null: As soon as weightlessness sets in in Earth orbit, everything floats, including bodily fluids. Most astronauts suffer from space sickness – similar to seasickness. You get sick, your eyes go crazy, your face swells up, your legs get longer and after a few sleepless nights (there is no day or night in space) many astronauts get severe back pain. Space researchers are trying to understand how the human body reacts without gravity. Could we need it to live?