White House tasks NASA to create a clock standard for time on the Moon
In a policy announcement yesterday, the White House has directed NASA to establish a coordinated lunar time standard (dubbed LTC) for time on the Moon, similar to Univeral or Greenwich time (UTC) now used on Earth.
A unified time standard—Coordinated Lunar Time (LTC)—will act as the established standard to enable cislunar operations and can be tied to Coordinated Universal Time (UTC), the primary time standard globally used to regulate clocks and time on Earth. This policy directs NASA to work with the Departments of Commerce, Defense, State, and Transportation to deliver a strategy for the implementation of LTC no later than December 31, 2026. NASA will also coordinate with other federal agencies as appropriate and international partners through existing international forums, including Artemis Accords partner nations.
As noted in the full policy statement [pdf]:
Due to general and special relativity, the length of a second defined on Earth will appear distorted to an observer under different gravitational conditions, or to an observer moving at a high relative velocity. For example, to an observer on the Moon, an Earth-based clock will appear to lose on
average 58.7 microseconds per Earth-day with additional periodic variations.
While this difference would be utterly unnoticed by people, the difference will become a problem for GPS systems and other very sensitive systems that depend on precise timing. The new policy will attempt to prevent such issues by getting ahead of the problem. It will also work to coordinate this new lunar universal time with other nations doing lunar exploration.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
In a policy announcement yesterday, the White House has directed NASA to establish a coordinated lunar time standard (dubbed LTC) for time on the Moon, similar to Univeral or Greenwich time (UTC) now used on Earth.
A unified time standard—Coordinated Lunar Time (LTC)—will act as the established standard to enable cislunar operations and can be tied to Coordinated Universal Time (UTC), the primary time standard globally used to regulate clocks and time on Earth. This policy directs NASA to work with the Departments of Commerce, Defense, State, and Transportation to deliver a strategy for the implementation of LTC no later than December 31, 2026. NASA will also coordinate with other federal agencies as appropriate and international partners through existing international forums, including Artemis Accords partner nations.
As noted in the full policy statement [pdf]:
Due to general and special relativity, the length of a second defined on Earth will appear distorted to an observer under different gravitational conditions, or to an observer moving at a high relative velocity. For example, to an observer on the Moon, an Earth-based clock will appear to lose on
average 58.7 microseconds per Earth-day with additional periodic variations.
While this difference would be utterly unnoticed by people, the difference will become a problem for GPS systems and other very sensitive systems that depend on precise timing. The new policy will attempt to prevent such issues by getting ahead of the problem. It will also work to coordinate this new lunar universal time with other nations doing lunar exploration.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Set the Moon to GMT. Done.
Well, as long as they don’t institute Daylight Savings Time up there . . .
You’ve really only got two options, right? You can either adjust the length of seconds on the moon, which will keep the time read in sync with Terran clocks (but screw up any measurements across time, like velocity or acceleration) or you can throw in a leap second every couplethree weeks to resync.
I suppose you could just not worry about syncing with Earth-time, but that seems unlikely given the effort made to keep clocks and calendars in sync with the motions of the Earth, some of which still apply to the moon.
With GPS all the physics details are hidden by the time you get to the end product; a time and position on earth. But with human observers in very different frames of reference for long times maybe there could be some confusion about observations unless everything is worked out and documented.
One GMT transmission a day is all that is needed to keep the clocks synced,
Waste of time. A distraction.
“similar to Univeral or Greenwich time (UTC)”
A bit trivial, but these are NOT the same. UTC is a time without any timezone information. All timezones are offsets from UTC. GMT is a timezone that is UTC with no offset. The distinction matters when computers are involved. GMT can be converted to another timezone, but UTC cannot.
UTC would of course be the base time count for everything. It already is.
But I was thinking more along the lines of a lunar day/night cycle vs an Earth day/night cycle.
If your lunar base made great use of windows you would thus go by a natural day/night cycle and that would be a little troubling.
Just stick to an Earth style day/night cycle and keep our biological clocks working correctly.
Lunar gravity time distortion is slightly different from no gravity with the larger difference from earths gravity.
Before digital, Earth time pieces have been set to the worldwide broadcast on short wave radio which counts down every minute of every day. I checked, it’s still there and can be synchronized to lunar time pieces. A low tech reliable solution that can be modernized to be laser precise.
yeah, waste of time, huge distraction.
58.7 microseconds difference per earth day adds up to about 2% of a second per year, meaning that in 50 years or so they’d have to leave out a second of LTC in order to stay synced with UTC (which time on earth already does every couple of years — or its opposite: introduce a leap-second — in order to stay synced with the solar and sidereal years).