The term that describes a person who travels to space is "astronaut." Astronauts undergo rigorous training to prepare for missions, which can include simulations, physical fitness exercises, and studying spacecraft systems. They may conduct scientific research, perform spacewalks, or operate spacecraft during missions. The term originated from the Greek words "astro," meaning star, and "nautes," meaning sailor, reflecting their role as navigators of the cosmos. Besides astronauts, other roles include cosmonauts, a term used in Russia, and taikonauts in China. Each spends years training for the blend of skills required in the challenging environment of space.