Chinese scientists have marked a significant milestone in space exploration by successfully conducting the world’s first daytime laser ranging in the Earth-moon space. This groundbreaking achievement overcomes the long-standing challenge of strong solar interference during daylight hours.
On Sunday, a research team from the Yunnan Observatories of the Chinese Academy of Sciences (CAS) captured the laser return signal from the retroreflector of the Tiandu-1 satellite, orbiting approximately 130,000 kilometers from Earth. Utilizing a newly upgraded near-infrared lunar laser ranging system equipped with a 1.2-meter telescope, the team detected the signal despite the intense background noise caused by sunlight.
“This is a major technological breakthrough for China in the field of precise deep-space orbit measurement,” said Li Yuqiang, a researcher at Yunnan Observatories. “Overcoming the interference of strong daylight opens new possibilities for navigation and positioning capabilities in Earth-moon space.”
The successful measurement addresses critical technical challenges, notably the suppression of solar background noise, which has traditionally hindered laser ranging activities during the day. This advancement is expected to bolster future deep-space exploration projects, including the proposed International Lunar Research Station.
The collaborative effort involved 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.
Tiandu-1, a communications and navigation technology test satellite, plays a pivotal role in this achievement. Launched recently, it is currently orbiting between the Earth and the moon, serving as a vital platform for testing and validating new space technologies.
