Pointing, acquisition, and tracking for the TBIRD CubeSat mission: system design and pre-flight results

On-orbit demonstration of 200-Gbps laser communication downlink from the TBIRD CubeSat

“…The downlink beamwidth in the model is 380 µrad FWHM, which was measured on orbit with an experiment in which the bus performed a high-resolution grid scan during a pass. 26 The agreement between irradiance measurement and model demonstrates that the closed-loop body pointing system and the ground telescope tracking performed well for the entirety of the pass.…”

“…The TBIRD space terminal has been described in detail previously. 23,24 The payload is approximately 3U in volume, weighs less than 3 kg, and consumes 100 W of power when all components are active. The optical subassembly is a bi-static design with separate apertures for downlink transmit and uplink receive.…”

“…Pull-in time is typically 10-30 seconds, after which the uplink signal is tracked at an accuracy of 20-35 µrad RMS per axis, keeping downlink pointing losses negligible throughout the pass. 26 The spacecraft has a contingency spiral pointing scan available to assist the acquisition process, but this has not been employed since it is able to open-loop point at the ground station to within the payload field of view.…”

“…22 The space terminal is a payload roughly 3U in volume that was built by MIT Lincoln Laboratory and hosted on a 6U CubeSat bus built by Terran Orbital (formerly known as Tyvak Nano-Satellite). 23,24 The ground terminal is located at NASA/JPL's Optical Communications Telescope Laboratory (OCTL) at Table Mountain Facility near Wrightwood, California. 25 OCTL has a 1-m diameter telescope and adaptive optics system that were augmented by JPL to support the TBIRD system.…”

“…Another paper in this session provides further detail on the on-orbit results of the pointing, acquisition, and tracking system. 26…”