The technical path to in-space testing of large optics

Abstract

Recent advances in technology and materials science have enabled a number of large telescopes on Earth. Adaptation of these methods to space systems (beyond those being demonstrated in the James Webb Space Telescope (JWST)) might provide an equivalent breakthrough in science productivity, but only if important problems related to integration and performance testing are resolved. This paper proposes a program of technology and process development that can lead to efficient and reliable methods for in-space performance testing, thereby overcoming the limitations imposed by testing in gravity, the limited size of test chambers, the challenges of creating synthetic starlight sources and other factors. Considerations are given to the inspace facilities that are required and the need for human presence or tele-presence during the test interval. Both deployed and assembled space systems are considered. The paper addresses the optimal allocation of various test activities including the role of modeling, and functional and performance testing. Risk issues are defined, along with the impacts that such an integration and test path imposes on the telescope designer.The principle goal of the paper is to define those parts of the test process that can (or must) be deferred until the system is in an operations-like environment and to define the processes and technologies that must be brought to maturity to assure that testing does not limit our ability to continue to upgrade our observational systems.