Drawing on lesser-known and often counter-imperial experiences and theories of continental seapower, this chapter develops spacepower concepts that more accurately resemble spacepower as we know it today. This draws out additional insights that theorise the defining feature of spacepower as a more subtle, secondary and supporting form of power. This new vision of spacepower in the celestial coastline of Earth orbit is detailed in Proposition V, and theorises the supporting functions of spacepower’s satellite infrastructure for the first time, as well as their influence on terrestrial strategy. Anti-satellite weapons, logistics, third parties and neutrals, as well as economic warfare in space are addressed and integrated into spacepower theory. Rather than an open ocean, Earth orbit resembles something more like a coastline, a littoral, or flank relative to Earth itself.