Journal of Astronomy and Space Sciences (Sep 2012)

Performance Analysis for Mirrors of 30 cm Cryogenic Space Infrared Telescope

  • Kwijong Park,
  • Bongkon Moon,
  • Dae-Hee Lee,
  • Woong-Seob Jeong,
  • Uk-Won Nam,
  • Youngsik Park,
  • Jeonghyun Pyo,
  • Wonyong Han

DOI
https://doi.org/10.5140/JASS.2012.29.3.321
Journal volume & issue
Vol. 29, no. 3
pp. 321 – 328

Abstract

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We have designed a 30 cm cryogenic space infrared telescope for astronomical observation. The telescope is designed to observe in the wavelength range of 0.5~2.1 μm, when it is cooled down to 77 K. The result of the preliminary design of the support structure and support method of the mirror of a 30 cm cryogenic space infrared telescope is shown in this paper. As a Cassegrain prescription, the optical system of a 30 cm cryogenic space infrared telescope has a focal ratio of f/3.1 with a 300 mm primary mirror (M-1) and 113 mm secondary mirror (M-2). The material of the whole structure including mirrors is aluminum alloy (Al6061-T6). Flexures that can withstand random vibration were designed, and it was validated through opto-mechanical analysis that both primary and secondary mirrors, which are assembled in the support structure, meet the requirement of root mean square wavefront error <λ/8 for all gravity direction. Additionally, when the M-1 and flexures are assembled by bolts, the effect of thermal stress occurring from a stainless steel bolt when cooled and bolt torque on the M-1 was analyzed.

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