Solar Sailing 201

Introduction

Solar Sailing 101 is a qualitative introduction to solar sailing. That is, there was almost no math involved. This document will introduce the basic mathematics behind solar sails. Upon completion, the reader should be able to:

• Calculate the acceleration of a solar sail in orbit around a star.
• Plot the orbit of a solar sail that is pointed straight at the sun.
• Using a computer, calculate the trajectory of a sail held at a constant angle with respect to the sun.

Gravity

Solar sails, like other objects, are subject to gravity when travelling through space. This discussion will be limited to gravity from the sun and not the planets or other bodies. This is simpler, because both sunlight (which pushes outward) and gravity (which pulls inward) come from the same nearly fixed source.

The acceleration $a_g$ of a solar sail due to the sun's gravity