The International Communications Satellite Systems Conference (ICSSC) is the oldest and one of the most influential technical conferences in the field. The 37th edition was held from 29 Oct - 1 Nov 2019 in Okinawa, Japan. These proceedings present a broad spectrum of space communications contributions from the conference, with highlights including high speed optical communications and feeder links, advanced digital payloads, broadband satellite communication architectures and applications. Subjects covered include integrated applications and architectures for vessels and IoT; DTN and HTS technologies; new satellite system architectures and components; high speed optical communications and feeder links; advanced digital payloads and components; satellite antenna technologies; propagation and modelling for satellite communications; future technologies for 5G and beyond; flexible HTS systems and advanced digital payloads; satellite networks design challenges and applications; new satellite components and transmitter and modem technologies; NGSO constellations and 5G integration; and NGSO and GSO system issues and interference mitigation techniques. Offering a wide range of expert perspectives on communications satellite systems, these proceedings will be of interest to engineers and researchers in academia and industry working on satellite, digital, and wireless communications and networks, as well as advanced students, policy makers and stakeholders in the field.