NASA studied this Grumman Aerospace concept for a partially reusable space transportation system during the Shuttle research effort in 1969-1972. This two-stage system featured a piloted fly-back orbiter mounted on a disposable tank attached to two recoverable liquid propellant boosters. The boosters and the orbiter's engines would ignite together for liftoff. When the boosters burned all their propellant, they would be jettisoned and fall to the ocean for recovery, while the orbiter's engines, still fed from the tank, powered the vehicle into orbit. In the final analysis, solid rocket boosters were chosen over liquid rocket boosters in a design quite similar to this one. NASA transferred a variety of concept models to the Museum after settling on the final Space Shuttle design.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.