The White House has directed NASA to develop a lunar timekeeping system to address the unique temporal challenges of the moon. The memo, issued by the head of the US Office of Science and Technology Policy (OSTP), calls for collaboration between NASA, other US agencies, and international partners to establish what’s termed as Coordinated Lunar Time (LTC) by the end of 2026.
LTC is not akin to Earth’s time zones but rather serves as a comprehensive time reference framework for lunar activities. Due to the moon’s lower gravity, time passes slightly faster there – about 58.7 microseconds per day compared to Earth. LTC aims to provide a consistent time standard essential for the precise coordination of lunar missions, including spacecraft and satellites requiring extreme accuracy.
NASA’s top communications and navigation official, Kevin Coggins, highlighted the necessity for each celestial body to have its own time standard, acknowledging the discrepancy in timekeeping between Earth and the moon. The upcoming Artemis program, slated to commence astronaut missions to the lunar surface in September 2026, underscores the urgency of establishing LTC. This initiative also aligns with plans for a scientific lunar base to facilitate future endeavors like missions to Mars, involving numerous companies, spacecraft, and countries.
Without a unified lunar time standard, challenges in data transfer security and synchronization of communications among Earth, lunar assets, and astronauts could arise, as noted by an OSTP official. Moreover, discrepancies in time could introduce errors in mapping and locating positions on or orbiting the moon.
Developing LTC may necessitate deploying atomic clocks on the lunar surface, while its implementation would require international agreements, possibly leveraging existing standards bodies and the Artemis accords involving 36 nations. Despite the absence of signatures from major space competitors like China and Russia, adherence to international standards such as Universal Coordinated Time (UTC) could influence LTC’s adoption.
While the International Space Station will continue to use UTC, determining when LTC begins poses a logistical challenge, compounded by Earth’s own time fluctuations requiring leap seconds. Unlike Earth, the moon won’t observe daylight saving time, ensuring simplicity in lunar timekeeping, as highlighted by Coggins.
