Interferometric Star Tracker - PhaseII

Laser communications (Lasercom) technology offers the promise of much higher rate data exchanges while reducing the size and weight of the telecommunications package for deep space missions. This improved system performance is due primarily to the narrow transmit signal beamwidth at the optical wavelength, which allows for more efficient delivery of the transmit signal to the receiver. The problem of pointing a laser signal can in general be decomposed into the problems of (i) stabilizing the optical line of sight and (ii) providing the appropriate pointing reference to the receiver location. Optical Physics Company (OPC) has adapted the precision interferometric star tracker it is currently developing under several DoD contracts for deep space lasercom beam pointing applications. The OPC interferometric star tracker can also be used to provide precise attitude measurements to the spacecraft for navigation and orbit determination purposes. The current concept for the beam pointing is for a star tracker to be mounted opposite to the downlink beam boresight. This configuration has the advantage that, for outer planet missions, the sun will almost always be away from the tracker, thus allowing the tracker to have a direct view of the sky.