NASA, in collaboration with U.S. government stakeholders, partners, and international organizations, has begun coordinating efforts to establish Standardized Lunar Time (LTC). The move is part of a White House policy initiative to create a future lunar ecosystem that could be scaled to other regions of our solar system.

Lunar time will be determined by a weighted average of the Moon’s atomic clock, similar to how scientists calculate Coordinated Universal Time (UTC) on Earth. However, the Moon’s exact position has not yet been determined, as current analysis suggests that an atomic clock placed on the Moon’s surface would “tick” a microsecond per day faster (a microsecond is one millionth of a second).

A hummingbird flaps its wings about 50 times per second. Each sweep is about 0.02 seconds, or 20,000 microseconds. In space, even small units of time, like 56 microseconds, can make a big difference.

“For an object moving at the speed of light, 56 microseconds is enough time to travel the equivalent of about 168 football fields. “If someone is in lunar orbit, an observer on Earth would think that the astronaut is about 168 football fields away from where they actually are, without the compensating effects of relativity during the day,” said Cheryl Gramling, chief of lunar positioning, navigation, synchronization and standards at NASA headquarters in Washington.

As the agency prepares to establish a permanent presence on the Moon and in orbit with the Artemis program, NASA’s SCaN team will establish a lunar time standard to ensure that critical time differences do not impact astronaut safety. The time systems approach can also be scaled to Mars and other objects in the Solar System, enabling long-term studies.

“As the commercial space industry grows and the number of countries conducting lunar missions increases, the need to standardize timing also increases. Overall timing is a critical part of safe, sustainable, and stable operations,” said Dr. Ben Ashman, Lunar Relay Navigation Development Lead for NASA’s SCaN program.