Coupled Microvibration Analysis of Space Optical Load Platform

Abstract

This paper investigates the microvibration induced by a pulse tube cryocooler mounting on a space camera, and it describes a full methodology and experimental verification to deal with microvibration predictions. A coupled transfer function matrix is introduced by improving the traditional disturbance model, which is apt to be more representative of the real boundary conditions. The coupled method corrects the microvibration input load by using force filters that depend on estimations of the interface accelerances. The impact of microvibration is predicted, based on transfer functions found from the modeled camera. A system-level microvibration test is performed to verify the predicted results. Dynamic coupling is shown to exist. After integrating the finite element analysis results with the optics design software, the performance of the optical system represented by the modulation transfer function is analyzed. The results show that the surface deformations caused by cooler microvibration are very small, which can be neglected compared with the rigid-body motion. This approach accurately predicts the microvibration and its influences, which provides a new way to analyze the microvibration of an optical load on spacecraft.