Someone who does this job will 'leave the world behind' and blast off into space. As part of their earlier training they may well have flown conventional ( = fixed-wing ) aircraft, but they also need to learn how to cope in weightless conditions, since there is no natural gravity in space. While they are away from the surface of the earth, they may be doing scientific experiments, making observations and servicing satellites ~ in conditions that are often uncomfortable, and occasionally very dangerous.