Scientists say the Moon needs its own lunar time zone. Here’s why. : ScienceAlert
On July 21, 1969, Neil Armstrong took that fateful first step towards the moon. The exact moment happened just as our planet’s universal standard time reached 2:56 a.m. But what time was it for Neil?
There is currently no answer to this question, but with plans in place to inhabit the Moon, that may have to change.
At a recent meeting in the Netherlands, members of space organizations around the world agreed that we need to implement an appropriate lunar time zone – an internationally accepted common lunar reference time that all future missions can use to communicate and navigate easily.
“A joint international effort is now launched to achieve this,” said navigation system engineer Pietro Giordano of the European Space Agency (ESA).
The recent Dutch meeting was organized and led by ESA researchers, but the discussion was extremely collaborative.
The aim is to put in place a mutually agreed framework, called the LunaNetwhich will provide a common interface for all future lunar missions, streamlining their network, navigation, detection, information and communication.
Timing will be the key to these future operations.
In the coming years, several robotics undercarriages will be sent to the Moon by various space organizations and private companies. In addition, ESA, NASA, the Japan Aerospace Exploration Agency (JAXA) and the Canadian Space Agency (CSA) are working together to establish an orbiting lunar station, called gatewayfrom where future expeditions can depart.
“These missions will not only be on or around the Moon at the same time, but they will also often interact – potentially relaying communications for each other, conducting joint observations or performing rendezvous operations,” bed an ESA press release.
Historically, every mission that has visited the Moon has used the atomic clocks on Earth to track their progress, synchronizing their time in space with their time on Earth.
It basically requires “calling over the radio” and asking people on Earth what time it is, while also taking into account how long it takes to make that call.
A normal old clock aboard a spaceship just won’t do. The forces of gravity and velocity are different on the Moon, meaning they impact the weather in different ways than forces closer to our own planet.
Concretely, this means that if a lunar astronaut brought a watch from Earth with him, it would run faster than normal by tens of microseconds per day. The speed depends on whether that astronaut is in orbit or standing on the Moon itself.
Under these complex conditions, stable timing tuned specifically to the Moon will be difficult to establish, but it could be more accurate and faster than synchronization with Earth time.
This is what scientists are discussing right now. Do we stick to earth time or do we switch to lunar time?
This latter scenario will require setting up a working lunar time system and a common coordinate system for the Moon’s surface, like what we use on Earth to track orbiting satellites.
This may take more energy and effort, but it could result in a much more accurate system – which could then be applied to other planets as well.
“Of course, the agreed time system will also have to be convenient for the astronauts,” explain Bernhard Hufenbach, head of strategic planning at ESA.
“It will be quite a challenge on a planetary surface where, in the equatorial region, each day lasts 29.5 days, including frigid fifteen-day lunar nights, with all of Earth just a small blue circle in the dark sky.”
This is a mathematician’s dream puzzle.
“Throughout human history, exploration has actually been a key driver for improving timing and geodetic reference models,” said Javier Ventura-Traveset, who coordinates ESA contributions to LunaNet.
“It’s certainly an exciting time to do this now for the Moon…”