Author Topic: Mars Timekeeping System  (Read 15422 times)

Offline Tony Whitehead

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Mars Timekeeping System
« on: 11/03/2016 02:53 AM »
I was thinking back to the Andy Weir novel, The Martian, and about how the time was based on elapsed mission time.  If things fall into place as Mr. Musk is planning, that method will have to necessarily change.  A quick Internet search later and I found this link:  http://ops-alaska.com/time/krutein/Marstime2.html

Comments?  Suggestions?

Online RonM

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Re: Mars Timekeeping System
« Reply #1 on: 11/03/2016 03:29 AM »
It might be useful for colonists to have a Mars calendar based on the martian year.

https://en.wikipedia.org/wiki/Timekeeping_on_Mars

http://www.giss.nasa.gov/tools/mars24/help/notes.html

A mars solar day (Sol) is 24 hours 39 minutes 35.244 seconds. I guess one second before midnight on Mars would occur at 24:39:34.244 instead of 23:59:59.  ???

Subdividing by more than a Sol will be confusing when communication with Earth. Of course, if the colonists want to use the SI metric system, then the second has to remain the same.

Offline biosehnsucht

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Re: Mars Timekeeping System
« Reply #2 on: 11/03/2016 04:42 AM »
I imagine you'd use both Earth days and Martian Sols (mostly unless corresponding with Earth or tracking Earthly holidays) to track local time (and use some variation of julian style calendar or something that at least has entirely newly defined months rather than trying to stretch out our regular 12 months to cover 668 days, or add ones to the existing names, since that would cause no end of confusion... ). You'd normally use Martian Sols locally, but generally any time keeping device (we live in the future now, there's not going to be many grandfather clocks operating on Sols) will be able to display the current date/time on Earth as well. There wouldn't be much attempt generally to try and force things to happen on Earth schedules, though I'm sure there's some people who would be celebrating Earth traditional holidays on the days corresponding on Earth just because they want to (so xmas twice a year, for example).

I think as for hours/minutes/seconds, keep the existing units and definitions, and just allow that every day has a weird fractional hour/minute/second. Again, we live in the future, our technology will save us from doing the math, we just know that there's ~24:39:30 in a day (ignoring the extra 5 seconds and change in common conversation, unless there's some kind of science/engineering reason it matters - you won't meat someone at the bar at 24:39:35.244, you'll say "I'll see you there around 24:30!").

As necessary the underlying time system may have various leap years/days/seconds/whatever to maintain sanity, since there's also not a perfectly divisible number of Sols in a Martian Year.

But generally, the h/m/s are the same, just more in a Sol, and different calenders with different names for months, and "new" (actually apparently already existing) words like yestersol and solmorrow, for conversational use. Technology handles all our timekeeping / conversion needs, just as it has been for some time (cell phones, etc).

I tried to find a reasonable division of sols into months that didn't involve silly 30/31/28 day nonsense but 668 sols, ignoring the partial sol, can only be broken down as far as 167 x 4 ... So I'm not sure if we use 4 day weeks and weird alternating month lengths (as we do on Earth), or 8 day weeks (and again weird month lengths, plus a half week somewhere), or stick to 7 days (of which they will rarely coincide with those of Earth, but might be important to some for religious reasons) and still, weird month lengths - and also a partial week again (this time of 3 days rather than 4). The easy option is just to forego weeks and months entirely and use just a straight up Julian system, but psychologically people may still want to have the idea of "weekends", etc. I just can't come up with a non-wonky system of weeks/months (just weeks is easier though).

Either way, it seems the most reasonable plan would be for those who wish to track Earthly traditions to do so separately in addition to local dates using the local Martian calendar, following the actual dates on Earth for their celebrations (xmas two times a year! yay! except not really). There might be new Martian traditions following the new Martian calendar, but probably best to make a clean break and just tear the bandaid off.

Offline MickQ

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Re: Mars Timekeeping System
« Reply #3 on: 11/03/2016 08:08 AM »
20 months of 33 sols leaves an 8 sol surplus that could be a designated festival/ carnival/settlement celebration period.  Martian clocks could run a little fast so that midnight on Earth and on Mars occur at the same instant or use the Martian Timeslip invented by Kim Stanlefy Robinson..  As far as I can see there is no easy way to sync the two planets together.

Offline Beittil

Re: Mars Timekeeping System
« Reply #4 on: 11/03/2016 08:32 AM »
I suppose in relation to Earth they could keep a schedule where they make contact based on UTC time, much like the ISS does.

Offline high road

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Re: Mars Timekeeping System
« Reply #5 on: 11/03/2016 09:24 AM »
Don't forget that people have prefered in the past to divide the year into 'useful' periods, where cycling events in the environment impacts daily activities in some way. So things like 'dust storm season', spare-solar-power season', 'annual meteor shower', 'holliday season' might make it onto the calendar eventually. That's how we ended up with our alternating month lenghts that we've been trying to standardize for milennia.

Religious feasts will continue to be held in reference to Earth time, like Islamic events use the Islamic calendar. But new religions might spring up.

Considering that the greatest impact on activity on Mars for a long time to come will be the arrival and departure of supply missions, maybe it'll be more effective to express time relative to the nearest launch windows, even if it's not fixed. By the time supply missions stop determining the activity in the colony, people might have gotten used to this system, so they no longer wish to change.

Offline Phil Stooke

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Re: Mars Timekeeping System
« Reply #6 on: 11/03/2016 09:50 AM »
We have been using Martian sols for landed missions since 1976 without any difficulty relating Mars time to Earth time.  So for time we need only look at how our Mars rover folk manage.  Dates are another issue, of course, but there is a perfectly good calendar of Mars dates in use now, just using Mars years and sols, used since 2000 on all Mars missions, orbital and surface.  People don't seem to need a week or month in the system.  I just want to emphasize that this subject has not just arisen in a vacuum, there is a longish history of this and a well-established literature, so changes are not very likely.

Offline guckyfan

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Re: Mars Timekeeping System
« Reply #7 on: 11/03/2016 10:41 AM »
We have been using Martian sols for landed missions since 1976 without any difficulty relating Mars time to Earth time.

That's a group of scientists and specialists handle their job. I am quite sure settlers will use something else. They want a structue in their timekeeping they can relate to.

As they would not be very much exposed to the conditions outside they could even use the earth calender in sync with earth. Only the days adapted to the slightly different length of day. After all the Australians celebrate Christmas in summer, too.

Offline JamesH65

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Re: Mars Timekeeping System
« Reply #8 on: 11/03/2016 11:22 AM »
We have been using Martian sols for landed missions since 1976 without any difficulty relating Mars time to Earth time.

That's a group of scientists and specialists handle their job. I am quite sure settlers will use something else. They want a structue in their timekeeping they can relate to.

As they would not be very much exposed to the conditions outside they could even use the earth calender in sync with earth. Only the days adapted to the slightly different length of day. After all the Australians celebrate Christmas in summer, too.

???? Just use Martian days/years. Makes outside jaunts much easier - daylight matches the clock. It's the people on Earth who would need to sync with Mars, not vica versa. The guys on Mars are going to have it difficult enough without having to worry about what time they phone home.

Online philw1776

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Re: Mars Timekeeping System
« Reply #9 on: 11/03/2016 04:04 PM »
Those living on Mars would want a sunlight oriented system for sols like we have on Earth.  I think it's a bad idea to alter the second proportionately as some elsewhere have suggested.  Although not noticed by Mars residents it could complicate engineering calculations and be a source of error.

My radical Mars quirky solution is to use normal Earth hours minutes and seconds but at midnight when all but the night shift and those wild & crazy late night Mars party animals are asleep, have the clocks go to Red Time where the extra 39 minutes 35.244 seconds are added and counted down before resuming at say 12:01.  Mars sols are preserved.  Everyone in the inner solar system is using standard seconds, etc.  And a party time is enshrined in unique Mars culture.
« Last Edit: 11/03/2016 04:05 PM by philw1776 »
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Offline JasonAW3

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Re: Mars Timekeeping System
« Reply #10 on: 11/03/2016 04:16 PM »
Those living on Mars would want a sunlight oriented system for sols like we have on Earth.  I think it's a bad idea to alter the second proportionately as some elsewhere have suggested.  Although not noticed by Mars residents it could complicate engineering calculations and be a source of error.

My radical Mars quirky solution is to use normal Earth hours minutes and seconds but at midnight when all but the night shift and those wild & crazy late night Mars party animals are asleep, have the clocks go to Red Time where the extra 39 minutes 35.244 seconds are added and counted down before resuming at say 12:01.  Mars sols are preserved.  Everyone in the inner solar system is using standard seconds, etc.  And a party time is enshrined in unique Mars culture.

      I played around with the number of seconds in a Mars Sol, working with Mars hours and Mars minutes, but overall, your's seems both the simplest and least problematic solution.  Almost having an additional 40 minutes of sleep per night would probably be welcome by any colonists, although it WILL cause some time synchronization issues with those on Earth.

      Now, what's your thoughts on a Mars Calendar?

      I'm thinking a 7 day week, (about 95.43 weeks a year) a 22 month year with 14 months with 30 days and 8 months with 31 days.  The odd bit at the end would be a Leap Day, to be used every couple of years or so.

      Naming the first ten days could use one through ten in Latin, with the other twelve months pretty much as January through December.

      Alternatively, you could have a year with 24 months, with about 95.5 weeks for the year, with 20 months having 4 weeks, for 28 days each having 4 weeks, and 4 months of 27 days each.  Thewy could be named First January, First February, etc. until First December, then start with Second January, Second February, etc.  This would keep the calendar to a fairly close approximation of the Earth calendar, adding a Leap Day to First February every so often to keep in approximate sync with Earth
« Last Edit: 11/03/2016 04:42 PM by JasonAW3 »
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Offline guckyfan

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Re: Mars Timekeeping System
« Reply #11 on: 11/03/2016 04:25 PM »
Only the days adapted to the slightly different length of day.

???? Just use Martian days/years. Makes outside jaunts much easier - daylight matches the clock.

Maybe you missed this part of my suggestion? I would not suggest having the days divert from local daylight. Only the calendar as close as possible with the earth calender might be a good idea. To make up for the different length of day, occasionally the 31. of a month would need to be skipped.

Offline Jim

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Re: Mars Timekeeping System
« Reply #12 on: 11/03/2016 04:56 PM »
Those living on Mars would want a sunlight oriented system for sols like we have on Earth.  I think it's a bad idea to alter the second proportionately as some elsewhere have suggested.  Although not noticed by Mars residents it could complicate engineering calculations and be a source of error.

My radical Mars quirky solution is to use normal Earth hours minutes and seconds but at midnight when all but the night shift and those wild & crazy late night Mars party animals are asleep, have the clocks go to Red Time where the extra 39 minutes 35.244 seconds are added and counted down before resuming at say 12:01.  Mars sols are preserved.  Everyone in the inner solar system is using standard seconds, etc.  And a party time is enshrined in unique Mars culture.

How does that work for multiple time zones?  And for shift work?
« Last Edit: 11/03/2016 04:56 PM by Jim »

Offline CraigLieb

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Re: Mars Timekeeping System
« Reply #13 on: 11/03/2016 04:59 PM »
Those living on Mars would want a sunlight oriented system for sols like we have on Earth.  I think it's a bad idea to alter the second proportionately as some elsewhere have suggested.  Although not noticed by Mars residents it could complicate engineering calculations and be a source of error.

My radical Mars quirky solution is to use normal Earth hours minutes and seconds but at midnight when all but the night shift and those wild & crazy late night Mars party animals are asleep, have the clocks go to Red Time where the extra 39 minutes 35.244 seconds are added and counted down before resuming at say 12:01.  Mars sols are preserved.  Everyone in the inner solar system is using standard seconds, etc.  And a party time is enshrined in unique Mars culture.

This is nearly what the settlers did in the fictional Mars novels by Robinson.
It was considered a period where non-violent, but outside norms behaviors were tolerated or even encouraged.
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Offline baldusi

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Re: Mars Timekeeping System
« Reply #14 on: 11/03/2016 06:07 PM »
I certainly believe that the SI second should be used. This means that a sol should be defined as either 88,775s or 88,776s.
88,775s factors are 5^2*53*67. So you could have a 25 martian hour with 53 martian minutes of 67 seconds.
88,776s factors are 2^3*3^4*137. So you could have 24 hours, but with just 137 martian minutes of 27 seconds. I guess you could also have 137 martian hours of 9 martian minute of 72 seconds.
Btw, a 25hr of 59minutes of 60 seconds would be off by 275.25seconds/sol.


Offline biosehnsucht

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Re: Mars Timekeeping System
« Reply #15 on: 11/03/2016 10:12 PM »
Apparently some (all?) of our existing Mars rovers use 24 hour clocks with "slow" seconds so that they stretch 24h of onboard time to the actual length of a Sol. I guess this was easier to use existing hardware clocks that only understand earth time?

I think modifying the duration of a second, is a terrible idea. Basic units should mean the same thing, and if you need similar-but-different units, they should be called something else.

Similarly, I think trying to force the martian months to coincide with Earth months is a bad idea, as it will just lead to confusion, as they inevitably drift apart and have to be forced back together with weird calendar gymnastics. If you're communicating with someone on the other planet and make reference to something in january, is that Earth January , Mars First January, Mars Second January, .... ? They should have unique names so intent is clear.

Offline CuddlyRocket

Re: Mars Timekeeping System
« Reply #16 on: 11/04/2016 01:25 AM »
I agree that you don't want to mess with the definitions of the basic units of measurements used in science and engineering. That will cause all sorts of problems. (Obviously, meters and kilograms can stay the same magnitude, but just changing the unit of time changes the definition of a meter; not to mention the definitions of velocity, acceleration, force, current, etc.) But there's nothing to stop the development of Martian equivalents with some defined conversion factor. After all, both the US and UK use miles, but the mile is defined as 1,609.344 meters by international agreement. It would probably help avoid confusion if the local equivalents used different words - otherwise you'd need to talk about 'standard' and 'local' seconds etc.

Colonists on Mars are going to have a lot of new stuff to deal with, and it's important in such circumstances not to gratuitously change things that don't need to change. People are used to days of 24 hours and weeks of seven days etc, and I see no reason to change them or make things unnecessarily complicated. Plus, there are probably good, if unarticulated, reasons why we've settled on our time periods with attempts to change them failing. They seem to fit human nature, somehow!

It seems the use of 'sol' has already become established, so you could keep that and have sols of 24 local hours (or whatever you choose to call this time unit) divided into 60 local minutes etc. You could have a seven sol week with weekends. Call the days Monsol, Tuesol, Wednesol, Thursol, Frisol, Satsol and Sunsol! (Other language versions may be available!)

As for the year, I don't think people are going to be happy with a year that's nearly twice as long as it is now. It could cause all sorts of legal problems relating to age. For instance, at what age do Martian kids start school? There are already difficulties with the different levels of development of children with birthdays early in the school year compared with those who have birthdays at the end. Imagine if there was twice this difference in any school class? No, Martians would probably end up with some mechanism to divide the year into two, so it's probably better to build this in from the start. I'd divide the Martian orbital period into two calendar years. Each would then be 343.5 days long, which is about 6% shorter. (The age of majority on Mars would probably be 19, rather than 18!)

I don't think seasonal changes will be as important on Mars, where people will live in artificial environments, but you could refer to 'early' and 'late' years or somesuch, if felt desirable (though the years should be numbered consecutively). Divide each year into twelve 'months' with some appropriate number of sols in each (there's ~334.25 sols in such a year), remembering to keep the half and quarter-years as near the same length as possible - very important for commercial contracts and something often forgotten by Martian calendar creators! Throw in the odd leap day to keep things consistent over time.

Online savuporo

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Re: Mars Timekeeping System
« Reply #17 on: 11/04/2016 04:28 AM »
While you all figure out the ever important mars calendars along with GPS constellations and other important details, such as BX ( Before SpaceX ) or Anno Elon is more appropriate way to start counting Sols once we get JPL out of the way, here are some functional Mars Timekeeping Systems

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Offline b0objunior

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Re: Mars Timekeeping System
« Reply #18 on: 11/04/2016 04:32 AM »
While you all figure out the ever important mars calendars along with GPS constellations and other important details, such as BX ( Before SpaceX ) or Anno Elon is more appropriate way to start counting Sols once we get JPL out of the way, here are some functional Mars Timekeeping Systems
You're kidding right? I really hope so.

Online savuporo

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Re: Mars Timekeeping System
« Reply #19 on: 11/04/2016 04:34 AM »
You're kidding right? I really hope so.
On an internet forum ? I would never
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