The tiny, 6.4-inch Vanguard TV3 satellite, first produced in 1957, was part of Project Vanguard, a program of the U.S. Naval Research Laboratory created to compete in the race to launch human-made satellites into orbit. The transmitter transistor within the satellite was developed by Alabama inventor and physicist C. Harry Knowles (1928-2020) and was launched within the nosecone of a Vanguard rocket.
TV3 Vanguard Satellite
Photo courtesy of the C. Harry Knowles Collection, Auburn University Digital Library