On August 13, the Tianqin Ranging Station at Sun Yat-sen University detected the return signal of the next-generation lunar laser reflector NGLR-1 for the first time, confirming the success of the ranging experiment. This is the first time Chinese scientists have detected the return signal of this lunar laser reflector, making my country the first country, after France, Germany, and the United States, to have achieved measurements on this collaborative target, demonstrating my country's leading capabilities in lunar laser measurement.
At 0:37 a.m. Beijing time on August 13, engineers Han Xida and Wu Xianlin from the Tianqin Ranging Station at Sun Yat-sen University led their team in detecting the laser return signal of the next-generation lunar retroreflector NGLR-1. They initially obtained 17 distance measurements. The experiment was suspended due to weather conditions. Subsequently, at 05:39 a.m., 38 distance measurements were obtained for NGLR-1, confirming the success of the ranging experiment.
In the 20th century, the United States and the Soviet Union placed a total of five laser reflector arrays on the moon for lunar measurement. In 2019, the Tianqin project team completed measurements of these five laser reflectors. On March 2nd of this year, the US Blue Ghost lunar lander launched the sixth laser reflector, NGLR-1, onto the Moon.
Wu Xianlin explained that these tiny "mirrors" are crucial windows for humanity to explore the mysteries of the universe. Each successful laser echo provides unique and crucial data for our understanding of gravity, spacetime, the lunar interior, and the evolution of the Earth-Moon system, helping us gain a deeper understanding of the fundamental laws of the universe and our home.
Han Xida explained that unlike previous-generation corner reflectors, NGLR-1 is not a pieced-together structure but a solid single unit with a 10-centimeter aperture. This can be understood as trying to detect a 10-centimeter object on the vast Moon. While its smaller target makes observation more challenging, it offers higher precision. It eliminates the range spread caused by the lunar libration effect of previous-generation laser reflectors, providing higher ranging accuracy and supporting long-term research in lunar physics, astrophysics, and cosmology.
The Tianqin Project, a space-based gravitational wave detection program proposed by Luo Jun, an academician of the Chinese Academy of Sciences, in 2014, aims to deploy three identical satellites in an equilateral triangle constellation approximately 170,000 kilometers long in Earth orbit around 2035. This constellation will be used to establish a space-based gravitational wave observatory and conduct cutting-edge research in fundamental physics, astrophysics, and cosmology. This achievement is part of the ongoing Tianqin Project.
