The MOUSE (Minimal Orbital Unmanned Satellite, Earth) is a full-scale design concept model for an artificial satellite. It weighs about 100 pounds, contains Geiger counters for measuring cosmic ray intensity, photo cells for scanning the earth, telemetry electronics for sending data back to earth, a magnetic data storage device as well as rudimentary solar energy cells. Dr. S. Fred Singer, then of the University of Maryland, designed the MOUSE as a refinement of a proposal in 1951 in the Journal of the British Interplanetary Society for the smallest possible device that could perform useful scientific research in space, and relay that information back to Earth. This model was built by the Franklin Institute in Philadelphia in 1954 to demonstrate the concept, and was displayed there prior to donation by Dr. Singer in 1962.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.