James Webb Space Telescope first light boresight to spacecraft alignment determination

摘要

The James Webb Space Telescope is a large deployable cryogenic space telescope that is pointed on the sky bycontrol of the attitude of the integrated spacecraft and telescope. The primary mirror has 18 hexagonal PrimaryMirror Segment Assemblies (PMSA) that are deployed; 3 on each of two deployable wings, and 12 on a fixedcentral section of the Primary Mirror Backplane Support Structure. The Secondary Mirror (SM) is deployed fromthe Secondary Support Structure that folds out from the backplane, and the complete Telescope and IntegratedScience Instrument Module are deployed in extension from the spacecraft. The resulting tolerances will result in a"first light" image that has a spread array of 18 individual images for each point source located within the field ofview. The initial attitude of the spacecraft will be adjusted to point the telescope to a desired star field for the initialWFSC commissioning process. The deployment tolerances will result in the telescope field of view being offsetfrom the desired location. By use of a sequence of pointings, a mosaic "first light" image that includes themultiplicity of the 18 misaligned segment images may be created that will allow the calibration of the offset betweenthe telescope boresight and the spacecraft attitude control system, allowing subsequent pointing to be doneaccurately to a fraction of the field of view of the instruments using spacecraft attitude control.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.