Nspace, astronauts don’t have gravity to keep them in place. that makes doing even simple tasks difficult. gene cernan was the first astronaut who worked on a task outside a spaceship. he said of the experience, “every time i’d push or turn a valve, it would turn my entire body at zero gravity. i had nothing to hold on to.” as he worked, gene cernan’s heart rate and temperature went so high that his fellow astronauts worried that he wouldn’t survive.