Humans have been interested in exploring what is out in space for a long time. We have sent robots and spacecraft to explore the universe and take pictures of planets, stars and galaxies far away. But sometimes it's hard to tell what things look like from just a picture. That's why sometimes people, called astronauts, have gone along with the spacecraft. Astronauts are specially trained people who wear special equipment and go along with the spacecraft on their journey. They help by being able to observe, experiment and collect information first-hand in space. They help us to learn even more about our universe.