It took decades to plan the International Space Station. Astronauts even practiced a rescue in space outside the space shuttle. They needed to know what to do in an emergency.
Building the ISS was like building a racecar as it zoomed around the track. The station orbits Earth once every 90 minutes. Each new section was brought up on a space shuttle or other spacecraft. Then it was added to the ISS very carefully. The builders had to be sure not to affect the station’s orbit.
The ISS is about the size of a football field. It took 13 years to build, and it cost $100 billion.
