Chinese scientists achieve daytime laser ranging in Earth-moon space

Chinese scientists have achieved satellite laser ranging in the Earth-moon space in daytime for the first time in the world, despite the strong daylight interference, said the Yunnan Observatories of the Chinese Academy of Sciences (CAS) Tuesday.

According to Li Yuqiang, a researcher at Yunnan Observatories, a research team on Sunday successfully captured the laser return signal from the retroreflector of the Tiandu-1 satellite, which is approximately 130,000 kilometers away from the Earth, using the newly upgraded near-infrared lunar laser ranging system of a 1.2-meter telescope.

This is the world's first daytime satellite laser ranging in the Earth-moon space, marking a new technological breakthrough for China in the field of precise deep-space orbit measurement, he added.

The measurement has resolved key technical challenges such as the suppression of strong solar background noise, which will help enhance navigation and positioning capabilities in the Earth-moon space. It will also support the argumentation and implementation of major deep-space exploration projects in the future, such as the International Lunar Research Station.

The team was formed by researchers from China's Deep Space Exploration Lab, Yunnan Observatories and Shanghai Astronomical Observatory of the CAS, Sun Yat-sen University, Shanghai Institute of Satellite Engineering, and Beijing Aerospace Control Center.

The Tiandu-1 was a communications and navigation technology test satellite. It was launched on March 20, 2024, and is now orbiting between the Earth and the moon.

(Cover: A demonstration of the distant retrograde orbit. /Technology and Engineering Center for Space Utilization)