NASA studied this concept for a partially reusable space transportation system during the Shuttle research effort in 1969-1972. This two-stage system featured an orbiter and disposable external fuel tank attached to a disposable first-stage similar to the Saturn V booster previously used to launch astronauts to the Moon. After the booster burned out and was jettisoned, the orbiter's engines, fed from the attached disposable tank, would ignite for final ascent into orbit. This concept sought to reduce cost by making use of proven, existing booster technology rather than developing a new launch vehicle for the orbiter. NASA transferred a variety of concept models to the Museum after settling on the final Space Shuttle design.