Explorer 1, officially 1958 Alpha 1, was the first artificial satellite placed in Earth orbit by the United States. It was released at 22:48 EST hours on January 31 (03:48 of February 1 in UTC) of 1958 from Launch Complex 26 (LC-26) of the Cape Canaveral Air Force Station aboard the Juno I rocket, as part of the International Geophysical Year and in response to the launching of Sputnik I and Sputnik II by the Soviet Union, thus giving rise to the space race, closely related to the Cold War.
The Vanguard 1 is the fourth satellite placed in orbit in history, the second by the United States, and the oldest satellite that currently remains in orbit as its predecessors (Sputnik 1, Sputnik 2 and Explorer 1) re-entered into atmosphere and were destroyed shortly after its release.
Sputnik 1, launched on October 4, 1957 by the Soviet Union, was the first artificial satellite in history.
