China has just launched the world’s first quantum communications satellite. The 600 kg spacecraft blasted off from the Jiuquan Satellite Center in the Gobi Desert at 0140 local time, 16 August. The satellite is both an extreme test of the weird properties of quantum mechanics, and a technology testbed for what could be the start of a global, unhackable communications network.
Officially known as the Quantum Science Satellite (QUESS), the mission has been renamed Mozi after the ancient Chinese philosopher said to be the first in history to conduct optical experiments.
A team led by Jian-Wei Pan of the University of Science and Technology of China in Hefei will conduct their own experiments with QUESS, using photons to test quantum entanglement – in which the quantum properties of two particles are linked even when separated – over a record-breaking 1200 kilometres.
The team will also test quantum key distribution, a form of secure communication in which the laws of quantum mechanics prevent eavesdroppers from snooping in. If successful, they hope to create a communications network.
“For sure, we will launch more satellites to construct a quantum constellation for global coverage,” says Pan.
First, QUESS must undergo three months of testing. “If everything is correct, it will be handed to the scientists for scientific experiment,” say Pan. “We have tried our best to make everything correct. Hopefully there will be nothing going wrong.”
Other groups around the world working on quantum satellites are watching the Chinese mission with interest.
“We can test many things on the ground, but final validation has to be done in orbit,” says Alexander Ling of the Centre for Quantum Technologies in Singapore. “Everyone working on free-space quantum communication is very excited.”