Space Officials Want a Time Zone for the Moon

Lunar timekeeping could help with navigation and communication, but experts say it will be difficult

The Moon
Time moves more quickly on the moon than on Earth because of gravity. NASA / Goddard / Lunar Reconnaissance Orbiter

With dozens of lunar missions planned worldwide over the next decade, the European Space Agency (ESA) has proposed establishing a new time zone on the moon to ease communication in a landscape that will be increasingly filled with spacecraft. 

Currently, each lunar mission uses the time zone of the nation that manages it, which are all linked to the Earth-based coordinated universal time (UTC). But this method is imprecise, and it means that spacecraft operated from different places are not in sync with one another.

The ESA announced efforts to standardize moon time on Monday night, though officials first raised the idea during a meeting of space leaders late last year, writes Marcia Dunn for the Associated Press (AP).

“We agreed on the importance and urgency of defining a common lunar reference time, which is internationally accepted and toward which all lunar systems and users may refer to,” ESA navigation system engineer Pietro Giordano says in a statement. “A joint international effort is now being launched toward achieving this.”

Having a standard lunar time would not only allow for easier communication, but it would also help astronauts navigate. Space agencies plan to install a global satellite navigation system (GNSS) on the moon starting around 2030, writes Nature’s Elizabeth Gibney. This would be similar to how GPS works on Earth, using atomic clock-carrying satellites to calculate locations. 

Still, experts haven’t yet ironed out exactly how the lunar time would work. Clocks move faster on the moon than they do on Earth because of gravity’s ability to warp time: Lunar clocks gain about 56 microseconds every 24 hours, though this also varies depending on where on the moon the clocks are located, per the ESA.

Officials could choose to synchronize lunar time with UTC, or it could be a whole new system separate from ours. 

Like on Earth, they could divide the moon up into distinct time zones, which might make sense if humans establish permanent lunar colonies, Jörg Hahn, an engineer working on ESA’s Moonlight lunar communications and navigation project, tells Nature. They’re also debating who should establish and maintain the new moon time. 

The push for creating a lunar time comes as NASA plans a mission to send the first astronauts to the moon in more than 50 years. China also aims to land its first crew on the moon around the end of the decade. With plans for future lunar base camps, satellites and landers—and hopes of moving deeper into space—officials say timekeeping is imperative.

“This will be quite a challenge,” Bernhard Hufenbach, a member of the Moonlight management team from ESA, says in the statement. “But having established a working time system for the moon, we can go on to do the same for other planetary destinations.”

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