UMBRAS - Design of a free-flying occulter for space telescopes

A free-flying occulter used with a space-based telescope can enhance the contrast in the region close to a star, allowing extrasolar planet searches. An occulting spacecraft design, emphasizing configuration, control, propulsion, mass estimates, and power requirements, is presented requiring no extension of existing technology or exotic engineering solutions. The design is scalable for use with telescopes having 1 to 10 metre apertures. Several innovations are employed to block starlight and suppress scattered sunlight. A station keeping control method is possible using various thruster types. With scientifically interesting rates at which different stars are surveyed, solarelectric propulsion allows the occulting craft to be packaged on existing launchers with no on-orbit assembly.