Stretched membrane with electrostatic curvature (SMEC) mirrors for extremely large space telescopes

Very lightweight mirrors can be constructed by stretching a membrane to form a flat surface. Adding tension to the membrane, making it flat, can be done by discrete attachment points, or by using a continuous boundary. Such lightweight mirrors are very attractive for space telescopes where a 100m aperture can be made up of smaller mirror segments.(1) Adding a slight curvature to each segments simplifies the optical train.(2) This article looks at the making of a curved membrane mirror, and demonstrates its use. Measurements of the last membrane, and the curved figure will be shown.