Scientists from South Africa and China have successfully established the world’s longest intercontinental ultra-secure quantum satellite link, spanning 12 900km.

Using the Chinese quantum microsatellite Jinan-1, launched into low Earth orbit, this milestone marks the first-ever quantum satellite communication link established in the southern hemisphere, Stellenbosch University (SU) says in a statement.

“In this demonstration, quantum keys were generated in real-time through quantum key distribution, enabling the secure encryption of images transmitted between ground stations in China and South Africa via one-time pad encryption – considered unbreakable,” the statement reads.

The results from this experiment, from a collaborative research initiative between scientists from SU and the University of Science and Technology of China were published in Nature on March 19.

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Stellenbosch’s ideal environmental conditions – clear skies and low humidity – allowed the local ground station to achieve an exceptional key generation rate of 1.07 million secure bits during a single satellite pass.

“Quantum communication leverages fundamental principles of quantum mechanics, guaranteeing highly secure information transfer. Quantum key distribution, a critical component, employs single photons to encode and transmit secure keys. Because single photons cannot be intercepted, copied, or measured without altering their quantum states, this technology provides unparalleled security, even against powerful adversaries,” the statement explains.

China is currently at the forefront of quantum communication technology, guided by quantum physicist Prof Jian-Wei Pan. The country’s extensive quantum infrastructure includes a 2 000km terrestrial fibre-based quantum network connecting 32 trusted nodes across major cities, from Beijing to Shanghai.

Prof Juan Yin was instrumental in developing China’s first quantum satellite, Micius, which previously demonstrated groundbreaking satellite-based quantum links, including a notable 7 600km intercontinental link between China and Austria in 2017. For this South Africa-China collaboration, Yin again led the Chinese research team.

The South African research team at SU’s department of physics was led by Dr Yaseera Ismail, the lead experimentalist responsible for successfully establishing the quantum satellite link.

“International and national collaborations are essential to drive cutting-edge research and push scientific boundaries. Implementing the first quantum satellite link in the southern hemisphere is an outstanding achievement for South Africa, demonstrating the significant potential to develop a thriving quantum ecosystem,” says Ismail.

Prof Francesco Petruccione, a professor of quantum computing in the School of Data Science and Computational Thinking and director of the National Institute for Theoretical and Computational Sciences at SU, pioneered quantum communication in South Africa, notably developing one of the world’s first fibre-optic quantum communication networks in Durban.

This landmark achievement also supports the forthcoming launch of the Stellenbosch Centre for Quantum Science and Technology, which aims to strengthen South Africa’s leading role in quantum research and innovation.

“This successful demonstration of quantum satellite technology firmly positions South Africa as a significant player in the rapidly evolving global quantum technology ecosystem. Collaborations such as this accelerate scientific breakthroughs, build local expertise, and enable translating advanced quantum research into tangible technological solutions,” says Petruccione.

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