Flight system acquisition, tracking, and pointing results from the deep space optical communications technology demonstration

NASA’s Deep Space Optical Communications (DSOC) Project, implemented by the Jet Propulsion Laboratory (JPL), utilized a novel acquisition, tracking and pointing (ATP) approach to successfully complete the first year of its technology demonstration, delivering high-rate optical downlink from deep space distances of 0.1 to 2.7 astronomical units (AU). The downlink laser was initially pointed with spacecraft assisted coarse pointing of the DSOC flight laser transceiver (FLT) boresight towards the DSOC ground laser transmitter (GLT). FLT sensors and actuators searched out the spacecraft pointing uncertainty region to acquire and track the GLT uplink optical beacon as a reference signal for platform stabilization. The beacon-assisted controller achieved sub-microradian-level downlink pointing control, implemented using on-board computed point-ahead angles that were equivalent to many downlinks laser beamwidths. In this paper we describe the DSOC ATP architecture and associated algorithms, summarize the operational performance results to date, and touch upon lessons learned and future avenues for improvement.