Dirty Bits in Low-Earth Orbit: The Carbon Footprint of Launching Computers

2025-08-08

AI Summary

The carbon footprint of low-Earth-orbit (LEO) satellite-based computing remains poorly quantified across its full life cycle, hindering sustainable space infrastructure development. Method: We conduct a comprehensive life cycle assessment (LCA) covering launch, on-orbit operation, and atmospheric reentry phases, integrating rocket propulsion parameters, orbital payload modeling, and reentry pyrolysis emission estimation. We develop ESpaS—a lightweight, open-source tool enabling the first quantitative comparison of carbon intensities for CPU, memory, and network units in both orbital and terrestrial environments. Contribution/Results: LEO computing exhibits carbon intensity nearly tenfold higher than terrestrial data centers, primarily driven by embodied emissions from launch and reentry. Even with next-generation reusable launch vehicles, this gap persists fundamentally. Our work establishes a carbon-aware space systems design paradigm and calls for cross-domain regulatory frameworks to govern sustainable orbital computing.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Machine Learning: Large Multimodal Models (LMMs)
• Constraint Satisfaction and Optimization: Satisfiability Modulo Theories

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Sustainability and carbon-aware systems for Web, mobile, and WoT
• Responsible Web: Sustainability and climate impact of web technologies
• Economics, Online Markets and Human Computation: Cost models of using LLMs in production systems

Abstract

Low-Earth Orbit (LEO) satellites are increasingly proposed for communication and in-orbit computing, achieving low-latency global services. However, their sustainability remains largely unexamined. This paper investigates the carbon footprint of computing in space, focusing on lifecycle emissions from launch over orbital operation to re-entry. We present ESpaS, a lightweight tool for estimating carbon intensities across CPU usage, memory, and networking in orbital vs. terrestrial settings. Three worked examples compare (i) launch technologies (state-of-the-art rocket vs. potential next generation) and (ii) operational emissions of data center workloads in orbit and on the ground. Results show that, even under optimistic assumptions, in-orbit systems incur significantly higher carbon costs - up to an order of magnitude more than terrestrial equivalents - primarily due to embodied emissions from launch and re-entry. Our findings advocate for carbon-aware design principles and regulatory oversight in developing sustainable digital infrastructure in orbit.

Problem

• Assessing carbon footprint of computing in Low-Earth Orbit satellites
• Comparing orbital vs terrestrial data center emissions
• Evaluating launch and re-entry emissions impact on sustainability

Innovation

• Lightweight tool ESpaS estimates orbital carbon intensities
• Compares launch tech and operational emissions
• Advocates carbon-aware design for orbital sustainability