TABLE OF CONTENTS A critical step in addressing membrane mirrors is to consider the telescope as a system, with the primary mirror as a subsystem. Systems engineering can be defined as the allocation and management of risk by apportionment of the critical system resources cost, schedule, and performance through the assignment of requirements to the subsystems. Requirements are a resource in that the methods chosen to achieve certain performance needs have significant impact upon decreasing the risk of mission failure. The most important idea to remember in the system design of gossamer mirrors and telescopes is that the problem is difficult. This concept is useful to keep in mind because the difficulty of the problem may well require nontraditional concepts in telescope design solutions. The first space telescope with ultra-low mass might include one of many realizations, with the following offered only as a sample of possibilities:
A traditional layout the apparently straightforward idea of placing doubly curved optics in a traditional telescope configuration yet making the optics thinner and correcting the errors near the detector.
A traditional geometry a deployed-foam backing structure that expands such that the mirror looks like a traditional mirror geometry, yet without the mass.
A nontraditional geometry the function of a primary mirror split into two singly curved surfaces.
A nontraditional optical design nontraditional curvatures and unique aperture masking that exploit both the manufacturable shapes of membranes and nontraditional diffractive properties of optics.
The vast experience in traditional approaches makes a traditional approach...
