Additive Manufacturing of Large Astronomical Mirrors via Interlocking Features

As part of the STTR topic AF22A-T002, the United State Air Force (USAF) is seeking a capability to additively manufacture parabolic/spherical telescope mirrors. Additive manufacturing (AM) of telescope mirrors enables unprecedented design flexibility, on-demand manufacturing, and the ability to fabricate mirrors in segments which can be shipped compactly and assembled on-location.  AM also addresses supply chain challenges with traditionally manufactured mirrors enabling mirrors to be manufactured as-needed with shorter lead times.  Two key challenges presented by AM are (1) a lack of established material, process, performance relationships and (2) size scale-up due to limited build volumes.  Spectral Energies (SE) and its partners at the University of Dayton Research Institute (UDRI) will address the first challenge by printing a variety of polymeric and metallic materials via micro-scale resolution AM processes (stereolithography, digital light processing, and direct metal laser sintering).  The team will evaluate AM material properties relevant to mirror performance metrics such as reflectivity, toughness, hardness, stiffness, and strength.  In parallel, the team will address the second challenge by designing and demonstrating innovative mechanical interlocking mechanisms that will enable mirrors to be printed in segments using currently available AM systems without sacrificing high resolution.