The idea of being an astronaut on board the International Space Station (ISS) is quite polarizing.

For some people it’s the stuff of dreams: a once-in-a-lifetime opportunity to see Earth from above, to go outside of the Earth’s atmosphere and into space. These people are likely full of admiration for the folks who go there, whilst also being a little envious of those astronauts who get the rare chance to crew the ISS.

For others, the idea of leaving the safety and certainty of their Earthly lives to board a fiery metal tube and be propelled away from their home planet, only to live for six months in a cramped metal container far from their loved ones is the stuff of nightmares. These people don’t feel any envy in the slightest.

We can assume that the astronauts who do travel to the ISS fall into the former category.

So given that their dream has become a reality, what do they actually dream about while they’re up there in space?

When it comes time for ISS astronauts to get some shut-eye, they are strapped in a sleeping bag in a small metal pod or ‘bedroom’. This allows the astronaut a little privacy, whilst their body snoozes inside the cosy fabric bag.

However, because of the lack of gravity, it’s actually pretty comfortable, as Chris Hadfield – a Canadian astronaut who has been to space three times and spent two stints onboard the ISS – explained in 2013:

“You might think it’s uncomfortable not having a mattress or a pillow, but without gravity of course, you don’t need anything to hold you up. You can just completely relax and you don’t even need a pillow. It’s space, you don’t even have to hold your head up.”

Studies show that the sleep astronauts get on board the ISS isn’t the best though. And this is likely because the human body isn’t used to a lack of gravity and the constant changes from day to night as the ISS orbits the Earth.

Time is a strange concept aboard the ISS, with the crews’ natural circadian rhythms understandably disrupted.

But when they actually get to sleep, what do they dream about?

Well, just like on Earth, the astronauts’ dreams vary.

American astronaut Suni Williams, who is currently aboard the ISS, explained in an interview with CNN that her dreams – both while in space and back on Earth – fluctuate between Earthly and space settings:

“My father was a neuroscientist and asked me that same question when I returned home the first time. And I didn’t really think too much about it when I was up here. But I do dream that I’m up here at times when I’m here. And I do dream that I’m home as well.

I think it, you know, it must be based on your experience and what you’re sort of familiar with. So a little of both. And what’s I think sort of cool is I took note of all of this. And after I got home last time, I actually dreamed that I was in space a couple of times.”

With an experience like that, it’s no wonder that it features in her dreams.

It’s not surprising that Williams’ dreams circulate between Earth and the ISS, since really these places are essentially just her home and her workplace.

And since dreams are a part of our memory working, helping us to learn, develop and remember skills and experiences for the future as well as just exploring our minds and the world around us, these are two places with which she is very familiar.

What might seem like impossible dreams for us are everyday reality for an ISS astronaut.

Moreover, experts advise that dreams help us to rehearse and play out situations that have happened in our past as well as things that we anticipate happening in our future.

So as astronauts dwell on their lives in space and the families they’ll be returning to back home, it’s only natural that they explore those things in their dreams too.

After all, despite being 250 miles above us, astronauts’ brains are just like ours.

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