Gravity Lens Beam [Draft Paper]
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Gravity Lensed Beamed Power for Interstellar Propulsion
Dani Eder ^{[1]}
Tirion Designs,
1309 Stroud Ave, Gadsden, AL 35903

 Abstract

 We consider the possibility of using the Sun as a gravitational lens to focus a highpower beam on a distant spacecraft. The beam energy is used to power a high exhaust velocity particle accelerator. This relieves the spacecraft of needing an internal power supply for propulsion. If the delivered energy is large enough, it can exceed the restmass energy of any fuel. If the particle energy of the exhaust is relativistic, the exhaust mass can exceed the restmass in the fuel tank. This has the potential for better performance than antimatter concepts and modifies the normal Tsiolkovsky rocket equation because fuel used does not equal exhaust mass.
Notes for Text
 The paper has not been written yet, but this section will hold notes for later inclusion
 Light ray deflection angle radians, where r is the impact parameter (undeflected miss distance from the object center), G is the universal gravitational constant, M is the mass of the body, and c is the speed of light. For the Sun, the gravitational parameter GM is 1.32 x 10^{20}m^{3}/s^{2}, so the formula reduces to the convenient form where r is in meters. Note that the radius to bend light 1 radian is exactly twice the Schwarzchild radius for a black hole of the same mass.
 To avoid disturbances from the Sun's atmosphere, we choose an impact parameter of 10^{9} meters, or 1.4 Solar radii. This gives a deflection of 5.9 x 10^{6} radian, or 1.2182 arcseconds, a value confirmed by eclipse tests of relativity nearly a century ago. Since the deflection occurs equally all around the perimeter of the Sun, parallel light rays come to a focus at a distance of 1/deflection angle = 169,319 x impact parameter = 169.319 billion km = 1131.8 AU.
 Need to reference previous work by Robert Forward on laserpushed lightsails focused by fresnel zone plate.
 Calculate optimum combination of collector size at spacecraft and beam source behind Sun. Consider sail type reflector focusing to solar cells vs direct beam collection with large array.
 Calculate maximum beam intensity for solar cells with beam frequency tuned to semiconductor bandgap, and allowing for doppler effects.
 Find numbers for lightweight particle accelerators.
 Extract relevant info from NBF discussion.
 Do literature search for beamed power and interstellar travel.
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 ↑ Author email: danielravennest@gmail.com.