The polycrisis is commonly described as a condition of cascading interdependence, yet International Relations still lacks a clear account of where cascades are transmitted and who controls the transmission. This paper argues that space infrastructure constitutes a distinct class of chokepoint, and that Australia's strategic position is defined less by what it owns in orbit than by what it hosts on the ground. Extending Marshall's maritime chokepoint concept to the space domain, the paper develops a framework of positional dependence, in which control over narrow nodes (deep-space radars, relay ground stations, downlink and launch windows, Southern Hemisphere geography) generates coercive leverage disproportionate to material capability.
Australia is the paradigmatic case. The 2026 National Defence Strategy makes self-reliance and the Strategy of Denial the organising logic of Australian planning, and the accompanying investment program commits to enhanced space domain awareness through the Deep Space Advanced Radar Capability with the United States and United Kingdom, alongside a rescoped multi-orbit Australian Defence Satellite Communications capability after the cancellation of JP 9102. This produces a paradox the paper interrogates: Australia's contribution to allied space power rests on infrastructure whose command, tasking and data architecture Canberra does not wholly control. Hosting, therefore, generates two forms of exposure. Entrapment renders Australian territory a target set in conflicts Canberra does not choose. Abandonment renders Australian access contingent on decisions made elsewhere, a risk sharpened by contemporary doubts about alliance reliability.
Methodologically, the paper applies George's structured, focused comparison to three cases of space-enabled coercion in which host-state politics shaped escalation outcomes, generating conditions under which chokepoint hosting confers leverage rather than vulnerability.
The contribution is conceptual and political. It relocates Australian sovereignty debates from platforms to positions and reframes self-reliance as a question of political control over infrastructure rather than its ownership.
