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Foundational Satellites
Sputnik 1, Explorer 1, and Vanguard 1 established artificial Earth orbit, space science, tracking, solar power, and the institutional momentum that created modern space programs.
- Missions
- 3
- People
- 0
- Vehicles
- 3
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The small machines that opened the Space Age
Sputnik 1, Explorer 1, and Vanguard 1 established artificial Earth orbit, space science, tracking, solar power, and the institutional momentum that created modern space programs.
Program details1957–1958International Geophysical Year · 1957–1958
Flight record3 flights3 robotic or uncrewed
First flown missionSputnik 1October 4, 1957
Latest flown missionVanguard 1March 17, 1958
Core capabilities
Program story
Sputnik 1 launched on October 4, 1957, becoming the first artificial satellite and opening the Space Age. Its radio signal could be heard around the world, while tracking its orbit provided atmospheric information.
Explorer 1 followed as the first successful United States satellite and discovered the Van Allen radiation belts. Vanguard 1 then demonstrated solar power and remains in orbit decades after its radio transmitters fell silent.
These compact spacecraft produced effects far beyond their size: rapid launch-vehicle development, new scientific disciplines, global tracking networks, and the creation and expansion of national space institutions.