【#Tech24H】Deep-space laser communication has long faced three major challenges: distances of hundreds of thousands of kilometers, making it extremely difficult to achieve precise beam alignment; signals weakening to near-undetectable levels by the time they reach Earth, and persistently low transmission speeds. Recently, China’s Earth-Moon laser communication test mission achieved a significant breakthrough, successfully establishing a twoway laser link over a distance of more than 400,000 kilometres between the Earth and the Moon, and realising twoway highspeed laser communication for the first time. This marks the official expansion of China’s space laser communication from nearEarth orbit into the cislunar space domain.[ By Zhang Liyan | Tang Ruohan ]