What was the first U.S. spacecraft?
On February 1, 1958, Explorer I, the first U.S. spacecraft, was launched by a modified Army Ballistic Missile Agency-Jet Propulsion Laboratory Jupiter C missile. It collected data leading to the discovery of the Van Allen radiation belts. It demonstrated the feasibility of temperature control by satellite surface treatment and showed that micrometeorites are not necessarily a major consideration in space travel near the Earth.
