SOLAR KITES - SMALL SOLAR SAILS WITH NO MOVING PARTS

The classical concept of a solar sail is of a large area of silvered p lastic deployed to reflect the Sun's rays thus propelling it This arra ngement would, however, be difficult to deploy and control, and imprac tical to launch from a low Earth orbit. This paper proposes an alterna tive concept to the classical solar sail - a small sail a few metres i n diameter called a solar kite. Such a kite may be steered using very small torque forces and can therefore be controlled without the need f or moving parts. Several such attitude control techniques are feasible : using windows of electrochromic material set in the sail; harnessing the effect of differential solar pressure on solar cells that are in or out of circuit; electrically heating,wires to alter the geometry. S uch solar kites may have a number of applications. Carrying a CCD came ra on a chip and a medium gain antenna, a kite could be used for inter planetary mission and return dust samples to Earth. A kite attached to a satellite in LEO could be used for orbit control, reducing the need for thruster propellant. Long strings of)rites, effectively large, on e-dimensional solar sails, would be easier to deploy and control than two-dimensional ones and could be operated from much lower altitudes, similar to 500 km. Published by Elsevier Science Ltd.