Separation of functions as an approach to development of large space telescope mirrors

The sole purpose of a mirror is to maintain a reflecting surface within specified (wavelength dependent) tolerances for figure and finish. Recent work is now enabling the use of separate approaches to figure and finish, in particular for space telescope mirrors. This approach may eventually yield a mirror with optical performance equal to the best that can be provided by glass, but offering other characteristics that may in fact be enabling for advanced telescope systems not only in space, but also on the ground and airborne. These system enabling characteristics include bwer areal densities, rapid and repeatable manufacturing capability, new and more extensive fabrication and production infrastructures, and (possibly) new performance capabilities.