ULTRA-LIGHT, SELF-CORRECTING, “LIVE” MIRRORS: Lowering the areal density of mirrors and maximizing performance with non-abrasive, additive, 3D-printed novel technology.

We propose to develop ultralight, self-correcting mirrors for use in the next generation of large optical telescopes and solar energy concentrators. Presently, the best mirrors have a density of about one-half a metric-ton per square-meter or more in order to provide the stiffness which is necessary to keep the optical shape under the variable conditions given by the changing gravity vector as the telescopes track a position on the sky, as well as to withstand variable wind conditions. We intend to replace such a massive mirror with a “sandwich” of very light, optically perfect, “fire-glass” (window pane) coated sheets stiffened with layers of Electro-active polymers that can be deposited through additive manufacturing 3D printers. The sheets of glass will be heated to ~800o C in a pressurized, tailored made kiln and allowed to relax (their backside) onto a suitable mould, cast to a predetermined off-axis aspheric (parabolic) shape, while keeping the temperature below the de-vitrification temperature of the glass thus preserving the excellent optical surface quality of fire-glass window pane. Using the addressable energy of the Electro-active polymers will provide not only dynamically self-controlled stiffness but also variable push-pull action real-time multi-sensing controlled and calibrated in order to keep the optical surface to a “live-perfect” shape under general operating conditions. These “Live-Mirrors” shall provide optical surfaces of as high a quality as those of the current best telescopes but with larger dynamic range and a reduction in weight and cost of more than one order of magnitude. Such mirrors will allow the development of 50-100 meter-class telescopes as well as of the next generation of space telescopes. On the ground, they will also offer very low cost options for the next generation of solar energy concentrators and for antennas used for optical communications.