<title>Ultralightweight and hyperthin rollable primary mirror for space telescopes</title>

Abstract

The aperture of monolithic space telescope primary mirrors placed on orbit is limited to payload faring diameters, the largest being about 4-meters. This requires a novel stowage approach for monoliths larger than 4-meters. Very large aperture telescopes, 50 to 100-meter diameters, planned for deployment in the next 10 to 20 years will also require very large mirror segments in an effort to manage the phasing of the entire surface. The larger the mirror panels the fewer that will be required for such apertures. If the mirrors can be made thin enough to be deformed into a cylinder or undeformed but closely nested, enough surface area can be placed on orbit to facilitate large aperture telescope mirrors. 8-meter monolithic mirrors can be rolled into a 2.5-meter diameter cylinder with the secondary support structure stowed in the cylinder to maximize the payload faring volume. Hyper-thin mirrors can be closely nested in order to maximize volume as well. Presented is a design and engineering model of a 0.9-meter diameter hyper-thin, ultra- lightweight spherical composite mirror and methods, which led to the fabrication of the mirror.