Astronauts live on the space station. It is a home and a lab. It goes around Earth. Five space agencies run it. They run it together. It has a part called the Cupola. The Cupola has seven windows. They look out at Earth.

Earth's gravity still pulls on the station. It is only about 10 percent weaker than on the ground. Astronauts float as they fall around Earth. The station falls with them. It is not because there is no gravity. The station moves about 5 miles a second. A trip around Earth takes about 92 minutes. They see 16 sunrises a day. They see 16 sunsets.

Astronauts wear spacesuits for spacewalks. Those are outside the station. Space has no air. It is not safe without a suit. They practice spacewalks on Earth. They use a huge pool of water. It is the closest you can get to microgravity on Earth.

Apollo 11 carried three men. They were Neil Armstrong, Michael Collins and Buzz Aldrin. It launched on July 16, 1969. Collins stayed in orbit. His ship was the command module Columbia. On July 20, Armstrong became the first person to walk on the Moon. Aldrin joined him there. They collected rock and soil.

Words to know

• orbit: circle around
• gravity: pull toward Earth
• microgravity: almost no pull