| Space

Always on Saturday... everyday life on the ISS

Saturdays on the ISS: ESA astronaut Alexander Gerst during the weekly 'house cleaning' out in space
Visit Alexander Gerst's Flickr gallery for more photos
Credit:
ESA/NASA

The International Space Station ISS orbits Earth every 90 minutes, which means that the astronauts witness 16 sunrises and sunsets every single day. All the same, Alexander Gerst and his colleagues maintain virtually the same circadian rhythm as we do in Europe. They are awake when we are awake, and sleep when we sleep. Coordinated Universal Time (UTC) applies on board the Space Station. During summer in Germany, we are two hours ahead of UCT, but only one hour ahead in winter. So the six astronauts living on the ISS are only just getting up while we are already on our way to work.

Just like most of us, the space voyagers on the ISS also maintain a five-day week. Saturday mornings are devoted to cleaning, and everyone chips in – this means vacuuming the air vents, as that is where dust, hair, particles from the astronauts' clothing and other things tend to accumulate. The surfaces must all be cleaned thoroughly, and the programme also includes general tidying. Small, lost objects are frequently retrieved from the air vents as well. The rest of the weekend is leisure time, which the astronauts use to video call their friends and families. Experiments are sometimes scheduled nonetheless. It is also a time to shoot videos – recorded messages – that are used for press events or experiments by young people.

Detailed itineraries define precisely what the crew members do at any given time – from 06:00 to 21:30. The astronauts can take their body temperature or resting pulse from their ‘beds’, even before the alarm clock rings at 06:00. The nights are spent in sleeping bags located in very small cabins. After all, it is important to ensure that the crew members do not just drift around the space station haphazardly. The circadian rhythm is adjusted a little from time to time, for instance when cargo vehicles or crew members dock or undock during the night. Then the astronauts are given a couple of extra hours to sleep in the afternoon, and the night-time hours begin a little later.

So what is an astronaut's day on the space station like? More next week in Part 2, here in the DLR Blog.