James Webb Space Telescope primary mirror deployment ambiguity effects

The James Webb Space Telescope (JWST) is a large space based astronomical telescope employing a primary mirror constructed of 18 hexagonal segments to create its large collecting area, and an image based wavefront sensor at the telescope focal plane to provide knowledge of system alignment. The combination of image sensing at the focal plane over a subset of the telescope's field of view and the resolution of the wavefront sensing system gives rise to a global alignment ambiguity between the primary and secondary mirror. This paper describes the possible magnitude of wavefront error impact outside the alignment region of the FOV for various global alignment modes under the constraint of the various ambiguity limiting factors at the currently estimated wavefront sensing resolution limit.