Timekeeping on the Moon explained

Timekeeping on the Moon is an issue of synchronized human activity on the Moon and contact with such. The two main differences to timekeeping on Earth is the length of a day on the Moon, being the lunar day or lunar month, observable from Earth as the lunar phases, and the differences between Earth and the Moon of how differently fast time progresses, with 24 hours on the Moon being 58.7 microseconds (0.0000587 seconds) faster,[1] resulting from the different masses of the Moon and Earth, the effect being called gravitational time dilation.

History

See also: History of timekeeping devices.

thumb|Buzz Aldrin wearing an Omega Speedmaster watch during Apollo 11 mission in 1969|alt=an astronaut with short hair and wearing a watch, flight suit and commset looks at the camera

The technology used for the timekeeping devices deployed to the Moon have varied over the decades. Several Omega Speedmasters have been on the Moon, synched to Central Standard Time (CST).[2]

The Apollo Guidance Computer (AGC) kept a triple-precision count of time in a real time clock cuing from a quartz oscillator; a standby option (although never used) would allow it to update this count every 1.28 second (~0.78 hertz) — more often when not standing by. In addition to maintaining the clock cycle, computer timekeeping allowed the AGC to display the capsule's vertical and horizontal movements relative to the Moon's surface, in units of feet per second.

Coordinated Lunar Time

Coordinated Lunar Time (LTC) is a proposed primary lunar time standard for the Moon.[3] In early April 2024, the White House asked NASA to work alongside US and international agencies for the purpose of establishing a unified standard time for the Moon and other celestial bodies by 2026.[4] The White House's request, led by the Office of Science and Technology Policy (OSTP), called for a "Coordinated Lunar Time", which was first proposed by the European Space Agency in early 2023.[5]

, there is no lunar time standard. As a result, activities on the Moon are coordinated using the time zone of where a mission's headquarters is based.[6] For example, the Apollo missions utilized the Central Time Zone as the missions were controlled from Houston, Texas.[7] Likewise, Chinese activities on the Moon run on China Standard Time. As more countries are active on the Moon and interact with each other, a different, unified system will be needed.

As part of an ongoing global billionaire space race[8] [9] and a wider international space race between the United States and China,[10] [11] a need exists for a universal time-keeping benchmark so that lunar spacecraft and satellites are able to fulfill their respective missions with precision and accuracy.[12] Due to differences in gravitational force and other factors, time passes fractionally faster on the Moon when observed from Earth.[13] [14]

Under the Artemis program, and supported by the Commercial Lunar Payload Services missions, astronauts and a proposed scientific moonbase are envisioned to take place on and around the lunar surface from the 2020s onwards.[15] The proposed standard would therefore solve a timekeeping issue.[16] According to OSTP Chief Arati Prabhakar, time would "appear to lose on average 58.7 microseconds per Earth-day and come with other periodic variations that would further drift Moon time from Earth time".[17]

The development of the standard is set to be a collaborative effort, initially amongst members of the Artemis Accords, but will be meant to apply globally. The initial proposal of the standard calls for four key features:[18]

LunaNet, an upcoming lunar communications and navigation service under development with the European Space Agency, calls for a Lunar Time System Standard which the LTC is meant to address.[19]

In August 2024, the US National Institute of Standards and Technology furthered development of the proposal by releasing a draft for the standard focused on defining the framework and mathematical model. The draft takes into account the gravitational differences on the Moon and was published to The Astronomical Journal.[20]

Notes and References

  1. Web site: 2024-04-06 . 2024-04-03 . Diana . Ramirez-Simon . Moon Standard Time? Nasa to create lunar-centric time reference system . the Guardian.
  2. . The Watches That Went to the Moon .
  3. Web site: April 3, 2024 . April 3, 2024 . https://web.archive.org/web/20240403162237/esa.int/Applications/Satellite_navigation/Telling_time_on_the_Moon . February 27, 2023 . Telling time on the Moon . live . European Space Agency.
  4. News: 2024-04-03 . 2024-04-02 . https://web.archive.org/web/20240402195402/reuters.com/science/white-house-directs-nasa-create-time-standard-moon-2024-04-02 . 2024-04-03 . Joey . Will . Roulette . Dunham . Reuters . Exclusive: White House directs NASA to create time standard for the moon . live.
  5. Web site: October 26, 2024 . March 1, 2023 . https://web.archive.org/web/20230301040012/nbcphiladelphia.com/news/national-international/should-the-moon-have-a-time-zone-europe-pushes-for-lunar-reference-time/3510971 . March 1, 2023 . Should the Moon Have a Time Zone? Europe Pushes for 'Lunar Reference Time' . live . NBC Philadelphia.
  6. Web site: April 3, 2024 . April 3, 2024 . https://web.archive.org/web/20240403175022/space.com/moon-time-lunar-clock-debate-wristwatch . Joe Rao . May 9, 2023 . Joe . Rao . What time is it on the moon? How a lunar clock debate led to an out-of-this-world timepiece . live . Space.com.
  7. 2024-04-03 . 2023-04-03 . https://web.archive.org/web/20230403113210/nature.com/articles/d41586-023-00185-z . 2023Natur.614...13G . 10.1038/d41586-023-00185-z . Elizabeth . 7946 . Nature . Gibney . 13–14 . 36693973 . 256230630 . What time is it on the Moon? . live . 614 . 2023.
  8. Web site: April 9, 2024 . February 2, 2022 . Terry . Nguyen . It's the dawn of a new space age — at least for billionaires . Vox.
  9. Web site: April 9, 2024 . April 7, 2024 . Sharmila . Kuthunur . White House directs NASA to create a new time zone for the moon . Space.com.
  10. Web site: April 4, 2024 . January 12, 2024 . Joey . Nivedita . Ryan . Roulette . Bhattacharjee . Woo . In moon race with China, U.S. setbacks test role of private firms . Reuters.
  11. Web site: April 4, 2024 . January 12, 2024 . https://web.archive.org/web/20240112012346/space.com/return-to-moon-china-space-race . July 20, 2023 . Rick . Tumlison . Return to the moon: The race we have to win (again) . live . Space.com.
  12. Web site: April 4, 2024 . January 24, 2024 . https://web.archive.org/web/20240124133333/space.com/does-moon-need-its-own-time-zone . March 1, 2023 . Robert . Lea . Does the moon need its own time zone? We may need to decide soon . live . Space.com.
  13. News: 2024-04-03 . 2024-04-03 . https://web.archive.org/web/20240403014614/theguardian.com/science/2024/apr/02/moon-nasa-coordinated-lunar-time . 2024-04-03 . Diana . 0261-3077 . en-GB . Ramirez-Simon . Moon Standard Time? Nasa to create lunar-centric time reference system . live . The Guardian.
  14. Web site: 2024-04-24 . en-US . 2024-04-22 . Sharmila . Kuthunur . What time is it on the Moon? We might soon know . Astronomy Magazine.
  15. Web site: 2024-04-03 . 2024-04-03 . https://web.archive.org/web/20240403000216/esa.int/Applications/Navigation/Telling_time_on_the_Moon . en . Telling time on the Moon . live . esa.int.
  16. Web site: April 4, 2024 . April 4, 2024 . https://web.archive.org/web/20240404225558/smithsonianmag.com/smart-news/the-moon-will-get-its-own-time-zone-called-coordinated-lunar-time-under-nasas-lead-180984076 . April 4, 2024 . Christian . Thorsberg . . NASA Will Create a New Time Zone for the Moon, Called Coordinated Lunar Time . live.
  17. Web site: April 4, 2024 . April 3, 2024 . https://web.archive.org/web/20240403220123/thehill.com/homenews/4573225-nasa-tasked-creating-time-zone-moon . April 3, 2024 . Lauren . Irwin . . NASA tasked with creating a time zone for the moon . live.
  18. Web site: April 4, 2024 . April 4, 2024 . https://web.archive.org/web/20240404144456/whitehouse.gov/wp-content/uploads/2024/04/Celestial-Time-Standardization-Policy.pdf . . April 2, 2024 . Policy on Celestial Time Standardization in Support of the National Cislunar Science and Technology (S&T) Strategy . live . The White House.
  19. Web site: 2024-04-03 . 2024-04-05 . https://web.archive.org/web/20240405115535/spacenews.com/white-house-directs-nasa-to-develop-lunar-time-standard . 2024-04-03 . Jeff . en-US . Foust . White House directs NASA to develop lunar time standard . live . SpaceNews.
  20. 2024-08-12 . NIST . en . What Time Is It on the Moon? .

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Timekeeping on the Moon".

Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2025, A B Cryer, All Rights Reserved. Cookie policy.