Scientists from South Africa and China have successfully established the world's longest intercontinental ultra-secure quantum satellite link, spanning 12,900 km. 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.
In this demonstration, quantum keys were generated in real-time through Quantum Key Distribution (QKD), enabling the secure encryption of images transmitted between ground stations in China and South Africa via one-time pad encryption—considered unbreakable. The results from this pioneering experiment from a collaborative research initiative between scientists from Stellenbosch University (South Africa) and the University of Science and Technology of China were published in Nature today
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.
China is currently at the forefront of quantum communication technology, guided by renowned quantum physicist Prof Jian-Wei Pan. The country's extensive quantum infrastructure includes a 2,000 km 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, previously demonstrated groundbreaking satellite-based quantum links, including a notable 7,600 km intercontinental link between China and Austria in 2017. For this South Africa-China collaboration, Prof Juan Yin again led the Chinese research team.
The South African research team at Stellenbosch University's Department of Physics was led by Dr Yaseera Ismail, the lead experimentalist responsible for successfully establishing the quantum satellite link. Prof Francesco Petruccione, Professor of Quantum Computing in the School of Data Science and Computational Thinking and Director of the National Institute for Theoretical and Computational Sciences (NITheCS) at Stellenbosch University, 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.
Reflecting on this achievement, Dr Yaseera Ismail emphasised the importance of collaboration: "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."
Prof Francesco Petruccione added: "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."
Prof Sibusiso Moyo, Deputy Vice-Chancellor for Research, Innovation and Postgraduate Studies at SU, said: "This breakthrough underscores the importance of supporting and investing in the basic sciences such as quantum computing. We are proud that our researchers are pushing the frontiers of science. This work is in line with SU's Vision 2040, to be Africa's leading research-intensive university recognised for its excellence and advancing knowledge in service of society. Congratulations to both teams."
