Solar sail

Solar sails (also called light sails, especially when they use light sources other than the Sun) are a proposed form of spacecraft propulsion utilizing large membrane mirrors. Radiation pressure is small and decreases by the square of the distance from the sun, but unlike rockets, solar sails require no fuel. Although the thrust is small, it continues as long as the sun shines and the sail exists.

Related Topics:
Light - Sun - Spacecraft propulsion - Membrane mirror - Radiation pressure

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Solar collectors, temperature-control panels and sun shades are occasionally used as expedient solar sails, to help ordinary spacecraft and satellites make minor corrections to their attitude and orbit without using fuel. This conserves fuel that would otherwise be used for maneuvering and attitude control. A few have even had small purpose-built solar sails for this use. Some unmanned spacecraft (such as Pioneer 10) have substantially extended their service lives with this practice.

Related Topics:
Attitude - Unmanned spacecraft - Pioneer 10

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The science of solar sails is well-proven, but the technology to manage large solar sails is still undeveloped. Mission planners are not yet willing to risk multimillion dollar missions on unproven solar sail unfolding and steering mechanisms. This neglect has inspired some enthusiasts to attempt private development of the technology.

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The concept was first proposed by German astronomer Johannes Kepler in the seventeenth century.http://www.rednova.com/news/space/151474/measuring_up_to_a_solar_sail/ It was again proposed by Friedrich Zander in the late 1920s and gradually refined over the decades.

Related Topics:
Johannes Kepler - Friedrich Zander

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