This device was mounted near the nose of a Shuttle orbiter and was used to establish its position once in orbit. A star tracker acquired a known star through its optics, and provided data on that acquisition to the Shuttle's on-board inertial measurement unit and computer to fix the orbiter's position.
This device flew on the Space Shuttle Columbia for its maiden mission in April 1981 and on 15 subsequent flights.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.