US space agency Nasa has been instructed by the White House to create a time zone that can be used on the Moon for future missions.
The Lunar Co-ordinated Time is meant to make missions safer and more efficient for ground control and astronauts who land there in future.
Time passes about 58 microseconds faster on the Moon because of its lower gravity and motion relative to Earth.
There's no official time zone for the Moon and each country with a space programme uses its own time zone, usually based on Universal Time or the location of mission control.
"Federal agencies will develop celestial time standardisation with an initial focus on the lunar surface and missions operating in Cislunar space, with sufficient traceability to support missions to other celestial bodies," the White House said on Tuesday.
Timely intervention
"An Earth-based clock will appear to lose on average 58.7 microseconds per Earth day with additional periodic variations.
"This holds important implications for developing standards and capabilities for operating on or around the Moon."
It said that Nasa will work with the Departments of Commerce, Defence, State and Transportation to provide a final strategy of the time zone by December 31, 2026.
The time zone is also being invented to help with navigation on the Moon, as astronauts or robotic crafts could struggle with using GPS (Global Positioning System satellites) that are used by people on Earth.
"At the Moon, synchronising each lunar asset with an Earth-based time standard is difficult — due to relativistic effects, events that appear simultaneous at the Earth (e.g. the start of a broadcast signal) are not simultaneous to an observer at the Moon," the document said.
During the Apollo missions, astronauts used the Co-ordinated Universal Time (UTC) to tell time, as mission control in Houston also uses the same time standard.
The US has renewed plans to explore the Moon, including sending astronauts there later this decade as part of the Artemis programme.
China is also working on plans to send humans to the lunar surface, with both countries aiming for the same region of the Moon.
