China unveils first lunar timekeeping software for Moon missions

Time passes differently on the Moon because of its weaker gravity, causing lunar clocks to tick faster than those on Earth by about 56 millionths of a second per day. While this difference is extremely small, it accumulates over time, making Earth-based timekeeping increasingly unreliable for long-term lunar operations and future permanent infrastructure.

Highly precise lunar–Earth synchronisation

Developed by a research team at the Purple Mountain Observatory in Nanjing, the new model accounts for both the Moon’s reduced gravitational pull and its motion through space. According to the researchers, the system can maintain accuracy within a few tens of nanoseconds over a period of 1,000 years.

From theory to practical software

The model has been packaged into user-friendly software called LTE440, short for Lunar Time Ephemeris. It enables users to compare lunar time with Earth time in a single step, eliminating the need for complex manual calculations. The team noted that LTE440 is in an early phase and will be expanded to support real-time navigation and future lunar clock networks.