Speckle Pattern Interferom-etry for JWVST

Development ofmanynew technologies is required tosuccessfully produce thelarge, lightweight, deployable, cryogenic telescope withsegmented primary mirror fortheJamesWebb SpaceTelescope (JWST) mission. Oneofthetechnologies isinterferometry toverify structural deformations inlarge, deployable, lightweight, cryogenic, precision structures tonanometer level accuracy. An instantaneous acquisition phaseshifting speckle interferometer was designed andbuilt tosupport the development ofJWSTOptical Telescope Element (OTE) primary mirrorbackplane. Thispaperdiscusses characterization of the Electronic Speckle Pattern Interferometer (SPS-DSPI) developed forJWSTtoverify itscapability tomeasurestructural deformations inlarge composite structures atcryogenic temperature.1