For years, quantum communication satellites have worked in one direction only — sending fragile quantum signals from space down to Earth. Research shows that quantum communication networks function properly when operating in reverse mode which enables scientists to build advanced quantum communication systems through optimized operations.
The Physical Review Research journal published research which proved that quantum signals could be transmitted between ground stations and an orbiting satellite. The research discovery creates uncertainty about present scientific understanding which will affect the development of upcoming quantum network infrastructure.
Turning Quantum Communication Upside Down
The current quantum satellite operations rely on a downlink communication method. Entangled particles of light are created aboard the satellite and sent to different locations on Earth, where they are used primarily for ultra-secure cryptographic communication. This method works well for encryption, which requires only a small number of photons.
Quantum computers require high-speed data transfer systems together with strong signal power to establish connections between distant continents.
The idea of generating entangled photons on Earth and sending them upward to a satellite, known as an “uplink,” was long considered unfeasible. Scientists believed that signal loss together with atmospheric interference and background light and alignment problems would prevent such transmissions from happening.
The new research proves otherwise.
A Feasible Quantum Uplink
The study, titled Quantum entanglement distribution via uplink satellite channels, was conducted by researchers from the University of Technology Sydney (UTS), including Professors Simon Devitt and Alexander Solntsev, alongside PhD candidates Srikara S and Hudson Leone.
The team used advanced modeling to show that two separate ground stations could transmit separate photons which would successfully reach a satellite located at 500 kilometers above Earth while maintaining the needed quantum interference.
The researchers included all natural elements which affect their experiment by studying how atmospheric turbulence and Earth background illumination and Moon reflected sunlight and optical system defects affect their results. The uplink method served as an operational solution which addressed particular system operational constraints.
Why This Matters
Ground-based transmitters operating from the ground provide essential advantages which space-based photon sources do not have. They can operate with higher power, are easier to maintain, and can generate much stronger signals. The system produces better results for generating large amounts of photons which future quantum networks need.
The proposed uplink system requires no sophisticated quantum equipment from the satellite. Instead, it only requires a compact optical device to interfere incoming photons and report the measurement results. The system enables satellites to become smaller while simultaneously decreasing their operational expenses and system intricacy.
Professor Devitt indicates that this transformation would enable the development of an actual quantum internet which would link quantum computers between different nations through satellite communication systems operating at low orbital heights.
Building on Global Progress
Quantum satellite communication has experienced rapid development in its current state. The Micius satellite which China launched in 2016 served as the first platform to demonstrate quantum-encrypted communication through space. The Jinan-1 microsatellite established a quantum link which spanned 12,900 kilometers between China and South Africa during 2025.
The new uplink research builds upon previous accomplishments through its ability to provide a larger-scale solution.
Testing the Future
The researchers propose using high-altitude drones and balloon-mounted receivers for initial testing of the concept before deploying the complete satellite system.
The future consequences of this development will impact secure messaging systems and all other related systems.
“In the future, quantum entanglement will be a bit like electricity,” Professor Devitt explains. “It will be generated and transmitted in the background, invisible to users, but powering technologies we rely on every day.”
Collaboration Driving Innovation
The project unites UTS Faculty of Engineering and IT with Faculty of Science to develop quantum networking and photonics and systems modeling capabilities. Scientists from various fields who collaborated have developed new technologies at an accelerated rate according to the research findings.
Quantum communication development needs Earth-based quantum signal transmission to space because it will create a basic connection for global quantum network integration.
