European Space Agency wants in on quantum comms satellites

It's fun to kick entangled photons into spaaaace

The European Space Agency is looking to build a communications satellite to send data securely using quantum key distribution.

On Thursday, it signed a contract with SES Techcom S.A, a satellite communications company based in Luxembourg, to develop QUARTZ (Quantum Cryptography Telecommunication System).

Quantum entanglement is a booming area of research. The strange phenomenon of pairs of particles being coupled together in such a way that the quantum state of each particle cannot be described independently of the state of the other is used to probe quantum mechanics, build quantum computers, and form cryptographic keys.

Satellites like QUARTZ act as a mediator between two ground stations that are trying to keep their communications secure. The information describing a string of random numbers is encoded as entangled photons. These are beamed from one ground station into space to the satellite and then sent back to the other Earth-based receiver. The key is then used to decrypt information.

If any adversaries try to tamper with the keys it changes the quantum state of the entangled photons, so the senders know someone has tried to intercept their communication.

Quantum entanglement is tricky to preserve over long distances, and most quantum key distribution is carried by optical fibers that extend to only a few hundred kilometers. By sending photons to and from satellites and ground stations, it allows the secret keys to be sent between people that are much further away.

“QUARTZ is the first commercial step in this direction, aiming to provide a reliable, globally-available system for carrying and dispensing the keys,” the European Space Agency said.

"Under QUARTZ and with the help of ESA, SES plans to develop the platform to be a robust, scalable and commercially-viable satellite-based QKD system for use in geographically-dispersed networks."

QUARTZ won’t be the first quantum communications satellite to set foot in space. The QUESS (Quantum Experiments at Space Scale) project lead by researchers from the Chinese Academy of Sciences launched the Micius satellite in 2016. In 2017, it was reported that the team had managed to keep photons entangled for 1,200 kilometers. ®