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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 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

EVA assembly of large space structure element

The results of a test program to assess the potential of manned extravehicular activity (EVA) assembly of erectable space trusses are described. Seventeen tests were conducted in which six "space-weight" columns were assembled into a regular tetrahedral cell by a team of two "space"-suited test subjects. This cell represents the fundamental "element" of a tetrahedral truss structure. The tests were conducted under simulated zero-gravity conditions. Both manual and simulated remote manipulator system modes were evaluated. Articulation limits of the pressure suit and zero gravity could be accommodated by work stations with foot restraints. The results of this study have confirmed that astronaut EVA assembly of large, erectable space structures is well within man's capabilities.

Bement, L. J.↗
NASA NTRS1981

Data Quality: 1979 Southeastern Virginia Urban Plume Study (SEV-UPS): Surface and Airborne studies

The SEV-UPS field study conducted during August 1979 involved the coordinated air quality data collection efforts of three different organizations operating a total of four aircraft and 12 ground stations. Incorporated into plans for that program were numerous quality assurance activities designed to identify potential hazards for data quality in time for their correction and to take data to allow assessment of the consistency of the data from different stations. The purpose of this study was to document QA procedures that were performed by participating agencies and revise data from all platforms for mutual compatibility. For the latter effort, cases were identified on 21 occasions on seven different days where two or more monitoring systems were operating in the same location at nearly the same time. Data from the systems involved were tabulated in 200 m altitude segments, averaged and compared to detect any bias between measurements made from different systems. The results of these comparisons along with the results of independent performance audits are presented.

White, J. H.↗
NASA NTRS1981

A feature of the behavior of He/+/ in the nightside high-latitude ionosphere during equinox

Observations of a hole of ionization in the nightside high-latitude ionosphere during equinox in which He(+) plays an important role in the relative abundance of the ionic constituents are reported. Ion abundance data were obtained during a period of very low magnetic activity from the retarding potential analyzer and magnetic ion mass spectrometer on board AE-D as the satellite passed across the polar region near midnight. Significant decreases in O(+) and H(+) concentrations are observed in the region between 1544 and 1547 UT within the polar cap, accompanied by the rise and dominance of He(+) ions to low altitudes. The dominance of He(+) is attributed to effects on photoproduction of changes in solar zenith angle as the plasma moves from the dayside to the nightside, where it stagnates or resides for periods greater than about 3 hours just poleward of the auroral zone. Model calculations of the physical processes involved in this mechanism are presented which in general tend to fit the observations.

Heelis, R. A.↗
NASA NTRS1981

Market analysis of seismic security systems

This report provides information on the commercialization potential of the NASA Activity Monitor. Data on current commercially available products, market size, and growth are combined with information on the NASA technology and the projected impact of this technology on the market.

Taglio, S.↗
NASA NTRS1984

Silicon-sheet and thin-film cell and module technology potential: Issue study

The development of high-efficiency low-cost crystalline silicon ribbon and thih-film solar cells for the energy national photovoltaics program was examined. The findings of an issue study conducted are presented. The collected data identified the status of the technology, future research needs, and problems experienced. The potentials of present research activities to meet the Federal/industry long-term technical goal of achieving 15 cents per kilowatt-hour levelized PV energy cost are assessed. Recommendations for future research needs related to crystalline silicon ribbon and thin-film technologies for flat-plate collectors are also included.

Shimada, K.↗
NASA NTRS1985

Active control landing gear for ground load alleviation

Results of analytical and experimental investigations of a series-hydraulic active control landing gear show that such a gear is feasible when using existing hardware and is very effective in reducing loads, relative to those generated by a conventional (passive year) gear, transmitted to the airframe during ground operations. Analytical results obtained from an active gear, flexible aircraft, take-off and landing analysis are in good agreement with experimental data and indicate that the analysis is a valid tool for study and initial design of series-hydraulic active control landing gears. An analytical study of a series-hydraulic active control main landing gear on an operational supersonic airplane shows that the active gear has the potential for improving the dynamic response of the aircraft and significantly reducing structural fatigue damage during ground operations.

Mcgehee, J. R.↗
NASA NTRS1984

Present state of knowledge of the upper atmosphere: An assessment report

A program of research, technology, and monitoring of the phenomena of the upper atmosphere, to provide for an understanding of and to maintain the chemical and physical integrity of the Earth's upper atmosphere was developed. NASA implemented a long-range upper atmospheric science program aimed at developing an organized, solid body of knowledge of upper atmospheric processes while providing, in the near term, assessments of potential effects of human activities on the atmosphere. The effects of chlorofluorocarbon (CFC) releases on stratospheric ozone were reported. Issues relating the current understanding of ozone predictions and trends and highlights recent and future anticipated developments that will improve our understanding of the system are summarized.

Source record↗
NASA NTRS1986

Manned Mars mission radiation environment and radiobiology

Potential radiation hazards to crew members on manned Mars missions are discussed. It deals briefly with radiation sources and environments likely to be encountered during various phases of such missions, providing quantitative estimates of these environments. Also provided are quantitative data and discussions on the implications of such radiation on the human body. Various sorts of protective measures are suggested. Recent re-evaluation of allowable dose limits by the National Council of Radiation Protection is discussed, and potential implications from such activity are assessed.

Nachtwey, D. S.↗
NASA NTRS1987

Understanding natural language for spacecraft sequencing

The paper describes a natural language understanding system, START, that translates English text into a knowledge base. The understanding and the generating modules of START share a Grammar which is built upon reversible transformations. Users can retrieve information by querying the knowledge base in English; the system then produces an English response. START can be easily adapted to many different domains. One such domain is spacecraft sequencing. A high-level overview of sequencing as it is practiced at JPL is presented in the paper, and three areas within this activity are identified for potential application of the START system. Examples are given of an actual dialog with START based on simulated data for the Mars Observer mission.

Katz, Boris↗
NASA NTRS1987

Space Station users contamination requirements

An account is given of the contamination sensitivities and requirements of various planned NASA Space Station users in all science categories, as well as the methods by which the Space Station will accomodate these requirements in the cases of attached payloads, core station-attached payloads, and platform payloads. Attention is given to the Space Station's external contamination environment, the degree of protection from contamination that the Space Station user must provide, the amount of warning users will receive prior to the initiation of potentially contamination-generating activities in the Space Station, and different contamination probabilities for the various parts of the Space Station.

Carosso, Nancy J. P.↗
NASA NTRS1990

EVA crewperson overboard - Simplified rescue aid (SIRA)

This paper discusses potential roles for extravehicular activity (EVA) in space logistics and the possibilities for a crewperson to become inadvertently detached from the work site. Factors which could cause the detachment will be presented and a rescue technique described. Finally, implications to the design and implementation of space logistics will be portrayed relative to minimizing or eliminating the adrift EVA crewperson possibility.

Fisher, H. T.↗
NASA NTRS1991

The science benefits of and the antenna requirements for microwave remote sensing from geostationary orbit

The primary objective of the Large Space Antenna (LSA) Science Panel was to evaluate the science benefits that can be realized with a 25-meter class antenna in a microwave/millimeter wave remote sensing system in geostationary orbit. The panel concluded that a 25-meter or larger antenna in geostationary orbit can serve significant passive remote sensing needs in the 10 to 60 GHz frequency range, including measurements of precipitation, water vapor, atmospheric temperature profile, ocean surface wind speed, oceanic cloud liquid water content, and snow cover. In addition, cloud base height, atmospheric wind profile, and ocean currents can potentially be measured using active sensors with the 25-meter antenna. Other environmental parameters, particularly those that do not require high temporal resolution, are better served by low Earth orbit based sensors.

Stutzman, Warren L.↗
NASA NTRS1991

Potential approaches to the spectroscopic characterization of high performance polymers exposed to energetic protons and heavy ions

A potential limitation to human activity on the lunar surface or in deep space is the exposure of the crew to unacceptably high levels of penetrating space radiations. The radiations of most concerns for such missions are high-energy protons emitted during solar flares, and galactic cosmic rays which are high-energy ions ranging from protons to iron. The development of materials for effective shielding from energetic space radiations will clearly require a greater understanding of the underlying mechanisms of radiation-induced damage in bulk materials. This can be accomplished in part by the detailed spectroscopic characterization of bulk materials that were exposed to simulated space radiations. An experimental data base thus created can then be used in conjunction with existing radiation transport codes in the design and fabrication of effective radiation shielding materials. Electron Paramagnetic Resonance Spectroscopy was proven very useful in elucidating radiation effects in polymers (high performance polymers are often an important components of structural composites).

Suleman, Naushadalli K.↗
NASA NTRS1992

Economic Geology of the Moon: Some Considerations

Supporting any but the smallest lunar facility will require indigenous resources due to the extremely high cost of bringing material from Earth. The Moon has also attracted interest as a resource base to help support near-Earth space activities, because of the potential lower cost once the necessary infrastructure has been amortized. Obviously, initial lunar products will be high-volume, bulk commodities, as they are the only ones for which the economics of lunar production are conceivably attractive. Certain rarer elements, such as the halogens, C, and H, would also be extremely useful (for propellant, life support, and/or reagents), and indeed local sources of such elements would vastly improve the economics of lunar resource extraction. The economic geology of the Moon is discussed.

Gillett, Stephen L.↗
NASA NTRS1996

Coronal structure and heating: Comparison between SXT/Yohkoh observations of an active region and magnetogram

We have studied the magnetic structure in AR 7150 (S09E06) observed on 29 April 1992 by the Soft X-Ray Telescope (SXT) on Yohkoh. The observed X-ray images are compared with force-free magnetic fields with different values of alpha, extrapolated from the Marshall Space Flight Center (MSFC) photospheric magnetogram observed at the same time. The results show that the magnetic field of the active region is not potential. Different groups of loops are characterized by different values of alpha. Bright loops correlation between the brightness of individual loops with the amount of twist. Further investigation of the magnetic state of the loop structure requires accurate nonlinear force-free calculations.

Cheng, C.-C.↗
NASA NTRS1996

A Comparison of Structurally Connected and Multiple Spacecraft Interferometers

Structurally connected and multiple spacecraft interferometers are compared in an attempt to establish the maximum baseline (referred to as the "cross-over baseline") for which it is preferable to operate a single-structure interferometer in space rather than an interferometer composed of numerous, smaller spacecraft. This comparison is made using the total launched mass of each configuration as the comparison metric. A framework of study within which structurally connected and multiple spacecraft interferometers can be compared is presented in block diagram form. This methodology is then applied to twenty-two different combinations of trade space parameters to investigate the effects of different orbits, orientations, truss materials, propellants, attitude control actuators, onboard disturbance sources, and performance requirements on the cross-over baseline. Rotating interferometers and the potential advantages of adding active structural control to the connected truss of the structurally connected interferometer are also examined. The minimum mass design of the structurally connected interferometer that meets all performance-requirements and satisfies all imposed constraints is determined as a function of baseline. This minimum mass design is then compared to the design of the multiple spacecraft interferometer. It is discovered that the design of the minimum mass structurally connected interferometer that meets all performance requirements and constraints in solar orbit is limited by the minimum allowable aspect ratio, areal density, and gage of the struts. In the formulation of the problem used in this study, there is no advantage to adding active structural control to the truss for interferometers in solar orbit. The cross-over baseline for missions of practical duration (ranging from one week to thirty years) in solar orbit is approximately 400 m for non-rotating interferometers and 650 m for rotating interferometers.

Surka, Derek M.↗
NASA NTRS1999

General Public Space Travel and Tourism: Workshop Proceedings - Volume 2

The Space Transportation Association and NASA conducted a General Public Space Travel study between 1996 and 1998. During the study, a workshop was held at Georgetown University. Participants included representatives from the travel, aerospace, and construction industries. This report is the proceedings from that workshop. Sections include infrastructure needs, travel packages, policy related issues, and potential near-term activities.

ONeil, D.↗
NASA NTRS1997

Magnetospheric Plasmas-Flow and Energization of the Ionospheric Source

In a paper of more than a decade ago, estimated the strength of the ionospheric source and its ability to supply the different plasma regions of the Earth's magnetosphere. The launch of the POLAR spacecraft with the Thermal Ion Dynamics Experiment (TIDE) and the active control of spacecraft potential thro6gh the Plasma Source Instrument (PSI) made possible for the first time the direct measurement of low energy ions moving from the ionosphere into the lobes of the magnetotail. A particle trajectory model has been used to trace particles representative 6f TIDE measurements, taken during the operation of PSI, back to the location of the ionospheric source and forward to the entry point of the ions to the plasma sheet.

Chappell, C. R.↗