New light-shielding technique for shortening the baffle length of a star sensor

Hiroyuki Kawano; Yukio Sato; Kenji Mitani; Hiroshi Kanai; Kazumori Hama

doi:10.1117/12.451327

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16 October 2002 New light-shielding technique for shortening the baffle length of a star sensor

Hiroyuki Kawano, Yukio Sato, Kenji Mitani, Hiroshi Kanai, Kazumori Hama

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Proceedings Volume 4767, Current Developments in Lens Design and Optical Engineering III; (2002) https://doi.org/10.1117/12.451327
Event: International Symposium on Optical Science and Technology, 2002, Seattle, WA, United States

Abstract

We have developed a star sensor with a short baffle of 140 mm. Our baffle provides a Sun rejection angle of 35 degrees with stray light attenuation less than the intensity level of a visual magnitude of Mv = +5 for a wide field of view lens of 13x13 degrees. The application of a new light shielding technique taking advantage of total internal reflection phenomena enables us to reduce the baffle length to about three fourths that of the conventional two-stage baffle. We have introduced two ideas to make the baffle length shorter. The one is the application of a nearly half sphere convex lens as the first focusing lens. The bottom surface reflects the scattering rays with high incident angles of over 50 degrees by using the total internal reflection phenomena. The other is the painting of the surface of the baffle with not frosted but gloss black paint. The gloss black paint enables most of the specular reflection rays to go back to outer space without scattering. We confirm the baffle performance mentioned above by scattering ray tracing simulation and a light attenuation experiment in a darkroom on the ground.

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Hiroyuki Kawano, Yukio Sato, Kenji Mitani, Hiroshi Kanai, and Kazumori Hama "New light-shielding technique for shortening the baffle length of a star sensor", Proc. SPIE 4767, Current Developments in Lens Design and Optical Engineering III, (16 October 2002); https://doi.org/10.1117/12.451327

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