The European Space Agency and the Institute of Optoelectronics at China’s Academy of Sciences both claim they’ve achieved gigabit links to satellites in geostationary orbit.

The ESA went first with a February 26th announcement of a successful experiment in which a terminal made by Airbus locked onto the Alphasat TDP 1 satellite, 36 000 km above Earth, and “maintained an error-free connection while transmitting data at 2.6 gigabits per second for several minutes.”

“Establishing laser links between moving targets at this distance is technically very challenging. Continuous movements, platform vibrations and atmospheric disturbances require extreme precision,” said François Lombard, Head of Connected Intelligence at Airbus Defence and Space, in a canned quote. “This milestone is a further development of our long successful laser communication history; it opens the door to a new era of laser satellite communications to meet defence and commercial needs in the next decades.”

China’s Institute of Optoelectronics claimed its tech achieved a 1 Gbps link to a satellite 40,000km away.

In a pair of announcements, the Institute says it developed a 1.8-meter laser ground station that needed just four seconds to make a connection to an unnamed satellite and then held the link for three hours.

During that time, data flowed at a symmetrical 1 Gbps.

Machine translation of the Institute’s announcements tells us the uplink “hinges on high-precision pointing closed-loop control, achieved through micro-radius-level dynamic tracking and real-time compensation using beacon light, ensuring the continuous and accurate projection of 1Gbps signal light onto the satellite.”

The downlink sees integration of “a high-order adaptive optics system and mode diversity coherent reception technology.” The first of those techs corrects for signal distortion caused by atmospheric turbulence in real time, and the second “intelligently synthesizes multiple signals to suppress fading, jointly ensuring clear, stable, and high-speed transmission of the downlink data stream.”

The Institute is enthusiastic about the potential for its tests to enable upload of complex instructions to satellites in high orbit, turning them “from ‘data relay stations’ to ‘intelligent processing hubs,’" and creating “infinite possibilities for us to reach a smart earth, a three-dimensional network, and even deeper space.”

Maybe as scientists they’re too polite to follow Airbus with mentions of potential military applications.

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China in January claimed it achieved 120 Gbps laser networks to low-Earth orbit, topping the 60Gbps it achieved last year. SpaceX’s Starlink service claims each of its third-generation satellites will offer terabit-per-second downlink capacity and more than 200 Gbps of uplink capacity.

Low-Earth orbit comms satellites are less than 1,000 km from terra firma, so don’t have to endure horrid latency.

More distant satellites present more complex problems. Networking wonks are therefore already hard at work adapting existing protocols to work in space, where network nodes can do things like disappearing behind a planet for long periods, or travel so far from Earth that latency stretches into seconds many minutes. Dropping a few packets is no laughing matter under those circumstances.

If these new laser techs can improve matters, they will be most welcome. ®