JWST wavefront sensing and control Charles Bowers (GSFC) The James Webb Space Telescope (JWST) is an infrared observatory (Dl~0.7-28microns) which will operate at ~40K in an orbit around the second Lagrange point, L2. It is a joint mission of NASA, the European Space Agency and the Canadian Space Agency with four instruments capable of wide field, diffraction limited imagery, multi-object spectroscopy, narrow band imaging, and coronagraphy. The primary mirror aperture of 6.6meters, comprised of 18 highly lightweighted, 1.3meter hexagonal segments, is larger than potential launch vehicles and so it is folded for launch, then unfolded, aligned and co-phased in space. This is accomplished in a series of steps of wavefront sensing and control (WFSC) utilizing precision actuators to properly configure the telescope and science instruments. Following initial commissioning, wavefront sensing and control will be periodically used to maintain the observatory configuration throughout its lifetime. This talk will provide a brief background of the JWST mission and discuss the WFSC process, operation and testing.