TOKYO - Countries are gearing up to establish a unified lunar time standard, with a key international conference in Paris in October set to take up the issue amid a global race to establish a presence on the Moon.
Member states will try to work it out at the plenary meeting of the General Conference on Weights and Measures, which decides global measurement standards, as operations including the construction of a permanent base and lunar navigation are expected to be in full swing from around 2030.
China and the United States are among the countries pursuing plans to land astronauts on the lunar surface and secure lunar resources.
Under the theory of general relativity, time on the Moon passes slightly faster than on Earth because lunar gravity is only about one-sixth of Earth's, meaning lunar time runs ahead of time on Earth by around 56 microseconds per day.
The difference between time on the Moon and on Earth is believed to pose problems for future lunar missions.
In building a lunar base, for example, operators must know the exact location where work is being done. Signals from satellites orbiting the Moon are expected to be used to calculate positions, similar to Earth's Global Positioning System.
Lunar time needs to be accurate, because a timing error of just 1 microsecond can change a calculated position by about 300 meters, potentially affecting robots working at a lunar base.
Mamoru Sekido, a research manager at Japan's National Institute of Information and Communications Technology, said international cooperation to coordinate and unify time standards for satellites operated by different countries is vital for lunar development.
There are two proposals for setting lunar time. One assumes a hypothetical clock at the Moon's center of mass and calculates lunar time from it, while the other uses a real clock placed at the Moon's average surface height as the reference, an approach that would be closer to how time is defined on Earth.
