Spooky Action at a Global Distance -- Analysis of Space-Based Entanglement Distribution for the Quantum Internet*

Recent experimental breakthroughs in satellite quantum communications have opened up the possibility of creating a global quantum internet using satellite links. This approach appears to be particularly viable in the near term, due to the lower attenuation of optical signals from satellite to ground, and due to the currently short coherence times of quantum memories. In this work, we propose a global-scale quantum internet consisting of a constellation of orbiting satellites that provides a continuous, on-demand entanglement distribution service to ground stations. We develop a technique for determining optimal satellite configurations with continuous coverage that balances the total number of satellites and entanglement-bit (ebit) rates. We then determine various optimal satellite configurations for a polar-orbit constellation, and we analyze the resulting satellite-to-ground loss and achievable ebit rates for multiple ground station configurations. We also provide a comparison between these ebit rates and the rates of ground-based quantum repeater schemes. Overall, our work provides the theoretical tools and the experimental guidance needed to make a satellite-based global quantum internet a reality.