China’s 400 Gbps Satellite Laser Link Just Changed the Game!

A record-breaking test by China’s Laser Starcom sets a new standard in orbital communication—and signals a bold new chapter in the space internet race.

By :SpaceEyeNews.

🚀 A Leap in Space-Based Communications

In a stunning display of innovation and precision, China has successfully completed what is now being recognized as the fastest laser communication link ever demonstrated between two satellites in orbit. Conducted by the Beijing-based commercial aerospace company Laser Starcom, this test achieved a 400 gigabit-per-second (Gbps) data link between two low Earth orbit (LEO) satellites—Guangchuan 01 and Guangchuan 02—flying 640 kilometers apart.

The test didn’t just break records; it showcased the maturity of China’s private space sector and its increasing competitiveness in the global race for space-based internet dominance. It also revealed how commercial players are now playing a crucial role in advancing orbital infrastructure once dominated solely by government agencies.

📡 The Mission Breakdown: Speed Meets Precision

The two satellites involved in the test were launched in November 2023 aboard a Zhuque-2 rocket, a methane-fueled vehicle developed by the commercial firm Landspace. The satellites were placed in low Earth orbit at high velocity—approximately 28,000 kilometers per hour (7.8 km/s)—yet managed to establish and maintain an incredibly stable laser link.

The test, conducted on March 18, 2024, achieved a transfer of 14.4 terabytes of data in just 6 minutes and 44 seconds. Although the claimed 400 Gbps speed includes service and protocol data, the effective user data throughput is still over 290 Gbps, making this the most robust intersatellite optical transmission ever reported.

One of the most technically challenging aspects of this achievement lies in the precision required. Laser links in space do not have the luxury of stable, guided channels like fiber optics. Instead, they rely on finely tuned steerable telescopes to maintain alignment between two moving targets. In this test, the company reported tracking errors of less than 5 microradians, or 0.0002865 degrees—an astoundingly precise figure when you consider the spacecraft were 640 km apart and orbiting the Earth at breakneck speed.

Maintaining such tight angular precision in a constantly shifting environment demonstrates not only advanced optical technology but also sophisticated onboard control systems capable of adapting to rapid orbital dynamics.

🛰️ What Sets This Test Apart Globally

The significance of this milestone becomes even clearer when compared to similar efforts worldwide. To date, SpaceX’s Starlink constellation—which has already deployed over 6,000 satellites—uses optical crosslinks rated around 100 Gbps. These allow its satellites to communicate with one another, bypassing the need for ground relays and enabling global low-latency internet coverage.

Meanwhile, Europe’s HydRON project (High-throughput Digital and Optical Network), backed by the European Space Agency (ESA), aims to demonstrate optical communication at speeds of 100 Gbps or higher. ESA’s long-term goal is to eventually reach 1 terabit per second (Tbps) rates, but those targets remain in the experimental phase.

In 2023, MIT’s Lincoln Laboratory, through its TBIRD (TeraByte InfraRed Delivery) project, demonstrated a 200 Gbps space-to-ground optical transmission using a compact satellite payload. That test tackled many challenges of space-to-ground data relay, including atmospheric turbulence, beam scattering, and automatic repeat protocols to ensure error-free transmission.

However, Laser Starcom’s intersatellite achievement—within orbit and across significant separation—marks a first-of-its-kind benchmark for both speed and stability in a peer-to-peer space communication test.

🌐 The Strategic Significance: More Than Just Speed

Beyond the technological marvel, this test represents a strategic pivot in the way global communication infrastructure is being developed.

Laser crosslinks like the one tested by Laser Starcom eliminate the traditional need for constant ground station access. In most current satellite networks, particularly older ones, data must travel from one satellite down to a ground station, be processed or routed, and then potentially uplinked again to a different satellite. This process creates latency, bottlenecks, and vulnerabilities, especially in contested regions or during conflict.

With inter-satellite laser communications, data can remain in orbit, moving directly between satellites with minimal delay and maximum security. For applications like real-time surveillance, military operations, disaster response, autonomous vehicles, and even high-frequency financial transactions, this ability is invaluable.

China’s broader ambitions in this space are no secret. Through projects like Guowang (国网) and Qianfan, the country plans to launch thousands of LEO satellites to create its own global broadband constellation. These would compete directly with Starlink, Amazon Kuiper, and Europe’s upcoming IRIS² network.

What this test reveals is that China’s private sector—once considered a follower in the aerospace race—is now stepping up as a technological leader. The country’s hybrid model of state-driven objectives combined with commercially delivered innovations is accelerating progress on all fronts.

🔬 From Earth to the Moon: Broader Applications

The implications of high-speed, high-precision orbital laser communications extend well beyond internet services.

For Earth observation satellites, the ability to transfer large volumes of imaging or scientific data in real-time is transformative. Typically, such satellites have only a few minutes per orbit to connect with ground stations. With orbital crosslinks, that data can be passed mid-orbit to a satellite with a better Earth-facing downlink, or stored and queued for optimized transmission.

Scientific payloads—whether observing Earth, space weather, or deep-space objects—generate increasingly data-heavy outputs. Traditional RF communication methods cannot keep up with the volume. Laser-based systems, with terabit-per-second scalability, offer the bandwidth required to support missions of growing complexity and resolution.

Perhaps most notably, laser communication systems will be vital for lunar and deep-space missions. China has announced plans for an International Lunar Research Station (ILRS) to be developed in partnership with Russia by the 2030s. Such a station will require fast, reliable, and high-volume communication channels with orbiters, landers, and eventually, human crews. Optical communication is expected to form the backbone of these future architectures.

🧩 Challenges That Remain

Despite the success, several technical and logistical hurdles still need to be addressed before such laser systems become standard.

Atmospheric interference: For space-to-ground links, atmospheric conditions can cause beam distortion or scattering, particularly due to turbulence, weather, or particulates. Adaptive optics and signal redundancy systems are still being optimized to mitigate these effects.
Thermal and power management: High-speed optical transmitters generate significant heat and consume considerable onboard power. These systems must be designed to function reliably in the thermal extremes of space.
Scaling: It’s one thing to achieve a successful test between two satellites—it’s another to deploy and manage hundreds or thousands of interconnected optical terminals in a full-scale constellation.
Security: While laser beams are inherently harder to intercept than radio signals due to their narrow focus, secure encryption and error correction protocols still need to be rigorously implemented and tested under various threat models.

Still, these are surmountable problems. What Laser Starcom’s success shows is that the fundamental components—precision pointing, high data throughput, real-time tracking—are already working as intended in the real world.

🧠 Final Word: Space Internet, Accelerated

China’s successful 400 Gbps intersatellite laser link doesn’t just push the boundaries of what’s technically possible—it pushes the entire world closer to a future where data doesn’t need to touch Earth at all to stay connected.

As nations and companies rush to establish satellite constellations for communications, surveillance, exploration, and control, the real contest may be less about who launches the most satellites and more about who connects them the fastest—and the smartest.

With this test, Laser Starcom has not only raised the bar; it has changed the conversation. The era of optical orbital networking has officially begun.

Reference:

https://spectrum.ieee.org/satellite-internet-china-crosslink