Electrostatic rocket exhaust effects on solar- electric spacecraft subsystems
Electrostatic rocket exhaust condensation on spacecraft solar electric panels cover glasses, noting deleterious effects
Hall, D. F.↗
SEARCH · Search NASA
Results for “SOLAR EFFECT”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Solar wind effects on atmosphere evolution at Venus and Mars
The weak intrinsic magnetism of Venus and Mars leaves these planets subject to some unique atmospheric loss processes. This paper reviews the ways in which material seems to be removed by the solar wind interaction, including atmospheric ion pickup by the solar wind, bulk removal and outflow of ionospheric plasma, and atmospheric sputtering by pickup ions. The factors in the planets' and sun's histories, such as planetary magnetism, solar luminosity, and past solar wind properties, that must ultimately be folded into considerations of the effects of the solar wind interaction on atmosphere evolution are discussed.
Luhmann, Janet G.↗
Solar storm effects on humans
Explore the source record for details and available documents.
solar propagation corona Sun↗
The effects of solar radiation on plant growth
This phase of this continuing project was completed in April, 1994, using Dahlgren #855 hybrid sunflower seeds and Park Seeds #0950 non-hybrid sunflower seeds in both the control groups and the tests groups. The control groups (1, 2, 3, 4, 5, and 6) were grown under normal, un-radiated, conditions. The tests groups (1a, 2a, 3a, 4a, 5a, and 6a) were grown onboard the Space Shuttle Discovery on the STS-60 flight in February 1994. All data from this experiment (both control and test groups) will be taken and recorded in a data log and compared against each other to determine the radiation effects of solar radiation on plant germination and growth.
Agard, Joslyn↗
The effects of solar particle events on the middle atmosphere
Solar particle events (SPEs) have been investigated since the late 1960's for possible effects on the middle atmosphere. Solar protons from SPEs produce ionizations, dissociations, dissociative ionizations, and excitations in the middle atmosphere. The production of HO(x) and NO(x) and their subsequent effects on ozone can also be computed using energy deposition and photochemical models. The effects of SPE-produced HO(x) species on the odd nitrogen abundance of the middle atmosphere as well as the SPE-produced long term effects on ozone. Model computations indicate fairly good agreement with ozone data for the SPE-induced ozone depletion caused by NO(y) species connected with the August 1972 SPE. The model computations indicate that NO(y) will not be substantially changed over a solar cycle by SPEs. The changes are mainly at high latitudes and are on time scales of several months, after which the NO(y) drifts back to its ambient levels.
Jackman, Charles H.↗
TEM Characterization of Solar Wind Effects on Genesis Mission Silicon Collectors
The Genesis Discovery Mission passively allowed solar wind (SW) to implant into substrates during exposure times up to ~853 days from 2001 to 2004. The spacecraft then returned the SW to Earth for analysis. Substrates included semiconductor wafers (silicon, sapphire, and germanium), as well as a number of thin films supported by either silicon or sapphire wafers. During flight, subsets of the SW collectors were exposed to one of 4 SW regimes: bulk solar wind, coronal hole solar wind (CH, high speed), interstream solar wind (IS, low speed) or coronal mass ejections (CMEs). Each SW regime had a different composition and range of ion speeds and, during their collection, uniquely changed their host SW collector. This study focuses on bulk vs IS SW effects on CZ silicon.
Allums, K. K.↗
Solar flare effects in the ionosphere.
Electron content increase in ionosphere due to bright solar flare events
Da Rosa, A. V.↗
Assessment of High-Voltage Photovoltaic Technologies for the Design of a Direct Drive Hall Effect Thruster Solar Array
A three-year program to develop a Direct Drive Hall-Effect Thruster system (D2HET) begun in 2001 as part of the NASA Advanced Cross-Enterprise Technology Development initiative. The system, which is expected to reduce significantly the power processing, complexity, weight, and cost over conventional low-voltage systems, will employ solar arrays that operate at voltages higher than (or equal to) 300 V. The lessons learned from the development of the technology also promise to become a stepping-stone for the production of the next generation of power systems employing high voltage solar arrays. This paper summarizes the results from experiments conducted mainly at the NASA Marshal Space Flight Center with two main solar array technologies. The experiments focused on electron collection and arcing studies, when the solar cells operated at high voltages. The tests utilized small coupons representative of each solar array technology. A hollow cathode was used to emulate parts of the induced environment on the solar arrays, mostly the low-energy charge-exchange plasma (1012-1013 m-3 and 0.5-1 eV). Results and conclusions from modeling of electron collection are also summarized. The observations from the total effort are used to propose a preliminary, new solar array design for 2 kW and 30-40 kW class, deep space missions that may employ a single or a cluster of Hall- Effect thrusters.
Mikellides, I. G.↗
Multi-Wavelength Modeling and Analysis of the Center-to-Limb Effects of Solar Spectroscopy and Helioseismology
An accurate interpretation of observed solar dynamics with different instruments requires modeling solar magnetoconvection indifferent regimes, as well as taking into account center-to-limb effects, magnetic fields, and turbulence. Realistic 3D radiative MHD modeling of the solar magnetoconvection and atmosphere allows us to generate synthetic observables that directly link the physical properties of the solar plasma to spectroscopic and helioseismic observables. In this work, we investigate the influence of the center-to-limb effects for a wide range of wavelengths, which correspond to the operational lines of HMI/SDO, Hinode, DKIST, and other instruments. In particular, we discuss the wavelength-dependency of the center-to-limb helioseismic observations of acoustic travel times that are used for diagnostics of the deep meridional circulation, as well as 'concave' Sun effect. The presented study will support interpretation of helioseismic inversion results by taking into account realistic coupling of subsurface and atmosphere, and geometry-related effects. In particular, it allows us to improve accuracy of solar subsurface measurements from the SoHO and SDO missions, and resolve the long-standing problem of the meridional circulation and evolution with the solar cycle.
SMD↗
Physical mechanisms of solar activity effects in the middle atmosphere
A great variety of physical mechanisms of possibly solar induced variations in the middle atmosphere has been discussed in the literature during the last decades. The views which have been put forward are often controversial in their physical consequences. The reason may be the complexity and non-linearity of the atmospheric response to comparatively weak forcing resulting from solar activity. Therefore this review focuses on aspects which seem to indicate nonlinear processes in the development of solar induced variations. Results from observations and numerical simulations are discussed.
Ebel, A.↗
Effects of solar magnetic field on cosmic rays
Aspects of the problem of galactic cosmic ray propagation, including inversion of the solar total magnetic field and an analysis of data related to the heliomagnetic cycle are discussed. It is noted that the global structure of the solar magnetic field results in an additional flux of galactic cosmic rays generated by curvature and gradient drifts. An analysis of heliomagnetic cycle data shows that the latitudinal gradient results in a N-S asymmetry, with the amplitude of the effect growing with depth in the atmosphere. The inversion of the solar total magnetic field, drift effects, and other space distributions are found to contribute to a 22-year cycle of solar activity.
Goncher, G. A.↗
Formulas for long period radiation pressure, lunar and solar gravitational effects on the motion of artificial satellites
Analytic formulations for satellite perturbations due to solar radiation pressure and lunar and solar gravitational forces
Fisher, D.↗
Transmission Electron Microscopy of Plagioclase-Rich Itokawa Grains: Space Weathering Effects and Solar Flare Track Exposure Ages
Limited samples are available for the study of space weathering effects on airless bodies. The grains returned by the Hayabusa mission to asteroid 25143 Itokawa provide the only samples currently available to study space weathering of ordinary chondrite regolith. We have previously studied olivine-rich Itokawa grains and documented their surface alteration and exposure ages based on the observed density of solar flare particle tracks. Here we focus on the rarer Itokawa plagioclase grains, in order to allow comparisons between Itokawa and lunar soil plagioclase grains for which an extensive data set exists.
Keller, Lindsay P.↗
Geocoronal structure - The effects of solar radiation pressure and the plasmasphere interaction
The theory of planetary exospheres is extended to incorporate solar radiation pressure in a rigorous manner, and an evaporative geocoronal prototype (classical, motionless exobase) is constructed using Liouville's theorem. Model calculations for density and kinetic temperature at points along the earth-sun axis (solar and antisolar directions) reveal an extensive satellite component, comprising approximately 2/3 of the total hydrogen density near 10 earth radii, and a temperature profile suggestive of an isotropic quasi-Maxwellian velocity distribution for the bound component. A geotail is also evident as an enhancement of the density at local midnight compared to local noon that increases outward (from approximately 25 percent at 10 earth radii to over 60 percent at 20 earth radii). Additional mechanisms acting upon the geocorona alter the basic evaporative case in notable ways. Solar ionization has been included in a simple fashion; the effect is to partially deplete the density without otherwise altering the structure. Interaction with a simple plasmasphere via the Boltzmann equation results in 'heating' the geocorona and enhancing the escape flux at the expense of the density of the bound component, an effect not appreciated in earlier studies; the geotail survives this interaction.
Bishop, J.↗
Space environmental effect on solar cells: LDEF and other flight tests
This paper summarizes results of several experiments flown on the Long Duration Exposure Facility (LDEF) to examine the effects of the space environment on materials and technologies to be used in solar arrays. The various LDEF experiments are compared to each other as well as to other solar cell flight data published in the literature. Data on environmental effects such as atomic oxygen, ultraviolet light, micrometeoroids and debris, and charged particles are discussed in detail. The results from the LDEF experiments allow us to draw several conclusions. Atomic oxygen erodes unprotected silver interconnects, unprotected Kapton, and polymer cell covers, but certain dielectric coatings can protect both silver and Kapton. Cells that had wrap-around silver contacts sometimes showed erosion at the edges, but more recently developed wrap-through cells are not expected to have these problems. Micrometeoroid and debris damage is limited to the area close to the impact, and microsheet covers provide the cells with some protection. Damage from charged particles was as predicted, and the cell covers provided adequate protection. In general, silicon cells with microsheet covers showed very little degradation, and solar modules showed less than 3 percent degradation, except when mechanically damaged. The solar cell choices for the Space Station solar array are supported by the data from LDEF.
Gruenbaum, Peter↗
A comparison of solar modulation effects on protons, electrons and helium nuclei
Galactic cosmic ray proton and He spectrum measurements in 1968 compared to electron spectra, explaining solar modulation features by models incorporating energy loss effects
Lezniak, J. A.↗
An analysis of the solar-activity effects in the upper atmosphere.
A study of the upper-atmosphere variations induced by solar activity was made by using 29,574 densities derived from the drag of ten satellites in the interval from 1958 to 1971. In a comparison of the respective merits of the Ca II plage index and the 10.7-cm solar flux to represent the erratic (27-day) component of the variation, the latter is shown to give invariably better results. The ratio of the temperature variations to the variations of the decimetric flux is shown to vary considerably with solar activity, but little with height or with local solar time. The time lag of the atmospheric variations behind those of the decimetric flux varies from a minimum of 0.9 day at noon to 1.6 days at midnight.
Jacchia, L. G.↗
An analysis of the solar-activity effects in the upper atmosphere
A study of the upper-atmosphere variations induced by solar activity was made by using 29,574 densities derived from the drag of 10 satellites in the interval 1958-1971. In a comparison of the respective merits of the Ca II-plage index and the 10.7 cm solar flux to represent the erratic ('27 day') component of the variation, the latter is shown to give invariably better results. The ratio of the temperature variations to the variations of the decimetric flux is shown to vary considerably with solar activity, but little with height or with local solar time. The time lag of the atmospheric variations behind those of the decimetric flux varies from a minimum of 0.9 day at noon to 1.6 days at midnight.
Jacchia, L. G.↗