China Achieves First Daylight Laser ranging in Earth-Moon space">
Beijing — April 29, 2025 —
In a landmark achievement, China’s Tiandu-1 satellite has successfully performed daylight laser ranging in Earth-moon space. This breakthrough, announced on April 29, 2025, overcomes previous limitations, as such measurements were formerly restricted to nighttime. The achievement expands the observation window for related technologies. Experts at the Deep Space Exploration lab (DSEL) confirmed the advanced technology, paving the way for more accurate space missions. The expansion allows for more frequent data collection and greater precision in understanding satellite orbits.
China Achieves First Daylight Laser Ranging in Earth-Moon Space
Table of Contents
April 29, 2025
Breaking the Night Barrier
China’s Tiandu-1 communication and navigation technology experiment satellite has achieved a groundbreaking feat: successful laser ranging in Earth-moon space under strong daylight interference. This marks a world first,overcoming the previous limitation of performing such measurements only at night.
Did You Know?
Laser ranging, also known as Satellite Laser Ranging (SLR), is a technique used to precisely measure the distance between a ground station and a satellite by measuring the time it takes for a laser pulse to travel to the satellite and back.
the Deep Space Exploration Lab (DSEL), the satellite’s developer, confirmed the achievement, highlighting it as a significant technological advancement in precision measurement for deep space orbits.
The Challenge of Earth-Moon Laser Ranging
Laser ranging in the vast expanse of Earth-moon space presents formidable challenges.DSEL explained the difficulty in a statement:
Due to the vast scale of Earth-moon space and the extremely high speed of satellite motion, conducting laser ranging on satellites in such an surroundings is akin to aiming at a single hair (sub-millimeter target) from 10,000 meters away while performing precise tracking and signal acquisition.
Previously, satellite laser ranging in Earth-moon space was restricted to nighttime due to light interference. This limitation constrained observation periods and resulted in insufficient frequency of orbital dynamic data collection.
Expanding the Observation Window
The successful laser ranging test under daylight conditions significantly expands the observation window for this technology. According to DSEL, this provides a practical engineering foundation for its widespread request.
Pro Tip
Expanding the observation window allows for more frequent and accurate data collection, which is crucial for improving our understanding of satellite orbits and predicting their future positions.
This advancement is expected to strongly support the validation and implementation of major deep space exploration missions, such as the International Lunar Research Station.
Tiandu-1 and -2: Pioneering satellites
the Tiandu-1 and -2 satellites, the first ever developed by DSEL, were launched into space alongside the Queqiao-2 relay satellite on March 20, 2024.They reached their target circumlunar orbits on march 29 and separated on April 3, according to Xinhua News Agency.
Since then, they have been conducting a series of technological experiments for lunar communication and navigation.
FAQ
- What is laser ranging?
- A technique to measure the distance to a satellite using lasers.
- Why is daylight laser ranging crucial?
- It expands observation windows and improves data collection frequency.
- What are Tiandu-1 and -2?
- Chinese satellites conducting lunar communication and navigation experiments.
