SPOQC mission tests CV payload transmitter.

Researchers at the University of York have designed, built, and tested a continuous variable (CV) payload transmitter for downlink-based quantum key distribution (QKD) from a CubeSat. This work is part of the Satellite Platform for Optical Quantum Communications (SPOQC) mission by Quantum Communications Hub, UK, which launched in March 2026. The continuous variable (CV) QKD scheme allows two parties to share a secret key over distance, and this mission extends these capabilities to a cost-effective platform. This development advances the possibility of worldwide quantum networks by using low Earth orbit satellites for long-distance key distribution. This achievement distinguishes itself from larger, more complex space-based QKD missions like Micius and Jinan-1 by using a smaller, cost-effective CubeSat platform, potentially broadening access to this technology. The University of York team designed and built the complete system, integrating both optical and electronic subsystems while adhering to strict size, weight and…