A lightweight telescope created using polymer membrane optics and developed by Ball Aerospace & Technologies Corp. was demonstrated for DARPA, the company reported recently. Ball is incrementally demonstrating technology needed to deploy a large, 20-m-diameter, space-based telescope in geosynchronous orbit (GEO, approximately 36,000 km high) as part of the Membrane Optic Imager Real-time Exploitation (MOIRE) program led by DARPA. Ball Aerospace & Technologies Corp. is incrementally demonstrating technology needed to deploy a large, 20-m-diameter, lightweight space-based telescope in geosynchronous orbit as part of the MOIRE program, led by DARPA. Courtesy of Ball Aerospace & Technologies Corp. Instead of using traditional glass mirrors or lenses, MOIRE seeks to diffract light with Fresnel lenses made from a lightweight membrane roughly the thickness of household plastic wrap. MOIRE would house the membranes in thin metal “petals” that would launch in a tightly packed configuration. Upon reaching its destination orbit, the satellite would then unfold the petals to create the full-size multilens optics. MOIRE is a ground-based experiment of a GEO-based system and seeks to develop the technologies required to create very large optic space platforms that reduce the areal density (the mass of the optics compared to the size of the spacecraft) by 4 to 5 times that of current systems. The program aims to examine technologies for manufacturing large membranes (up to 20 m), large structures to hold the optics flat, and also demonstrate the secondary optical elements needed to turn a diffraction-based optic into a wide-bandwidth imaging device. “This is the first design to use transparent membranes on a large scale,” said Aaron Seltzer, director of Advanced Development for Ball Aerospace’s National Defense business unit. “The result is a telescope with exceptionally low mass per unit of collecting area.” With a proposed diameter of 20 m, MOIRE’s membrane optic “lens” would be the largest telescope optic ever made and dwarf the traditional glass mirrors used in the world’s most famous telescopes. Courtesy of DARPA. Ball worked with NeXolve and Lawrence Livermore National Laboratory to produce MOIRE’s optical-quality polymer membranes and the precision etching needed to generate the diffraction pattern. Most recently, Ball completed construction and testing of one-eighth of a 5-m-diameter annular segmented telescope to verify functionality of the MOIRE design. “The ground demonstration substantiates that this innovative technology could work on next-generation space telescopes to greatly reduce their costs and enable larger telescopes,” said Ball Aerospace president Rob Strain. “This technology could apply to a wide range of applications providing various forms of information to a multitude of users.” The Ball demonstration telescope uses six primary diffractive optical elements. Additional technologies demonstrated by Ball for the MOIRE telescope include the use of secondary diffractive optical elements to correct chromatic dispersion, stability of the membranes, and the use of laser metrology and active optics to align the primary and secondary optics. The MOIRE program began in March 2010. Phase 1 verified the proof of concept for the program design, and Phase 2, which is now underway, seeks to reduce many of the risks involved in using diffractive optics for space imaging systems. Following the successful ground-based proof of concept for MOIRE, the Ball team intends to pursue additional funding to move the technology forward, the company said. For more information, visit: www.ballaerospace.com