Cryogenic Cofired Multilayer Actuator Development for a Deformable Mirror in the Next Generation Space Telescope

Xinetics is working with NASA to develop a cryogenic deformable mirror technology to meet the specific needs of the Next Generation Space Telescope. One of the critical technical issues is the development of a cryogenic actuator with sufficient displacement and temperature stability. This paper discusses the two year effort to achieve a cofired electroceramic multilayered cryogenic actuator. The development began by testing materials from 300 to 35 K via a cut and bond actuator technology that led to a cryogenic electroceramic material down selection. After selecting a doped SrTiO3, a cofired actuator process specific to the cryogenic ceramic was developed. The assembled cryogenic actuators achieved the 3 μm displacement (stroke) between 35 and 65 K required by the deformable mirror design. The discrete cryogenic actuators were assembled into an engineering model cryogenic 349-channel deformable mirror that was delivered to NASA in October 2001.