Space-borne large optics will be required in future missions for astronomy and earth observations. In order to realize large-optics missions, JAXA has started the study of the ground measurement techniques of large optics. The 6m diameter radiometer thermal vacuum chamber (6m chamber) at Tsukuba Space Center will be used for tests of JAXA's future large-optics missions like Space Infrared Telescope for Cosmology and Astrophysics (SPICA). We measured the vibration environment of the 6m chamber for the feasibility study of precise optical measurement. We placed a test mirror inside the chamber and measured the surface figures of the mirror from outside the chamber with a high-speed interferometer, while the chamber was being vacuum-pumped and cooled by liquid nitrogen; we also directly measured the vibrational levels with accelerometers concurrently. The measurements were performed for each phase of the chamber system operation including pumping and cooling processes. This paper presents the results about optical measurement under the vibration environment on the 6m chamber. We confirm that the vibrations from pumps and shroud have negligible effects on optical measurements owing to a vibration isolation system in the 6m chamber.

Date Published: 26 August 2009
PDF: 8 pages
Proc. SPIE 7436, UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts IV, 74360Q (26 August 2009); doi: 10.1117/12.825937

Published in SPIE Proceedings Vol. 7436:
UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts IV
Howard A. MacEwen; James B. Breckinridge, Editor(s)