An astronaut is a person trained, equipped, and deployed by a human spaceflight program to serve as a commander or crew member of a spacecraft. The term comes from the Ancient Greek words meaning "star sailor" and applies to all human space travelers regardless of nationality
. Astronauts undergo rigorous training to prepare for the physical and mental challenges of space travel, including simulated spacewalks, survival training, and instruction on spacecraft systems. They often have diverse backgrounds in engineering, science, aviation, or the military and must meet stringent qualifications
. Their primary role is to explore space, conduct scientific research, gather data, and expand human understanding of the universe. They participate in missions such as space shuttle flights, stays aboard the International Space Station (ISS), and potentially future missions to the Moon or Mars
. Different terms are used based on nationality: astronauts (generally for Americans, Europeans, Canadians, Japanese), cosmonauts (for Russians), and taikonauts (for Chinese astronauts)
. In summary, an astronaut is a professional space traveler trained to operate spacecraft and conduct scientific and exploratory missions beyond Earth’s atmosphere
