Micius, named after an ancient Chinese scientist and philosopher, is a satellite launched from a military base in the Gobi desert. Soon photons will be fired at it to see whether quantum physics will allow the secure encryption of long-range communication.

The theory being tested is called quantum entanglement, in which two photons have an invisible and instantaneous connection — a property Albert Einstein described as “spooky action at a distance”, reports the FT.  If the entanglement endures over the distance between Micius and Earth, with information passing through a network of satellites, it will in principle allow for virtually unhackable communications.

The research team will first test sending a secure key from Beijing to the city of Urumqi, on China’s frontier with Central Asia, and then from Beijing to Vienna. The weak signal means it can only be tested at nighttime. If this experiment is successful the team hopes to launch a second satellite within the next four to five years, he said: “for a quantum network, one satellite is not sufficient”

In a quantum Internet, made up of quantum computers, eavesdropping on communication would be impossible. The satellite might also be used for experiments in quantum science over distances that were previously unachievable.  In terrestrial systems the complementary nature of photons degrades after about 300km. The record distance for quantum communication using fibre optics is just over 100km.

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