Space Quantum Communication

Dear Colleagues,

Space quantum communication represents a rapidly expanding research frontier at the intersection of quantum information science, photonics, and space engineering. Moving quantum communication capabilities from terrestrial networks to space is a critical step toward realizing a truly global quantum internet.

In recent years, remarkable experimental progress has been achieved in satellite-based quantum key distribution (QKD), long-distance entanglement distribution, and space-qualified quantum technologies. Demonstrations of QKD through low-Earth-orbit satellites have already shown the feasibility of secure quantum links over thousands of kilometers, far surpassing the limitations of optical fibers. Meanwhile, rapid advances in enabling technologies—such as high-rate single-photon sources, low-noise detectors, adaptive optics, and ultra-stable time synchronization—are improving the performance and scalability of quantum communication systems. Equally important are recent developments in quantum memory and quantum repeater technologies, which promise to overcome distance limitations by enabling the storage, synchronization, and retrieval of quantum states. The successful integration of quantum memories into spaceborne and ground-based platforms will be a decisive milestone toward establishing large-scale, entanglement-based quantum networks.

This Special Issue aims to bring together contributions that explore the theoretical and experimental aspects of space quantum communication. Topics of interest include quantum communication protocols for space applications, satellite-based QKD, entanglement distribution via satellites, quantum memory development for space systems, photonic and optoelectronic components for space environments, quantum repeater architectures, quantum channel modeling, and hybrid ground-to-space network design.

Dr. Laszlo Bacsardi
Dr. Morio Toyoshima
Guest Editors

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