Today's random "fact."
Originally posted by: jagec
Originally posted by: Fritzo
A cubic yard of air weight about two pounds. The average person breathes about 940 cubic yards of air per day, or 1880 lbs. of air. When air is put into this perspective, it's not difficult to see why the logistics of space travel is so difficult to manage.
So, enjoy your two tons of inhaled gases today!
Yeah, but you can reuse ALL of the nitrogen, and much of the oxygen.
Yup. What's really a problem is the water. It's heavy, and it's in everything - food, drinks, and excrement.
I suppose the water could be "extracted" from waste, which would require the addition of heavy processing equipment. But the food value is permanently gone without some kind of energy input, like from sunlight into plants, which could convert that excrement back into edible food. But having a hydroponic farm on a spaceship is presently quite impractical, especially one capable of growing enough to feed a person.
1) Astronauts like to remain alive, meaning that they have to be gently lofted into space, and then gently lowered. This adds expense. Robotic probes can be subjected to many more G's than a person.
2) To remain alive, astronauts need food, water, a bathroom, and personal space. You can't switch them off, fold them up, and make them dormant for months or years at a time. Food, water, and lavatory facilities add lots of weight, as does creating a roomy pressurized enclosure.
3) Astronauts like to come back. Robots really couldn't care less if they're worked to death.
Air is but one of many concerns of space travel.
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