Development of Motorized Slewing Mirror Stage for the UFFO Project

¹ National Taiwan University, Taipei, Taiwan
² Yonsei University, Seoul, Korea
³ Ewha Womans University, Seoul, Korea
⁴ LAL, University of Paris-Sud 11, Orsay, France
⁵ Technical University of Denmark, Copenhagen, Denmark
⁶ Instituto de Astrofísica de Andalucía, CSIC, Granada, Spain
⁷ National Space Organization, Hsinchu, Taiwan
⁸ Korea Institute of Industrial Technology, Cheonan, Korea
⁹ Korea Advanced Institute of Science and Technology, Deajeon, Korea
¹⁰ University of Valencia, Valencia, Spain
¹¹ National United University, Miao-Li, Taiwan
¹² Sungkyunkwan University, Suwon, Korea
¹³ Moscow State University, Moscow, Russia

Abstract

The Ultra-Fast Flash Observatory (UFFO) is a space observatory for optical follow-ups of gamma ray bursts (GRBs), aiming to explore the first 60 seconds of GRBs optical emission. UFFO is utilized to catch early optical emissions from GRBs within few sec after trigger using a Gimbal mirror which redirects the optical path rather than slewing entire spacecraft. We have developed a 15 cm two-axis Gimbal mirror stage for the UFFO-Pathfinder which is going to be on board the Lomonosov satellite which is to be launched in 2013. The stage is designed for fast and accurate motion with given budgets of 3 kg of mass and 3 Watt of power. By employing stepping motors, the slewing mirror can rotate faster than 15 deg/sec so that objects in the UFFO coverage (60 deg × 60 deg) can be targeted in ~1 sec. The obtained targeting resolution is better 2 arcmin using a close-loop control with high precision rotary encoder. In this presentation, we will discuss details of design, manufacturing, space qualification tests, as well as performance tests.