This is a 1:48 scale model of the Titan IIIC, one of many launch vehicles derived from the Titan II intercontinental ballistic missile. It had as its core vehicle the two liquid-fuel lower stages of the Titan IIIA rocket and a third stage carrying the payload. There were also two strap-on solid-fuel boosters. The Titan IIIC launched a series of military and civilian satellites into orbit from 1965-1982. This model was built and donated by Martin Marietta Corporation.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.