The Moon might soon get its own time zone, an issue the European Space Agency (ESA) believes is urgent.
Space organisations are considering how we can keep time on the Moon, as we enter a “new era of lunar exploration”.
In the next decade, space organisations from around the world have several Moon missions planned.
Currently, time is kept on the Moon, but it is dependent on where the mission is based on Earth, meaning each mission to the Moon operates on its own timescale, ESA explained.
“Up until now, each new mission to the Moon is operated on its own timescale exported from Earth, with deep space antennas used to keep onboard chronometers synchronised with terrestrial time at the same time as they facilitate two-way communications,” the agency said.
“This way of working will not be sustainable however in the coming lunar environment.”
Which is why there is a push for the Moon to have its own time. The discussion is part of a larger effort to agree on a common LunaNet architecture, which would cover communication and navigation services.
LunaNet is a framework of mutually agreed upon standards, protocols and interface requirements that will allow future lunar missions to work together, Javier Ventura-Traveset, ESA’s Moonlight Navigation Manager, explained.
‘Importance and urgency’
At a meeting at the ESA’s European Space Research and Technology Centre (ESTEC)ESA, navigation system engineer Pietro Giordano said implementing time on the Moon was a matter of urgency .
“During this meeting at ESTEC, we agreed on the importance and urgency of defining a common lunar reference time, which is internationally accepted and towards which all lunar systems and users may refer,” he said.
“A joint international effort is now being launched towards achieving this.”
With luna crews using earth time in relation to their country of origin, the way things are working now, the ESA believes this approach will soon be unsustainable.
“Once complete, the Gateway station will be open to astronaut stays, resupplied through regular NASA Artemis launches, culminating in a human return to the lunar surface, progressing to a crewed base near the lunar south pole,” ESA explained.
The benefits of Moon time
“Meanwhile numerous un-crewed missions will also be in place – each Artemis mission alone will release numerous lunar CubeSats – and ESA will be putting down its Argonaut European Large Logistics Lander.”
These missions will be around or on the Moon at the same time and will be interacting with one another.
Bernhard Hufenbach, a member of the Moonlight Management Team from ESA’s Directorate of Human and Robotic Exploration says an agreed time system will be practical for astronauts moving forward.
Jörg Hahn is the ESA’s chief Galileo engineer and is advising on lunar time aspects.
He explained interoperability of time and geodetic reference frames have already been achieved on Earth for Global Navigation Satellite Systems. Today, all smartphones use GNSS.
This success can be replicated on the Moon, though timekeeping up there will present its own challenges, he added.
“Such as taking into account the fact that time passes at a different rate there due to the Moon’s specific gravity and velocity effects,” Dr Hahn said.
Rigorous timekeeping is needed for accurate navigation, ESA explained.
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“This is because a satnav receiver determines its location by converting the times that multiple satellite signals take to reach it into measures of distance – multiplying time by the speed of light,” the agency said.
Mr Hufenbach also acknowledged having a time for the Moon will be a challenge, explaining a day on the Moon is 29.5 days on earth, plus there are freezing fortnight-long lunar nights.
“But having established a working time system for the Moon, we can go on to do the same for other planetary destinations,” he said.
