A shop method for testing large mirrors using a square-array sampling screen has been developed. The main features of this method are simple test setup independent of random air turbulence, high surface sampling rate, reliability and repeatability of results, detection of surface departures +/-0.1lambda (at 5000 A) or greater from the ideal surface, and self-calibration. Only large-area departures can be accurately detected by this method.
Over the last few years significant progress has been made in the development of silicon carbide (SiC) for mirror applications. These improvements include lightweighting techniques, higher production yields, and larger diameter apertures. It is now necessary to evaluate and address the systems engineering challenges facing this material to ensure space qualification and integration into future space applications. This paper highlights systems engineering challenges, suggests areas of future development, and proposes a systematic path forward that will outline necessary steps to space qualify this new material.
Future large-aperture optical space systems will need to use lightweight materials that meet stringent requirements, and that reduce program and launch costs. Lightweight optical systems produced quickly and cost-effectively, and the resultant lighter payloads, can reduce these costs. Mirrors for future systems have areal density goals of less than 5 kg/m 2 and will need to use new materials 1 . A promising one is silicon carbide (SiC) because of its physical and mechanical properties. These enable the production of low areal density, high quality mirrors, as well as lightweight athermal telescope structures. Athermal structures are desirable because they simplify designs and reduce tolerance requirements to maintain performance during on-orbit temperature changes. The use of SiC to make mirrors and structures is in the developmental stage and has limited space heritage. To ensure the use of this material in space applications, qualification and system performance in the space environment must be addressed. This paper provides an overview of SiC, along with recommendations to further the development of SiC into a mature technology that can be successfully integrated into future large-aperture optical space programs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.