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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Primary separation between three aircraft using traffic displays

The use of a sophisticated traffic and map display termed electronic flight rules (EFR) by general aviation pilots for primary seperation in low density airspace is studied. The experimental flights were made under four conditions: with and without sensor noise in the traffic information and with and without communications for traffic coordination. Pilots were required to maintain two miles horizontal and 500 ft vertical separation from other aircraft for 24 different traffic situations repeated randomly for each of the four experimental conditions. Of 1152 aircraft encounters 12.8 percent were in violation of separation minimums. In general, the effects of sensor noise were minimal, communications affected some of the measures, and the group effect was quite significant. When pilots were able to communicate and coordinate their maneuvers, the time to resolve conflict was reduced.

Chappell, S. L.↗
NASA NTRS1980

Solar optical telescope primary mirror controller

The development of a technique to control the articulated primary mirror (APM) of the solar optical telescope (SOT) is discussed. Program results indicate that a single, all digital controller has sufficient capability to totally handle the computational requirements for control of the SOT APM.

Brown, R. J.↗
NASA NTRS1985

Primary propulsion of electrothermal, ion and chemical systems for space-based radar orbit transfer

An orbit transfer mission concept has been studied for a Space-Based Radar (SBR) where 40 kW required for radar operation is assumed available for orbit transfer propulsion. Arcjet, pulsed electrothermal (PET), ion, and storable chemical systems are considered for the primary propulsion. Transferring two SBR per shuttle flight to 1112 km/60 deg using electrical propulsion systems offers an increased payload at the expense of increased trip time, up to 2000 kg each, which may be critical for survivability. Trade offs between payload mass, transfer time, launch site, inclination, and height of parking orbits are presented.

Wang, S. Y.↗
NASA NTRS1984

On the accuracy of Cs beam primary frequency standards

A new and much more exact method for evaluation of the velocity distribution in 10 to the 15th power of the frequency of the clock. It seems feasible to improve the accuracy even further with better measurements. The evaluation of the C-field, however, is still limited to a few parts in 10 to the 14th power because of the uncertainties linked to the method used, and this uncertainty remains one of the major limitations of NRC's primary clocks.

Boulanger, J. S.↗
NASA NTRS1985

Primary cosmic ray spectra in the range 20-60 GeV/n

Energy spectra for primary cosmic rays C-Fe above 20 GeV/n were measured on a balloon flight from Greenville S.C. in June 1982 with a hybrid electronic counter-emulsion chamber experiment. Fluxes above the atmosphere appear in general agreement with previously published values. The heavy events included in this data will be used along with the JACEE passive chamber data to provide a heavy composition direct measurement from 10 to the 12th power to approximately 10 to the 15th power eV total energy.

Burnett, T. H.↗
NASA NTRS1985

EAS fluctuation approach to primary mass composition investigation

The analysis of muon and electron fluctuation distribution shapes by statistical method of invers problem solution gives the possibility to obtain the relative contribution values of the five main primary nuclei groups. The method is model-independent for a big class of interaction models and can give good results for observation levels not too far from the development maximum and for the selection of showers with fixed sizes and zenith angles not bigger than 30 deg.

Stamenov, J. N.↗
NASA NTRS1985

Electron and muon parameters of EAS and the composition of primary cosmic rays in 10(15) to approximately 10(16) eV

Estimation of the relative intensities of protons and heavy nuclei in primary cosmic rays in the energy region 10 to the 15th power approx. 10 to the 17th power eV, was done by a systematic comparison between all available observed data on various parameters of extensive air showers (EAS) and the results of simulation. The interaction model used is an extrapolation of scaling violation indicated by recent pp collider results. A composition consisting of various percentages of Fe in an otherwise pure proton beam was assumed. Greatest overall consistency between the data and the simulation is found when the Fe fraction is in the region of 25%.

Cheung, T.↗
NASA NTRS1985

The primary cosmic ray mass composition at energies above 10(14) eV

It is shown in this paper that the experimental data on extensive air showers at the energy interval 10 to the 15th power - 10 to the 17th power eV seems to be described best if it is assumed that the Galactic cosmic rays are described by some sort of a two component picture. The first component is of a mixed composition similar to that at lower energies and the second is dominated by protons. Overall spectrum starts to be enriched in protons at energies about 10 to the 15th power eV bu the effective mass of the primaries remains constant up to energies around 10 to the 16th power eV. That results from the fact that composition gradually changes from multi-component to mixture of protons and heavies. That picture receives also some sort of support from recent observations of relatively high number of nergetic protons in JACEE and Concorde experiments.

Gawin, J.↗
NASA NTRS1985

Alfven wave scattering and the secondary to primary ratio

The cosmic ray abundances have traditionally been used to determine the elemental and isotopic nature of galactic ray sources and average measures of propagation conditions. Detailed studies of the physics of propagation are usually paired with relatively straightforward estimates of the secondary-to-primary (S/P) ratios. In the work reported here, calculations of elemental abundances are paired with a more careful treatment of the propagation process. It is shown that the physics of propagation does indeed leave specific traces of Galactic structure in cosmic ray abundances.

Bretthorst, G. L.↗
NASA NTRS1985

Note on the detection of high energy primary cosmic gamma rays by air shower observation

A mountain altitude experiment is planned at Mt. Norikura in Japan to search for point sources of astrophysical high-energy gamma rays in the 10 to the 15th power eV range. The advantages of mountain level observation of IR showers is stressed, especially in the case of high-energy gamma primaries from Cygnus X3 and other similar point sources.

Kasahara, K.↗
NASA NTRS1985

Ultra high energy events in ECHOS series and primary energy spectrum

The compilation of ultra high energy jets suggests at present the existence of a bump in primary energy spectrum (with the standard concept of high energy collisions). The pseudo-rapidity distribution exhibits some typical anomalies, more than the (P sub t) behavior, which are (may be) the fingerprints of quark gluon plasma transition. The next results of Emulsion Chamber on Supersonic (ECHOS) will be in both cases determinant to confirm those tendancies, as well as an important effort of the cosmic ray community to develop in that sense a flying emulsion chamber experiment.

Capdevielle, J. N.↗
NASA NTRS1985

The thickness of the shower disc as observed in showers produced by primaries above 10 (19)eV

The thickness of the shower disk has been measured in showers initiated by primaries of energy to 10 the 19th power eV using the large area water Cerenkov detectors of the Haverah Park array. Results are presented which (1) provide supporting evidence for the accuracy of analysis procedures in giant showers, (2) offer an evaluation of the mini-array technique for the detection of giant showers and (3) extend earlier work on developmental fluctuations above 10 to the 19th power eV.

Lawrence, M. A.↗
NASA NTRS1985

Multimuons events and primary composition

Nucleon decay detectors at large depths offers now a total area larger than 1000 sq m to registrate muons of energy exceeding 1 TeV. Near complete high energy muon families are detected in those arrays. An extensive 3D Monte-Carlo simulation was conducted in view to understand the spatial distribution of those events and the possible link with elementary act or primary composition. As pion or kaon parents have a very small decay probability at so high energy, multimuon phenomena occurs at high altitude where the atmospheric density is small after the most energetic collisions.

Acharya, B. S.↗