Quantum secure communications, and in particular QKD, a mature quantum technology for the distribution of encryption keys, have the potential to one day underpin the world’s digital communications. To deliver quantum secured communication between continents, techniques need to be developed to transfer encryption (quantum) keys between ground stations and satellites, and between satellites. This represents a huge opportunity for the space industry. There is growing international interest and investment around Satellite QKD, creating potential for global market opportunities. Early large-scale QKD deployment will be over (already laid down) optical fibre. But quantum keys cannot be transmitted through undersea cables over long distances as photons are lost and crucially cannot pass through the optical amplifiers used in underwater cables. The only way to create global QKD-secured communications will be with satellites. Although there is some photon loss in the atmosphere, it is low enough that quantum light signals could be sent between satellites and ground stations to provide key distribution at useful rates. To make this work, there is a need for collaboration with the space industry to develop new technology and infrastructure to transmit and receive quantum keys between ground stations, satellites and other aerial vehicles. As the technology advances, the space sector will become the providers of launch and management for the QKD satellites that will become an integral part of the world’s future communications infrastructure.

Quantum communications in space opens up new opportunities for the UK space sector in areas including: satellite hosts – delivery platform options, dedicated or shared (for hosted payloads); satellite systems and subsystems – acquisition, pointing and tracking, fine steering mirrors, system and flight software; quantum payloads, photonics components – lasers, non-linear crystals, detectors; optimisation of size, weight and power constraints on small satellites; optical ground stations – telescopes and mounts, tracking systems.