What time is it on the moon? Europe pushing for lunar time zone

The European Space Agency wants to give the moon its own time zone. That could be a challenge in a place where there are 29.5 Earth days between two sunrises and clocks run faster than they do on Earth.

There are actually 29.5 Earth days between two sunrises on the moon

An airplane passes in front of a full moon
The European Space Agency wants to give the moon its own time zone. Right now, moon missions use the time zone of the country operating the spacecraft for the mission. (Marco Ugarte/The Associated Press)

With more lunar missions than ever on the horizon, the European Space Agency wants to give the moon its own time zone. That could be a challenge in a place where there are 29.5 Earth days between sunrises and clocks run faster than they do on Earth. But as more spacecraft are launched beyond Earth's orbit, there's a greater need to standardize times at their space destinations.

This week, ESA said space organizations around the world are considering how best to keep time on the moon. The idea came up during a meeting in the Netherlands late last year, with participants agreeing on the urgent need to establish "a common lunar reference time," said the space agency's Pietro Giordano, a navigation system engineer.

For now, a moon mission runs on the time of the country that is operating the spacecraft. European space officials said an internationally accepted lunar time zone would make it easier for everyone, especially as more countries and even private companies aim for the moon and NASA gets set to send astronauts there.

The space station's time zone solution

NASA had to grapple with the time question while designing and building the International Space Station, fast approaching the 25th anniversary of the launch of its first piece.

While the space station doesn't have its own time zone, it runs on Coordinated Universal Time, or UTC, which is meticulously based on atomic clocks. That helps to split the time difference between NASA and the Canadian Space Agency, and the other partnering space programs in Russia, Japan and Europe.

The international team looking into lunar time is debating whether a single organization should set and maintain time on the moon, according to ESA.

Clocks run faster on the moon

There are also technical issues to consider. Clocks run faster on the moon than on Earth, gaining about 56 microseconds each day, the space agency said. Further complicating matters, ticking occurs differently on the lunar surface than in lunar orbit.

Astronaut Edwin (Buzz) Aldrin Jr. walking on the moon.
In this July 20, 1969, file photo, astronaut Buzz Aldrin, lunar module pilot, is photographed walking near the lunar module during the Apollo 11 mission. Clocks run faster on the moon, and differently on the moon's surface than in orbit. (The Associated Press)

Perhaps most importantly, lunar time will have to be practical for astronauts there, noted the space agency's Bernhard Hufenbach. NASA is shooting for its first flight to the moon with astronauts in more than a half-century in 2024, with a lunar landing as early as 2025.

"This will be quite a challenge" with each day lasting as long as 29.5 Earth days, Hufenbach said in a statement. "But having established a working time system for the moon, we can go on to do the same for other planetary destinations."

Mars Standard Time, anyone?


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