Abstract: Apparatus is described for use with a solar concentrator such as a parabolic dish (12, FIG. 2) which concentrates sunlight onto the small opening (18) of a solar receiver (16), for protecting the receiver in the event of a system failure that could cause concentrated sunlight to damage the receiver. The protective apparatus includes a structure which can be moved from a stowed position (30) where it does not block sunlight, to a deployed position (30A) wherein it forms a tube which substantially completely surrounds an axis (26) connecting the receiver opening to the center of the concentrator at locations between the receiver and the concentrator.

Abstract: An inexpensive, lightweight reflective assembly member having good optical quality is provided. The reflective assembly is particularly adaptable to accommodating temperature variations without providing destructive thermal stresses and reflective slope errors. The reflective assembly may consist of a thin lamina reflective surface member and a lightweight substrate member of cellular structure. The respective materials may be chosen so that the coefficient of thermal expansion will be approximately the same. The substrate can comprise a cellular glass block while the reflective lamina member can be a thin sheet of glass with appropriate reflective coating. The lamina and cellular substrate member can be bonded together to form the reflective assembly. The method of fabrication includes abrading the cellular substrate with an abrasive master die to form an appropriate concave surface.