Abstract
Increasing data bandwidth requirements from spacecraft systems is beginning to pressure existing microwave communications systems. Free-Space optical communications allows for larger bandwidths for lower relative power consumption, smaller size and weight when compared to the microwave equivelant. However optical communication does has a formidable challenge that needs to be overcome before the advantages of the technology can be fully utilized. In order for the communication to be successful the transmitter and receiver terminals need to be pointed with a high accuracy (generally in the order of 10 radians) for the duration of communication. In this paper we present a new concept for precise pointing of optical communications terminals (termed the Precise Pointing Mechanism). In this new concept we combine the separate pointing mechanisms of a conventional optical terminal into a single mechanism with a targeted goal of less than 3 radians pointing accuracy within a field of view of 10 by electromagnetically actuating the whole telescope assembly over 6 degrees-offreedom. This paper discusses the principles of operation of this new terminal, the design and modeling of an engineering model using a combination of permanent magnets and reluctance force electromagnets to provide the actuation with the required pointing precision.