Dimensional Stability Ground Test and in-Orbit Prediction of SiC Telescope Frame for Space Gravitational Wave Detection

Benliang Sang,Xiaoqin Deng,Bo Peng,Wei Sha,Wei Tao

doi:10.1109/access.2022.3152490

Abstract

Telescope is the key element of space brone gravitational wave detector. Its dimensional stability is required to be better than 1 pm/Hz 1/2 at 0.1 mHz. And SiC is the current most likely material for manufacturing telescope with high dimensional stability. Therefore, a potential SiC telescope frame is designed and tested. In addition, in orbit dimensional stability is predicted by a numerical model. The ground dimensional stability of SiC frame is tested with a fiber-based interferometer, and the temperature change data are collected at the same time. The results of which show that when room temperature fluctuation frequency is greater than 10 mHz, the dimensional stability is about 300 pm/Hz 1/2 . A numerical model is established which is consistent with the measured data. The in-orbit dimensional stability is evaluated using the numerical model and the thermal environment of Taiji, whose numerical simulation results shows that when space temperature fluctuation frequency is about 0.1 mHz the dimensional stability would be 6.49 pm/Hz 1/2 .

Highlights

T O achieve the goal of direct detection of low-frequency gravitational wave signals, space borne gravitational wave detection program Taiji plans to build a space laser interference link as shown in Figure 1, which is based on the Michelson interference principle [1]
When the room temperature stability was greater than 0.0011◦C/Hz1/2, the dimensional stability was better than 300 pm/Hz1/2 for f > 10 mHz
The test results s√howed that the dimensional stability can reach 300 pm/ Hz@f > 10 mHz wh√en the room temperature stability is better than 0.0011◦C/ Hz

Summary

INTRODUCTION

T O achieve the goal of direct detection of low-frequency gravitational wave signals, space borne gravitational wave detection program Taiji plans to build a space laser interference link as shown in Figure 1, which is based on the Michelson interference principle [1]. Sanjuán et al [11] manufactured a CFRP telescope frame to simulate the supporting structure of the primary and secondary mirror They used a laser interferometer to measure the overall CTE, dimensional stability and long-period outgassing effect of the frame. Sanjuán et al [13] built a SiC telescope frame and tested its dimensional stability at room temperature (23◦C) and space temperature (−60◦C) separately. Through the analysis of the space thermal environment of the Taiji orbit, we got the in-orbit temperature fluctuation data of the telescope and the data was imported into the numerical model to obtain the precise in-orbit dimensional stability of the SiC telescope frame

OPTICAL SYSTEM AND OPTICAL MECHANICAL STRUCTURE DESIGN OF TAIJI TELESCOPE

Scattered light

RESULTS AND ANALYSIS

CONCLUSION