Over the past decade, satellite communications have undergone a profound transformation. What was once a collection of isolated space assets can no longer remain fragmented; it must evolve into a dense, dynamic, and interconnected orbital infrastructure. Mega-constellations in Low Earth Orbit (LEO), alongside Medium Earth Orbit (MEO) and Geostationary Orbit (GEO) systems, are reshaping the architecture of global connectivity. Despite the rapid proliferation of satellites, the sky itself remains segmented across orbital layers, constrained by ground dependence, and limited by intermittent interconnectivity.

This keynote explores how we move from isolated constellations to a fully networked orbital ecosystem; in other words, how we connect the unconnected sky.

At the core of this transformation are intersatellite links (ISLs), enabling satellites to communicate directly and form resilient space-based mesh networks. By reducing reliance on ground gateways, lowering latency, and enabling dynamic routing across orbital planes and between orbital layers, ISLs are redefining satellites from bent-pipe relays into autonomous network nodes in space.

Beyond infrastructure, the keynote examines the expanding user landscape across multiple domains. Satellite constellations are no longer serving only fixed ground terminals; they are becoming the backbone of a vertically integrated connectivity architecture, linking ground users, aerial platforms such as UAVs and high-altitude systems, and space-based assets including other satellites and future in-orbit services.

“Connecting the Unconnected Sky” outlines the technological enablers (RF and optical ISLs), architectural principles, and research directions required to transform orbital assets into a seamless, multi-layer communication architecture, laying the foundation for a truly global, resilient, and persistent space-based network infrastructure.