Saturn-Shuttle and reusing the tanks and other hardware for later flights). The Shuttle would handle space station logistics, while Saturn V would launch components. This would have allowed the International Space Station, using a Skylab or Mir configuration with both U.S. and Russian docking ports, to have been lifted with just a handful of launches. The Saturn-Shuttle concept also would have eliminated the Space Shuttle Solid Rocket Boosters that ultimately precipitated the Space Shuttle "Challenger" accident in 1986. Because the shuttle orbiter would be riding piggyback on the external tank, and the need to prevent damage to the delicate thermal protection
Space Shuttle two different upper stages developed for the STS (single-stage Payload Assist Module or two-stage Inertial Upper Stage). The Space Shuttle was stacked in the Vehicle Assembly Building, and the stack mounted on a mobile launch platform held down by four frangible nuts on each SRB, which were detonated at launch. The Shuttle stack launched vertically like a conventional rocket. It lifted off under the power of its two SRBs and three main engines, which were fueled by liquid hydrogen and liquid oxygen from the ET. The Space Shuttle had a two-stage ascent. The SRBs provided additional thrust during liftoff and