To study the effects of micro-gravity in space, NASA pays test subjects to lie still for weeks on end
When humans eventually live on the moon and Mars, the discomforts of eating freeze-dried food and drinking our own urine will hardly be our only space nuisances. Apparently, our feet will tingle, we'll get headaches and toothaches, our eyes will be runny, and we'll have chronically stuffy noses.
Scientists have a pretty good notion of what will happen to your body when you're walking on the moon or traveling gravity-free for two years en route to Mars -- thanks to a cadre of bed-ridden test subjects.