SpaceX plans to use the Falcon Heavy to carry satellites—and someday people—into space. Three boosters produce more than 5 million pounds of thrust to lift the rocket off the ground. The boosters carry the spacecraft to specific points on its trajectory (the curved path of a flying object). Then they detach and land back on Earth to be reused.
The February launch was just a test, so the Falcon Heavy didn’t carry real cargo. That’s why Musk decided to go with something fun instead. His car is now headed beyond the orbit of Mars.