Space Meals

Then comes the day's first of three meals. Space food has vastly improved in taste and variety since the purely freeze-dried days of the Apollo missions. But space meals are prepared and eaten under the same basic restrictions: food and drink has to be somehow confined, or else it will wander off around the station. This is obviously messy and unhygienic; but if free-falling food gets into station equipment, it can also be dangerous. So drinks and soup are served in plastic bags and sipped with straws. But with a little care, astronauts can eat more solid dishes with a knife and fork - magnets keep the utensils from floating away from the dining table. Prolonged microgravity dulls tastebuds, so spicy food is usually a crew favourite.

After eating, astronauts settle down to the assigned tasks of the day, either supervising experiments or performing routine maintenance on station equipment. It takes a complex array of machinery to keep people alive and well in orbit. Daily, each human breathes the equivalent of 0.9 kg. of liquid oxygen - enough air to fill a 3.5 cubic metre room - and drinks a total of 2.7 kg of water. To minimize on resupply needs, the ISS life-support systems are designed to recycle as much as possible. Waste water from urine and moisture condensed from the air is either purified and reused direct, or broken down by electrolysis to provide fresh oxygen. Carbon dioxide 'scrubbers' chemically remove that toxic gas from the air.

One substance that is not recycled on ISS is solid human waste: it is collected, compressed and stored for disposal. The space toilet that does the collecting has a somewhat intimidating appearance. But it is a huge improvement on the sanitary arrangements that earlier astronauts had to endure. When power failures on Mir forced cosmonauts to fall back on emergency plastic bags, morale plummeted until their orbiting "convenience" was back on line.