Has anyone done a Mars time study?


There have been sorta Mars like mission simulations with people way out on an old lava flow or something… but I’m not sure if any of them tried Mars time too. Since they’re outside and Earth isn’t Mars time… if they did, then eventually they’d be doing stuff outside at night…

I know that JPL tried having their people running rovers and such on Mars… run on Mars time and it messed people up. It wasn’t a formal study though and I think that it was probably mainly due to them still having to live here on Earth and interact with family… friends… and businesses that aren’t open 24 hours…

So… has anyone done a Mars mission simulation with everything indoors and like a “Mars room” to do “EVAs” in so they can control the day night cycle to match Mars?


Mars has a 2.5% longer day than Earth. So it’s not a mayor problem, and I have not heard of such experiments. JPL staff have problems with circadian rhythms because they were in contact with the outside world living in a different rhythm. There will be only one rhythm for astronauts on Mars. It’s also will not create problems for the NASA Mission Control Center, as they are already working around the clock in three shifts.


assumption is bad.

While I tend to think the difference won’t be a problem. Especially for me as I think my cycle shifts slightly everyday and I end up with a reversed day/night from everyone else for a while until shifts all the way again…

But if no one has actually done a study on it… then we don’t know and are just guessing.











Check these out:

  • Kaladchibachi, S., D.C. Negelspach, and F. Fernandez (2018). Circadian phase-shifting by light: Beyond photons. Neurobiology of Sleep and Circadian Rhythms. Vol 5. pp 8-14.

  • Arendt J. and B. Middleton (2017). Human seasonal and circadian studies in Antarctica (Halley, 75°S). General and Comparative Endocrinology. Vol 258. pp 250–258.

Basically, these indicate that you’re right that social pressure acts as a major zeitgiber (timer giver) to reset peoples’ clocks regardless of what the light is doing. For most people (and bugs) though, the most important zeitgiber is light. Anything over 1000 lux (i.e. an overcast day) in the eyes for 10 minutes should phase shift you up to about 30 minutes a night. Which way (and how much) it shifts you depends on what time of night it happened, with earlier lights shifting you backward and later lights shifting you forward.

That means, on a Mars base (as long as sun doesn’t shine in through any windows) you can set whatever cycle you like just by programming the internal lights. It’s a good bet a Mars base would be buried to protect from radiation, so it’s is entirely reasonable for a base to ignore the dawn/dusk cycle and use its own lights to set the time. It’s quite likely people on Mars would try to sync themselves up to be on whatever time cycle mission support back on Earth is on, so, in that case, they would have something close a 24 clock (plus a few fractions of a second for relativity).

I’m like you though @FITorion. I’ve actually kept a sleep diary, and it shows (as long as I don’t have to meet someone else’s schedule) my circadian rhythm is almost exactly 36 minutes longer than 24 hours. In essence, I’m naturally on Mars time.

Some people are a little shorter than 24 and some are a little longer. I can’t remember which way we tend to lean, but the variation is around +/- 1 hour. I think it’s stated in one of those articles I cited (it’s been a while since I read them).

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I don’t think they’d go with Earth Mission control time while on Mars… for the simple reason that they are there to study and interact with Mars… that means going outside… or even as simple as growing food in the green house…

You wouldn’t want to be roving around Mars or be descending a cliff in the dark. It’d be a safety hazard and a waste of time setting up a bunch of flood lights before searching what ever area you’re trying to study for your samples.

Mission control runs on shifts. There will always be someone there for the crew. The crew doesn’t need to match their schedule. The ISS isn’t on Houston time…

They’d use Mars local … unless it was shown that doing so was in some way more hazardous than dealing with Mars night.


In my vision, crops are grown entirely indoors with LEDs. Sure, you have to power them electrically and eat the efficiency losses, but they don’t lose light to dust storms or other weather effects (making the crop development very predicable). And, that way, the plants can then be placed deep under the surface where no cosmic radiation penetrates.

As for EVAs, a Mars base (using Earth time) would still be in-sync with the Martian daylight about 1/2 to 2/3rds of the time. So it’s not really that big of an inconvenience. You’d just have to design the schedule carefully or have a “late” shift do the exploration every now and then.

As for exploration, I foresee radiation problems there also. This would be pretty unavoidable during the “drive around and look at things” phase of exploration. But, once you’ve found a site of interest, you’d probably want to build a little protected habitat right on top of it (or at the very least a radiation shelter, complete with backup air/water/power/communications… maybe some scientific field instruments). In which case, you’re quite likely to have lights all around anyway.

Honestly, it’s the radiation that’s driving me to this conclusion. Everyone’s going to want to be underground as much as possible, and the local daylight just isn’t going to matter much. Thus, you might as well synchronize yourselves to make interactions with Earth easier… That is, at least, until there’s another base on Mars which you interact with more: then a Mars local time might make more sense.


Don’t get me wrong though, I’m not against Mars time… Like I said, with how I sleep, I’m already there. If there were enough other people on the mission like me, I’d be all for it.

The problem is I don’t know how many other people are likely to be “long day” type people, so an exact 24 hour light schedule makes sense as the “natural” compromise for all crew.


yeah I’m thinking more about the First mission… Not Settlements… yet.

But If we’ve been there long enough to have significant facilities deep under ground… then maintaining Earth schedule wouldn’t be top of anyone’s list. And there would very likely be multiple such places.

Once you’re got heavy equipment for excavation and tunneling and manufacturing to be able to build in situ your under ground dwelling … your at Permanent settlement stage. The first missions at most would get to pilling up rock around the habs on the surface.

In any case … maintaining an Earth schedule seems like more effort than it’s worth when Mars is out your airlock and Earth is 10-20min light delay for communications away. Unless there’s some physiological reason to do it.


Radiation is absolutely not a problem for plant to growth on the Mars surface. Measurements of the Curiosity rover showed dose 0.64±0.12 mSv/day. Annual plants thus receive a dose of the order 0,1 Sv - it’s not a big deal. Induced radiation in crops will be less by orders of magnitude, so these plants will not be dangerous for eating.

People on Mars should live in soil-covered buildings, and crops can be grown in inflatable greenhouses right on the surface. Excavation not needed. Growing crops under LEDs does not make your life predictable, if you are still dependent on the energy production by solar panels on the surface. In my opinion, we must to grow crops under sunlight. During dust storms we can stop production of rocket fuel and transfer this energy on LEDs installing in open greenhouses. This is several times more effective way to use energy than your option.


Radiation fluxes during a direct hit of a SEP event would be much higher. I’m not sure how the plants would fare against such radiation (better than people, I know)… though I am keeping an eye out for this research. I know we wouldn’t want people to be above ground during one. Furthermore, if I’m propagating my plants from flowers (and not clonal lines, kept in a shielded lab), I definitely wouldn’t want them out on surface. Cultural Fidelity (low mutation rate) would be key to long term sustainability.

If you look on Page 10 here (it’s the same article as what you linked, but with more formatting… I’d actually already read it), you’ll see that Curiosity got hit by a couple of SEP’s during transit. The proton flux went from 10e-4 to 10e+1, a 100,000x increase during the event. These things typically last days, so it’s a dose worthy of avoiding when possible.

Also, if your plants are on the surface, then eventually someone is going to have to service the equipment or harvest the plants, and during that time they’re going to be exposed. The way NASA is about radiation exposures, even 0.64 mSv/day is going to give the lifetime risk calculators a fit. Since this risk can be eliminated in its entirety simply by moving everything under the dirt, I figure this is something they’ll want to do.

I don’t disagree though that using the sun would make things much more energy efficient. In regard to energy, my contention is simply that direct solar radiation is not very reliable. Especially, when you’ve got random multi-month-long dust storms to fight against. Solar panels aren’t the only way to go though; there’s also Kilopower Nuclear Generators and fuel cells (recombining your propellant supply of methane and O2 to get electron flow) to get you through the solar droughts.

In the long run, although they are more expensive, growth chambers are more reliable than greenhouses. In those first few years or decades, Reliability wont just be King: it’s going to be the God Emperor of Mars.

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Here we go, page 24 of this review cites a study on food crop lethal exposure rates:

The relevant citations are:

  • [80] BOTTINO, P.J., SPARROW, A.H., The effects of exposure time and rate on the survival and yield of lettuce, barley, and wheat, Radiat. Bot. 11 (1971) 147.
  • [81] LAPINS, K.O., BAILEY, C.H., HOUGH, L.F., Effects of gamma rays on apple and peach leaf buds at different stages of development, Radiat. Bot. 9 (1969) 379.

Based on the above doses (1 Gy = 1000 mSv for gamma radiation), the 77 mSv/year background rate on Mars (or 234 mSv/year with SEPs) is practically nothing to these plants (lettuce typically doesn’t grow for more than a month or two before being harvested). So it sounds like surface greenhouses are very doable (as long as we keep the flowering/seed production in a shielded area).

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I love where this conversation is going.