Facing the entrance ofthe clean tent, the thermal cycling chamber is located on the left side. All of the grating facets are characterized and run through 8 cycles at the specified survival temperature extremes. The gratings are re-measured to insure that no change in performance has occurred. On the right side, another reliability test is performed. The gratings are subjected to the acoustic levels specified for launch survival and re-measured to insure that no change in performance has occurred. A microscope and video camera are located in the center of the tent for inspection of each grating for any physical defects that might affect performance or reliability of the grating.