In article ,
says...

John Doe wrote:
On planet earth, the day is roughly 24 hours long.

On the ISS, a day is about 90 minutes long, but they fake 24 hour in
terms of sleep/awake cycles.

Have they (or do they plan) on experimenting with whether the human
body could adapt to a different length of a day ? (for instance, a 20
hour day, or 30 hour day etc etc).

mars appears to have similar length of a day compared to earth, so I
guess such experiements may not be so important afterall, but still
would be interesting to know if the body can adapt to a change in day
duration and what proportion of sleep/awake is needed.

There's not special reason to do this on the ISS. Such research has been
done on Earth.

In fact, I don't think you'd want to do it on ISS because in an
experiment, you typically want to have one variable. Microgravity on
ISS would introduce a second variable, so without a control group on ISS
itself (not likely given the very small crew size), the results wouldn't
be terribly conclusive.

Jeff
--
The only decision you'll have to make is
Who goes in after the snake in the morning?