At a Glance
- Chinese astronomers unveiled LTE440, the world’s first public lunar timekeeping software.
- The tool compensates for the Moon’s weaker gravity, which causes clocks to gain 58 microseconds every 24 hours.
- LTE440 automates calculations and stays accurate for 1,000 years, according to its creators.
- Why it matters: Precise lunar time is vital for navigation, communications, and upcoming crewed missions from NASA, China, and commercial partners.
China has leap-frogged global competitors by releasing the first publicly available software designed to keep accurate time on the Moon. Researchers at the Purple Mountain Observatory describe the package, dubbed LTE440 (Lunar Time Ephemeris), as ready for immediate use by any nation or company planning future lunar missions.
How Lunar and Earth Time Diverge
Einstein’s general relativity shows that gravity and motion alter the flow of time. Because lunar gravity is roughly one-sixth of Earth’s, a clock on the Moon runs faster, picking up 58 microseconds per Earth day. Over weeks and months the gap widens enough to scramble navigation fixes and radio coordination.
Current missions avoid the problem by anchoring schedules to coordinated universal time (UTC), a reference tied to Earth-bound atomic clocks. As traffic to the Moon increases, engineers say a dedicated lunar standard is essential.
Inside LTE440
LTE440 crunches precise orbital data to track the ever-changing Earth-Moon time difference. Users can query the software for any moment and receive an instant conversion, removing the need for hand calculations.
- Accounts for relativistic effects of the Moon’s motion through space
- Updates automatically as ephemeris data improve
- Distributed free and open-source to encourage adoption
The development team claims accuracy for the next millennium, meaning mission planners can set trajectories years ahead without recalibrating.
Global Push for a Moon Clock
NASA’s Artemis 2 crewed lunar fly-by could lift off as early as February, with Artemis 3’s landing currently targeted for 2028. The agency intends to build a sustained human presence on the surface.
China aims to put its first astronauts on the Moon by 2030, intensifying the timetable for a shared time standard.
The White House has formally directed NASA to craft a Coordinated Lunar Time before the end of this year. In 2025, Congresswoman Jennifer McClellan advanced the Celestial Time Standardization Act through the House Science, Space and Technology Committee to cement a U.S. role in setting the standard.
> “I want to be sure that the United States generally, and NASA specifically, is the leader in creating that time standard,” McClellan told News Of Fort Worth in 2024. “So this bill will help make sure that we’re taking the lead by having NASA, on behalf of the U.S., lead development of a celestial time standard.”
Europe and Commercial Sector Join In
The European Space Agency has invited private companies to submit ideas for a standardized Moon clock, hoping to merge proposals into a single international framework. Commercial partners-from satellite builders to lunar logistics start-ups-say a unified time reference will simplify contracts and reduce costly errors.
Although China’s release gives it first-mover advantage, international negotiators still face technical and political hurdles before a single lunar time zone wins global acceptance.
Key Takeaways
- LTE440 is the first publicly available tool that compensates for relativistic time drift between Earth and the Moon.
- The software’s microsecond-level accuracy will aid navigation, docking, and surface operations for upcoming crewed missions.
- With NASA, China, ESA, and commercial firms all targeting the Moon this decade, a shared time standard is quickly becoming mission-critical.
