the United States wants to determine the time it is on the Moon

The White House has just asked NASA to decide what time it is on our satellite. For scientific reasons, but not only.

The White House Office of Science and Technology Policy explains in its memo that the Biden administration wants to “establish time standards on and around celestial bodies other than Earth.” He therefore asks the American space agency to set the time it is on the Moon, by December 2026. This unified time standard would be called LTC: “Coordinated Lunar Time”.

The reason for this request is that clocks run faster on the Moon. It has a weaker gravitational pull than Earth because of its smaller mass, and time passes just a little faster on the Moon than on Earth: an average of 58.7 microseconds per day. This means that if we put an atomic clock on the Moon, after 50 years it would be one second faster than the same one on Earth.

Space competition

The Americans want to be the first to define what time it is on the Moon because they want to go back, and potentially stay there for a while before going to Mars. NASA’s Artemis program plans a moon landing with humans by September 2026, a first in more than 50 years. And as the competition in this race for presence in space is increasingly important, the Americans want to impose their tempo.

India, Russia, Japan and China are in the running. Beijing, for example, wants to land its first astronauts on the Moon before 2030. The United States wants leadership in defining a time standard. Washington reminds us that it would be chaos if this were not the case on Earth, and explains that a good standardization of lunar time will benefit everyone. This will, for example, allow greater precision in the mooring of vehicles, communication or navigation.