Although space colonization appears to belong to the world of science fiction, private corporations owned by Silicon Valley billionaires—and supported by the US state—have spent billions making it a reality. Analyses of space colonialism have sometimes viewed these projects as distinct from earthly histories of colonialism, instead locating them within traditions of libertarianism, neoliberalism, or techno-utopianism. By reconstructing technology elites’ political visions for celestial settlements within the literature on colonial-era corporations and property, this study argues that the idea of outer space as an empty frontier relies on the same logic of territorialization that was used to justify terrestrial colonialism and indigenous dispossession. It further traces how the idea of “engineering territory” has inspired wider Silicon Valley political exit projects such as cyberspace, seasteading, and network states, which, rather than creating spaces of anarchical freedom, are attempting to recreate the territorial state in new spaces.