This is one of several full-scale replicas of Explorer 1 in the NASM collection. It consists of the payload section attached to an empty Sergeant fourth-stage, solid-fuel rocket motor. It was transferred to NASM by the U.S. Army Ordnance Museum in 1988. Explorer 1, also known unofficially as Satellite 1958 alpha, was the first American satellite to successfully orbit the Earth. Data from this and two subsequent Explorer satellites led to the discovery by James Van Allen of a belt of intense radiation surrounding the Earth.
Transferred from the U.S. Army Ordnance Museum