In 1957, the USSR became the first nation to place an object in Earth orbit. But far from being satisfied with this feat, two years later the Soviet federation launched its first space probe to the Moon. Despite a high failure rate of its first space adventures, the ideological competition with the United States pushed the USSR to want to go further and further. After the Moon, the planet Mars and Venus became targets of the Soviet space program in 1960 and 1961. If Roscosmos today retains a painful memory of the planet Mars, it is quite different with Venus. We could even say that the Soviet Space Program has had a long and fruitful love affair with our suffocating neighbor. This story is called Venera.
The Venera program aims to unravel the mysteries of Venus
The Venera program refers to about 30 space probes that were launched by the USSR towards Venus between 1961 and 1985. This resulted in overflight missions, orbiters, landers and even balloon probes. These huge means brought the very few images we have of the surface of Venus. These space probes thus helped to unveil a planet that until the late 1950s was still very mysterious.
Observed from terrestrial telescopes in visible light, Venus appears as a white ball. It is impossible to pierce its thick atmosphere and there are a lot speculations about the nature of its surface. Its diameter and mass, however, are very close to those of the Earth, which is why it is qualified as the twin sister of the Earth. The first probes of the Venera program are designed in the hope of breaking through this white veil, thanks in particular to the technological advances that accompanied the Second World War. The other ambition is of course to achieve this before the Americans.
Failures accumulate at the beginning of the Venera program
The first Soviet probe attempting the voyage took off in February 1961. At the time, it still does not have the name of Venera. Sometimes called Sputnik 7, the spacecraft unfortunately fails to leave the Earth and finally disintegrates over Siberia. Many Soviet probes of the time share this destiny, whether they go to Venus or to the planet Mars. The second attempt that took place a few months later is a little more successfull. Venera pulls out of Earth’s gravity and becomes the first spacecraft to enter an interplanetary trajectory. Despite this successful launch, luck lasts only a few days. A week after take-off, contact is lost with the Soviet space probe. It ended up flying over Venus but could not give us any of its observations.
The first encouraging signs of the Venera program
The following year, the Soviet engineers made three new attempts in less than three weeks. These three space probes have unfortunately not had the opportunity to deploy their solar panels. They explode with their launchers at different stages of their ascent. The year 1964 is as catastrophic. In 1965, Moscow plans to launch four space probes to Venus in two weeks. Two of them manage to leave Earth’s orbit, which at the time is a small feat. Of the other two probes, one remains blocked in Earth orbit and the other misses the launch window.
In order not to confuse the space probes, let’s talk about the very particular nomenclature of the Soviet probes of the time. They only received their baptismal name when they traveled successfully to their target. The two space probes that managed to leave towards Venus in 1965 are therefore called Venera 2 and Venera 3, although they are respectively the eighth and ninth attempts to reach Venus. The third space probe remained locked in Earth orbit adopted the name of Cosmos, while it was a part of the Venera program.
Venera 2 and Venera 3 reached the Venus area without a hitch in the first quarter of 1965. Venera 2 is a flyover mission equipped with eight scientific instruments including cameras. To put these instruments into operation, the space probe must cut off its communications with the Earth. Despite an overview and probably optimal information, communications have never been restored. Venera 2 continues on its way carrying away its secrets.
Venera 3 to Venera 6 finally reach the atmosphere of Venus
Venera 3 and the first atmospheric probe to penetrate the cloud layers of Venus on March 1, 1966, a feat that Soviet scientists digest bitterly because the radio contact with the space probe was lost 12 days before. Impossible to know how the descent took place. The probe had to deploy a parachute and eventually descend to the surface of Venus. We can nevertheless reasonably think that Venera 3 is the first human object to have touched the surface of another planet than the Earth.
When the tenth Venera space probe took off in June 1967, the Venera program was always failed. However, it is a new design office that has been responsible for the design of this spacecraft and this is perhaps what allows it to become the first Venera probe to fulfill its mission. It adopts the name of Venera 4 and enters the Venusian atmosphere on October 18, 1967. At the time, we still know almost nothing about our neighbor. The Americans did a flyby in 1962 with Mariner 2, but the space probe delivered very little information. Venera 4 is equipped to land on a solid or liquid surface. It manages to deploy her parachute and maintain communications with the Earth. It descends quietly for 93 minutes by communicating measurements of temperature pressure or chemical composition.
Finally, after so many failures, Soviet scientists begin to unravel the mysteries of Venus. And it’s a real hell that is revealed. Temperatures are in hundreds of degrees Celsius. Venera 4 is simply crushed by the atmospheric pressure of Venus while it is still 27 kilometers from the surface of Venus. To be able to land there, it is necessary to design more resistant space probes.
From Venera 4, however, the program suffers much less failures. In 1969, while the whole world has its eyes on the Moon, Venera 5 and Venera 6 enter the Venusian atmosphere. They bring little additional information compared to Venera 4. Venera 6 died 11 kilometers from the surface of Venus. It is the following year that the real feat take place.
Venera 7 is the first probe to reach the surface of Venus
Venera 7 is specifically designed to survive the Venusian hell. More resilient than its big sisters, it must be able to withstand temperatures of 540 degrees Celsius and enormous pressure. This is what allowed it to hold up to the surface of Venus. After a smooth descent, the lander touches the ground and continues to transmit for almost 23 minutes. Venera 7 thus becomes the first space probe to touch the ground of another planet than the Earth and to survive there. Although it does not carry a camera, its abrupt landing makes it possible to understand that the ground of Venus is solid.
Russian engineers now know precisely the temperature and pressure conditions on the surface of Venus. Venera 8 can therefore be designed in a lighter way than its big sister, which allows it to carry many more scientific instruments. Venera 8 managed to land on Venus in July 1972. It survives even twice as long as Venera 7, 50 minutes. It makes the first local measurements of wind speed and brightness, but does not embark a camera.
Venera 9 and Venera 10 send the first images of the surface of Venus
In 1975, accumulated experience begins to pay. From that year until the end of the Venera program, all the missions are a success. The Venera program is also gaining ambition. The Venera 9 and Venera 10 probes are thus much more massive than the previous space probes. They each implement an orbiter, a first in the program, and a lander. Among the eight instruments on board each lander there are panoramic cameras. However, we must deal with the digital technology of the time. At best they can capture monochrome images of 500 out of 128 pixels. Despite its limitations, the bet is successful. The two landers manage to survive about an hour on the surface of Venus and transmit their precious pictures to the orbiters which in turn send them to Earth.
In less than a year, humanity discovered the landscapes of its two neighbors. In October 1975, the surface of Venus is revealed to us by Venera 9 and Venera 10, and in July 1976 the surface of the planet Mars is photographed by the NASA Viking lander. Suddenly, the solar system becomes almost familiar. The Venera program continues during the late 1970s and early 1980s. In 1981, Venera 13 provided color photos of the surface of Venus. This space probe sets the record for survival on Venus, with just over two hours on the surface of Venus. This allows it to drill the crust of Venus.
Venera 15 and Venera 16 map Venus through its thick atmosphere
Orbiters of Venera 15 and Venera 16 mapped the surface of the planet to radar, giving us an overview of what is hidden under Venus’ white veil. In 1985, the last two missions of the Venera program were launched in collaboration with many European states. They were actually missions towards Halley’s comet that drop the lander and for the first time balloons probe into the atmosphere of Venus. These balloons survived more than 45 hours floating at about 50 kilometers in height. The strong winds located at this altitude make them travel thousands of kilometers, thus making it possible to measure the direction and the intensity of the atmospheric movements.
Even today, the Venera program is the only one to have placed robots on the surface of Venus. Since this immense Soviet effort, missions to Venus are much rarer. The Venera program could, however, be resurrected. Roscosmos has in its projects a mission called Venera-D which could carry by the mid-2020s a new orbiter and a new lander to Venus. These may be the opportunity to finally have images of the surface of Venus at the same definition of those we have on the planet Mars.
Images by reddit r/space / Zamonin & Rave [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)] / SOVFOTO-GETTY / SVF2-GETTY / NASA / ESA / JAXA