We're all discussing effects of Martian sunlight exposure on structures, plants, solar panels, but I don't think I've seen any discussion of its effect on humans. There's a number of effects of sunlight on health, both adverse and beneficial. Some can be fought with supplements, like Vitamin D deficiency, others not so much.

Seasonal affective disorder (SAD) is a mood disorder subset in which people who have normal mental health throughout most of the year exhibit depressive symptoms at the same time each year, most commonly in the winter. People may sleep too much or have little energy. The condition in the summer can include heightened anxiety. [Wikipedia].

And suffering from this, I can say it can be quite crippling. Artificial light really doesn't cut it. In difficult, dangerous environment like Mars, this could spell doom of the colony as people simply fail to find the energy to perform the necessary tasks. And as I understand it, the amount of sunlight is comparable to deep shade or a cloudy day at best, and the access to natural sunlight through windows/skylights will be restricted due to risk of exposure to ionizing radiation (coming with solar wind and CME). And it won't be seasonal, but permanent.

Are there plans, experiments, solutions that address this concern? "Just add more LEDs" may seem as the simple solution, but will it be enough?

  • $\begingroup$ Great question! I'm sure you know about light therapy for SAD - could be a viable treatment on Mars too if it's shown to be effective . $\endgroup$
    – Jack
    Commented Jun 18, 2018 at 8:44
  • $\begingroup$ Could be worth mentioning Mars receives ~45% irradiance compared to Earth, but as you point out - staying inside to avoid ionizing radiation would be the problem $\endgroup$
    – Jack
    Commented Jun 18, 2018 at 8:48
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    $\begingroup$ There's been a few studies that indicate that SAD doesn't exist, at least in the sense its a lack of sunlight. Rather seasonal depression seems to be a mix of mood disorders with a variety of causes. Not to say it's not sunlight related at all, but more nuanced. $\endgroup$
    – GdD
    Commented Jun 18, 2018 at 10:15
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    $\begingroup$ Highly related topic - Circadian rhythm and its problems on the ISS $\endgroup$
    – Jack
    Commented Jun 19, 2018 at 13:22
  • $\begingroup$ There is a Psychology & Neuroscience SE; a question like "What does current scientific research on SAD tell us about how to design space colonies?" might do quite well there! $\endgroup$
    – uhoh
    Commented Nov 9, 2018 at 2:10

1 Answer 1


I understand your concern, but I don't think SAD will be a problem on Mars, provided moderate care and attention is paid to lighting.

The problem is really no different than for shift workers on Earth or for those who spend their lives mostly (or entirely) indoors or at high latitudes.

The brightness of Martian sunlight won't be much of a factor, since direct exposure won't be possible due to the low pressure atmosphere; it will always have to be through glass or another transparent material, most of which also tend to filter UV.

Artificial light is really the best solution. High-quality, full-spectrum indoor lights will be important for long-term health and well-being.

From a pure aesthetic and psychological health perspective, I do hope Mars colony designers adopt brightly lit, wide-open spaces. Otherwise, feeling like you're living in a submarine could get tiring after a while, but the issue there isn't really SAD.

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    $\begingroup$ I think you need to start sourcing these answers that start with "I think". Not that I disagree with it. My friend manages his through artificial lighting thats brighter than the sun- sits on his desk pointed at his face 24/7 during the winter. So you could be correct- but a source proves you are correct. $\endgroup$ Commented Oct 8, 2018 at 4:01
  • $\begingroup$ If you have personal experience with the topics- citing yourself is always acceptable too :). $\endgroup$ Commented Oct 8, 2018 at 4:23
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    $\begingroup$ If a reasoned argument isn't enough, then this site probably isn't for me. Oh well. If I wanted to spend hours posting documents and references for every answer, I'd go to Wikipedia. $\endgroup$
    – RickNZ
    Commented Oct 8, 2018 at 4:58
  • $\begingroup$ Pretty much was all I was saying. Link a wikipedia reference! It just leads the average user into going somewhere else and doing their own research. Im not attacking! Merely suggesting. $\endgroup$ Commented Oct 8, 2018 at 7:01

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