World’s first mobile quantum satellite station is now up and running in China

China has been successful in developing the world’s first portable ground station for sending and receiving secure quantum communications. The station which is up and running has connected to China’s Quantum Science Satellite, nicknamed Mozi, which was launched in August 2016.

Ji-Gang Ren at the University of Science and Technology of China in Hefei and his colleagues used the mobile station to send a secure data transmission from Jinan in north-east China.

When Mozi was first launched, the ground station in use weighed more than 10 tonnes, while the new mobile station weighs about 80 kilograms and is small enough to be installed on top of a car.

The significant downsizing comes with a slight reduction in transmitting power. The mobile ground station transmits data at a rate of between 4000 and 10,000 bits per second, compared with about 40,000 bits per second for larger stations, says Ren.

The team used the mobile ground station to perform quantum key distribution, a form of secure communication in which particles of light, called photons, are transmitted. It enables two parties to share a secret key that is used to encrypt and decrypt information.

A key was relayed via Mozi between the mobile ground station in Jinan and a fixed station in Shanghai.

Ren says that the idea to build a mobile quantum ground station came through demands from users, such as the state-owned Industrial and Commercial Bank of China (ICBC), for equipment that didn’t require purpose-built infrastructure.

ICBC and the People’s Bank of China are already using satellite-based quantum key distribution between distant cities, such as Beijing in north-east China and Urumqi in the far north-west.

Portable ground stations will be used by these banks in the near future, says Ren. They are also being used by the municipal government in Jinan.