The properties of four candidate mirror materials--beryllium, silicon carbide,
a silicon carbide/aluminum iretal-matrix carposite and aluminum--are corrpared.
Because of its high specific stiffness and dirrensional stability under changing
mschanical and thermal loads , beryllium is the best choice . Berjllium mirrors have
been made irore cost-conpetitive by new processing technologies in which mirror
blanks are isostatically pressed to near-net shape directly fran beiyllium pc1ers.
Isostatic pressing also improves material properties and mskes it possible to
develop mirror rraterials with superior properties.