NASA Space Shuttle Enterprise OV-101, the unique atmospheric test orbiter, preserved at the Intrepid Sea, Air & Space Museum.

Enterprise is notable for not having a functional heat shield or engines for spaceflight and is distinguishable by its test article markings and lack of operational equipment.

Enterprise is the prototype orbiter that led to the entire Space Shuttle program; it never flew in space, but performed high-profile glide and landing tests.