Venera 4: The First Attempt to Land on Venus
Venus, the second planet from the Sun, has long fascinated humanity with its bright appearance and mysterious clouds. However, behind its beauty lies a harsh and hostile world, where the surface temperature is hot enough to melt lead, the atmospheric pressure is 90 times that of Earth, and the air is filled with corrosive sulfuric acid. Exploring this extreme environment poses enormous technical and scientific challenges, but also offers a unique opportunity to learn more about the evolution and diversity of terrestrial planets.
In 1967, the Soviet Union launched Venera 4, the first spacecraft to attempt a landing on Venus. Venera 4 was part of a series of missions that aimed to study the planet’s atmosphere, surface, and magnetic field. Venera 4 consisted of two parts: a main module that flew by Venus and relayed the signals from the lander, and a spherical capsule that detached from the main module and entered the atmosphere. The capsule was equipped with a parachute and various instruments to measure the temperature, pressure, density, and composition of the atmosphere.
Venera 4 successfully reached Venus on October 18, 1967, and began its descent. It transmitted valuable data on the atmospheric structure and chemistry, revealing that Venus had a very thick and dense atmosphere, mostly composed of carbon dioxide, with traces of nitrogen, oxygen, and water vapor. It also detected a weak magnetic field and no radiation. However, as the capsule plunged deeper into the atmosphere, the temperature and pressure increased dramatically, exceeding the design limits of the spacecraft. At about 25 km above the surface, the capsule stopped sending signals, probably due to the overheating of its batteries. Venera 4 never reached the ground, and its fate remains unknown.
Venera 4 was a partial success, as it was the first spacecraft to survive the entry into another planet’s atmosphere and to perform in situ analysis of its environment. However, it also revealed that Venus was much more inhospitable than expected, and that the existing technology was not sufficient to withstand its conditions. The Soviet engineers and scientists learned from the failure of Venera 4, and improved their subsequent probes, by strengthening their thermal protection and adding cameras and soil analyzers.
The later Venera missions achieved remarkable feats, as they managed to land on Venus eight times between 1970 and 1982, and to send back images and samples of the Venusian soil, despite the extreme conditions that limited their lifespan to a few minutes. The Venera landers provided the first and only direct observations of the surface of Venus, showing a barren and rocky landscape, with volcanoes, craters, and fractures. They also measured the temperature, pressure, wind, and chemical composition of the surface and the lower atmosphere, and detected seismic and lightning activity.
The Venera program inspired and stimulated the international scientific community, and contributed to the advancement of planetary science and exploration. Today, Venus remains a fascinating and challenging target for future missions, as many questions about its history, evolution, and current processes are still unanswered.
