The Explorers program is a NASA exploration program that provides flight opportunities for physics, geophysics, heliophysics, and astrophysics investigations from space. Launched in 1958, Explorer 1 was the first spacecraft of the United States to achieve orbit. Over 90 space missions have been launched since. Starting with Explorer 6, it has been operated by NASA, with regular collaboration with a variety of other institutions, including many international partners.
An Explorer mission observes Sagittarius A*, the Milky Way's central black hole, flaring.
Launch of Explorer 1 on the Juno I launch vehicle.
Explorer 1, the first Earth satellite orbited by the United States
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Explorer 1 was the first satellite launched by the United States in 1958 and was part of the U.S. participation in the International Geophysical Year (IGY). The mission followed the first two satellites, both launched by the Soviet Union during the previous year, Sputnik 1 and Sputnik 2. This began a Space Race during the Cold War between the two nations.
Explorer 1 in its orbital configuration, with the launch vehicle's fourth stage attached
The satellite Explorer 1 is mated to its booster at LC-26.
Explorer 1 schematic
Explorer 1 launch control console on display at Huntsville Space and Rocket Center. The red arrow points to the manually turned launch key switch.