1957: the signal from Sputnik 1
The first artificial satellite changed space exploration and Cold War competition.
Event period: 1957 CE — separate from publication date
Also known as: Sputnik · satellite
Reaching orbit
The Soviet Union launched Sputnik 1 into Earth orbit on 4 October 1957. Its radio transmitter could be monitored internationally. The mission belonged both to the International Geophysical Year and to a period of intense geopolitical competition.
Seeing and hearing are different
NASA’s historical account distinguishes the small satellite from the larger, more reflective rocket stage that also reached orbit. Many ground observers saw the latter. Identifying the object matters when reading eyewitness descriptions.
Claims and evidence
Sputnik 1 reached orbit on 4 October 1957 and transmitted radio signals.
Sources
- 65 Years Ago: Sputnik Ushers in the Space Age — NASA
Launch on 4 October 1957; radio transmitter; distinction between satellite and visible rocket stage.
Source accessed 2026-10-28
