1966

Venera 3 Reaches Venus

Most of the media attention on the 1960s space race between the United States and the Soviet Union focused on the human spaceflight program and the quest to land the first astronauts on the Moon. But the race extended farther across the solar system as well. After the successes of the Luna 3 and Zond 3 lunar orbiters and their far-side photos and the Ranger 7, 8, and 9 lunar impact probes between 1959 and 1965, both the Soviets and the Americans began to focus more of their robotic missions on studying the nearby planets Venus and Mars.

Venus, Earth, and Mars form a triad of generally similar terrestrial planets that, when studied in detail, reveal important differences about planetary surface and climate evolution. Based on telescopic observations, the surface of Venus was known to be shrouded continuously in clouds; only radar observations from the Arecibo radio telescope in the early 1960s were able to reveal some details about the surface below. Mariner 2 became the first robotic probe to fly past Venus in 1962, but much about Venus remained unknown, including a basic consensus about the planet’s surface temperature and atmospheric pressure.

The Russians initiated the Venera robotic probe program to study Venus in more detail, using a series of flybys, orbiters, atmospheric probes, and landers. The Venera 1 (1961) and 2 (1965) Venus flyby missions failed before reaching the planet, but the Venera 3 mission did reach the planet and enter the atmosphere before losing radio contact with the Earth. While no scientific data were returned from the mission, Venera 3 nonetheless became the first human artifact sent into another planet, crashing into Venus on March 1, 1966.

Persistence paid off for the Soviet space program, however; the follow-on missions of Venera 4, 5, and 6 in 1967–1969 were successful, with Venera 4 providing the first direct measurements of the chemistry, temperature, and pressure of the atmosphere of another planet, and Venera 5 and 6 providing more measurements of wind speeds, temperature, and pressure. These missions, and the successful 1967 US Mariner 5 mission flyby, revealed Venus to be a hellish world, with a surface pressure more than 90 times that of the Earth and surface temperatures above 840°F (450°C).

SEE ALSO Venus (c. 4.5 Billion BCE), Sputnik 1 (1957), Far Side of the Moon (1959), First on the Moon (1969), Second on the Moon (1969), Fra Mauro Formation (1971), Roving on the Moon (1971), Lunar Highlands (1972), Last on the Moon (1972), Venus Mapped by Magellan (1990).

A 1966 Soviet postage stamp commemorating the mission of Venera 3 to the surface of Venus.