ll 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 satellite at a distance of about 1,000 kilometers (600 miles),” Pan said last year in a Google Hangout session hosted by Physics World.
The Quantum Science Satellite will also conduct communications experiments within China between ground stations in Beijing and Urumqi.
The experimental quantum communications satellite is the latest in a string of Chinese research missions.
China sent a dark matter probe into orbit in December 2015, becoming the country’s first dedicated space-based astrophysics observatory.
The recoverable Shijian 10 capsule launched in April with 19 experiments, including a groundbreaking investigation that showed mammal embryos can develop in space. The craft landed back on Earth after nearly 13 days in orbit.
Later this year, China plans to launch the Hard X-ray Modulation Telescope, a dual-purpose satellite designed to scan the sky and discover new X-ray light sources, while carrying out pointed observations to study black holes and neutron stars in detail.
Researchers are developing the missions — the most ambitious space science projects in China’s history — in parallel with the country’s more well-known human spaceflight and rocket programs.
China’s second human-rated space lab, named Tiangong 2, is scheduled for launch next month from Jiuquan. Two astronauts aboard the Shenzhou 11 capsule will launch as soon as October to dock with Tiangong 2 for a 30-day mission.
The heavy-lift Long March 5 rocket is also scheduled for its maiden flight before the end of 2016, giving China the ability to launch a sample return mission to the moon next year and large segments of the country’s planned space station in the early 2020s.
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