Prediction Method for Moisture-release Surface Deformation of a Large Mirror in the Space Environment

우주환경에서 대형 반사경의 습기 방출에 의한 형상 변화 예측방법

  • Song, In-Ung (Space Optics Laboratory (SOL), Department of Astronomy, Yonsei University) ;
  • Yang, Ho-Soon (Space Optics Team, Korea Research Institute of Standards and Science) ;
  • Khim, Hagyong (Space Optics Team, Korea Research Institute of Standards and Science) ;
  • Kim, Seong-Hui (Satellite Payload Development Division, Korea Aerospace Research Institute) ;
  • Lee, Hoi-Yoon (Space Optics Team, Korea Research Institute of Standards and Science) ;
  • Kim, Sug-Whan (Space Optics Laboratory (SOL), Department of Astronomy, Yonsei University)
  • 송인웅 (연세대학교 천문우주학과, 우주광학연구실) ;
  • 양호순 (한국표준과학연구원 첨단측정장비연구소 우주광학팀) ;
  • 김학용 (한국표준과학연구원 첨단측정장비연구소 우주광학팀) ;
  • 김성희 (한국항공우주연구원 위성연구본부) ;
  • 이회윤 (한국표준과학연구원 첨단측정장비연구소 우주광학팀) ;
  • 김석환 (연세대학교 천문우주학과, 우주광학연구실)
  • Received : 2018.05.31
  • Accepted : 2018.07.09
  • Published : 2018.08.25


In this paper, we propose a new method to predict a mirror's surface deformation due to the stress of moisture release by a coating in the environment of outer space. We measured the surface deformation of circular samples 50 mm in diameter and 1.03 mm thick, using an interferometer. The results were analyzed using Zernike fringe polynomials. The coating stress caused by moisture release was calculated to be 152.7 MPa. This value was applied to an analytic model of a 1.25 mm thickness sample mirror, confirming that the change of surface deformation could be predicted within the standard deviation of the measurement result ($78.9{\pm}5.9nm$). Using this methodology, we predicted the surface deformation of 600 mm hyperbolic mirror for the Compact Advanced Satellite, which will be launched in 2019. The result is only $2.005{\mu}m$ of focal shift, leading to 2.3% degradation of modulation transfer function (MTF) at the Nyquist frequency, which satisfies the requirement.


Supported by : 국가과학기술연구회, 항공우주연구원


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