Development of a laser communication terminal for large LEO constellations

The long-awaited deployment of space-based communication systems designed to link even the most remote and under-served regions of our planet is rapidly being pursued. Solutions include a combination of radio frequency space-to-ground links and free-space optical (FSO) satellite-to-satellite links forming the backbone of the network. Over the last eight years ViaLight Communications has successfully developed and demonstrated high-speed laser communication in air-to-air, air-to-ground and ground-to-ground applications and has started development of a Low Earth Orbit (LEO) optical terminal, building on the heritage of operating in the harsh environment of the stratosphere. Key performance parameters of the LEO terminal will include a data rate of 10 Gbps full duplex over distances of 4000 km, a mass of less than 20 kg and a design lifetime of 5 years. The Systems Requirements Review was successfully passed in early 2017 and completion of the qualification is planned for 2019. A demonstration mission in LEO is planned in 2019/2020. Three key elements represent the key performance parameters (KPPs) that anyone trying to compete in this emerging market must perform well - Affordability, Performance, and Schedule. It is only through the proper balance of these three elements of project performance that such a deployment can be successful. With the planned deployment in a large constellation, considering the paradigm of “New Space”, the cost per terminal will be a driving factor for the design, much more than in previous FSO projects carried out to validate the technology in real-world environments. The paper will share the focus areas of each of these KPPs in practical areas of project management and define the challenges faced when striving to meet these objectives with such a complex system. A keen focus of the interdependency of all the design elements of a FSO laser terminal will be explored to illustrate how the numerous components from various suppliers must be engineered, to ensure that reliability, manufacturability, and sustainability goals can also be met throughout the process.