Coordinated Lunar Time or LTC is a proposed primary lunar time standard for the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

. In early April 2024,

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

was asked by the

White House The White House is the official residence and workplace of the president of the United States. It is located at 1600 Pennsylvania Avenue NW in Washington, D.C., and has been the residence of every U.S. president since John Adams in 1800. ...

to work alongside domestic and international agencies for the purpose of establishing a unified standard time for the Moon and other celestial bodies by 2026. The White House's request, led by the

Office of Science and Technology Policy An office is a space where an organization's employees perform administrative work in order to support and realize objects and goals of the organization. The word "office" may also denote a position within an organization with specific dut ...

, called for a "Coordinated Lunar Time", which was first proposed by the

European Space Agency , owners = , headquarters = Paris, Île-de-France, France , coordinates = , spaceport = Guiana Space Centre , seal = File:ESA emblem seal.png , seal_size = 130px , image = Views in the Main Control Room (1205 ...

in early 2023. Currently, the time on the Moon is different for each country involved. As a result, activities on the Moon are coordinated using the time zone of where a mission's headquarters is based. For example, the

Apollo missions The Apollo program was a United States human spaceflight program carried out from 1961 to 1972 by the National Aeronautics and Space Administration (NASA), which landed the first astronauts on the Moon. The program used the Saturn IB and Saturn ...

utilized the

Central Time Zone The North American Central Time Zone (CT) is a time zone in parts of Canada, the United States, Mexico, Central America, some Caribbean Islands, and part of the Eastern Pacific Ocean. Central Standard Time (CST) is six hours behind Coordinate ...

(CDT) as the missions were controlled from Houston, Texas.

History

As part of an ongoing global

billionaire space race The billionaire space race is the rivalry among entrepreneurs who have entered the space industry from other industries - particularly computing. This private industry space race of the 21st century involves sending rockets to the ionosphere (meso ...

and a wider international

space race The Space Race was a 20th-century competition between two Cold War rivals, the United States and the Soviet Union, to achieve superior spaceflight capability. It had its origins in the ballistic missile-based nuclear arms race between the tw ...

between the United States and China, a need exists for a universal time-keeping benchmark so that lunar

spacecraft A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...

and

satellites A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotop ...

are able to fulfill their respective missions with precision and accuracy. Due to differences in

gravitational force In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the strong ...

and other factors, time passes fractionally faster on the Moon when observed from Earth. Under the

Artemis program The Artemis program is a robotic and human Moon exploration program led by the United States' National Aeronautics and Space Administration (NASA) along with three partner agencies: European Space Agency (ESA), Japan Aerospace Exploration ...

, and supported by the

Commercial Lunar Payload Services Commercial Lunar Payload Services (CLPS) is a NASA program to contract transportation services able to send small robotic landers and rovers to the Moon's south polar region mostly with the goals of scouting for lunar resources, testing in situ ...

missions, astronauts and a proposed scientific "

Moonbase A moonbase is a facility on the surface of the Moon, enabling human activity on the Moon. As such, it is different from a lunar space station in orbit around the Moon, like the planned Lunar Gateway of the Artemis program. Moonbases can be for ...

" are envisioned to take place on and around the lunar surface from the 2020s onwards. The proposed standard would therefore solve a current timekeeping issue. According to OSTP Chief

Arati Prabhakar Arati Prabhakar (born February 2, 1959) is an American engineer serving as the 12th director of the Office of Science and Technology Policy, White House Office of Science and Technology Policy (OSTP) and Science Advisor to the President since Oct ...

, currently, 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". The development of the standard is set to be a collaborative effort, initially amongst members of the

Artemis Accords The Artemis Accords are a series of non-binding multilateral agreements between the United States government and other world governments participating in the Artemis Program, an American-led effort to return humans to the Moon by 2025, with the u ...

, but will be meant to apply globally. The initial proposal of the standard calls for four key features: * traceability back to

Coordinated Universal Time Coordinated Universal Time or UTC is the primary time standard by which the world regulates clocks and time. It is within about one second of mean solar time (such as UT1) at 0° longitude (at the IERS Reference Meridian as the currently used ...

, * accuracy sufficient for navigation and science, * resilience to disruptions, and * scalability to potential environments beyond

cislunar Outer space, commonly shortened to space, is the expanse that exists beyond Earth and its atmosphere and between celestial bodies. Outer space is not completely empty—it is a near-perfect vacuum containing a low density of particles, predo ...

space.

LunaNet LunaNet is a NASA and ESA project and proposed data network aiming to provide a "Lunar Internet" for Cis-lunar space, cis-lunar spacecraft and installations. It will be able to Store and forward, store-and-forward data to provide a Delay-tolerant ...

, an upcoming lunar communications and navigation service under development with the

, calls for a Lunar Time System Standard which the LTC is meant to address.

References

Timekeeping Moon

External links

*{{URL, https://www.whitehouse.gov/wp-content/uploads/2024/04/Celestial-Time-Standardization-Policy.pdf, Celestial Time Standardization Memo

History

See also

References

External links