Quantum Experiments at Space Scale (QUESS) is an international project which aims to establish a quantum-encrypted European-Asian network by 2020, and a global network by 2030. These experiments are conducted using Micius also known as the Quantum Science Satellite (QSS). Researchers believe the latest experiments conducted using Micius are bringing them closer towards constructing an ultra-long-distance global quantum network.
Micius has successfully demonstrated the first intercontinental quantum key distribution (QKD) by relaying signals between multiple ground stations from China to Austria. A joint China-Austria team of researchers published a study in Physical Review Letters on January 19, 2018 reporting a decoy-state quantum key distribution between Micius operating in a low-Earth orbit (LEO) and various ground stations (OGS).
Micius was built by the Chinese Academy of Sciences, weighs roughly 1,100 lbs, and was originally launched into space on August 15, 2016. The science satellite has the ability to facilitate quantum optics experiments over long distances which allows for the development of different quantum technologies. A quantum key communicator, a quantum entanglement emitter, a quantum entanglement source, a quantum experiment controller and processor, and a high-speed coherent laser communicator are all installed on the spacecraft.
Micius relies on QKD as a means of communication. In a demonstration, the satellite has relayed quantum encrypted data over 4,700 miles in the form of images and a video stream. “This was, on the one hand, the transmission of images in a one-time pad configuration from China to Austria as well as from Austria to China. Also, a video conference was performed between the Austrian Academy of Sciences and the Chinese Academy of Sciences, which also included a 280 kilometer [174 mile] optical ground connection between Xinglong and Beijing,” the scientists wrote.