Research and development of silicon solar cells for low solar intensity and low temperature applications Quarterly progress report
Research and development of silicon solar cells for low solar intensity and low temperature applications
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Research and development of silicon solar cells for low solar intensity and low temperature applications
Thermal and electrical performances of silicon solar cell designs at high solar intensities
Solar electric propulsion performance and trajectory data for indirect solar probes, extra-ecliptic missions, and rendezvous with Ceres, D-Arrest, and Encke
Equilibrium anisotropy in flux solar flare particles calculated from particle spectra and solar wind speeds
Solar UV radiation measurements by OSO-3, obtaining flux variation over solar rotation period
Si solar cells low temperature and solar intensity performance optimization by identifying and eliminating low output problems
Si solar cell low temperature low solar illumination intensity I-V performance deficiencies, considering corrective design modifications
Venus-Mercury flyby vehicle solar cells, cover glasses, adhesives and Kapton film, investigating space radiation effects on solar absorptance and transmittance
Type 3 solar LF radio burst storms, considering streamer density, inhomogeneities and solar wind speed
Solar flare activity and sunspot distribution over central meridian from optical data by NASA solar particle alert network 1967-69
The results of a study concerned with the effects of the Martian environment on the performance of solar cells are given. The results indicate that the efficiency of a power system composed of solar cells will be greatly reduced when subjected to dust storms such as may occur on Mars. Two factors are responsible for this, (1) accumulation of dust on the protective covers, and (2) damage to covers by pitting, cracking, and chipping. It is recommended that this type of power system not be used on Mars landing vehicles. Experimental procedures are described and results are summarized and damage assessed.
The specification defines the solar constant and the zero air mass solar spectral irradiance for use in thermal analysis, thermal balance testing, and other tests of spacecraft and spacecraft components and materials. It is based upon data from experimental measurements made from high altitude aircraft, balloons, spacecraft, and the earth's surface. The stated accuracies are based on the estimated accuracies of the measurements, calibrations, and radiometric scales.
Problems were identified, using N/P solar cells at low temperature and low intensity; these problems were solved and the solutions incorporated in a manufacturing procedure. Theoretical analysis of the effects of low temperature and low intensity on the various solar cell characteristics indicated that the following behavior might be expected: (1) lower short circuit current,(2) higher open circuit voltage,(3) series resistance becoming less significant, and (4) shunt resistance becoming more critical.
In this paper we describe an experiment designed to measure solar and celestial X-rays in the energy range between 15 to 250 keV. The experiment was flown on the fifth Orbiting Solar Observatory which was launched on Jan. 22, 1969. Up to the time of this writing the instrument continues to operate satisfactorily.
The theory of the propagation of solar cosmic rays in the solar wind is reviewed, with particular emphasis on the diffusive transport during the decay phase of events. Recent evidence is shown to corroborate the prediction that the diffusion coefficient is small for protons with energies of the order of 1 Mev. It is concluded that the transport equation explains the principal phenomena quite well, in that most effects are reasonably understood.
Solar wind plasma and magnetic field data were used to identify rotational and tangential discontinuities during the first 40 days of the flight of Mariner 5. Of the 40 rotational discontinuities found, 36 were clustered in three distinct 3- to 6-day intervals. These three intervals were characterized by high solar wind bulk velocities, high magnetic field magnitudes, low densities, high correlation between velocity and magnetic field changes, and the presence of smooth Alfven waves. The rotational discontinuities had magnetic field changes that were generally close to the direction of magnetic field changes for smooth Alfven waves. Although the primary component of these changes was perpendicular to the equatorial plane for both, the radial component for the discontinuities was generally larger. The normals to the tangential discontinuity surfaces strongly preferred a direction near the ecliptic plane and perpendicular to the spiral field direction.
The effects of the reduction in the thermal conductivity due to heavy ions on electron temperatures in the solar corona and solar wind are examined. Large enhancements of heavy ions in the corona appear to be necessary to give appreciable changes in the thermal gradient of the electrons.
Photovoltaic devices have been fabricated for solar and short-wavelength laser energy conversion using the thin metal film-semiconductor (Schottky barrier) approach. Studies of the metal film optical characteristics and the voltage outputs were emphasized. Air mass zero efficiencies of 8 to 9% in GaAs and laser conversion efficiencies of 25% at 4880 A in GaAs(0.6)P(0.4) are presently measured, with projected efficiencies of 15 and 45%, respectively. The techniques, if applied successfully to semiconductor thin films, could have an impact in solar energy terrestrial application.