explainer
NASA is tasked with determining the moon's standard time zone, but it's more complicated than you might think.
The U.S. government has tasked its space agency, NASA, with establishing a standard time zone for the moon, known as Coordinated Lunar Time (CLT).
In a memo issued April 2, the U.S. Office of Science and Technology Policy (OSTP) said: [the area within the moon’s orbit]It has sufficient traceability to support missions to other celestial bodies. ” “Traceability” means that the CLT can remain synchronized with time zones around the globe.
This note provides an overview of the following features of the new CLT:
- Traceability to Coordinated Universal Time (UTC – a compromise for both English and French speakers).
- Accurate enough to support precise navigation and science.
- Resilience to loss of contact with the Earth (meaning the CLT can operate independently of the Earth).and
- Scalability to space environments beyond the Earth-Moon system (meaning that other space stations beyond the Moon could use CLT as well).
Don't expect your favorite time zone or calendar app to have CLT as an option just yet. NASA needs to establish CLT by the end of 2026.
Why does the moon need its own time zone?
In layman's terms, we need a reliable “lunar time” geosynchronous system. Due to the lower gravity on the Moon, time moves slightly faster on the Moon than on Earth. That's only 58.7 microseconds (one second is one million microseconds) faster. Every 24 hours of his Earth time.
Although it is the centerpiece of Hollywood blockbusters such as Interstellar, this is not science fiction. The passage of time is affected by gravity, known as “gravitational time dilation.”
Although small, these time differences can cause problems in synchronizing the space station with satellites in lunar orbit.
“Imagine if the world didn't synchronize its clocks to the same time. How disruptive that would be and how difficult everyday life would be,” an anonymous OSTP official told Reuters. Ta.
How can we tell the time on the moon?
Earth uses UTC, or Coordinated Universal Time, to synchronize time zones around the world. UTC is determined by more than 400 atomic clocks maintained at national time laboratories in approximately 30 countries around the world. Atomic clocks use the vibrations of atoms to track time with extreme precision.
A similar atomic clock has been installed on the moon's surface and can read the exact time.
This precision timing system, known as positioning, navigation, and timing (PNT), allows communications systems to measure and maintain precise timing. The Ordnance Survey, a British organization that has been producing maps since 1791, describes the PNT as having three core elements:
- Positioning – The ability to accurately determine one's position and orientation primarily in two dimensions on a printed map, although orientation can also be determined in three dimensions if desired.
- Navigation – Determine both your current and desired location (relative or absolute) and apply corrections to course, direction, and speed to reach your desired location from anywhere in the world, from underground (below the surface of the earth) Function to do. From the surface and from the surface to space.
- Timing – The ability to maintain accurate and accurate time from anywhere in the world.
Does NASA have plans for time zones elsewhere in the universe?
There is no mention of other planetary time zones, but in 2019 NASA's Deep Space Atomic Clock (DSAC) mission tested atomic clocks to improve spacecraft navigation in deep space. The DSAC mission was launched on June 22, 2019, on a SpaceX Falcon Heavy rocket. The rocket he tested an atomic clock in Earth's orbit for a year.
Typically, spacecraft keep accurate time by bouncing a signal to an atomic clock on Earth, which then sends the signal back to the spacecraft. The mission tested whether the onboard atomic clock would maintain accurate time without relying on two-way communication between the spacecraft and the atomic clock on Earth. Timing accuracy is concerned with obtaining an accurate position while allowing the spacecraft to successfully reach its desired location in space.
As NASA's Jet Propulsion Laboratory, the center for robotic exploration of the solar system, explains: “A two-way system that sends a signal from Earth to the spacecraft and back to Earth and back to the spacecraft takes an average of 40 minutes. It takes 40 minutes for your phone's GPS to calculate your location. Imagine if humans traveled to the Red Planet, where they might miss their turn or take several freeway exits before catching up. [Mars]It would be better if the system were one-way, allowing explorers to immediately determine their current location rather than waiting for information to come back from Earth. ”
The mission was successfully completed in 2021, with the onboard atomic clock maintaining correct timing and navigation position.