astra: extract claims from 2026-02-27-odc-thermal-management-physics-wall

- Source: inbox/queue/2026-02-27-odc-thermal-management-physics-wall.md
- Domain: space-development
- Claims: 1, Entities: 0
- Enrichments: 3
- Extracted by: pipeline ingest (OpenRouter anthropic/claude-sonnet-4.5)

Pentagon-Agent: Astra <PIPELINE>

domains/space-development/orbital-data-centers-require-1200-square-meters-of-radiator-per-megawatt-creating-structural-ceiling-on-gigawatt-scale-compute.md

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+---
+type: claim
+domain: space-development
+description: Radiative heat dissipation in vacuum scales linearly with surface area, making the 1.2 km² radiator requirement for 1 GW compute a fundamental constraint independent of launch costs or technology improvements
+confidence: experimental
+source: TechBuzz AI / EE Times, February 2026 — physics calculation based on Stefan-Boltzmann law for thermal radiation
+created: 2026-04-14
+title: Orbital data centers require ~1,200 square meters of radiator per megawatt of waste heat, creating a structural ceiling on gigawatt-scale compute that is physics-based not engineering-solvable
+agent: astra
+scope: structural
+sourcer: "@techbuzz"
+related_claims: ["[[power is the binding constraint on all space operations because every capability from ISRU to manufacturing to life support is power-limited]]", "[[orbital data centers require five enabling technologies to mature simultaneously and none currently exist at required readiness]]", "[[space-based computing at datacenter scale is blocked by thermal physics because radiative cooling in vacuum requires surface areas that grow faster than compute density]]"]
+---
+
+# Orbital data centers require ~1,200 square meters of radiator per megawatt of waste heat, creating a structural ceiling on gigawatt-scale compute that is physics-based not engineering-solvable
+
+In orbit, all heat dissipation must occur via thermal radiation because there is no air, water, or convection medium. The Stefan-Boltzmann law governs radiative heat transfer, yielding a requirement of approximately 1,200 square meters of radiator surface per megawatt of waste heat dissipated. This scales linearly: a 1 GW terrestrial data center would require 1.2 km² (35 km × 35 km) of radiator area in space. This is not an engineering problem that can be optimized away — it's a physics constraint. Even liquid droplet radiators (LDR), which are 7x lighter than conventional radiators, still require the same surface area for heat dissipation; they only reduce mass, not area. The Starcloud-2 mission (October 2026) deployed 'the largest commercial deployable radiator ever sent to space' for a multi-GPU satellite, suggesting that even small-scale ODC demonstrations are already pushing radiator technology limits. The thermal constraint is binding before launch cost constraints: at $10/kg launch cost, you still cannot deploy enough radiator area for gigawatt-scale compute with current or near-term radiator technology. This creates a structural ceiling on ODC scaling that is independent of the launch cost reduction trajectory.