How does spacecraft exit orbit into space?

Spacecraft do not exit orbit in order to enter space. When a space craft is launched, once it is going fast enough to not fall back down, it is now in orbit. It's the same principle as spinning a yo-yo around your hand. At this point, if the space craft speeds up even faster, it could eventually reach a speed in which it is no longer able to be held onto by earth's gravity. Regardless of if this happens, it will still be in space. An object is defined as entering space once it reaches an altitude of 100 km. At this height, in order to maintain orbit, it would require a speed of at least 7.85 km/s.