nd China via conventional networks like the Internet. The key is needed to break the encrypted code.
“The satellite can then establish a quantum cryptographic key, for example, between China and Austria to be the first worldwide secure quantum communication,” Zeilinger said in an interview with Spaceflight Now.
The benefit of quantum communication is in its security. According to a report by Nature in July, the key is derived from the polarization of a string of photons, and any attempt to hack or tinker with the messages is immediately detectable.
“Hack-proof” messages could aid military and government officials, lead to more secure banking services, and help protect personal and corporate intellectual property.
“The idea of the satellite is that you use the quantum channel, as it is called, to establish a key between China and Europe, a secret key which is known only to the two players … And then they can use it to encode and decode a message, and that encoded message can then be sent by any means, like the Internet or whatever you want,” Zeilinger said.
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Pan Jianwei, the Chinese leader of the Quantum Science Satellite project, was a graduate student under Zeilinger in the 1990s. Pan recruited his former teacher and adviser to lead the European side of the mission, which includes several ground stations that will connect with partners in China.
Pan said one of his biggest worries about the mission is ensuring the technology aboard the satellite all works. Some of the equipment has never flown in space before.
“These kinds of experiments have never been done in the sky,” Pan said in an interview with Chinese state television before the launch. “In order to receive good signals from such a long distance, the materials we use for making signals are the best in the world. At the same time, we should make sure the detector works well in high radiation levels because the detector will work for the next two years.”
The technology has tight tolerances, and the telescopes on the satellite and on the ground must be precisely pointed as the craft flies overhead.
Under the properties of quantum theory, the pair of photons should remain entangled over the 4,600-mile (7,400-kilometer) distance from Vienna to Beijing. The Quantum Science Satellite will try to prove it.
“According to quantum mechanics, there is no limit,” Zeilinger said. “But there are people who have the idea that the effect of the phenomenon of coherence between two different places degrades over large distances, which I don’t believe, but it’s interesting to test whether quantum communication survives any distance, as predicted by the theory.”
If the experiment works, Chinese scientists hope to launch a fleet of satellites to create a global quantum communications network. Companies in Europe, China and the United States already use quantum communications in a limited short-range capacity through fiber-optic cables, and Pan said China is working on a terrestrial quantum link between Beijing and Shanghai.
Zeilinger, who is now president of the Austrian Academy of Sciences, expects quantum communications could lead to breakthroughs in the way people and companies send messages.
“I’m personally convinced that when you look at the development of quantum computation and quantum communication, and then you look at the huge efforts which have been done in many countries now, including the U.S., I’m convinced there will be a quantum Internet someday, and there will be quantum computers which will be connected by quantum teleportation,” Zeilinger told Spaceflight Now.
Quantum teleportation involves replicating the properties of one photon and applying them to another particle in a different location. In the case of the Quantum Science Satellite, Pan’s team plans teleportation experiments by sending signals from the ground to the spacecraft.
“We will be able to transfer the quantum state of a single particle from the ground station to the s