Unraveling Physical Space Limits for LEO Network Scalability

Low Earth Orbit (LEO) satellite network is undergoing an explosive expansion to enable high-speed Internet for numerous users anywhere on Earth. However, as a cyber-physical network, the LEO network's sustainable expansion is constrained by its harsh, crowded, and imbalanced physical environment. This position paper dives into two physical constraints for the LEO network scalability: the scale-out limit by satellite safety distances in crowded outer space, and the scale-up limit by the mismatch between the uniform LEO network capacity supply and geographically non-uniform global distribution of user demands. Traditional networking research pays less attention to these physical scaling limits, which may imply a call for a cyber-physical co-design to help the LEO network grow in the challenged space environment.