240 research outputs found
Escape Trajectories of Solar Sails and General Relativity
General relativity can have a significant impact on the long-range escape
trajectories of solar sails deployed near the sun. Spacetime curvature in the
vicinity of the sun can cause a solar sail traveling from 0.01 AU to 2550 AU to
be deflected by as much as one million kilometers, and should therefore be
taken into account at the beginning of the mission. There are a number of
smaller general relativistic effects, such as frame dragging due to the slow
rotation of the sun which can cause a deflection of more than one thousand
kilometers.Comment: 6 pages, 3 figures. Proceedings of the Sixth IAA Symposium on
Realistic Near-Term Advanced Scientific Space Missions. Missions to the Outer
Solar System and Beyond, pp. 67-72, Aosta, Italy, 6-9 July, 200
Solar Radiation Pressure and Deviations from Keplerian Orbits
Newtonian gravity and general relativity give exactly the same expression for
the period of an object in circular orbit around a static central mass.
However, when the effects of the curvature of spacetime and solar radiation
pressure are considered simultaneously for a solar sail propelled satellite,
there is a deviation from Kepler's third law. It is shown that solar radiation
pressure affects the period of this satellite in two ways: by effectively
decreasing the solar mass, thereby increasing the period, and by enhancing the
effects of other phenomena, rendering some of them detectable. In particular,
we consider deviations from Keplerian orbits due to spacetime curvature, frame
dragging from the rotation of the sun, the oblateness of the sun, a possible
net electric charge of the sun, and a very small positive cosmological
constant.Comment: 4 pages, minor typo corrected, additional comment
Microscopic Approach to Analyze Solar-Sail Space-Environment Effects
Near-sun space-environment effects on metallic thin films solar sails as well
as hollow-body sails with inflation fill gas are considered. Analysis of
interaction of the solar radiation with the solar sail materials is presented.
This analysis evaluates worst-case solar radiation effects during
solar-radiation-pressure acceleration. The dependence of the thickness of solar
sail on temperature and on wavelength of the electromagnetic spectrum of solar
radiation is investigated. Physical processes of the interaction of photons,
electrons, protons and helium nuclei with sail material atoms and nuclei, and
inflation fill gas molecules are analyzed. Calculations utilized conservative
assumptions with the highest values for the available cross sections for
interactions of solar photons, electrons and protons with atoms, nuclei and
hydrogen molecules. It is shown that for high-energy photons, electrons and
protons the beryllium sail is mostly transparent. Sail material will be
partially ionized by solar UV and low-energy solar electrons. For a hollow-body
photon sail effects including hydrogen diffusion through the solar sail walls,
and electrostatic pressure is considered. Electrostatic pressure caused by the
electrically charged sail's electric field may require mitigation since sail
material tensile strength decreases with elevated temperature.Comment: 10 pages, 6 figures. Talk given on the 59 International Astronautical
Congress, Glasgow, Scotland, 29 September - 2 October, 200
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