Herschel Space Telescope: impact of new material strain data on optical test and model correlation

Successful launch and imagery from the Herschel Space Telescope has demonstrated a nominally in focus telescope. There still remains a discrepancy between the prediction and measurement of the telescope back focal length prior to launch. New material strain data has been applied to the structural/optical model of the telescope. The new data significantly closed the gap between the previous optical test measurement and prediction. However, a discrepancy still exists. Model results and techniques will be presented and discussed.