NASA confirmed on Friday that it’s developing a new lunar time system for the moon. The White House released a policy memo in April directing NASA to create a new standard by 2026. More than five months later (government time, you see), NASA confirmed that it will work with “U.S. government stakeholders, partners, and international standards organizations” to establish Coordinated Lunar Time (LTC).
We only need to look to Einstein to understand why the Moon needs its own time zone. His theory of relativity dictates that time varies with speed and gravity, so that time runs slightly faster on our celestial neighbor (because gravity is weaker). This means that Earth’s clocks on the Moon would gain about 56 microseconds per day – enough to throw off calculations and potentially pose a danger to future missions that require precision.
“For something traveling at the speed of light, 56 microseconds is enough time to cover a distance of about 168 football fields,” Cheryl Gramling, NASA’s lead for timekeeping and standards, said in a press release. “If someone was orbiting the Moon, an observer on Earth who wasn’t correcting for the effects of relativity over the course of a day would think the orbiting astronaut was about 168 football fields away from their actual location.”
National Aeronautics and Space Administration (NASA)
An April White House memo directed NASA to work with the Departments of Commerce, Defense, State, and Transportation to chart a path to implementing the LTC by the end of 2026. Global stakeholders will play a role, particularly signatories to the Artemis Accords. The agreement, which came into force in 2020, includes 43 nations that are committed to the norms expected to be observed in space, and that number continues to grow. Notably, China and Russia have refused to join.
NASA’s Space Communications and Navigation (SCaN) program is leading the effort. One of the goals of LTC is to be able to extend it to other celestial bodies in the future, including Mars. The time base is determined by a weighted average of atomic clocks on the Moon, the location of which is still under debate. Such a weighted average is similar to how scientists calculate Coordinated Universal Time (UTC) on Earth.
NASA plans to return crewed missions to the moon through its Artemis program: Artemis 2, scheduled for September 2025, will send four astronauts into lunar orbit, followed a year later by Artemis 3, which aims to land astronauts near the moon’s south pole.
