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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

Mission Study and Optics Development Support for Constellation X

This document is the Final Report for NASA Cooperative Agreement NCC5-268 between NASA Goddard Space Flight Center (GSFC) and the Smithsonian Astrophysical Observatory (SAO). The Agreement is entitled "Constellation X-ray Mission Study and Optics Development." The report is required by the terms of the Agreement. There were four modifications to the Agreement. The period of performance was from February 1, 1998 through March 31, 1999. The report summarizes the main areas of SAO activity. Other than the design and analysis related to the SXT Mirror (see Section 4.0), most of the work was carried out jointly with personnel from GSFC and Marshall Space Flight Center (MSFC). Consequently, we do not mean to imply that such activities were carried out exclusively by SAO. Rather, we have tried to describe the SAO participation in these efforts.The report summarizes the main areas of SAO activity. Other than the design and analysis related to the SXT Mirror (see Section 4.0), most of the work was carried out jointly with personnel from GSFC and Marshall Space Flight Center (MSFC). Consequently, we do not mean to imply that such activities were carried out exclusively by SAO. Rather, we have tried to describe the SAO participation in these efforts. As is appropriate to a Cooperative Agreement, SAO worked with GSFC in an integrated team mode. SAO was involved in the mission management, technology development, and mission definition. The organization is shown in Figure 1. While overall management responsibility resided with GSFC, scientific lead and subordinate responsibilities were shared between GSFC and SAO.

Tananbaum, H.↗
NASA NTRS2007

Two-Dimensional Synthetic Aperture Radiometry over Land Surface During Soil Moisture Experiment in 2003 (SMEX03)

Microwave radiometry at low frequencies (L-band, approx. 1.4 GHz) has been known as an optimal solution for remote sensing of soil moisture. However, the antenna size required to achieve an appropriate resolution from space has limited the development of spaceborne L-band radiometers. This problem can be addressed by interferometric technology called aperture synthesis. The Soil Moisture and Ocean Salinity (SMOS) mission will apply this technique to monitor global-scale surface parameters in the near future. The first airborne experiment using an aircraft prototype of this approach, the Two-Dimensional Synthetic Aperture Radiometer (2D-STAR), was performed in the Soil Moisture Experiment in 2003 (SMEX03). The L-band brightness temperature data acquired in Alabama by the 2DSTAR was compared with ground-based measurements of soil moisture and with C-band data collected by the Polarimetric Scanning Radiometer (PSR). Our results demonstrate a good response of the 2D-STAR brightness temperature to changes in surface wetness, both in agricultural and forest lands. The behavior of the horizontally polarized brightness temperature data with increasing view-angle over the forest area was noticeably different than over bare soil. The results from the comparison of 2D-STAR and PSR indicate a better response of the 2D-STAR to the surface wetness under both wet and dry conditions. Our results have important implications for the performance of the future SMOS mission.

Ryu, Dongryeol↗
NASA NTRS2011

LES of a Jet Excited by the Localized Arc Filament Plasma Actuators

The fluid dynamics of a high-speed jet are governed by the instability waves that form in the free-shear boundary layer of the jet. Jet excitation manipulates the growth and saturation of particular instability waves to control the unsteady flow structures that characterize the energy cascade in the jet.The results may include jet noise mitigation or a reduction in the infrared signature of the jet. The Localized Arc Filament Plasma Actuators (LAFPA) have demonstrated the ability to excite a high-speed jets in laboratory experiments. Extending and optimizing this excitation technology, however, is a complex process that will require many tests and trials. Computational simulations can play an important role in understanding and optimizing this actuator technology for real-world applications. Previous research has focused on developing a suitable actuator model and coupling it with the appropriate computational fluid dynamics (CFD) methods using two-dimensional spatial flow approximations. This work is now extended to three-dimensions (3-D) in space. The actuator model is adapted to a series of discrete actuators and a 3-D LES simulation of an excited jet is run. The results are used to study the fluid dynamics near the actuator and in the jet plume.

Brown, Clifford A.↗
NASA NTRS2014

ISAAC Advanced Composites Research Testbed

The NASA Langley Research Center is acquiring a state-of-art composites fabrication capability to support the Center's advanced research and technology mission. The system introduced in this paper is named ISAAC (Integrated Structural Assembly of Advanced Composites). The initial operational capability of ISAAC is automated fiber placement, built around a commercial system from Electroimpact, Inc. that consists of a multi-degree of freedom robot platform, a tool changer mechanism, and a purpose-built fiber placement end effector. Examples are presented of the advanced materials, structures, structural concepts, fabrication processes and technology development that may be enabled using the ISAAC system. The fiber placement end effector may be used directly or with appropriate modifications for these studies, or other end effectors with different capabilities may either be bought or developed with NASA's partners in industry and academia.

Wu, K. Chauncey↗
NASA NTRS2013

A Structural Model Decomposition Framework for Systems Health Management

Systems health management (SHM) is an important set of technologies aimed at increasing system safety and reliability by detecting, isolating, and identifying faults; and predicting when the system reaches end of life (EOL), so that appropriate fault mitigation and recovery actions can be taken. Model-based SHM approaches typically make use of global, monolithic system models for online analysis, which results in a loss of scalability and efficiency for large-scale systems. Improvement in scalability and efficiency can be achieved by decomposing the system model into smaller local submodels and operating on these submodels instead. In this paper, the global system model is analyzed offline and structurally decomposed into local submodels. We define a common model decomposition framework for extracting submodels from the global model. This framework is then used to develop algorithms for solving model decomposition problems for the design of three separate SHM technologies, namely, estimation (which is useful for fault detection and identification), fault isolation, and EOL prediction. We solve these model decomposition problems using a three-tank system as a case study.

Roychoudhury, Indranil↗
NASA NTRS2004

Waste Processing Research and Technology Development at NASA Ames Research Center

The current "store and return" approach for handling waste products generated during low Earth orbit missions will not meet the requirements for future human missions identified in NASA s new Exploration vision. The objective is to develop appropriate reliable waste management systems that minimize maintenance and crew time, while maintaining crew health and safety, as well as providing protection of planetary surfaces. Solid waste management requirements for these missions include waste volume reduction, stabilization and storage, water recovery, and ultimately recovery of carbon dioxide, nutrients and other resources from a fully regenerative food production life support system. This paper identifies the key drivers for waste management technology development within NASA, and provides a roadmap for the developmental sequence and progression of technologies. Recent results of research and technology development activities at NASA Ames Research Center on candidate waste management technologies with emphasis on compaction, lyophilization, and incineration are discussed.

Fisher, John↗
NASA NTRS1989

Helmet mounted display systems for helicopter simulation

Simulation scientists continually pursue improved flight simulation technology with the goal of closely replicating the 'real world' physical environment. The presentation/display of visual information for flight simulation is one such area enjoying recent technical improvements that are fundamental for conducting simulated operations close to the terrain. Detailed and appropriate visual information is especially critical for Nap-Of-the-Earth (NOE) helicopter flight simulation where the pilot maintains an 'eyes-out' orientation to avoid obstructions and terrain. This paper elaborates on the visually coupled Wide Field Of View Helmet Mounted Display (WFOVHMD) system technology as a viable visual display system for helicopter simulation. In addition the paper discusses research conducted on the NASA-Ames Vertical Motion Simulator that examined one critical research issue for helmet mounted displays.

Haworth, Loran A.↗
NASA NTRS1985

Research study of droplet sizing technology leading to the development of an advanced droplet sizing system

An instrument to measure the size and velocity of droplets was developed. The instrument uses one of two techniques, as appropriate. In the first technique two small laser beams of one color identify the center of a larger laser beam of a different color. This defines a region of almost uniform intensity where the light scattered by the individual droplets can be related to their size. The first technique uses the visibility of a Doppler burst and validates it against the peak intensity of the signal's pedestal. Results are presented for monodisperse, bimodal, trimodal, and polydisperse sprays produced by the Berglund-Liu droplet generator and a pressure nozzle. Size distributions of a given spray obtained using three different size ranges show excellent self-consistency in the overlapping region. Measurements of sprays of known characteristics exhibit errors in the order of 10%. The principles of operation and design criteria of the instrument are discussed in great detail.

Hess, C. F.↗
NASA NTRS1978

On-orbit checkout of satellites, volume 2. Part 3 of on-orbit checkout study

Early satellite failures significantly degrading satellite operations are reviewed with emphasis on LANDSAT D, the Technology Demonstration Satellite, the ATREX/AEM spacecraft, STORMSAT 2, and the synchronous meteorological satellite. Candidates for correction with on-orbit checkout and appropriate actions are analyzed. On-orbit checkout subsystem level studies are summarized for electrical power, attitude control, thermal control, reaction control and propulsion, instruments, and angular rate matching for alignment of satellite IRU.

Pritchard, E. I.↗
NASA NTRS1984

Determination of the key parameters affecting historic communications satellite trends

Data representing 13 series of commercial communications satellites procured between 1968 and 1982 were analyzed to determine the factors that have contributed to the general reduction over time of the per circuit cost of communications satellites. The model by which the data were analyzed was derived from a general telecommunications application and modified to be more directly applicable for communications satellites. In this model satellite mass, bandwidth-years, and technological change were the variable parameters. A linear, least squares, multiple regression routine was used to obtain the measure of significance of the model. Correlation was measured by coefficient of determination (R super 2) and t-statistic. The results showed that no correlation could be established with satellite mass. Bandwidth-year however, did show a significant correlation. Technological change in the bandwidth-year case was a significant factor in the model. This analysis and the conclusions derived are based on mature technologies, i.e., satellite designs that are evolutions of earlier designs rather than the first of a new generation. The findings, therefore, are appropriate to future satellites only if they are a continuation of design evolution.

Namkoong, D.↗
NASA NTRS1990

Gamma ray observatory dynamics simulator in Ada (GRODY)

This experiment involved the parallel development of dynamics simulators for the Gamma Ray Observatory in both FORTRAN and Ada for the purpose of evaluating the applicability of Ada to the NASA/Goddard Space Flight Center's flight dynamics environment. The experiment successfully demonstrated that Ada is a viable, valuable technology for use in this environment. In addition to building a simulator, the Ada team evaluated training approaches, developed an Ada methodology appropriate to the flight dynamics environment, and established a baseline for evaluating future Ada projects.

Source record↗
NASA NTRS1992

Propulsion simulator for magnetically suspended wind tunnel models

Simulation of propulsion induced aerodynamic forces and moments, which arise as a result of interactions between propulsive jets and the free stream, is one of the most desired capabilities in magnetic suspension wind tunnels. The feasibility of generating exhaust jets of appropriate characteristics onboard magnetically suspended models was examined. Four concepts of remotely operated propulsion simulators was considered. Three conceptual designs involving conventional technologies such as compressed gas cylinders, liquid monopropellants, and solid propellants were developed. The fourth concept, a laser assisted thruster, which can potentially simulate both inlet and exhaust flows, was found to require very high power levels. The measurement of aerodynamic forces and/or moments were demonstrated, including the effects of exhaust jets, in MSBS wind tunnels. Two propulsion simulator models were developed, a small scale and a large scale unit, both using compressed, liquified CO2 as propellant. Results of the wind tunnel tests with the small scale simulator are discussed.

Joshi, P. B.↗
NASA NTRS1997

High Resolution Studies of Sunspots and Flux Tubes

This contract started as a three-year research study of sunspots and magnetic flux tubes in the solar atmosphere, using tunable filter images collected with a CCD camera during observing runs at the Canary Islands observatories in Spain. Scientific results are reported at conferences and published in the appropriate journals. The contract is being performed by the Solar and Astrophysics Laboratory (S&AL), part of the Lockheed Palo Alto Advanced Technology Center (ATC) of Lockheed Martin Missiles and Space (LMMS). The principal investigator is Dr. Alan Title, and the research is done by him and other scientific staff at S&AL, often in collaboration with visiting scientists and students from other institutions. An extension to the contract has been awarded for developing the Solar Lite technology demonstration telescope, a 1-meter solar telescope with silicon carbide optics made at the Vavilov Optical Institute in St. Petersburg, Russia. The highlights during this reporting period included the continuation of the fabrication efforts on the Solar Lite optical components at Vavilov State Optical Institute, including the completion of the Gregorian telescope field stop. A visit was made to the Vavilov Institute to review the progress and inspect the optical components.

Source record↗
NASA NTRS2002

Radiation Exposure Effects and Shielding Analysis of Carbon Nanotube Materials

Carbon nanotube materials promise to be the basis for a variety of emerging technologies with aerospace applications. Potential applications to human space flight include spacecraft shielding, hydrogen storage, structures and fixtures and nano-electronics. Appropriate risk analysis on the properties of nanotube materials is essential for future mission safety. Along with other environmental hazards, materials used in space flight encounter a hostile radiation environment for all mission profiles, from low earth orbit to interplanetary space.

Wilkins, Richard↗
NASA NTRS2008

Review of NASA's(TradeMark) Exploration Technology Development Program

To meet the objectives of the Vision for Space Exploration (VSE), NASA must develop a wide array of enabling technologies. For this purpose, NASA established the Exploration Technology Development Program (ETDP). Currently, ETDP has 22 projects underway. In the report accompanying the House-passed version of the FY2007 appropriations bill, the agency was directed to request from the NRC an independent assessment of the ETDP. This interim report provides an assessment of each of the 22 projects including a quality rating, an analysis of how effectively the research is being carried out, and the degree to which the research is aligned with the VSE. To the extent possible, the identification and discussion of various cross-cutting issues are also presented. Those issues will be explored and discussed in more detail in the final report.

Source record↗
NASA NTRS2012

Advancement of a 30K W Solar Electric Propulsion System Capability for NASA Human and Robotic Exploration Missions

Solar Electric Propulsion has evolved into a demonstrated operational capability performing station keeping for geosynchronous satellites, enabling challenging deep-space science missions, and assisting in the transfer of satellites from an elliptical orbit Geostationary Transfer Orbit (GTO) to a Geostationary Earth Orbit (GEO). Advancing higher power SEP systems will enable numerous future applications for human, robotic, and commercial missions. These missions are enabled by either the increased performance of the SEP system or by the cost reductions when compared to conventional chemical propulsion systems. Higher power SEP systems that provide very high payload for robotic missions also trade favorably for the advancement of human exploration beyond low Earth orbit. Demonstrated reliable systems are required for human space flight and due to their successful present day widespread use and inherent high reliability, SEP systems have progressively become a viable entrant into these future human exploration architectures. NASA studies have identified a 30 kW-class SEP capability as the next appropriate evolutionary step, applicable to wide range of both human and robotic missions. This paper describes the planning options, mission applications, and technology investments for representative 30kW-class SEP mission concepts under consideration by NASA

Smith, Bryan K.↗
NASA NTRS2013

The Influence of Unsteadiness on the Analysis of Pressure Gain Combustion Devices

Pressure gain combustion (PGC) has been the object of scientific study for over a century due to its promise of improved thermodynamic efficiency. In many recent application concepts PGC is utilized as a component in an otherwise continuous, normally steady flow system, such as a gas turbine or ram jet engine. However, PGC is inherently unsteady. Failure to account for the effects of this periodic unsteadiness can lead to misunderstanding and errors in performance calculations. This paper seeks to provide some clarity by presenting a consistent method of thermodynamic cycle analysis for a device utilizing PGC technology. The incorporation of the unsteady PGC process into the conservation equations for a continuous flow device is presented. Most importantly, the appropriate method for computing the conservation of momentum is presented. It will be shown that proper, consistent analysis of cyclic conservation principles produces representative performance predictions.

Paxson, Daniel E.↗
NASA NTRS2016

Spacecraft Charging and Auroral Boundary Predictions in Low Earth Orbit

Auroral charging of spacecraft is an important class of space weather impacts on technological systems in low Earth orbit. In order for space weather models to accurately specify auroral charging environments, they must provide the appropriate plasma environment characteristics responsible for charging. Improvements in operational space weather prediction capabilities relevant to charging must be tested against charging observations.

Minow, Joseph I.↗