Where do the parts that detach from the space shuttle go?

Answer 1

The two white Solid Rocket Boosters land in the sea aided by drogue chutes, and are recovered by ships for return to their manufacturer to be prepared for re-use.

The large External Fuel Tank burns up as it re-enters the atmosphere.

Answer 2

The parts that detach from a space shuttle during launch, such as the solid rocket boosters and external tank, fall back to Earth into the ocean. They are not reused and are disposed of after each launch.