Mariner 2 made the first successful flyby of Venus on December 14, 1962, becoming the first spacecraft to conduct a successful planetary encounter.
The spacecraft launched on August 27, 1962, after the launch failure of its predecessor, Mariner 1. Mariner 2 passed Venus at a distance of about 34,800 kilometers and returned scientific measurements during the encounter.
Its instruments showed that Venus was extremely hot and had no detectable global magnetic field like Earth’s. The mission also measured the solar wind beyond Earth’s orbit, providing early evidence that this stream of charged particles continues through interplanetary space.
Mariner 2 did not enter orbit or land. It was a flyby probe, and its success demonstrated that robotic spacecraft could travel to another planet and transmit useful scientific data. Later NASA missions, including Magellan, used radar to study Venus’s surface in much greater detail.