High Actuated Primary Mirror to Enable Prime Focus Coronograph Telescope

The Highly Actuated Primary Mirror is an evolutionary advance that will form the basis of coronagraphic telescopes such as the Terrestrial Planet Finder to direct image planets planets orbiting nearby stars. Used in a Prime Focus coronagraph, it completely eliminates optics between the Primary and coronagraphic occulter. This mirror has the stroke and spatial frequency bandwidth to completely control the mid spatial frequency scatter from the primary mirror, giving high contrast performance. It features a lightweight mirror structure fabricated from silicon carbide, which is compatible with both ambient and cryogenic environments. Actuators with angstrom level precision are used for mirror shape control and optical replication is used to form the mirror surface. The mirror will advance primary mirror technology in terms of channel count (941 to 4,317), spatial resolution (100-mm to 10-mm), and dimensional stability (l/10 to l/100). From a NASA perspective, the highly actuated design is applicable to both earth observing and space imaging surveillance. From a commercial perspective, it enables the cost-effective, volume production of high precision aspheres, which will be in big demand for 0.1-mm lithography systems. Rapid response replication of the optical surface, the mirror substrate, and the control actuators form a new paradigm in mirror manufacture.