Reflection from Inclined, Relativistic Light Sails

Abstract

We present a new formula for relativistic reflection of solar radiation from a light sail moving at a velocity v inclined at an arbitrary angle θ, using an elementary two-body analysis. The formula is shown to reduce to the formulas of Euclid, Einstein, and Gjurchinovski in the relevant limits. Our results are of relevance for computing optimal geometries for relativistic light sails.