Satellite-based quantum key distribution in the Arctic: a case study of Finnish Lapland

The advent of quantum computing necessitates the transition from conventional encryption systems to quantum-resistant alternatives. Quantum key distribution (QKD) represents one such approach. Nevertheless, fibre-based QKD is constrained by severe limitations in transmission distance. A promising solution is satellite-based QKD, wherein a satellite establishes secure communication with a ground station. However, daylight presents a considerable challenge for QKD devices, which are highly sensitive to ambient light. Implementing satellite-based QKD in Arctic regions is particularly compelling due to their distinctive annual cycle and prolonged periods of darkness; yet, this possibility has received limited attention in the existing literature. This study assessed the feasibility of satellite-based QKD in regions above the Arctic Circle by simulating a satellite QKD link to three ground stations located in Finnish Lapland: Rovaniemi, Sodankylä, and Utsjoki. The simulation tool comprised MATLAB code for modelling the quantum link, satellite orbital data generated using the Python Skyfield library, and local weather data collected for the year 2024, including cloud cover, rain, snow, ice crystals, and fog. Our findings suggest that while the polar night provides favourable conditions for wintertime quantum communication, continuous daylight during summer and high cloud-cover probabilities may lead to extended service interruptions, severely limiting the achievable secret key material. Optimizing satellite overpass timing substantially reduces outage periods caused by background light; however, this optimization becomes ineffective during summer months due to the persistently high ambient light levels. These constraints underscore the need for robust key-storage mechanisms and careful evaluation of potential use cases. It is recommended that advanced filtering techniques be investigated as a potential means to mitigate summer outage periods caused by excessive ambient light.