• China successfully conducted the world's first daytime laser-ranging test in Earth-moon space, achieving precise measurement despite solar interference.
• The experiment involved the Tiandu-1 satellite and demonstrates China's improved capabilities in deep-space communication and navigation.
• This advancement supports China's ambitious lunar plans, including the International Lunar Research Station and future crewed missions.

Chinese scientists have achieved a groundbreaking milestone by successfully conducting a daytime laser-ranging experiment between Earth and the moon. The experiment involved firing a laser from a ground station and bouncing it off a retroreflector on the Tiandu-1 satellite, which is orbiting the moon at a distance of approximately 130,000 kilometers (81,000 miles) from Earth. This feat demonstrates China's enhanced capabilities in deep-space communication and navigation, overcoming the challenges posed by daytime sunlight interference. The successful test has significant implications for future lunar missions and China's broader space exploration program.

• What: China has conducted the world's first daytime laser-ranging test in Earth-moon space, bouncing a laser off the Tiandu-1 satellite orbiting the Moon.
• Who: The experiment was conducted by the Deep Space Exploration Laboratory (DSEL) with support from various institutions, including the Shanghai Academy of Spaceflight Technology, the Chinese Academy of Sciences' Yunnan Observatories, and others.
• When: The test was conducted on April 26 and 27, 2024, following the launch of the Tiandu 1 satellite in March 2024.
• Where: The laser was sent from a station on Earth to the Tiandu-1 satellite orbiting the Moon, approximately 130,000 kilometers (81,000 miles) away.

China's successful daytime laser-ranging test marks a significant advancement in deep-space technology. Overcoming the challenge of solar interference, the experiment demonstrates China's enhanced precision measurement capabilities in Earth-moon space. This achievement supports China's ambitious lunar exploration program, including the International Lunar Research Station, by improving navigation and communication reliability. The development also has implications for future long-distance communication technologies, potentially enabling higher data rates for missions to Mars and beyond. As China continues to invest in space exploration, its advancements may lead to increased competition and collaboration among space-faring nations.

LRO’s altimeter wasn’t built for this type of application, so the chances of pinpointing a tiny retroreflector on the Moon’s surface are already low.

The future is uncertain. [Laser communication] is not an ongoing effort and what the path forward is to developing ground infrastructure (which is critical for operations) is still a question that NASA has to grapple with and come up with sponsorship and all that.

China's successful daytime laser-ranging test to the moon represents a significant step forward in deep-space exploration technology. This achievement enhances China's capabilities in precision measurement, navigation, and communication, supporting its ambitious lunar plans. The successful experiment underscores China's growing role in the global space race and its commitment to advancing space exploration technologies. As China continues to develop its lunar program, the implications for international cooperation and competition in space will continue to evolve.