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
Famous quotes containing the words mathematical and/or survey:
“It is by a mathematical point only that we are wise, as the sailor or the fugitive slave keeps the polestar in his eye; but that is sufficient guidance for all our life. We may not arrive at our port within a calculable period, but we would preserve the true course.”
—Henry David Thoreau (1817–1862)
“By contrast with history, evolution is an unconscious process. Another, and perhaps a better way of putting it would be to say that evolution is a natural process, history a human one.... Insofar as we treat man as a part of nature—for instance in a biological survey of evolution—we are precisely not treating him as a historical being. As a historically developing being, he is set over against nature, both as a knower and as a doer.”
—Owen Barfield (b. 1898)