You don't recall correctly. "At an altitude of approximately 45 km (24 nautical miles), the boosters separate from the orbiter/external tank, descend on parach

You don't recall correctly. "At an altitude of approximately 45 km (24 nautical miles), the boosters separate from the orbiter/external tank, descend on parachutes, and land in the Atlantic Ocean. ... They are recovered by ships, returned to land, and refurbished for reuse." https://www.nasa.gov/returntoflight/system/system_SRB.html https://www.nasa.gov/returntoflight/system/system_SRB.html