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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 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Ice reconnaissance by satellite

The paper describes the significant milestones in the use of satellites for snow and ice monitoring. The feasibility of such monitoring was demonstrated by the Tiros 2 satellite in 1961. Nimbus 1 showed that breaks in the sea ice can be easily monitored during continuous nighttime conditions; Nimbus 3 showed the practicality of delineating regions of active melting of ice and snow in temperate areas. Landsat data have been found to be particularly useful for monitoring and studying glaciers and their attendant surface features. Ice concentration can be determined with reasonable accuracy from a sequence of electronically scanned microwave radiomenter images made aboard Nimbus 5. In the future we can expect improved sensors and spacecraft systems with longer operating lives.

Gloersen, P.↗
NASA NTRS1975

Reconnaissance mapping from aerial photographs

The author has identified the following significant results. Engineering soil and geology maps were successfully made from Pennsylvania aerial photographs taken at scales from 1:4,800 to 1:60,000. The procedure involved a detailed study of a stereoscopic model while evaluating landform, drainage, erosion, color or gray tones, tone and texture patterns, vegetation, and cultural or land use patterns.

Weeden, H. A.↗
NASA NTRS1977

Selecting reconnaissance strategies for floodplain surveys

Multispectral aircraft and satellite data over the West Branch of the Susquehanna River were analyzed to evaluate potential contributions of remote sensing to flood-plain surveys. Multispectral digital classifications of land cover features indicative of floodplain areas were used by interpreters to locate various floodprone area boundaries. The digital approach permitted LANDSAT results to be displayed at 1:24,000 scale and aircraft results at even larger scales. Results indicate that remote sensing techniques can delineate floodprone areas more easily in agricultural and limited development areas as opposed to areas covered by a heavy forest canopy. At this time it appears that the remote sensing data would be best used as a form of preliminary planning information or as an internal check on previous or ongoing floodplain studies. In addition, the remote sensing techniques can assist in effectively monitoring floodplain activities after a community enters into the National Flood Insurance Program.

Sollers, S. C.↗
NASA NTRS1979

Focus compensation techniques for reconnaissance

To maintain optimum resolution under varying environmental conditions, a focusing compensation system has been developed. The system is capable of detecting not only changes in pressure (altitude) and the general lens temperature but also the radial thermal gradients in the lens. Theoretical considerations show that the lens is most affected by these factors. The developed system uses a laser measurement system with environmental sensors to generate a focus correction for environment and range changes.

Mckeough, J.↗
NASA NTRS1982

Reconnaissance and recovery of the brighter asteroids. Brief summary of the entire project

An inexpensive method of baking large (8- by 10-inch) IIIa-J plates in 2 percent forming gas was found and successfully tested. The large storage capacity and fine grain structure of the emulsion made the sky fog negligible on plates of one-hour exposure at Link. Plates were taken through the end of October 18, 1981 on various asteroids from the recent critical lists published in the Minor Planet Circulars and the Russian Ephemeris of Minor Planets.

Edmonson, F. K.↗
NASA NTRS1983

Airborne reconnaissance in the civilian sector - Agricultural monitoring from high-altitude powered platforms

Design concepts and mission applications for unmanned high-altitude powered platforms (HAPPs) are discussed. A chemically powered HAPP (operating altitude 18-21 km, wingspan 26 m, payload 91 kg, endurance 2-3 days) would use current turboprop technology. A microwave-powered HAPP (operating altitude around 21 km, wingspan 57.9 m, payload 500 kg, endurance weeks or months) would circle within or perform boost-glide maneuvers around a microwave beam of density 1.1 kw/sq m. Of two solar-powered-HAPP designs presented, the more promising uses five vertical solar-panel-bearing fins, two of which can be made horizontal at night, (wingspan 57.8/98.3 m, payload 113 kg, endurance weeks or months). The operating altitude depends on the latitude and season: this HAPP design is shown to be capable of year-round 20-km-altitude flights over the San Joaquin Valley in California, where an agricultural-monitoring mission using Landsat-like remote sensors is proposed. Other applications may be better served by the characteristics of the other HAPPs. The primary advantage of HAPPs over satellites is found to be their ability to provide rapidly available high-resolution continuous or repetitive coverage of specific areas at relatively low cost.

Youngblood, J. W.↗
NASA NTRS1985

Remote reconnaissance of submerged aquatic vegetation: A radiative transfer approach

The effectiveness of LANDSAT TM and MSS sensors for detecting submerged aquatic vegetation (SAV) is assessed. The problem is approached from a theoretical standpoint in which volume reflectance from SAV under a variety of conditions is simulated. The focus is on the spectral and radiometric qualities of TM bands 1, 2 and 3 and MSS bands 4 and 5.

Ackleson, S. G.↗
NASA NTRS1989

Impact cratering in low-gravity environments - Results of reconnaissance experimentation on the NASA KC-135A reduced-gravity aircraft

A program of flight experimentation was performed on the NASA KC-135A reduced-gravity aircraft to evaluate the potential for conducting impact experiments in reduced-gravity environments and to collect impact-cratering data at gravity levels below 1 g. Lead pellets were launched into coarse-grained sand at velocities of about 65-130 m/sec while the gravitational acceleration was maintained at 0.59-0.05 g. A total of 64 craters were studied and, after allowance is made for the atmospheric pressure over the target (0.83 atm), their diameters are found to have been consistent with scaling predictions made on the basis of ground-based experimentation. Formation times were also obtained for 33 of these craters and constitute a distribution that is somewhat different from that described by the ground-based data. Nevertheless, the KC-135 data set as a whole falls on the trend formed by the ground-based results. The overall agreement between the two data sets attests to the stability of the aircraft as a platform for impact experimentation.

Cintala, M. J.↗
NASA NTRS1990

The lessons of Varsovian's reconnaissance

The role played by advanced technology is illustrated with respect to the anticipated era of discovery and exploration (in space): how bold new exploration initiatives may or may not be enabled. Enabling technology makes the mission feasible. To be truly enabling, however, the technology must not only render the proposed mission technically feasible, but also make it viable economically; that is, low enough in cost (relative to the economy supporting it) that urgent national need is not required for justification, low enough that risks can be programmatically tolerated. An allegorical parallel is drawn to the Roman Empire of the second century AD, shown to have possessed by that time the necessary knowledge, motivation, means, and technical capability of mounting, through the use of innovative mission planning, an initiative similar to Columbus' voyage. They failed to do so; not because they lacked the vision, but because their technology was not advanced enough to make it an acceptable proposition economically. Speculation, based on the historical perspective, is made on the outcome of contemporary plans for future exploration showing how they will be subjected to the same historical forces, within limits imposed by the state of technology development, that shaped the timing of that previous era of discovery and exploration.

Bents, D. J.↗
NASA NTRS1989

High altitude reconnaissance aircraft design

A Universities Space Research Association (USRA) sponsored (undergraduate) study is presented on the feasibility and design of a high altitude reconnaissance/research aircraft. The aircraft mission was to carry 1,000-3,000 lb of atmospheric pollutant monitoring equipment for 1-5 hr at an altitude of 100,000-130,000 ft. Three configurations subject to the same mission requirements were studied in detail. The three designs analyzed were the tandem-wing-twin-boom, joined wing, and conventional twin-boom configurations. The performance of the three proposed configurations is presented and shows that high altitude flight is possible with current technology. Different possible propulsion systems were investigated and suggestions are made for further investigation and better optimization of the designs.

Poladian, D.↗
NASA NTRS1999

A Reconnaissance of the 900-1200 A Spectra of Early O Stars in the Magellanic Clouds

Far-UV spectrograms of ten very hot stars in the Magellanic Clouds were obtained with the Hopkins Ultraviolet Telescope during the Astro-2 mission in March 1995. Very few normal OB stars were observed during Astro-1, and the only significant prior sample of such objects in this wavelength range was that obtained by Copernicus of stars near the Sun. The Magellanic Cloud sample offers the advantages of low reddening, a range in metallicity, and more extreme temperatures and luminosities than represented in the near solar neighborhood. Several interesting phenomena were found in the HUT MC sample, including very strong O VI wind profiles in O3 spectra; anomalous CNO wind features corresponding to abundances altered by stellar nucleosynthesis; weak wind features due to the metal deficiency of the Small Magellanic Cloud; and interstellar molecular hydrogen features originating in the MCs. The results were presented and discussed as a small atlas, and they were shown at the Pittsburgh AAS meeting in June 1995. A correlative atlas of Copernicus data was also prepared and published under the auspices of this grant. These publications will serve as resources for the characterization of the FUSE observations of related objects to hopefully be obtained soon. I believe that the large differences among the strong wind features in the HUT data, corresponding to CNO and systemic metallicity effects, are amenable to some relative quantitative analysis, and I shall endeavor to promote such in conjunction with HST data at longer wavelengths for the same stars (which has also not yet been completely analyzed) at a future opportunity.

Walborn, Nolan↗
NASA NTRS1999

Radar Reconnaissance of Near-Earth Asteroids

Groundbased radar observations of NEAs can help identify space resources with commercial potential and can dramatically reduce the cost and risk of the initial spacecraft missions to those objects. The near-Earth asteroid (NEA) population is thought to contain approximately 1500 objects as large as a kilometer, approximately 300,000 as large as 100 meters, and more than 100,000,000 as large as 10 meters. More than 10% of the NEAs are more accessible in terms of mission delta-V (i.e., fuel required) than the Moon, Mars, or the moons of Mars. Fewer than 1000 NEAs have been found, but the discovery rate is increasing rapidly. Once an asteroid is discovered (necessarily by wide-field optical telescopes), radar can provide otherwise unavailable information about its size, shape, spin state, and surface properties if it approaches within the range of the Goldstone (California) or Arecibo (Puerto Rico) radar telescopes. Asteroids generally appear as unresolved points through groundbased optical telescopes, but radar measurements of the distribution of echo power in time delay (range) and Doppler frequency (radial velocity) can yield images with resolution as fine as a decameter. Image sequences that furnish adequate orientational coverage can be inverted to construct geologically detailed 3-D models, to define the rotation state precisely, and to constrain the object's internal density distribution. Estimates of radar scattering properties characterize the surface's cm-to-m-scale roughness as well as its bulk density, which for asteroids depends primarily on porosity and metal concentration. A useful spin-off of radar detection is orbit refinement that simplifies navigation of flyby and rendezvous spacecraft.

Ostro, S. J.↗
NASA NTRS1999

Reconnaissance of the Nearby Stars

Accomplishments by the PI during this grant period include: 1. Creating, enhancing, and testing the NStars Database website. During the spring and summer of 1999, the PI performed roughly a dozen extensive "stress tests" of the website. Each test included checking data for individual stars and conducting searches that produced lists of stars from the Database to verify that each entry was correct. In the process, errors were discovered and rectified before the website was made public in July 1999. 2. "Advertising" NStars as a Project to astronomers worldwide. 3. Providing data that has been incorporated into the NStars Database. 4. Observations in Support of the NStars Project.

Henry, Todd↗
NASA NTRS1999

Radar Reconnaissance of Near-Earth Asteroids

Groundbased radar observations of NEAs can help identify space resources with commercial potential and can dramatically reduce the cost and risk of the initial spacecraft missions to those objects. The near Earth asteroid (NEA) population is thought to contain approx. 1500 objects as large as a kilometer, approx. 300,000 as large as 100 meters, and more than 100,000,000 as large as 10 meters. More than 10% of the NEAs are more accessible in terms of mission delta-V (i.e., fuel required) than the Moon, Mars, or the moons of Mars. Fewer than 1000 NEAs have been found, but the discovery rate is increasing rapidly. Once an asteroid is discovered (necessarily by wide-field optical telescopes), radar can provide otherwise unavailable information about its size, shape, spin state, and surface properties if it approaches within the range of the Goldstone (California) or Arecibo (Puerto Rico) radar telescopes. Asteroids generally appear as unresolved points through groundbased optical telescopes, but radar measurements of the distribution of echo power in time delay (range) and Doppler frequency (radial velocity) can yield images with resolution as fine as a decameter. Image sequences that furnish adequate orientational coverage can be inverted to construct geologically detailed 3-D models, to define the rotation state precisely, and to constrain the object's internal density distribution. Estimates of radar scattering properties characterize the surface's cm-to-m-scale roughness as well as its bulk density, which for asteroids depends primarily on porosity and metal concentration. A useful spin-off of radar detection is orbit refinement that simplifies navigation of flyby and rendezvous spacecraft.

Ostro, S. J.↗
NASA NTRS2002

Reconnaissance of Near-Earth Objects

NASA sponsorship of asteroid research for this grant has resulted in 30 publications and major new results relating near-Earth asteroids to known meteorite groups, most especially ordinary chondrites. Analysis of observations continues.

Binzel, Richard P.↗
NASA NTRS2002

HiRISE: The High Resolution Imaging Science Experiment for Mars Reconnaissance Orbiter

HiRISE, an experiment on the 2005 MRO mission, will provide an unprecedented combination of ground sampling dimension (25-50 cm/pixel), signal-to-noise ratio (greater than 100:1 at all latitudes), swath width (5-10 km), partial 3-color coverage, greater than 2% coverage of Mars at 1 m/pixel or better, and stereo imaging. Additional information is contained in the original extended abstract.

McEwen, A. S.↗