Deployable Membrane Reflectors

This paper is concerned with the design of a new type of multi-purpose deployable membrane reflector. The reflector structure consists of a central expandable hub, a number of thin-walled foldable ribs connected radially to the hub, and a precision-shaped membrane supported and tensioned by the ribs. This concept is known as a collapsible rib-tensioned surface reflector. A methodology for the design of reflectors of this type that meet specified requirements is presented; both offset and symmetric configurations can be designed. For a reflector aperture of 10 m diameter and a focal length of 7.8 m, a root-mean-square surface accuracy of about 2 mm is achievable; this result scales linearly with the diameter. The design of a 1.5 m diameter prototype is presented, and the accuracy and deployment behaviour of a physical model are measured experimentally.