The communications satellite that China launched from the Gobi Desert on Tuesday is unlike any other system in orbit, eliciting more scrutiny from cyber-security experts than the wireless engineers that usually design the communications payloads in satellites.
It is the world’s first quantum satellite, equipped with transmitters that send messages by exploiting the mysterious laws of quantum theory. The method is vastly different from traditional communications, which send signals either with radio waves or visible light.
The satellite is called the Quantum Experiments at Space Scale, or Quess. After reaching an altitude of 310 miles, it will orbit earth every 90 minutes, according to a report by China’s state news agency Xinhua.
The scientists behind the project will attempt to beam messages to the ground taking advantage of the “quantum entanglement” between photons, or particles of light. The aim is to connect two ground stations, according to the Xinhua report. If successful, the link would extend over 1,200 kilometers between Shanghai and Beijing.
Inside the quantum satellite is a crystal that produces pairs of entangled photons that remain inextricably linked even when one is transmitted over a long distance. According to an article about the Chinese satellite published in the journal Nature in July, messages can be sent by manipulating one of the photons, which will cause changes in the other particle.
The quantum technology is not expected to send signals faster than today’s communications. One of the project’s major concerns is “to boost the rate of data transmission using single photons from megabits to gigabits per second,” according to the Nature article.
But if the technology works, the transmission would be extremely secure, impervious to hacking or wiretapping. Any interference with transmission would be detectable, the Nature article said, allowing people to communicate “safe in the knowledge that any eavesdropping would leave its mark.”
Quantum scientists have already tested the new communications over the air and inside fiber optic cables. But the photons are usually bounced, absorbed, or interfered with in the process, limiting the technology’s range. In trials, scientists have only been able to transmit data over 300 km, and the idea is that space will present fewer obstacles to quantum communication.
