SSC14-IX-6 Design of a Free-Space Optical Communication Module for Small Satellites

Free-space optical (FSO) communication technology has the potential to provide power-efficient communication links for small satellites that outperform traditional radio frequency approaches. Extremely high-gain apertures at optical carrier frequencies enable significantly improved performance. We present a design for a miniaturized CubeSat-scale optical transmitter capable of supporting downlink rates up to at least 10 Mbps. Our design incorporates a fine-steering mechanism that augments the capabilities of the host spacecraft’s attitude determination and control system. In this work, we develop an optical layout that optimizes link performance metrics while staying within the size, weight, and power constraints of a payload within a standard 3U CubeSat. The selection criteria for critical components (detectors, optical sources, and steering mechanisms) are described. Simulation results showing sufficient beacon tracking performance (better than ±210 μrad 3-σ ) are presented. Finally, single-axis simulation results are shown for the staged pointing control system that show the benefits of the fine stage.