Living - and working - in space
Weightlessness, radiation, complex short- and long-term physiological changes, and psychological imbalances all form part of the picture of life in space.
But it's the nitty-gritty of everyday life aboard the ISS that fascinates most earthbound observers: how do the residents eat, sleep and go to the toilet? And who takes out the trash?
These minutiae of daily life present serious technological challenges when living space is limited ... and costs millions per square metre. Consequently, food is largely dehydrated and tightly sealed in pouches to prevent floating particles from damaging highly sensitive equipment. This also cuts down on weight and storage space.
Drifting off to sleep
Sleeping is another unexpected adventure. Some astronauts prefer to float free, gently bouncing off a wall once in a while, but most prefer to be zipped into sleeping bags that come complete with pillows which are fastened to their heads by straps. Without showers and bathtubs, the ISS residents take sponge baths, carefully storing refuse for return to Earth, while advanced air-suction systems take care of bodily wastes.
The ISS is powered by sunlight converted into electricity by massive solar arrays, while water - initially expensively transported by spacecraft - is extensively recycled and much cleaner than tap water. Similarly, air is recycled.
A room with a view
ISS residents exercise regularly to maintain muscle and body tissue in microgravity, and spend their free time playing computer games, listening to CDs or watching DVDs, reading, and emailing their families ... or simply enjoying the view.
And who does take out the trash? Every spacecraft that visits the ISS returns to Earth as an extremely expensive garbage truck, but the unmanned Russian Progress does so in a particularly spectacular fashion: as it re-enters Earth's atmosphere, both the craft and its cargo of refuse burn up over the ocean.
Unexpected side effects
Life aboard ISS is hardly the glamorous picture of life in space that we see in movies and on TV, but it's still the dream of thousands, if not millions. And it has some interesting side effects: Russian cosmonauts report that, months after they're back on Earth, they're still surprised when they let go of something - and it crashes to the floor!