Coordinated Lunar Time (LTC)

News Excerpt:

The US Government has directed the National Aeronautics and Space Administration (NASA) to create a time standard for the Moon by 2026.

What is the proposed Lunar Time Standard?

  • The US government has asked NASA to finalise the strategy for establishing a Coordinated Lunar Time (LTC) by the end of 2026.
  • Various international bodies and private companies can coordinate their activities on the lunar surface using the Lunar Time Standard.

Time standards:

  • Time standards specify how to measure time intervals and define units like seconds, minutes, and hours. 
    • They are different from time zones, which are dependent on geographical areas.
  • Time standards synchronise clocks and establish rules for adjusting leap years and seconds to achieve accuracy.

How does Earth’s time standard work?

  • Most of the clocks and time zones of the world are based on Universal Coordinated Time (UTC).
  • UTC is set by the International Bureau of Weights and Measures in Paris, France. 
  • UTC is essentially an internationally agreed standard for world time.
  • It is tracked by a weighted average of more than 400 atomic clocks placed in different parts of the globe. 
    • Atomic clocks measure time in terms of the resonant frequencies of atoms such as cesium-133. 
      • Resonant frequencies are the natural frequency of an object where it tends to vibrate at a higher amplitude.
      • In atomic time, a second is defined as the period in which a caesium atom vibrates 9,192,631,770 times. 
      • As the vibration rates at which atoms absorb energy are highly stable and ultra-accurate, atomic clocks make for an excellent device for gauging the passage of time.
  • To obtain their local time, countries need to subtract or add a certain number of hours from UTC depending on how many time zones they are away from Greenwich (0 degree longitude) meridian. 
    • If a country lies on the west of the Greenwich meridian, it has to subtract from the UTC, and if on the east of the meridian, it has to add.

Why does the moon need its own time system?

  • Time moves quicker on the Moon by 58.7 microseconds every day as compared to Earth due to less gravity. 
    • An atomic clock on the moon will tick at a different rate than a clock on Earth.
  • Someone on the moon would experience UTC time as distorted, with a terrestrial-based clock appearing to lose 58.7 microseconds each Earth day.
  • That may seem like a tiny difference, but the issues could mount when coordinating activities on the moon, such as a spacecraft seeking to dock on the moon or to undertake a data transfer at a specific time.

Significance of Moon Clock:

  • The LTC would provide a time-keeping benchmark for lunar spacecraft and satellites that require extreme precision for their missions. 
    • Without a unified lunar time standard, it would be challenging to ensure that data transfers between spacecraft are secure and that communications between Earth, lunar satellites, bases and astronauts are synchronised.
    • Discrepancies in time could also lead to errors in mapping and locating positions on the Moon.
  • The necessity for precise coordination and operational efficiency in lunar missions has become increasingly apparent with several countries, including India, US, China and Russia, as well as private players gearing up for lunar expeditions in the latter half of the 2020s. 
    • The US plans to return to the Moon in 2026.

Linking Moon And Earth Time:

  • The focus of the lunar standard time needs to be on four areas:
    • Traceability to UTC.
    • Accuracy sufficient to support precision navigation and science.
    • Resilience to loss of contact with Earth.
    • Scalability to space environments beyond the Earth-Moon system.


  • Implementing a unified time standard for the Moon requires extensive global cooperation and consensus on the scientific intricacies of timekeeping.
  • NASA may face an uphill task of getting US’s two main space rivals, Russia and China, on board.

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