The White House on Tuesday directed NASA to establish a unified standard of time for the moon and other celestial bodies. The United States aims to set international norms in space amid a growing lunar race among nations and private companies.

The head of the White House Office of Science and Technology Policy (OSTP), according to a memo seen by Reuters, instructed the space agency to work with other parts of the U.S. government to devise a plan by the end of 2026 for setting what it called a Coordinated Lunar Time (LTC).

The differing gravitational force and potentially other factors on the moon and other celestial bodies change how time unfolds relative to how it is perceived on Earth. The LTC would, among other things, provide a time-keeping benchmark for lunar spacecraft and satellites that require extreme precision for their missions.

"The same clock that we have on Earth would move at a different rate on the moon," Kevin Coggins, NASA's space communications and navigation chief, said in an interview.

OSTP chief Arati Prabhakar's memo said that for a person on the moon, an Earth-based clock would appear to lose on average 58.7 microseconds per Earth day and come with other periodic variations that would further drift moon time from Earth time.

"Think of the atomic clocks at the U.S. Naval Observatory (in Washington). They're the heartbeat of the nation, synchronizing everything. You're going to want a heartbeat on the moon," Coggins said.

Mohamed al-Arab, a Lebanese Muslim, shows the different timings on his watch and mobile phone, amid a dispute between political and religious authorities over a decision to extend winter time, in Beirut, Lebanon, March 26, 2023. (credit: REUTERS/MOHAMED AZAKIR)
Mohamed al-Arab, a Lebanese Muslim, shows the different timings on his watch and mobile phone, amid a dispute between political and religious authorities over a decision to extend winter time, in Beirut, Lebanon, March 26, 2023. (credit: REUTERS/MOHAMED AZAKIR)
Under its Artemis program, NASA aims to send astronaut missions to the moon in the coming years and establish a scientific lunar base that could help set the stage for future missions to Mars. Dozens of companies, spacecraft, and countries are involved in the effort.

A "unified lunar time standard" to help in data transfers 

An OSTP official said that without a unified lunar time standard, it would be challenging to ensure that data transfers between spacecraft are secure and that communications between Earth, lunar satellites, bases, and astronauts are synchronized.

The official said time discrepancies could also lead to errors in mapping and locating positions on or orbiting the moon.

"Imagine if the world wasn't syncing their clocks to the same time - how disruptive that might be and how challenging everyday things become," the official said.

Most clocks and time zones on Earth are based on Coordinated Universal Time, or UTC. This internationally recognized standard relies on a vast global network of atomic clocks placed in different locations worldwide. They measure changes in the state of atoms and generate an average that ultimately makes up a precise time.

According to the OSTP official, atomic clocks may need to be deployed on the lunar surface.

The official also said that as commercial activities expand to the moon, a unified time standard would be essential for coordinating operations, ensuring transaction reliability, and managing lunar commerce logistics.

NASA announced in January that it has scheduled its first astronaut lunar landing since the end of the Apollo program in the 1970s for September 2026. A mission flying four astronauts around the moon and back is scheduled for September 2025.

While the United States is the only country to have put astronauts on the moon, others have lunar ambitions. Countries are eyeing potential mineral resources on the moon, and lunar bases could help support future crewed missions to Mars and elsewhere.

China said last year it aims to put its first astronauts on the moon by 2030. In January, Japan became the fifth country to put a spacecraft on the moon. Last year, India became the first country to land a spacecraft near the unexplored lunar south pole, and it announced plans to send an astronaut to the moon by 2040.

The OSTP memo stated, "U.S. leadership in defining a suitable standard—one that achieves the accuracy and resilience required for operating in the challenging lunar environment—will benefit all spacefaring nations."

The memo said defining how to implement Coordinated Lunar Time will require international agreements through "existing standards bodies" and among the 36 nations that have signed a pact called the Artemis Accords involving how countries act in space and on the moon. China and Russia, the two leading U.S. rivals in space, have not signed the Artemis Accords.

The OSTP official said Coordinated Universal Time might influence how Coordinated Lunar Time is implemented. The U.N.'s International Telecommunication Union defines Coordinated Universal Time as an international standard.