ESA, Telesat and RAL Space successfully demonstrate Q-Band satellite link over low Earth orbit

This project was funded as an ARTES Advanced Technology activity under the Space for 5G/6G and Sustainable Connectivity programme line, supported by the UK Space Agency. The resulting achievement represents a significant leap forward in satellite communication technologies, validating the performance of millimetre-wave Q-Band communications in LEO. 

The team, brought together experts from the ESA Connectivity and Secure Communications, and Technology, Engineering and Quality directorates, and also marked the first mission for ESA Technology's mobile laboratory van which will support future campaigns, and leveraged expertise from the Technology directorate's Wave Interaction and Propagation section. 

A Q-Band receiver developed by RAL Space was mounted on Chilbolton Observatory’s large 25m dish, which is normally used as a LEO satellite tracking radar. The team at the observatory used this radar tracking capability to monitor the state of the satellite and its orbit effectively during each pass. The team established a stable link with a collocated Ka-Band uplink antenna to the Telesat LEO 3 satellite, and maintained connectivity from approximately 15° elevation to a maximum of 80°.  The Telesat LEO 3 satellite also provided frequency up-conversion to Q-Band, amplification and retransmission to ground. The Telesat satellite station transmitted a DVBs signal with fixed QPSK ¼ modulation and fixed power, with the ESA modem locked with a margin of up to 13 dB and Es/N0 of up to 10.66 dB. 

In addition, thanks to a Software Defined Radio (SDR) available at the receiver, the RAL scientists and engineers collected critical wave propagation data for the entire satellite visibility periods. This allows us to evaluate the characteristics of atmospheric Q-Band propagation channel,. including in-excess attenuation, total attenuation and its components, scintillation and Doppler effect. Such propagation experiments are carried out in collaboration with Joanneum Research, Austria, for their experience with LEO measurements gained in the ESA ARTES W-Cube project. 

By studying Q-band and higher frequency communications, ESA is driving a fundamental shift in how satellite communication systems are conceived. This follows on from the legacy of Alphasat TDP5 and the Aldo Paraboni experiment, where ESA and a Thales Alenia Space-led Italian consortium, conducted a similar technological demonstration in geostationary (GEO) orbit. As the satellite communications market moves further into leveraging LEO capabilities, this latest demonstration showcases ESA’s commitment to driving European industry capabilities in an increasingly competitive global market. 

Demonstrations like this support a potential, more intensive use of Q-Band by LEO constellations, which, in turn, brings several critical advantages such as considerably smaller antennas, making it particularly attractive for aerial and land-mobile satellite communications. The Q-Band over LEO is also attractive for aerial (drone/HAPS) relay backhaul using the 5G New Radio (NR) standard, which is a novel approach for 5G networks. Additionally, Q-Band may be an attractive option for downlinking LEO traffic to gateways, freeing up Ku- and Ka-Band spectrum for additional user traffic. 

The most significant implication is the potential for consumers and business to access a much wider frequency spectrum. Satellite and terrestrial networks convergence is unlocking new innovations which will help connect communities, support emergency response systems, and enabling new possibilities for 5G and future 6G communications across the economy and society. 

Fabrizio De Paolis, ESA’s 5G/6G Implementation Manager, said: “We’re proud to be building truly world-leading connectivity capabilities in Europe and Canada, demonstrations like this showcase how ESA is working hand-in-hand with our industry partners. driving our competitiveness on the global scale.” 

Antonio Franchi, ESA’s Head of Space for 5G/6G and Sustainable Connectivity programme line, said: “We are proud to see our collaboration with Telesat - and now RAL Space - continue to grow, unlocking new opportunities through higher frequency communications. This latest demonstration, supported by the dedicated teams from ESA, is a key step toward enabling new 5G and 6G NTN capabilities. It highlights how our Member States are driving innovation to meet both market needs and societal challenges. Congratulations once again to the entire team!" 

Alberto Ginesi, Head of the Telecom Systems and Techniques Section of the Directorate of Technology, Engineering, and Quality, said: “The quest for higher frequency has always been at the centre of ESA R&D investigations over the last half century. This achievement represents yet another important milestone in that direction and reaffirms the role that the Agency wants to play in helping its member/supporting state industry in exploring innovative systems and technologies.” 

Antonio Martellucci, propagation engineer and Nicolas Floury Head of Wave Interaction and Propagation Directorate of Technology, Engineering, and Quality, said, “The experimental assessment of the satellite radio channel and atmospheric propagation effects at high frequencies is an essential step for the design and operation of efficient and reliable satellite services and provides the foundation for radio regulatory studies. This is made possible by the commitment to develop propagation instruments and experimental techniques in ESA programmes.” 

Mario Neri, Telesat’s Director of Spectrum Strategy, Innovation and Space Sustainability said “Telesat applauds this cooperation with ESA and RAL space. Telesat has been continuously innovating to meet the connectivity demands of the future, and the data collected from this demonstration is invaluable as we consider higher frequency bands for future expansion of the Telesat Lightspeed LEO constellation. I’d personally like to recognise and thank Telesat’s engineering professionals who supported this programme.” 

Dr Emal Rumi, Principal Research and Development Engineer at STFC RAL Space said: “We’re witnessing a shift in satellite communications as many operators move from targeting distant geostationary orbits only to increasingly including low earth orbits. This Q-band breakthrough addresses two crucial challenges – the increasing demand for high-speed data, and the rapid growth of LEO telecommunication satellites. Chilbolton Observatory has been driving telecommunication research since the 1980s, and this milestone demonstrates that our expertise in RF design and signal propagation studies is just as relevant today to support partners delivering new research, technologies, and services.”