The laser has the power of a night light, the satellite is 36,000 kilometers above our heads. However, data flow is five times faster than that of Starlink. It is the technological prowess that Chinese scientists have just accomplished. They managed to overcome one of the biggest obstacles to the Internet of the future. A step forward that positions the Chine Like an essential actor in the new space race.
What does this Chinese technological feat consist of?
The feat is in size. Chinese researchers have managed to transmit data at a speed of 1 gigabit per second (GBPS) from a satellite in very high orbit (geostationary, 36,000 km) using a laser Very low power, barely 2 watts. It is a performance which, on paper, largely surpasses network capacities Starlink de SpaceX, whose thousands of satellites operate at an altitude 60 times lower. Succeeding such a long -distance transmission with so little power was considered an immense challenge.
How did they manage to overcome atmospheric obstacles?
The main enemy of laser communication from space is the turbulence of our atmosphere. It deforms and weakens the light signal, a bit like the heat deforms the air above a road in summer. To counter this effect, the Chinese team has developed an innovative method called “Synergie Ao-MDR”.
- Adaptive optics (AO): The reception telescope, on Earth, is equipped with 357 micro-mirrors which deform in real time to “straighten” the laser beam and correct the distortions.
- Reception in diversity mode (MDR): The signal, even corrected, is still dispersed. This technique makes it possible to capture it on several channels and an algorithm permanently chooses the three best signals to reconstruct the data reliably.
It is the combination of these two techniques which made it possible to obtain a stable and powerful signal, despite the distance and the low power of the laser.
What are the implications of this advance?
This success is not just a simple laboratory experience. It could change the situation for global communications. By proving that it is possible to transmit very high speed data from the geostationary orbit with little energy, the Chine opens the way to an internet by satellite Faster and more efficient. This technology could exceed the bandwidth limits of traditional radio waves and have concrete applications: streaming in very high definition without interruption, more precise GPS, and above all, more reliable communications for future spatial exploration missions to the Moon or Mars.
No more questions
Why is it so difficult to communicate with a laser from space?
The major challenge is the atmospheric turbulence. The different layers of the earth’s atmosphere, with their variations in temperature and density, act like thousands of moving lenses. They deviate and deform the laser beam in an unpredictable way, which blurs the signal and can cut communication.
Is this technology really better than Starlink?
In terms of raw speed on a single connection, the Chinese experience (1 GBPS) is greater than the typical flows of Starlink (a few hundred Mbps at best). However, you have to compare what is comparable. This is a technological demonstration from a single satellitewhile Starlink is an already operational sales service with thousands of satellites. The advantage of China is to do it from a much more distant orbit.
Who are the scientists behind this feat?
It is a team of Chinese researchers led by the teacher Wu Jian of the University of PEKIN Posts and Telecommunications, in collaboration with Liu Chao fromChina Academy of Sciences. The experience took place at the Lijiang Observatory.
