Venus is covered with layers of dense clouds that continually hide its surface. Scientists have always speculated at what was beneath those clouds. Perhaps that was one of the reasons that the Venera program was launched. Through the Venera program, the former USSR sent a series of 16 spacecraft towards the planet Venus.
Venera 1-6: The First Attempts
Venera 1, the first spacecraft of the series, was launched in February 1961. Its task was to strike Venus and become the first man-made device to reach another planet [sounds good]. Unfortunately, we lost contact of it 15 days after the launch [sounds bad]. Venera 2 and Venera 3 also fell silent as they approached Venus. Some scientist believe that the heat from the Sun caused the radio link to cease.
Venera 4, which set off on June 12, 1967, was much more sophisticated and successful. As it neared Venus, the spacecraft released its landing probe and they both (main probe and landing probe) went into the atmosphere. As expected, the main probe burned up from the immense friction, but the landing probe had a protective heat shield and was spared. Instead, the landing probe was crushed by the atmospheric pressure before it could reach the surface [evidently a more preferable fate]. Nevertheless, Venera 4 transmitted precious data back to Earth. The atmosphere was found to be 95% carbon dioxide and the recorded atmospheric pressure was 22 times of the pressure of Earth's surface.
Venera 5 and Venera 6 were virtual duplicates of Venera 4, except for they were more rugged in construction. The two probes also had slightly smaller parachutes to enable them to sink through the atmosphere more quickly. This way, they would have a slightly larger chance of reaching the planet's surface. Regrettably, they suffered the same fate as Venera 4 and were consumed by the atmosphere [surprise, surprise].
Venera 7-16: The Work Pays Off
A major turning-point in the Venera program was Venera 7. Venera 7 became the first probe to land on Venus still transmitting. It was the first spacecraft to land on any planet other than Earth. Venera 7 withstood the 475*C (887*F) surface temperature and enormous atmospheric pressure for 23 minutes. Venera 8 followed and lasted 50 minutes.
Venera 9 was the first Venus orbiter. It released the lander into Venus and then orbited around Venus. The lander took the first pictures of Venus on the planet's surface. Venera 10 was launched in 1975 and its lander lasted 6.5 minutes. Venera 11 and 12 flew past Venus as planed, but malfunctioned and returned no photos.
Venera 13 and Venera 14 were both orbiter-lander combinations. They returned the first colored images of the surface of Venus and made measurements on the composition of the planet's soil. Venera 15 and Venera 16, the last probes for the Venera program, each carried a radar-mapping antenna. They orbited the planet and mapped out 30 percent of the surface.
Conclusion
When the Venera program ended in 1984, the Soviet scientists published an atlas of Venusian topography. Their conclusions included the fact that two thirds of Venus is covered by hilly terrain, one fourth by flat lowland and one tenth is mountainous. They also determined that Venus has hot spots (700*C {1292*F}) and cold spots (500*C {932*F}). Scientists theorize that thick lava sheets may cover Venus.
Overall, the Venera program had a very discouraging start. However, through strong determination, the Soviets eventually achieved the tremendous feat of landing on another planet and contributed greatly to our knowledge of the Solar System.
