Design and fabrication of a large primary reflector structure for space laser power beaming

Design and fabrication of a large primary reflector structure for space laser power beamingPaul MacNeal and Ken JewettJet Propulsion Laboratory, California Institute of Technology4800 Oak Grove Drive, Pasadena, California 91109ABSTRACTThis paper discusses the design issues and fabricatiQn consideration& specifically related to a large twelve meter,graphite-epoxy space truss that has been developed to provide support of the primary mirror system for the SpacE LaserENErgy (SELENE) Beam Transmission Optical System (BTOS). Details of the optical system and wavefront correctorconcepts have been discussed in prior papers. Specific issues which are addressed in this paper include opticalperformance needs, environmental requirements, and lowcost fabrication techniques.2. INTRODUCTIONBTOS is a portion of a larger project entided SpacE Laser Electric ENErgy (SELENE). The SELENE project ismanaged by Marshall Space Flight Center and utilizes a high energy, free electron laser to transfer energy from theground to orbiting spacecraft or other targets such as a lunar colony. BTOS is the system that transmits the beamenergy from the laser to the target. BTOS receives a one meter diameter energy beam which has been cleaned up sothat the Strehl ratio is 0.9 or greater.To satisfy requirements for the SELENE missions, which include a Strehi ratio greater than 0.5,