IEEE Access

Quantum Key Distribution for Optical Satellite Communications: An Engineering-Oriented Review

A. Popescu, A. M. Badescu

Published Jan 1, 2026• 0 citations

Abstract

Satellite quantum key distribution (SatQKD) is widely regarded as a promising approach for extending quantum-secure key establishment beyond the distance limitations of terrestrial optical fiber links. However, practical assessment of SatQKD remains difficult because published results rely on heterogeneous assumptions regarding channel loss, orbital visibility, atmospheric conditions, detector behavior, finite-key analysis, and classical post-processing efficiency. As a result, comparisons across protocols, architectures, and mission concepts are often difficult to interpret from an operational engineering perspective. This paper presents an engineering-oriented review of SatQKD in the context of hybrid optical satellite communication systems. The review synthesizes prior results reported across protocol-level, link-budget, orbital, finite-key, and network-level studies. Within this scope, service-level notions such as pass-integrated and availability-limited key delivery are used as an interpretive lens for discussing practical relevance under orbital intermittency, atmospheric attenuation, receiver non-idealities, finite-key constraints, and classical post-processing limitations. The contribution of this review is a cross-layer engineering synthesis of prior SatQKD results reported under heterogeneous assumptions, aimed at supporting more consistent operational interpretation across protocols, architectures, and mission concepts.

DOI: 10.1109/access.2026.3696419

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