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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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Subsystem weight trade-offs for design optimization of out-of-orbit Mars soft lander, using atmosphere and surface environmental Monte Carlo model
Critical structural design trade studies for delta wing space shuttle orbiter
The results of analytical and simulation studies of the stellar-inertial measurement system (SIMS) for an earth observation satellite are presented. Subsystem design analyses and sensor design trades are reported. Three candidate systems are considered: (1) structure-mounted gyros with structure-mounted star mapper, (2) structure-mounted gyros with gimbaled star tracker, and (3) gimbaled gyros with structure-mounted star mapper. The purpose of the study is to facilitate the decisions pertaining to gimbaled versus structure-mounted gyros and star sensors, and combinations of systems suitable for the EOS satellite.
Analytical trade studies are presented that consider passive TPS configurations using the following material categories: (1) reuseable surface insulation - surface-coated rigidized ceramic fiber; (2) low density charring ablators; and (3) carbon-carbon and high density ablators for leading edge areas. Emphasized are effects on TPS weight by variations in entry trajectories and material thermal characteristics.
Backup or supporting data for the design analyses and trade studies which defined the astronomy sortie missions are presented. The subjects discussed are: (1) configuration of space shuttle orbiter, (2) electronic subsystems, (3) electric power requirements, and (4) payload requirements. Mathematical models are developed to illustrate the orbital rendezvous capabilities.
A spaceborne LADAR sensor, which will meet the requirements for rendezvous and docking with a cooperative object in synchronous orbit is presented. The sensor is being configured around a pulsed CO2 laser which can be constructed and deployed using technology which presently exists or is being developed, and which appears to lend itself very well to the envisioned family of space missions. In order to determine the applicability of the type of sensor being considered, the performance of a family of candidate sensors is being traded off as a function of size, weight, and power consumption. The maximum ranges being considered are 50, 100, 200, and 300 nautical miles.
An optimization procedure for the provision of an acoustic lining configuration that is balanced with respect to engine performance losses and lining attenuation characteristics was established using a method which determined acoustic attenuation design requirements through parametric trade studies using the subjective noise unit of effective perceived noise level (EPNL).
A candidate mirror, hexagonally lightweighted, is analyzed under various loadings using as complete a procedure as possible. Successive simplifications are introduced and compared to an original analysis. A model which is a reasonable compromise between accuracy and cost is found and is used for making trade-off studies of the various structural parameters of the lightweighted mirror.
Analyses and trade studies were performed for the evaluation of the most desirable solutions to space tug subsystem requirements. These were accomplished at system, subsystem, and at component levels. The criteria, the candidate options evaluated, the selection process, and the recommended solutions that have been integrated together in the configuration descriptions are reported.
The interaction between the efficiency of the structural design and the cost of the structure used was studied. It is shown that future effort is best directed at producing a low cost structure of medium efficiency, but with the ability to withstand normal service wear. The trade-off between aerodynamic drag and structure weight in selecting a length to diameter ratio for the hull is evaluated along with the implications of power plan type and fuel cost on the economics of the airship. The choice of lifting gas is considered.
The current predicted acoustic environment for the shuttle orbiter payload bay will produce random vibration environments for payload components and subsystems which potentially will result in design, weight and cost penalties if means of protecting the payloads are not developed. Results are presented of a study to develop, through design and cost effectiveness trade studies, conceptual noise suppression device designs for space shuttle payloads. The impact of noise suppression on environmental levels and associated test costs, and on test philosophy for the various payload classes is considered with the ultimate goal of reducing payload test costs. Conclusions and recommendations are presented.
The need to store and retrieve large quantities of data at modest cost has generated the need for an economical, compact, archival mass storage system. Very significant improvements in the state-of-the-art of mass storage systems have been accomplished through the development of a number of magnetic, electro-optical, and other related devices. This study was conducted in order to do a trade-off between these data storage devices and the related technologies in order to determine an optimum approach for an archival mass data storage system based upon a comparison of the projected capabilities and characteristics of these devices to yield operational systems in the early 1980's.
A systems study was conducted on an aircraft concept, representative of a supersonic-cruise military aircraft (supercruiser). The study results indicate that supersonic ranges in excess of 4000 n.mi. at a Mach number of 2.62 are possible with a 500 lbf class aircraft. Trade studies, to determine the sensitivity of supersonic range to parameters which would improve maneuverability, indicate that thrust-weight ratios of as much as 0.5 can be used without significantly decreasing supersonic range; however, increasing the thrust-weight ratio to 1.0 decreases the range capability by about 1100 n.mi. The range penalty for increasing the aircraft limit load-factor from 4.0 to 9.0 is about 500 n.mi. The increased fuel volume of several configurations improved the supersonic range capability by about 1200 n.mi. but, due to associated losses in supersonic L/D, had an insignificant effect on the range at a Mach number of 2.62.
Solar thermal conversion performance is assessed in this paper for representative point focusing distributed systems. Trade-off comparisons are made in terms of concentrator quality, solar receiver operating temperature, and power conversion efficiency. Normalized system performance is presented on a unit concentrator area basis for integrated annual electric energy production.
Data Systems Dynamic Simulation is a simulation system designed to reduce cost and time and increase the confidence and comprehensiveness of Data Systems Simulation. It is designed to simulate large data processing and communications systems from end-to-end or by subsystem. Those features relevant to system timing, control, sizing, personnel support activities, cost and external influences are modeled. Emphasis is placed on ease of use, comprehensive system performance measures, and extensive post simulation analysis capability. The system has been used to support trade studies of the NASA data system needs in the 1985 to 1990 time frame.
Phase I of the Near-Term Hybrid Vehicle Program involved the development of preliminary designs of electric/heat engine hybrid passenger vehicles. The preliminary designs were developed on the basis of mission analysis, performance specification, and design trade-off studies conducted independently by four contractors. THe resulting designs involve parallel hybrid (heat engine/electric) propulsion systems with significant variation in component selection, power train layout, and control strategy. Each of the four designs is projected by its developer as having the potential to substitute electrical energy for 40% to 70% of the petroleum fuel consumed annually by its conventional counterpart.
Data for hydroponic plant growth in a manned system test is combined with nutritional recommendations to suport trade-off calculations for closed and partially closed life support system scenarios. Published data are used as guidelines for the masses of mineral nutrients needed for higher plant production. The results of calculations based on various scenarios are presented for various combinations of plant growth chamber utilization and fraction of mineral recycle. Estimates are made of the masses of material needed to meet human nutritional requirements in the various scenarios. It appears that food production from a plant growth chamber with mineral recycle is favorable to reduction of the total launch weight in missions exceeding 3 years.
Trade-offs between antenna cost and gain made for nine antennas as a feasibility study for the experimental land mobile satellite system, M-SAT(X) reported. This system is under development by JPL-NASA for a mobile telephone system to be used throughout the continental USA and Alaska. The mobile antenna is a key element in the development of this system.