THREE-AXIS ATTITUDE SIMULATORS FOR BIFOCAL RELAY MIRROR SPACECRAFT

摘要

This paper presents two three-axis attitude control simulators developed at the Naval Postgraduate School for developing and validating acquisition, tracking, and pointing technologies for Bifocal Relay Mirror Spacecraft. The spacecraft consists of two optically coupled telescopes used to redirect the laser light from ground-based, aircraft-based or spacecraft-based sources to distant points on the earth or in space. The first attitude control simulator, Single Relay Mirror Spacecraft Simulator, can simulate spacecraft three-axis motion, and optical system simulating a single space telescope. The spacecraft bus simulator has three reaction wheels and thrusters as actuators, rate gyros, sun sensors, on board processors, batteries, and is supported on a spherical air bearing. The optical system consists of a laser source, a fast steering mirror, a jitter sensor, and a video camera as a tracking sensor. The paper presents design of the simulator and experimental results. The second three-axis attitude control simulator, Bifocal Relay Mirror Spacecraft Simulator, under development, provides higher agility and higher pointing performance and simulates two space telescopes. The spacecraft bus simulator is supported on a spherical air bearing and has three variable speed control moment gyros (CMGs), three fiber optic rate sensors, batteries, on-board processor, sun sensors, magnetometers, highly accurate attitude sensors simulating star trackers, and automatic balancing. The flexible simulators are also included to study flexibility effects. The optical payload consists of two space telescopes with fast steering mirrors, tracking sensors, and jitter and beam pointing controllers.