An astronaut is a person trained to travel and work in space. The word comes from Greek roots meaning “star sailor,” which perfectly captures what astronauts do: they sail among the stars, leaving Earth behind to explore the cosmos.

Becoming an astronaut requires years of intense preparation. Candidates must master complex science and engineering, maintain peak physical fitness, and learn to solve problems under extreme pressure. They train in giant swimming pools that simulate weightlessness, study spacecraft systems until they know every switch and button, and practice for emergencies that might happen hundreds of miles above Earth.

In space, astronauts conduct scientific experiments, repair satellites and space stations, and test new technologies. They experience things most people only dream about: floating in zero gravity, watching the sun rise sixteen times a day, and seeing Earth as a beautiful blue marble against the blackness of space. Astronauts have walked on the Moon, lived aboard space stations for months at a time, and helped build the International Space Station piece by piece.

The work demands courage and discipline, but also curiosity and wonder.