Published On 5/20/2026
In a step that may reshape the future of space communications, a Chinese team succeeded in sending data from a satellite in geostationary orbit at an altitude of 36 thousand kilometers, using a laser beam whose power does not exceed two watts only, that is, less than the consumption of a small LED lamp.
Despite this modest capacity, the data transfer speed reached 1 gigabit per second, which is about 5 times faster than the usual speeds of the Starlink network.
The achievement was not just a demonstration of technical power, but a scientific experiment to prove that space-based optical communications can work efficiently even from geostationary orbit, which is known to be extremely difficult due to the enormous distance and effects of the Earth’s atmosphere.
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The experiment was conducted using a ground-based telescope with a diameter of 1.8 meters at the Lijiang Observatory in southwestern China, supported by an advanced signal processing system capable of extracting data from a laser beam distorted and scattered by air turbulence.
The atmosphere…the biggest enemy of the laser beam
The main problem was not in the laser itself, but in the long journey it made through the turbulent atmosphere over Yunnan Province. The air consists of layers of varying temperature, density, and refractive index, which leads to the scattering of light and distortion of the light wave front.
Within milliseconds, the coherent laser beam turns into a blurry, vibrating spot when it reaches the observatory, so scientists used two main techniques to address the problem:
- The first is “Adaptive Optics”, which relies on a deformable mirror that includes 357 tiny moving mirrors that adjust their shape instantaneously to compensate for atmospheric distortions.
- The second is pattern diversity reception, where the distorted beam is divided into several spatial channels, and then the best signals are selected among them to reconstruct the original data.
Each technique alone was insufficient to exceed the 1 Gbit/s barrier when using such a weak laser, so the team combined the two methods in one system.
How did the system rebuild the destroyed signal?
The project was led by researcher Wu Jian of the Beijing University of Posts and Telecommunications, in collaboration with Liu Zhao of the Chinese Academy of Sciences. After the signal enters the telescope, it first goes through a stage of optical correction via the adaptive mirror, not with the aim of returning the beam to its ideal state, but rather to reduce optical clutter enough to salvage the signal.
The light then entered a multilevel optical converter, which divided the signal into eight independent channels. A digital processor then analyzed the eight channels and selected only the three best channels, while ignoring the weakest and noisiest signals.
This method increased the “usability of the signal” from 72% to 91.1%, an improvement that allowed a speed of 1 Gbit/s to be achieved using extremely small transmission power. According to the South China Morning Post, this speed is enough to transfer a high-definition movie between Shanghai and Los Angeles in less than five seconds.
Why is the stationary orbit important despite its difficulty?
Low Earth Orbit (LEO) satellites like Starlink have the advantage of being close to Earth, orbiting at an altitude of only a few hundred kilometers. As for the Chinese satellite, it was in fixed orbit, that is, about 60 times farther away.
Although this distance makes communications more complex, a fixed orbit has a crucial advantage: continuity. The moon remains apparently fixed over one point on the Earth, which allows for the establishment of a permanent connection without interruption or switching between the satellites.
This type of link is suitable for emergency networks, secure military channels, and large data transfer stations that require a stable connection around the clock. Laser communications also provide much higher data capacities than radio waves, in addition to being more resistant to interference and interference.
The real achievement was on Earth, not in space
What is interesting about the experiment is that the satellite itself was not exceptional, as the laser used with a power of only 2 watts is not considered powerful by space standards. But the real innovation was the ground station’s ability to “rescue” the signal after it had been destroyed by the atmosphere.
This changes the traditional concept of space communications development, which usually focuses on improving the satellites themselves. In the Chinese experience, the greatest technical burden was transferred to the ground, through highly complex reception and processing systems.
Although the current “Lijiang” system is not a consumer technology that can be used at home, it may represent a future model for giant ground stations that connect satellites to fiber-optic networks to provide faster and more stable communications around the world.
