Publications Conference paper · Orbital computing · 2026

Dark Clouds Rising in Low-Earth Orbit: On Environmental Limits to Massive Orbital AI

Robin Ohs, Gregory F. Stock, Andreas Schmidt, Juan A. Fraire, Jörg Ott, and Holger Hermanns

ACM Workshop on LEO Networking and Communication (LEO-NET), co-located with ACM SIGCOMM, pp. 1960–1965, 2026

Abstract

In 2026, we saw rising numbers of proposals for orbital data centers to facilitate AI, e.g., by SpaceX (up to one million satellites), Blue Origin, and Google—yet none include rigorous lifecycle sustainability analysis. We present ESpaS-ODC, a lifecycle carbon model that accounts for the three subsystems physically unavoidable at GPU-class power densities but absent from prior work: a thermal radiator sized from ISS data, solar-array degradation and eclipse margin, and cold-standby spares for no-repair access. Applying the model to an edge data center in a 510 km orbit reveals that the service-overhead-scaled radiator weighs about eleven times the GPU it serves and that modeled power and thermal infrastructure dominate launched component mass—not compute. Using mission duration T as the denominator to amortize launch, re-entry, and manufacturing carbon, model-boundary parity with a global-average terrestrial DC occurs within the first two mission years in our parameter sweep. With respect to a renewables-powered green-energy DC (Finland grid intensity: 68 gCO2e/kWh, PUE: 1.2), parity requires multi-year missions with cold-standby spares compensating the shorter component lifetimes. Idealized dawn-dusk SSO (no-eclipse regime, β > βcrit) eliminates the eclipse battery, cutting modeled component mass significantly (e.g., 25% on the 1 kW-ODC for a 3 yr mission), but leaves the radiator unchanged: high-beta orbits solve the battery problem, not the thermal problem. Finally, carrying one full cold spare (r = 2) increases amortized carbon per GPU hour by 40% on Starship and 34% on Falcon-9 at T = 3 yr, while its dependability benefit remains to be quantified.

Two heatmaps of carbon per GPU-hour against mission years and number of spares, for Starship and for Falcon 9 — Figure CC BY 4.0

Cite

DOI 10.1145/3789240.3827598

BibTeX

@inproceedings{ohs2026darkclouds,
  author    = {Ohs, Robin and Stock, Gregory F. and Schmidt, Andreas and Fraire, Juan A. and Ott, J{\"o}rg and Hermanns, Holger},
  title     = {Dark Clouds Rising in Low-Earth Orbit: On Environmental Limits to Massive Orbital {AI}},
  booktitle = {ACM Workshop on LEO Networking and Communication (LEO-NET), co-located with ACM SIGCOMM},
  pages     = {1960--1965},
  year      = {2026},
  doi       = {10.1145/3789240.3827598}
}

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