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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 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

Introduction to Advanced Engine Control Concepts

With the increased emphasis on aircraft safety, enhanced performance and affordability, and the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. The Controls and Dynamics Branch at NASA (National Aeronautics and Space Administration) Glenn Research Center (GRC) in Cleveland, Ohio, is leading and participating in various projects in partnership with other organizations within GRC and across NASA, the U.S. aerospace industry, and academia to develop advanced controls and health management technologies that will help meet these challenges through the concept of Intelligent Propulsion Systems. The key enabling technologies for an Intelligent Propulsion System are the increased efficiencies of components through active control, advanced diagnostics and prognostics integrated with intelligent engine control to enhance operational reliability and component life, and distributed control with smart sensors and actuators in an adaptive fault tolerant architecture. This presentation describes the current activities of the Controls and Dynamics Branch in the areas of active component control and propulsion system intelligent control, and presents some recent analytical and experimental results in these areas.

Sanjay, Garg↗
NASA NTRS1992

Integration of thermal and environmental control systems during Space Station Freedom early assembly phase

An overview of Space Station Freedom Thermal Control System (TCS) and Environmental Control and Life Support System (ECLSS) integration is presented for Stages 2-6. Particular attention is given to issues associated with integrating five distinct, functioning spacecraft with hardware not specifically designed for intermediate stages. Areas specifically addressed include integrated ECLSS temperature and humidity control performance, thermal load balancing, performance and verification requirements, interface verification procedures, TCS activation sequence, resource allocation and Space Shuttle integration.

Di Pietro, David A.↗
NASA NTRS1992

On neutralized currents in the solar corona

Using Ampere's integral law applied to vector magnetograph transverse field data, the current pattern in an active region associated with flaring activity is analyzed. The greater sensitivity of this integral formalism of Ampere's law may allow one to identify regions of weak return current around the actual positive current region. The effects of Faraday rotation on the inferred magnetic field measurements, and hence on the deduced current pattern, are discussed. It is concluded that the current patterns in the region consist either of a neutralized current system, well modeled by a coaxial cable, or of a potential field, with the apparent currents in the core an artifact induced by magneto-optical effects. In either case, the data do not convincingly show an unneutralized current system.

Wilkinson, Ladye K.↗
NASA NTRS1995

Active-Pixel Image Sensor With Analog-To-Digital Converters

Proposed single-chip integrated-circuit image sensor contains 128 x 128 array of active pixel sensors at 50-micrometer pitch. Output terminals of all pixels in each given column connected to analog-to-digital (A/D) converter located at bottom of column. Pixels scanned in semiparallel fashion, one row at time; during time allocated to scanning row, outputs of all active pixel sensors in row fed to respective A/D converters. Design of chip based on complementary metal oxide semiconductor (CMOS) technology, and individual circuit elements fabricated according to 2-micrometer CMOS design rules. Active pixel sensors designed to operate at video rate of 30 frames/second, even at low light levels. A/D scheme based on first-order Sigma-Delta modulation.

Fossum, Eric R.↗
NASA NTRS2022

SPARCS Payload Assembly, Integration, and Test Update

The Star-Planet Activity Research CubeSat (SPARCS) is a 6U CubeSat under construction that is devoted to the photometric monitoring of M stars in the far-UV (FUV) and near-UV (NUV), to measure the time-dependent spectral slope, intensity and evolution of low-mass star high-energy radiation. We report on the progress made in the assembly, integration and test of the instrument payload at Arizona State University using a custom TVAC chamber and optical stimulus that provides calibration light sources and the custom contamination control environment that the FUV demands. The payload consists of a custom 90mm clear aperture telescope developed by Hexagon/Sigma Space, combined with a dichroic plate to separate the FUV and NUV beams developed by Teledyne Acton and Materion, married with twin focal plane array cameras separately optimized for their band passes as developed by JPL.

FUV↗
NASA NTRS1994

Surface characterization and contamination analysis

The research activity for this first year has focussed on three distinct activities: (1) the use of an integrating sphere to improve upon the gathering of spectral data from a variety of surfaces; (2) the use of optical fiber spectrometry to determine levels of contamination from tape residues on critical bonding surfaces; and (3) an exploratory activity in the use of spectroscopic ellipsometry for the analysis of thin films of contaminants on critical surfaces has also begun.

Workman, Gary L.↗
NASA NTRS2014

Asteroid Crewed Segment Mission Lean Development

The next generation of human spaceflight missions presents numerous challenges to designers that must be addressed to produce a feasible concept. The specific challenges of designing an exploration mission utilizing the Space Launch System and the Orion spacecraft to carry astronauts beyond earth orbit to explore an asteroid stored in a distant retrograde orbit around the moon will be addressed. Mission designers must carefully balance competing constraints including cost, schedule, risk, and numerous spacecraft performance metrics including launch mass, nominal landed mass, abort landed mass, mission duration, consumable limits and many others. The Asteroid Redirect Crewed Mission will be described along with results from the concurrent mission design trades that led to its formulation. While the trades presented are specific to this mission, the integrated process is applicable to any potential future mission. The following trades were critical in the mission formulation and will be described in detail: 1) crew size, 2) mission duration, 3) trajectory design, 4) docking vs grapple, 5) extravehicular activity tasks, 6) launch mass and integrated vehicle performance, 7) contingency performance, 8) crew consumables including food, clothing, oxygen, nitrogen and water, and 9) mission risk. The additional Orion functionality required to perform the Asteroid Redirect Crewed Mission and how it is incorporated while minimizing cost, schedule and mass impacts will be identified. Existing investments in the NASA technology portfolio were leveraged to provide the added functionality that will be beneficial to future exploration missions. Mission kits are utilized to augment Orion with the necessary functionality without introducing costly new requirements to the mature Orion spacecraft design effort. The Asteroid Redirect Crewed Mission provides an exciting early mission for the Orion and SLS while providing a stepping stone to even more ambitious missions in the future.

Gard, Joe↗
NASA NTRS2004

Research and Technology Activities Supporting Closed-Brayton-Cycle Power Conversion System Development

The elements of Brayton technology development emphasize power conversion system risk mitigation. Risk mitigation is achieved by demonstrating system integration feasibility, subsystem/component life capability (particularly in the context of material creep) and overall spacecraft mass reduction. Closed-Brayton-cycle (CBC) power conversion technology is viewed as relatively mature. At the 2-kWe power level, a CBC conversion system Technology Readiness Level (TRL) of six (6) was achieved during the Solar Dynamic Ground Test Demonstration (SD-GTD) in 1998. A TRL 5 was demonstrated for 10 kWe-class CBC components during the development of the Brayton Rotating Unit (BRU) from 1968 to 1976. Components currently in terrestrial (open cycle) Brayton machines represent TRL 4 for similar uses in 100 kWe-class CBC space systems. Because of the baseline component and subsystem technology maturity, much of the Brayton technology task is focused on issues related to systems integration. A brief description of ongoing technology activities is given.

Barrett, Michael J.↗
NASA NTRS1988

Transformational derivation of programs using the Focus system

A program derivation support system called Focus is being constructed. It will formally derive programs using the paradigm of program transformation. The following issues are discussed: (1) the integration of validation and program derivation activities in the Focus system; (2) its tree-based user interface; (3) the control of search spaces in program derivation; and (4) the structure and organization of program derivation records. The inference procedures of the system are based on the integration of functional and logic programming principles. This brings about a synthesis of paradigms that were heretofore considered far apart, such as logical and executable specifications and constructive and transformational approaches to program derivation. A great emphasis has been placed, in the design of Focus, on achieving small search spaces during program derivation. The program manipulation operations such as expansion, simplification and rewriting were designed with this objective. The role of operations that are expensive in search spaces, such as folding, has been reduced. Program derivations are documented in Focus in a way that the high level descriptions of derivations are expressed only using program level information. All the meta-level information, together with dependencies between derivations of program components, is automatically recorded by the system at a lower level of description for its own use in replay.

Reddy, Uday S.↗
NASA NTRS1991

An evaluation of strategic behaviors in a high fidelity simulated flight task - Comparing primary performance to a figure of merit

The usual method of evaluating flight performance during a simulation is to collect as many primary performance measurements as possible. Then analyze all the measurements to find one sensitive to the manipulations imposed on the pilot during the scenario. Although this method can be useful, it is usually unreliable from one study to another. A simulation was conducted to test an integrated figure of merit (FOM) constructed using a standardized procedure. Pilots flew two full-mission scenarios in an instrument trainer with three degrees of motion freedom. The primary performance measurements selected assessed the pilot's performance in accuracy, smoothness, and activity. The results suggest that the integrated FOMs performed comparably to the primary performance measurements in determining which flight imposed the higher demands on the pilot. The standardized construction process allow adjustments to the FOM, so it can be used in different applications.

Bortolussi, Michael R.↗
NASA NTRS2012

Next Generation Life Support Project Status

Next Generation Life Support (NGLS) is one of several technology development projects sponsored by NASA s Game Changing Development Program. The NGLS Project is developing life support technologies (including water recovery and space suit life support technologies) needed for humans to live and work productively in space. NGLS has three project tasks: Variable Oxygen Regulator (VOR), Rapid Cycle Amine (RCA) swing bed, and Alternative Water Processor (AWP). The RCA swing bed and VOR tasks are directed at key technology needs for the Portable Life Support System (PLSS) for an Advanced Extravehicular Mobility Unit, with focus on test article development and integrated testing in an Advanced PLSS in cooperation with the Advanced Extra Vehicular Activity (EVA) Project. An RCA swing-bed provides integrated carbon dioxide removal and humidity control that can be regenerated in real time during an EVA. The VOR technology will significantly increase the number of pressure settings available to the space suit. Current space suit pressure regulators are limited to only two settings whereas the adjustability of the advanced regulator will be nearly continuous. The AWP effort, based on natural biological processes and membrane-based secondary treatment, will result in the development of a system capable of recycling wastewater from sources expected in future exploration missions, including hygiene and laundry water. This paper will provide a status of technology development activities and future plans.

Barta, Daniel J.↗
NASA NTRS1984

Communications protocols for a fault tolerant, integrated local area network for Space Station applications

The evolutionary growth of the Space Station and the diverse activities onboard are expected to require a hierarchy of integrated,local area networks capable of supporting data, voice and video communications. In addition, fault tolerant network operation is necessary to protect communications between critical systems attached to the net and to relieve the valuable human resources onboard Space Station of day-to-day data system repair tasks. An experimental, local area network is being developed which will serve as a testbed for investigating candidate algorithms and technologies for a fault tolerant, integrated network. The establishment of a set of rules or protocols which govern communications on the net is essential to obtain orderly and reliable operation. A hierarchy of protocols for the experimental network is presented and procedures for data and control communications are described.

Meredith, B. D.↗
NASA NTRS2011

Physical, Ecological, and Societal Indicators for the National Climate Assessment

The National Climate Assessment (NCA) is being conducted under the auspices of the U.S. Global Change Research Program (USGCRP), pursuant to the Global Change Research Act of 1990, Section 106, which requires a report to Congress every 4 years. The current NCA (http://globalchange.gov/what-we-do/assessment/) differs in multiple ways from previous U.S. climate assessment efforts, being: (1) more focused on supporting the Nation s activities in adaptation and mitigation and on evaluating the current state of scientific knowledge relative to climate impacts and trends; (2) a long-term, consistent process for evaluation of climate risks and opportunities and providing information to support decision-making processes within regions and sectors; and (3) establishing a permanent assessment capacity both inside and outside of the federal government. As a part of ongoing, long-term assessment activities, the NCA intends to develop an integrated strategic framework and deploy climate-relevant physical, ecological, and societal indicators. The NCA indicators framework is underdevelopment by the NCA Development and Advisory Committee Indicators Working Group and are envisioned as a relatively small number of policy-relevant integrated indicators designed to provide a consistent, objective, and transparent overview of major variations in climate impacts, vulnerabilities, adaptation, and mitigation activities across sectors, regions, and timeframes. The potential questions that could be addressed by these indicators include: How do we know that there is a changing climate and how is it expected to change in the future? Are important climate impacts and opportunities occurring or predicted to occur in the future? Are we adapting successfully? What are the vulnerabilities and resiliencies given a changing climate? Are we preparing adequately for extreme events? It is not expected that the NCA societal indicators would be linked directly to a single decision or portfolio of decisions, but subsets of indicators, or the data supporting the indicator, might be used to inform decision-making processes such as the development and implementation of climate adaptation strategies in a particular sector or region.

Kenney, Melissa A.↗
NASA NTRS1996

Integrating International Space Station payload operations

The payload operations support for the International Space Station (ISS) payload is reported on, describing payload activity planning, payload operations control, payload data management and overall operations integration. The operations concept employed is based on the distribution of the payload operations responsibility between the researchers and ISS partners. The long duration nature of the ISS mission dictates the geographical distribution of the payload operations activities between the different national centers. The coordination and integration of these operations will be assured by NASA's Payload Operations Integration Center (POIC). The prime objective of the POIC is the achievement of unified operations through communication and collaboration.

Noneman, Steven R.↗
NASA NTRS1983

The physics of a single-event upset in integrated circuits: A review and critique of analytical models for charge collection

When an energetic particle (kinetic energy 0.5 MeV) originating from a radioactive decay or a cosmic ray transverse the active regions of semiconductor devices used in integrated circuit (IC) chips, it leaves along its track a high density electron hole plasma. The subsequent decay of this plasma by drift and diffusion leads to charge collection at the electrodes large enough in most cases to engender a false reading, hence the name single-event upset (SEU). The problem of SEU's is particularly severe within the harsh environment of Jupiter's radiation belts and constitutes therefore a matter of concern for the Galileo mission. The physics of an SEU event is analyzed in some detail. Owing to the predominance of nonlinear space charge effects and the fact that positive (holes) and negative (electrons) charges must be treated on an equal footing, analytical models for the ionized-charge collection and their corresponding currents as a function of time prove to be inadequate even in the simplest case of uniformly doped, abrupt p-n junctions in a one-dimensional geometry. The necessity for full-fledged computer simulation of the pertinent equations governing the electron-hole plasma therefore becomes imperative.

Vonroos, O.↗
NASA NTRS2011

Project Report: Automatic Sequence Processor Software Analysis

The Mission Planning and Sequencing (MPS) element of Multi-Mission Ground System and Services (MGSS) provides space missions with multi-purpose software to plan spacecraft activities, sequence spacecraft commands, and then integrate these products and execute them on spacecraft. Jet Propulsion Laboratory (JPL) is currently is flying many missions. The processes for building, integrating, and testing the multi-mission uplink software need to be improved to meet the needs of the missions and the operations teams that command the spacecraft. The Multi-Mission Sequencing Team is responsible for collecting and processing the observations, experiments and engineering activities that are to be performed on a selected spacecraft. The collection of these activities is called a sequence and ultimately a sequence becomes a sequence of spacecraft commands. The operations teams check the sequence to make sure that no constraints are violated. The workflow process involves sending a program start command, which activates the Automatic Sequence Processor (ASP). The ASP is currently a file-based system that is comprised of scripts written in perl, c-shell and awk. Once this start process is complete, the system checks for errors and aborts if there are any; otherwise the system converts the commands to binary, and then sends the resultant information to be radiated to the spacecraft.

sequencing↗
NASA NTRS1972

Experimental active and passive dosimetry systems for the NASA Skylab program

Active and passive dosimetry instrumentation to measure absorbed dose, charged particle spectra, and linear energy transfer spectra inside the command module and orbital workshop on the Skylab program were developed and tested. The active dosimetry system consists of one integral unit employing both a tissue equivalent ionization chamber and silicon solid state detectors. The instrument measures dose rates from 0.2 millirad/hour to 25 rads/hour, linear energy transfer spectra from 2.8 to 42.4 Kev/micron, and the proton and alpha particle energy spectra from 0.5 to 75 Mev. The active dosimeter is equipped with a portable radiation sensor for use in astronaut on-body and spacecraft shielding surveys during passage of the Skylab through significant space radiations. Data are transmitted in real time or are recorded by onboard spacecraft tape recorder for rapid evaluation of the radiation levels. The passive dosimetry systems consist of twelve (12) hard-mounted assemblies, each containing a variety of passive radiation sensors which are recoverable at the end of the mission for analysis.

Schneider, M. F.↗