Picometer Level Spatial Metrology for Next Generation Telescopes

Future space observatory missions require controlling wave front error and system alignment stability to picometer scale. Picometer stability performance demands precision knowledge of the mirror and metering structure materials to the same level. A high-speed electronic speckle pattern interferometer was designed and built to demonstrate measurements of both static and dynamic responses of picometer level amplitudes in mirror and structural materials subjected to very low energy disturbances. This paper summarizes the current status of tests to impart a dynamic disturbance of picometer scale and measure the response of specular and diffuse materials. The results show that subpicometer scale effects can be accurately measured in an open test environment outside a vacuum chamber.