China has successfully demonstrated two-way laser communication between Earth and the moon, becoming the second country after the United States to achieve this milestone. The project, led by the Chinese Academy of Sciences, involved an experimental satellite orbiting the moon—a satellite that reached lunar orbit despite a launch setback earlier in 2024—and ground-based telescopes located in Yunnan province.

The system achieved a downlink speed of 100 megabits per second (Mbps) and an uplink speed of 1.25 Mbps, according to official reports. While this represents a significant step forward for China’s space communication capabilities, the data rates remain considerably lower than those recorded by NASA in 2013. During a similar lunar laser communications demonstration a decade ago, NASA achieved download speeds of 622 Mbps and upload speeds of 20 Mbps—approximately six times faster for downloads and sixteen times faster for uploads.

Jonathan McDowell, a space historian based in London and former Harvard astronomer, characterized the Chinese and U.S. efforts as comparable but noted the speed gap. He said he was uncertain about the factors contributing to the difference in performance.

Yang Lei, head of the Chinese research team and a specialist in deep-space laser communications, emphasized the advantage of laser technology over conventional methods. He explained that transmitting an 8K high-definition image of the lunar surface would take about four to five minutes using a conventional 54 Mbps microwave link, whereas the 100 Mbps laser link demonstrated by China could reduce this time to roughly 12 seconds.

Laser communication technology is gaining strategic importance as both China and the United States prepare for renewed crewed missions to the moon and aim to establish sustained presences near its south pole. NASA has set a target for its first crewed lunar landing in more than 50 years by 2028.

Current communication systems between Earth and the moon, including China’s Queqiao-2 relay satellite that supports lunar far-side missions, primarily use radio waves. These signals, however, tend to weaken over long distances as they disperse broadly. By contrast, lasers operate at much higher frequencies and can concentrate energy into very narrow beams. This enables higher data rates with smaller and lighter equipment, but also presents significant challenges due to the precision required to maintain the signal over the roughly 384,000-kilometer distance between Earth and the moon.

"Earth-moon communication is like threading a needle from thousands of kilometers away," Yang observed, highlighting the delicate nature of maintaining such a focused laser link across space.