub 2 was shown to significantly enhance the activity of a commerically-available platinum on tin (IV) oxide (Pt/SnO2) catalyst relative to an oxidative or inert pretreatment or no pretreatment. Pretreatment at temperatures of 175 C and above caused an initial dip in observed CO or O sub 2 loss or CO sub 2 formation in a test gas mixture of 1 percent CO and 0.5 percent O sub 2 in a He gas matrix before a steady-state yield was obtained. This dip was found to be caused by dehydration of the surface of the catalyst and was readily eliminated by humidifying the catalyst or the test gas mixture. It was also found that too much moisture resulted in a lower overall yield of CO sub 2. Under similar conditions, it is hypothesized that the effect of the humidification is to increase the concentration of OH groups on the surface of the catalyst. The effect of having high concentration of CO sub 2 in the test gas mixture upon the loss of CO and O sub 2 as well as the effect of periods of relaxation of the catalyst under non-test gas conditions was studied. The purpose of these studies was to gain an insight into the mechanism of CO oxidation on this type of catalyst.

Vannorman, John D.↗

The effect of H2O and pretreatment on the activity of a Pt/SnO2 catalyst

CO oxidation catalysts with high activity at 25 C to 100 C are important for long-life, closed-cycle operation of pulsed CO2 lasers. A reductive pretreatment with either CO or H2 has been shown to significantly enhance the activity of a commercially available platinum on tin (IV) oxide (Pt/SnO2) catalyst relative to an oxidative or inert pretreatment or no pretreatment. Pretreatment at temperatures of 175 C and above causes an initial dip in the observed CO2 yield before the steady-state yield is attained. This dip has been found to be caused by dehydration of the catalyst during pretreatment and is readily eliminated by humidifying the catalyst or the reaction gas mixture. It is hypothesized that the effect of humidification is to increase the concentration of OH groups on the catalyst surface which play a role in the reaction mechanism.

Vannorman, John D.↗

Examination of the evolutionary growth requirement of the U.S. Space Station Freedom propulsion system

A trade study, performed to examine different propulsion systems into which the modular hydrazine system may evolve after the completion of the assembly phase, is discussed and results of this study are presented. Propulsion system options include: the modular hydrazine system, a modified hydrazine system, hypergolic bipropellant systems, an oxygen-hydrogen system, hypergolic bipropellant/hydrazine hybrid systems, and the oxygen-hydrogen/hydrazine hybrid system. Trade study criteria and methodology are reviewed. Water availability and growth and nongrowth configurations are discussed. Recommendations are made on the type of Space Station propulsion system that should be developed for long-term operations at minimal life cycle cost. It is suggested that, due to growth of the station shown in the assembly complete configuration, the oxygen-hydrogen propulsion system should be further developed so that related technology will be mature by assembly complete.

Morano, Joseph S.↗

A review of findings of a study of rocket based combined cycle engines applied to extensively axisymmetric single stage to orbit vehicles

Extensively axisymmetric and non-axisymmetric Single Stage To Orbit (SSTO) vehicles are considered. The information is presented in viewgraph form and the following topics are presented: payload comparisons; payload as a percent of dry weight - a system hardware cost indicator; life cycle cost estimations; operations and support costs estimation; selected engine type; and rocket engine specific impulse calculation.

Foster, Richard W.↗

Design challenges for tomorrow's manned launch systems

This paper attempts to capture some of the technical and national challenges facing the design of America's next manned launch system (MLS). There are three basic paths for pursuing tomorrow's MLS; each with variations. Some characteristics that will be sought regardless of the concept selected include low development (or front-end) and life-cycle costs, safety, operability, availability, and a host of other 'ilities'. In order to discriminate among the concepts, a robust design environment and a variety of new and improved analysis tools are needed that produce critical metrics in a timely, efficient manner from a large study space. This paper presents some of the challenges in development, integration, and application of optimization, costing, operations modeling, and several engineering disciplinary tools including geometry modeling, structures, aerodynamics/aeroheating, and trajectory/performance.

Rowell, Lawrence F.↗

Re-engineering NASA's space communications to remain viable in a constrained fiscal environment

Along with the Red and Blue Teams commissioned by the NASA Administrator in 1992, NASA's Associate Administrator for Space Communications commissioned a Blue Team to review the Office of Space Communications (Code O) Core Program and determine how the program could be conducted faster, better, and cheaper. Since there was no corresponding Red Team for the Code O Blue Team, the Blue Team assumed a Red Team independent attitude and challenged the status quo, including current work processes, functional distinctions, interfaces, and information flow, as well as traditional management and system development practices. The Blue Team's unconstrained, non-parochial, and imaginative look at NASA's space communications program produced a simplified representation of the space communications infrastructure that transcends organizational and functional boundaries, in addition to existing systems and facilities. Further, the Blue Team adapted the 'faster, better, cheaper' charter to be relevant to the multi-mission, continuous nature of the space communications program and to serve as a gauge for improving customer services concurrent with achieving more efficient operations and infrastructure life cycle economies. This simplified representation, together with the adapted metrics, offers a future view and process model for reengineering NASA's space communications to remain viable in a constrained fiscal environment. Code O remains firm in its commitment to improve productivity, effectiveness, and efficiency. In October 1992, the Associate Administrator reconstituted the Blue Team as the Code O Success Team (COST) to serve as a catalyst for change. In this paper, the COST presents the chronicle and significance of the simplified representation and adapted metrics, and their application during the FY 1993-1994 activities.

Hornstein, Rhoda Shaller↗