The Grating and Filter Wheel Mechanisms of the JWST NIRSpec instrument allow for reconfiguration of the
spectrograph in space in a number of NIR sub-bands and spectral resolutions. Challenging requirements need to be met
simultaneously including high launch loads, the large temperature shift to cryo-space, high position repeatability and
minimum deformation of the mounted optics. The design concept of the NIRSpec wheel mechanisms is based on the
ISOPHOT Filter Wheels but with significant enhancements to support much larger optics. A well-balanced set of design
parameters was to be found and a considerable effort was spent to adjust the hardware within narrow tolerances.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.