English: Solid Rocket Booster during stacking at processing facility
KENNEDY SPACE CENTER, FLA. - In a Vehicle Assembly Building (VAB) high bay, an aft center segment of a Solid Rocket Booster (SRB) is lowered toward an aft segment already secured to a Mobile Launch Platform. These segments are part of the right SRB for the Space Shuttle Return to Flight mission, STS-114. Two SRBs are stacked on a Mobile Launch Platform for each Shuttle flight and later joined by an External Tank. The twin 149-foot tall, 12-foot diameter SRBs provide the main propulsion system during launch. They operate in parallel with the Space Shuttle main engines for the first two minutes of flight and jettison away from the orbiter with help from the Booster Separation Motors, about 26.3 nautical miles above the Earth’s surface.