Full-scale engineering model of the International Ultraviolet Explorer (IUE) satellite, including optical systems, all mechanical components and detector systems. This close-to-operational system was built and retained at Goddard to act as a systems test object during the lifetime of the mission. When the mission was extended, it was retired and went on display at the Goddard Visitor's Center, where the instrument section was encased in clear plastic. It was transferred to the National Air and Space Museum in 2005.

The IUE was a satellite sponsored and operated jointly by NASA, SERC and the European Space Agency, and dedicated to gathering astronomical data in the ultraviolet range of the spectrum. The instrument collected spectral data in real time and was capable of being operated by a visiting astronomer at one of two ground stations: in Madrid, and at Goddard. The observer could perform preliminary evaluation and analysis during the observing session, operating the system much like a modern ground-based telescope. In its 18 years of operation the IUE provided data for thousands of scientific papers; IUE real time operations terminated on September 27, 1996 (Ponz). The IUE was launched by a Thor-Delta rocket on January 26, 1978 and placed into a geosynchronous orbit around the Earth. It carried a 45-centimeter (17.7-inch) Cassegrain reflecting telescope with two spectrographs that sensed a major part of the ultraviolet region of the spectrum (1150-3250 Angstroms).