Mathematical Survey
Solar sail vessels are classified by their lightness number which is the ratio of the acceleration due to the light force on the sail to the force of gravity. (These both vary with the inverse square of distance, so the ratio is constant for any vehicle.) A typical reflective surface needs to provide about 4 square meters of reflective area for every 5 grams of vehicle weight to have a lightness factor of 1.
The light force can be separated into the normal force (away from the light source) and the tangential force as a function of the angle A of the sail face to the light. The Normal Force per area = 8/9 + 1/9 . The Tangential Force per area = 4/9 .
Read more about this topic: Solar Sail
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