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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 1,027 records · Page 57

All sources NASA NTRS DOE OSTI

NASA NTRS1972

Closed loop dynamics of in-core thermionic reactor systems.

Use of a point model of an in-core thermionic converter to investigate alternative schemes for providing closed-loop reactor control. It was found that schemes based on variable-gain power regulation buffers which use the reactor current as the control variable provide complete protection from thermionic burnout and also provide a virtually constant voltage to the user. A side benefit is that the emitter temperature transients are small; even for a complete electric load drop the emitter temperature transient is less than 100 K. The current regulation scheme was selected for further study with a distributed parameter model which was developed to account for variations in thermionic and heat transfer properties along the length of a cylindrical converter. It was found that, even though the emitter temperature distribution is about 200 K along the converter length, the dynamic properties are unchanged when using the current control scheme.

Sawyer, C. D.↗

NASA NTRS1980

Coal conversion products Industrial applications

The synfuels economic evaluation model was utilized to analyze cost and product economics of the TVA coal conversion facilities. It is concluded that; (1) moderate yearly future escalations ( 6%) in current natural gas prices will result in medium-Btu gas becoming competitive with natural gas at the plant boundary; (2) utilizing DRI price projections, the alternate synfuel products, except for electricity, will be competitive with their counterparts; (3) central site fuel cell generation of electricity, utilizing MBG, is economically less attractive than the other synthetic fuels, given projected price rises in electricity produced by other means; and (4) because of estimated northern Alabama synfuels market demands, existing conventional fuels, infrastructure and industrial synfuels retrofit problems, a diversity of transportable synfuels products should be produced by the conversion facility.

Warren, D.↗

NASA NTRS1983

FAA certification requirements for future fuels, fuel systems and powerplants

The current FAA procedures for approving fuels, along with a comment or two as to what might be done relative to assuring the safety of using these alternative fuels, whatever they may be are addressed.

Horeff, T. C.↗

NASA NTRS1983

On the clock mechanism and the implausibility of the 35 day precessing disk in HZ Herculis/Hercules X-1

The concept of the precessing accretion disk in HZ Her/Her X-1 in its varied forms, to account for the 35 day periodicity in the X-ray flux, has met many objections from a number of workers on various grounds, but it is still being invoked in current publications. These objections are reviewed and additional arguments are presented against the precessing accretion disk model. The implausibility of the disk models is demonstrated. An alternate clock mechanism, based on nonlinear oscillations in the normal star, which provides the modulation of the mass flow is discussed.

Kondo, Y.↗

NASA NTRS1982

Cost estimates for flat plate and concentrator collector arrays

The current module and installation costs for the U.S. National Photovoltaic Program's grid-connected systems are significantly higher than required for economic viability of this alternative. Attention is accordingly given to the prospects for installed module cost reductions in flat plate, linear focus Fresnel concentrator, and point focus Fresnel concentrator candidate systems. Cost projections indicate that all three systems would meet near-term and midterm goals, provided that module costs of $2.80/W(p) and $0.70/W(p), respectively, are met. The point focus Fresnel system emerges as the most viable for the near term.

Shimada, K.↗

NASA NTRS1984

Alternate nozzle ablative materials program

Four subscale solid rocket motor tests were conducted successfully to evaluate alternate nozzle liner, insulation, and exit cone structural overwrap components for possible application to the Space Shuttle Solid Rocket Motor (SRM) nozzle asasembly. The 10,000 lb propellant motor tests were simulated, as close as practical, the configuration and operational environment of the full scale SRM. Fifteen PAN based and three pitch based materials had no filler in the phenolic resin, four PAN based materials had carbon microballoons in the resin, and the rest of the materials had carbon powder in the resin. Three nozzle insulation materials were evaluated; an aluminum oxide silicon oxide ceramic fiber mat phenolic material with no resin filler and two E-glass fiber mat phenolic materials with no resin filler. It was concluded by MTI/WD (the fabricator and evaluator of the test nozzles) and NASA-MSFC that it was possible to design an alternate material full scale SRM nozzle assembly, which could provide an estimated 360 lb increased payload capability for Space Shuttle launches over that obtainable with the current qualified SRM design.

Kimmel, N. A.↗

NASA NTRS1989

Hypersonic propulsion

The paper reviews the whys and hows of the concept of supersonic combustion for hypersonic propulsion. Attention is given to the problem areas, the current research and development efforts, and their implications. The operating boundary of the SCRAMJET is reasonably well defined. The paper also explores some air-breathing alternatives that may go beyond SCRAMJETS.

Cheng, SIN-I.↗

NASA NTRS1992

Deformation mechanisms of NiAl cyclicly deformed near the brittle-to-ductile transformation temperature

One of the ongoing challenges of the aerospace industry is to develop more efficient turbine engines. Greater efficiency entails reduced specific strength and larger temperature gradients, the latter of which means higher operating temperatures and increased thermal conductivity. Continued development of nickel-based superalloys has provided steady increases in engine efficiency and the limits of superalloys have probably not been realized. However, other material systems are under intense investigation for possible use in high temperature engines. Ceramic, intermetallic, and various composite systems are being explored in an effort to exploit the much higher melting temperatures of these systems. NiAl is considered a potential alternative to conventional superalloys due to its excellent oxidation resistance, low density, and high melting temperature. The fact that NiAl is the most common coating for current superalloy turbine blades is a tribute to its oxidation resistance. Its density is one-third that of typical superalloys and in most temperature ranges its thermal conductivity is twice that of common superalloys. Despite these many advantages, NiAl requires more investigation before it is ready to be used in engines. Binary NiAl in general has poor high-temperature strength and low-temperature ductility. On-going research in alloy design continues to make improvements in the high-temperature strength of NiAl. The factors controlling low temperature ductility have been identified in the last few years. Small, but reproducible ductility can now be achieved at room temperature through careful control of chemical purity and processing. But the mechanisms controlling the transition from brittle to ductile behavior are not fully understood. Research in the area of fatigue deformation can aid the development of the NiAl system in two ways. Fatigue properties must be documented and optimized before NiAl can be applied to engineering systems. More importantly though, probing the deformation mechanisms operating in fatigue will lead to a better understanding of NiAl's unique characteristics. Low cycle fatigue properties have been reported on binary NiAl in the past year, yet those studies were limited to two temperature ranges: room temperature and near 1000 K. Eventually, fatigue property data will be needed for a wide range of temperatures and compositions. The intermediate temperature range near the brittle-to-ductile transition was chosen for this study to ascertain whether the sharp change occurring in monotonic behavior also occurs under cyclic conditions. An effort was made to characterize the dislocation structures which evolved during fatigue testing and comment on their role in the deformation process.

Antolovich, Stephen D.↗

NASA NTRS1992

A prototype automatic phase compensation module

The growing demands for high gain and accurate satellite communication systems will necessitate the utilization of large reflector systems. One area of concern of reflector based satellite communication is large scale surface deformations due to thermal effects. These distortions, when present, can degrade the performance of the reflector system appreciable. This performance degradation is manifested by a decrease in peak gain, and increase in sidelobe level, and pointing errors. It is essential to compensate for these distortion effects and to maintain the required system performance in the operating space environment. For this reason the development of a technique to offset the degradation effects is highly desirable. Currently, most research is direct at developing better material for the reflector. These materials have a lower coefficient of linear expansion thereby reducing the surface errors. Alternatively, one can minimize the distortion effects of these large scale errors by adaptive phased array compensation. Adaptive phased array techniques have been studied extensively at NASA and elsewhere. Presented in this paper is a prototype automatic phase compensation module designed and built at NASA Lewis Research Center which is the first stage of development for an adaptive array compensation module.

Terry, John D.↗

NASA NTRS1992

Technology Transfer and the Civil Space Program. Volume 2: Workshop proceedings

The objectives were to (1) provide a top-level review of the Integrated Technology Plan (ITP) and current civil space technology plans, including planning processes and technologies; (2) discuss and assess technology transfer (TT) experiences across a wide range of participants; (3) identify alternate categories/strategies for TT and define the objectives of transfer processes in each case; (4) identify the roles of various government 'stakeholders', aerospace industry, industries at large, and universities in civil space technology research, development, demonstration, and transfer; (5) identify potential barriers and/or opportunities to successful civil space TT; (6) identify specific needs for innovations in policy, programs, and/or procedures to facilitate TT; and (7) develop a plan of attack for the development of a workshop report. Papers from the workshop are presented.

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NASA NTRS1994

The Pacor 2 expert system: A case-based reasoning approach to troubleshooting

The Packet Processor 2 (Pacor 2) Data Capture Facility (DCF) acquires, captures, and performs level-zero processing of packet telemetry for spaceflight missions that adhere to communication services recommendations established by the Consultative Committee for Space Data Systems (CCSDS). A major goal of this project is to reduce life-cycle costs. One way to achieve this goal is to increase automation. Through automation, using expert systems, and other technologies, staffing requirements will remain static, which will enable the same number of analysts to support more missions. Analysts provide packet telemetry data evaluation and analysis services for all data received. Data that passes this evaluation is forwarded to the Data Distribution Facility (DDF) and released to scientists. Through troubleshooting, data that fails this evaluation is dumped and analyzed to determine if its quality can be improved before it is released. This paper describes a proof-of-concept prototype that troubleshoots data quality problems. The Pacor 2 expert system prototype uses the case-based reasoning (CBR) approach to development, an alternative to a rule-based approach. Because Pacor 2 is not operational, the prototype has been developed using cases that describe existing troubleshooting experience from currently operating missions. Through CBR, this experience will be available to analysts when Pacor 2 becomes operational. As Pacor 2 unique experience is gained, analysts will update the case base. In essence, analysts are training the system as they learn. Once the system has learned the cases most likely to recur, it can serve as an aide to inexperienced analysts, a refresher to experienced analysts for infrequently occurring problems, or a training tool for new analysts. The Expert System Development Methodology (ESDM) is being used to guide development.

Sary, Charisse↗

NASA NTRS1994

Water Purification Systems

Clearwater Pool Technologies employs NASA-developed silver/copper ionization to purify turtle and dolphin tanks, cooling towers, spas, water recycling systems, etc. The pool purifier consists of a microcomputer to monitor water conditions, a pair of metallic electrodes, and a rheostat controller. Ions are generated by passing a low voltage current through the electrodes; the silver ions kill the bacteria, and the copper ions kill algae. This technology has found broad application because it offers an alternative to chemical disinfectants. It was originally developed to purify water on Apollo spacecraft. Caribbean Clear has been using NASA's silver ionization technology for water purification for more than a decade. Two new products incorporate advancements of the basic technology. One is the AquaKing, a system designed for areas with no source of acceptable drinking water. Another is the Caribbean Clear Controller, designed for commercial pool and water park applications where sanitizing is combined with feedback control of pH and an oxidizer, chlorine or bromine. The technology was originally developed to purify water on Apollo spacecraft.

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NASA NTRS2011

Dynamic Weather Routes: A Weather Avoidance Concept for Trajectory-Based Operations

The integration of convective weather modeling with trajectory automation for conflict detection, trial planning, direct routing, and auto resolution has uncovered a concept that could help controllers, dispatchers, and pilots identify improved weather routes that result in significant savings in flying time and fuel burn. Trajectory automation continuously and automatically monitors aircraft in flight to find those that could potentially benefit from improved weather reroutes. Controllers, dispatchers, and pilots then evaluate reroute options to assess their suitability given current weather and traffic. In today's operations aircraft fly convective weather avoidance routes that were implemented often hours before aircraft approach the weather and automation does not exist to automatically monitor traffic to find improved weather routes that open up due to changing weather conditions. The automation concept runs in real-time and employs two keysteps. First, a direct routing algorithm automatically identifies flights with large dog legs in their routes and therefore potentially large savings in flying time. These are common - and usually necessary - during convective weather operations and analysis of Fort Worth Center traffic shows many aircraft with short cuts that indicate savings on the order of 10 flying minutes. The second and most critical step is to apply trajectory automation with weather modeling to determine what savings could be achieved by modifying the direct route such that it avoids weather and traffic and is acceptable to controllers and flight crews. Initial analysis of Fort Worth Center traffic suggests a savings of roughly 50% of the direct route savings could be achievable.The core concept is to apply trajectory automation with convective weather modeling in real time to identify a reroute that is free of weather and traffic conflicts and indicates enough time and fuel savings to be considered. The concept is interoperable with today's integrated FMS/datalink. Auxiliary(lat/long) waypoints define a minimum delay reroute between current position and a downstream capture fix beyond the weather. These auxiliary waypoints can be uplinked to equipped aircraft and auto-loaded into the FMS. Alternatively, for unequipped aircraft, auxiliary waypoints can be replaced by nearby named fixes, but this could reduce potential savings. The presentation includes an overview of the automation approach and focuses on several cases in terms of potential savings, reroute complexity, best auxiliary waypoint solution vs. named fix solution, and other metrics.

McNally, B. David↗

NASA NTRS2017

NASA Near Earth Network (NEN) Support for Lunar and L1/L2 CubeSats

The NASA Near Earth Network (NEN) consists of globally distributed tracking stations, including NASA, commercial, and partner ground stations, that are strategically located to maximize the coverage provided to a variety of orbital and suborbital missions, including those in LEO, GEO, HEO, lunar and L1/L2 orbits. The NENs future mission set includes and will continue to include CubeSat missions. The majority of the CubeSat missions destined to fly on EM-1, launching in late 2018, many in a lunar orbit, will communicate with ground based stations via X-band and will utilize the NASA Jet Propulsion Laboratory (JPL) developed IRIS radio. The NEN recognizes the important role CubeSats are beginning to play in carrying out NASAs mission and is therefore investigating the modifications needed to provide IRIS radio compatibility. With modification, the NEN could potentially expand support to the EM-1 lunar CubeSats.The NEN could begin providing significant coverage to lunar CubeSat missions utilizing three to four of the NENs mid-latitude sites. This coverage would supplement coverage provided by the JPL Deep Space Network (DSN). The NEN, with smaller apertures than DSN, provides the benefit of a larger beamwidth that could be beneficial in the event of uncertain ephemeris data. In order to realize these benefits the NEN would need to upgrade stations targeted based on coverage ability and current configuration/ease of upgrade, to ensure compatibility with the IRIS radio. In addition, the NEN is working with CubeSat radio developers to ensure NEN compatibility with alternative CubeSat radios for Lunar and L1/L2 CubeSats. The NEN has provided NEN compatibility requirements to several radio developers who are developing radios that offer lower cost and, in some cases, more capabilities with fewer constraints. The NEN is ready to begin supporting CubeSat missions. The NEN is considering network upgrades to broaden the types of CubeSat missions that can be supported and is supporting both the CubeSat community and radio developers to ensure future CubeSat missions have multiple options when choosing a network for their communications support.

Schaire, Scott↗

NASA NTRS2020

Artificial Gravity in Mars Orbit for Crew Acclimation

NASA’s current baseline plan for a crewed Mars mission anticipates a transit time of up to three hundred days in microgravity and 3-14 days on the Martian surface for gravity acclimation before the crew can safely perform their first Extra-Vehicular Activity (EVA). While there are multiple options for how initial surface operations will be performed, all current designs involve acclimation on the surface, and the impacts on the mission schedule, required supplies, and crew lander systems are significant. This paper proposes an alternative option utilizing artificial gravity, which offers benefits in terms of mission scope, mass savings, crew health, and long-term strategic vision. By moving the acclimation requirement to the orbiting habitat’s existing systems, rather than adding redundant systems to the lander, the Mars Descent Vehicle (MDV) can be a much smaller, simpler, and lighter design. Rather than the lander being designed to support crew for days, it would be mere hours. While ambitious, the concept of pre-acclimation in orbit can be not only safe and feasible, but done with fairly minimal changes to the planned architecture and overall mass requirements. The data used draws on decades of established research and demonstrates how this capability can be not only used for pre-acclimation, but also to support crew during early orbital-only missions, surface abort contingency scenarios, return-to-orbit abort scenarios, and as an early proof of capability into larger and more ambitious artificial gravity designs needed for extended exploration missions in the future.

Rowe, Justin↗

NASA NTRSDate not supplied

Advancements in Logistics Reduction for Exploration Missions

Management of logistics on exploration missions includes both looking for ways to minimize the quantities, mass and volume of various consumables, supplies, spares and equipment as well as ways to minimize the crew time needed for locating and handling those items. Also included are ways to minimize the waste, handling and resultant products from the processes of maintaining a crew on these missions. The Logistics Reduction project encompasses technologies for management of waste, trash, autonomous logistics, and clothing. This paper provides a status of work in these areas including recent accomplishments and challenges encountered. Future objectives will also be covered along with the work currently in progress. Specifically, the paper will cover technologies in waste management, namely, the Universal Waste Management System (UWMS) or exploration toilet and work on an alternative waste collection container, the Alternate Fecal Canister. Trash management technologies work on the Trash Compaction and Processing System (TCPS) and Trash to Gas (TtG) is summarized with progress to date as well as information on how Jettison as an option is related. Progress and summary of recent accomplishment on the RFID (Radio Frequency ID) Enabled Autonomous Logistics Management (REALM) and the Autonomous Logistics (AL) technologies is detailed. Advanced Clothing System (ACS) and work in the area of Systems Engineering and Integration (SE&I) is also included. Status of the technologies, accomplishments and how the focus areas inform program decisions will be addressed.

human spaceflight↗

NASA NTRSDate not supplied

Advancements in Logistics Reduction Technologies for Exploration Missions

human spaceflight↗

NASA NTRSDate not supplied

Logistics Reduction Advancements and Future Plans for NASA's Exploration Missions

Management of logistics on exploration missions includes both looking for ways to minimize the quantities, mass and volume of various consumables, supplies, spares, and equipment as well as ways to minimize the crew time needed for locating and handling those items. Also included are ways to minimize the waste, handling, and resultant products from the processes of maintaining a crew on these missions. The Logistics Reduction project encompasses technologies for management of waste, trash, autonomous logistics, and clothing. This paper provides a status of work from 2023 in these areas including recent accomplishments and challenges encountered. Future objectives and plans for 2024 will also be covered along with the work currently in progress. Specifically, the paper will cover technologies in waste management, namely, the Universal Waste Management System (UWMS) or exploration toilet and work on an alternative waste collection container, the Alternate Fecal Canister. Trash management technologies work on the Trash Compaction Processing System (TCPS) and Trash to Gas (TtG) is summarized with progress to date as well as information on how Jettison as an option is related. Progress and summary of recent accomplishment on the RFID (Radio Frequency ID) Enabled Autonomous Logistics Management (REALM) and the Autonomous Logistics (AL) technologies is detailed. Advanced Clothing System (ACS) and work in the area of Systems Engineering and Integration (SE&I) is also included. Status of the technologies, accomplishments and how the focus areas inform program decisions will be addressed.

Toilet↗