High Accuracy Coronagraph Flight WFC Model For WFIRST-CGI Raw Contrast Sensitivity Analysis

A high-accuracy high-fidelity flight wavefront control (WFC) model is developed for detailed WFIRST-CGI raw contrast sensitivity analysis. Built upon features of recently testbed validated model, it is further refined to combine a full Fresnel propagation diffraction model for high accuracy contrast truth evaluation, and an economical compact model for WFC purposes. Extensive individual raw contrast error sensitivities are evaluated systematically, both as known imperfections and as unknown calibration errors, for two CGI modes: spectroscopy mode and wide field-of-view mode with shaped pupil coronagraph. More than 90 distinct error items were identified, including system aberrations, optical misalignment, component fabrication errors, telescope interface related errors, etc. The result forms the basis for raw contrast error budget flow down to a sub-system level, where detailed specifications needed to aid in component design and manufacturing, mechanical alignment and instrument integration, and verification and validation operations. Evaluations are automated, making it relatively easy for repeat runs of revised design or at new desired error quantity. Observations from the comprehensive analysis and top error sensitivities and contrast floor contributors are noted and discussed. Error budget flowdown process is also briefly described.