https://www.cas.cn/syky/202503/t20250319_5059292.shtml

https://www.nature.com/articles/s41586-025-08739-z

Quantum secure communication based on quantum key distribution is the only communication method that can achieve full security so far and could greatly improve the level of information security transmission of existing information systems. Using satellite platforms for free-space quantum key distribution can break through transmission limitations such as optical fiber and achieve global quantum secure communication.

Previously, Chinese researchers used a quantum science experimental satellite “Mozi”  to achieve satellite-to-ground quantum key distribution, but its cost was high and its coverage was limited.  In July 2022, China launched the world’s first quantum micro-nano satellite. The cost of this micro-nano satellite is said to be  only one twentieth of that of the ‘Mozi’, and the satellite’s own weight and payload weight are also reduced by about one order of magnitude, but the frequency of the light source is increased by about 6 times.

A quantum micro-nano satellite operated by CAS University of Science and Technology of China now established optical links with ground optical stations in Jinan, Hefei, Wuhan, Beijing, Shanghai, and Stellenbosch, South Africa, to realize real-time satellite-to-ground quantum key distribution experiments. Using satellites as trusted relays, the research team further realized key sharing and data relay between Beijing Station and Stellenbosch Station in South Africa, which are more than 12,900 kilometers apart on the ground.