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Tel Aviv University inaugurated the first satellite observatory for quantum optical communication

The observatory, one of the most advanced in the world, will be used for tracking, sensing, hyperspectral photography and optical and quantum communication with satellites in orbit around the Earth

Quantum communication satellite. Illustration: depositphotos.com
Quantum communication satellite. Illustration: depositphotos.com

Tel Aviv University inaugurated the first ground station in Israel, and among the most advanced in the world, for tracking, whispering, hyperspectral photography and optical and quantum communication with satellites in orbit around the Earth. The new ground station will also make it possible to conduct experiments in quantum optical communication.

In the first phase of the project, the researchers will try to establish optical communication followed by quantum communication between ground stations, between ground stations and drones and then between ground stations and a satellite of one of the international partners. The hope is that within two to three years, all the resources will be mobilized to build a dedicated blue-white quantum satellite.

track while moving

The station includes a satellite observatory dome with a diameter of 4.25 meters, a tracking system, a primary high-speed camera and secondary tracking cameras, laser equipment, single photon detectors and a tracking robot that enables the simultaneous carrying of two telescopes. At this stage, the arm holds a 24-inch telescope, and in the second stage, the observatory will be equipped with another telescope, designed for photography in the infrared range, as well as dedicated thermal and hyperspectral cameras. In addition to the usual optical communication, which uses lasers or LEDs of different wavelengths, the new ground station will also allow experiments to be conducted in quantum optical communication. Advanced communications use the quantum properties of individual photons to transmit encrypted information. 

"The ground station is intended for viewing satellites, which are small bodies 400-500 km high that move at about 30,000 km/h," says Prof. Yaron Oz, head of the Center for Quantum Science and Technology at Tel Aviv University. "The ability to track satellites is a very delicate skill. The satellite passes very quickly, and at that time you need to photograph it in the center of the image and in several different ranges of the electromagnetic spectrum to learn details about it. This is the first and only satellite observatory in Israel, and it is among the most advanced in the entire world."

"Theoretically, quantum communication is completely encrypted," explains Prof. Oz. "It is impossible to attack it in cyberspace and copy the information, because in quantum mechanics there is a principle that prevents copying. As soon as a third party tries to listen to the message, it destroys the original signal, for example changing the polarization of the photons, and both parties communicating can know that someone tried to listen. That's how it is in theory. In practice, there are quite a few research questions that need to be answered. For example, what do you do with noise in a signal that was not created as a result of listening, for example from the weather? Should you use qubits or qubits, photons with more than two states? And in general, how much information can be transmitted in this way during the limited transmission time when the satellite passes over the ground station? The list of open questions is long. It should be understood that quantum communication is a completely experimental field. There are protocols from experiments conducted in laboratories, but the only country that has successfully demonstrated such communication is China already in 2016. Apparently the Americans also succeeded, but they did not publish anything about it in the scientific press. Apart from these two superpowers, a few countries like Germany, Singapore and now Israel are preparing the ground for demonstrating the ability."

The goal: a dedicated blue and white quantum satellite

In the first phase of the project, the researchers will try to establish optical communication followed by quantum communication between ground stations, between ground stations and drones and then between ground stations and a satellite of one of the international partners. Within two to three years, the researchers hope to raise the resources to build a dedicated blue-white quantum satellite.

"We work with the wall and tower method," says Prof. Oz. "In the beginning, we will place a transmitter on the roof of the second building of the School of Physics, in an attempt to produce an immune quantum key at a rate of hundreds to thousands of bits per second, with the aim of learning and improving the placement, switching and synchronization capabilities of the light sources and the individual photon detectors. In the future we would like to reduce the transmission system and integrate it into an airborne system, initially in drones, and establish a network of quantum communication. In the end, we would also like to launch our own satellite, which will try to communicate quantumly with the ground station and with a similar satellite of Singapore."

Prof. Adi Aryeh also participates in the groundbreaking project From the Ivy and Alder Fleishman Faculty of Engineering, Prof. Haim Suchovski and Prof. Erez Etzion from the School of Physics and Astronomy, the director of the optical ground station Michael Tsukran, Dr. Gary Rosenman, and the research students Yuval Raks and Tomer Nahum. The project is funded by the University's Quantum Center, led by Prof. Yaron Oz and under the administrative management of Ronit Akerman, and by the Israel Space Agency at the Ministry of Innovation, Science and Technology.

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