Dimensional stability sensitivity analysis based on transfer function models for telescope in space gravitational wave detectors

Abstract

The telescope serves as a vital component of the space gravitational wave detector. In TianQin project, the exceptional dimensional stability of the telescope must be better than 1 pm Hz−1/2 @0.1 mHz–1 Hz. To assess the in-orbit dimensional stability of the telescope, a transfer function model was developed to evaluate the stability of the primary and secondary mirror spacing structure, considering the three primary thermal sources. It has been discovered that the stability of the spacer structure is influenced not only by the thermal expansion coefficient of the material but also by its heat capacity, density, and frequency band. Zerodur offers distinct advantages in terms of overall thermal performance. Specifically, the stability of the spacer constructed by it can be effectively controlled at 0.14 pm Hz−1/2@0.1 mHz–1 Hz, which is an achievement in the field of ultra-stability structure design.