<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;World_Without_Sun" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;World_Without_Sun</a> ? Available at <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=6cIjgL2lkwA" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=6cIjgL2lkwA</a> . Don&#x27;t know what details it covers - just found out about it now when researching your question.<p>Edit: <a href="https:&#x2F;&#x2F;youtu.be&#x2F;6cIjgL2lkwA?t=1138" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;6cIjgL2lkwA?t=1138</a> says that the aquanauts take turns &#x27;sunbathing&#x27; in UV rays for 10 minutes each day, for health and morale.  At around 18:00 &quot;Their sense of time has become hazy. They neglect the clock and the calendar.&quot;