Sputnik 1 was the first artificial satellite launched by Humans. It was built by the Earth's Soviet Union, and was launched on October 4, 1957. This launch ushered in the space age.
The Vulcans T'Mir, Mestral, Stron, and their captain went to Earth to investigate the launch. Down on the surface, the Human Jack offered to point out the satellite to T'Mir; she told him she'd seen it. (TNG: "Loud As A Whisper", okudagram; ENT: "Carbon Creek")