China’s quantum communication satellite, launched last August, is officially operational after four months of in-orbit testing, the Chinese Academy of Sciences (CAS) said Wednesday.

Testing of the satellite, payloads and space-ground links have been completed, the CAS said, adding that everything was operating properly.

The Quantum Experiments at Space Scale (QUESS) satellite is the first-ever space-ground test platform for quantum communication, said Wang Jianyu, executive deputy chief engineer of the project.

The research team has begun to carry out experiments and preliminary data has been obtained, said Pan Jianwei, chief scientist on the project.

China successfully launched the world’s first quantum satellite from Jiuquan Satellite Launch Center on Aug. 16, 2016.

QUESS will explore “hack-proof” quantum communications by transmitting unhackable keys from space, and provide insight into the strangest phenomenon in quantum physics — quantum entanglement.