APS News | This Month in Physics History

March 1966: The First Human-Made Object Makes Impact With Another Planet

Venera 3, a spacecraft launched by the Soviet Union, crashes into Venus on March 1, 1966.

Published Feb 16, 2023
Venus photo
Venus, shrouded in clouds.

Though named for a goddess of beauty, the planet Venus is, by Earthly standards, an odious place. Above a craggy volcanic terrain, clouds of sulfuric acid swirl, trapping noxious carbon dioxide like a greenhouse. The heavy atmosphere exerts 92 times more pressure than Earth’s, and the temperature can reach a blistering 475 degrees Celsius (about 900 Fahrenheit).

On March 1, 1966, a spherical landing capsule crashed down on the Venusian crust and encountered these infernal conditions. Part of a spacecraft named Venera 3 (“Venera” is Russian for “Venus”), the uncrewed probe was launched by the Soviet Union in November 1965 — one in a long line of attempts to reach and study the planet. The probe’s communication system failed in February, so it couldn’t transmit data back to Earth. But when it hit Venus, near the shadow where night was turning into day, it became the first human-made object to touch the surface of another planet.

Venera 3, the first human object to strike the surface of another planet.

Venus, the second planet from the Sun and the second brightest object in the night sky, has long captivated humanity. But astronomers in the early 1900s “found Venus a really frustrating object,” because its dense cloud layer obscured its surface, says space writer Brian Harvey in Russian Planetary Exploration: History, Development, Legacy and Prospects. Some scientists thought the planet, nearly the same size as Earth, could host life on its land or in its clouds. And in the public imagination, “Venus was a dripping wet, steaming, swampy, carboniferous planet,” Harvey writes.

After the launch of Sputnik in 1957, Sergei Korolev, the chief designer of the Soviet space program, began planning a barrage of missions to the Moon, Venus, and Mars. “The level of activity … in this period was frenzied,” writes James Harford in the biography Korolev: How One Man Masterminded the Soviet Drive to Beat America to the Moon. The United States rushed to get its own probes to other worlds. The Space Race was in full swing.

Korolev’s team aimed to send up at least one probe during every available launch window (about every 19 months for Venus and 24 months for Mars). To meet such an ambitious goal, they designed a new type of spacecraft, denoted “MV” for Mars-Venus, which was standardized for ease of production but could be customized with different instruments based on the needs of each mission. Engineers also created a new version of the R-7 rocket, the world’s first intercontinental ballistic missile, that could launch large payloads to the planets.

Early efforts weren’t fruitful. The first Venus probe, sent in February 1961, fell back down to Earth 22 days after launch, and a second, which blasted off in the same window, lost radio contact after traveling for 10 days. Three more Soviet Venus missions, planned for launch in 1962, stalled, as did one from the U.S. — though on Dec. 14, 1962, the Americans pulled off a victory when their Mariner II probe flew past Venus and gathered data on its scorching temperatures, becoming the first ever successful interplanetary mission.

Amid these woes, Soviet engineers retooled the MV’s thermal regulation system and outfitted its lander to better endure the stresses of descending onto Venus. This new probe was shaped somewhat like a baby’s bottle, cylindrical with a tapered top, and was attached to a spherical landing capsule. A sheet of solar panels was affixed to its flank. In all, the craft weighed around 960 kilograms (more than 2,100 pounds), or about as heavy as a giraffe.

Two MVs were prepared for the fall 1965 launch window: Venera 2, which would fly by Venus, and Venera 3, which would land. Researchers stocked Venera 3 with scientific instruments, including ion traps, spectrometers, a cosmic ray sensor, and a magnetometer. Strapped to its side was the spherical landing probe that would drop down to Venus by parachute, packed with devices to measure the temperature, pressure, density, and chemical composition of the atmosphere. Another curious object was loaded on board: a metallic emblem, made of titanium and thermoresistant enamel and emblazoned with the U.S.S.R. state seal. This symbol was to be deposited on the surface of the planet; many Soviet space probes carried them during this era.

Venera 2 launched on Nov. 12. It flew within 24,000 kilometers (almost 15,000 miles) of the planet on Feb. 27, 1966, then lost contact with Earth before it could communicate any data. Venera 3 was fired off on Nov. 16. On March 1, 1966, after 105 days of traveling through the solar system, it entered Venus’s atmosphere. But by this time all communication with the craft had been lost; a later post-mortem found that its solar panels and several internal components had overheated. Still, calculations of Venera 3’s trajectory led scientists to believe that it crashed down on Venus that day.

No data could be collected, but with the U.S.S.R. and U.S. battling for Space Race milestones, some Soviet scientists still considered the mission a success. Control system designer Boris Chertok, Korolev’s number two in the Soviet space program, lists the outcome of Venera 3 as “Mission accomplished” in his 1999 memoir Rockets and People: Hot Days of the Cold War. “Venera 3 delivered a pendant with the emblem of the Soviet Union to the surface of the mysterious planet,” he writes. “We can say this with complete confidence, despite the fact that we lost radio contact with the spacecraft before its approach to the planet.”

What’s left of Venera 3 still lies somewhere on Venus’s hostile surface, a reminder of humanity’s first contact with another world.

Both the Soviet Union and the U.S. made further trips to Venus in the following decades (Venera 9 and 10 took the first photos of its surface in 1975), but Earth’s sister planet is still shrouded in mystery. Several future missions to Venus are planned, including NASA’s DAVINCI, which is scheduled for launch in 2029 and will study whether the planet’s atmosphere holds components of water. If all goes to plan, DAVINCI will drop down to Venus’s surface and gather data as it descends. It could last up to 18 minutes on the mountainous terrain before succumbing to the hellish pressure and heat — if it survives the landing.

Tess Joosse

Tess Joosse is a science writer based in the Midwest.

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