The Dragon is a spacecraft. It is on a rocket. The rocket goes to space.
The rocket is special. It is reusable. People can use it more than one time.
The rocket goes to space and then returns. It lands on a ship. The ship is robotic. It is at sea.
The Dragon flies to space. It flies to the International Space Station. It becomes part of the ISS. It brings the ISS mice and seeds. The astronauts do experiments with them. The Dragon returns to Earth in May.