NASA’s Mariner 2 became the first successful interplanetary probe when it flew past Venus on 14 December 1962. It was also the first spacecraft to conduct a successful close encounter with another planet.
Mariner 2 launched on 27 August 1962 after the failure of its predecessor, Mariner 1. During its journey, it measured the solar wind and cosmic dust and transmitted observations of Venus’s environment. Its instruments showed that Venus had extremely high temperatures and no strong global magnetic field.
The spacecraft passed Venus at a distance of about 34,800 kilometers and continued transmitting for several months afterward. Mariner 2’s success helped establish robotic planetary exploration as a practical scientific activity. Later Venus missions, including the Soviet Venera series, achieved orbiters and landers.