This is one of several examples of the Explorer 1 payload section in the collection, consisting of machined and painted metal shells with no instrumentation. This outer shell protected the payload instrumentation, as represented by other objects in the coolection.

Explorer 1, also known unofficially as Satellite 1958 alpha, was the first American satellite to successfully orbit the earth. The launch of Sputnik 1 on October 4, 1957 and the launch failure of the Vanguard 1 satellite in December of that year seemed to symbolize America's failure to lead in the Cold War-driven Space Race. Since the mid-1950's Caltech's Jet Propulsion Laboratory (JPL) had underway a development program for missile reentry vehicles in conjunction with the Army Ballistic Missile Agency (ABMA). Soon after the Vanguard explosion the JPL- ABMA team were authorized to adapt the Jupiter-C reentry test vehicle to an instrumented Earth satellite. The resulting Explorer 1 satellite was successfully launched and placed into Earth orbit on January 31, 1958. The satellite transmitted data on micrometeorites and cosmic radiation for 105 days. 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 Jet Propulsion Laboratory via NASA to the Museum in February 1975.