The atmosphere of Venus is over ninety-five per cent carbon dioxide, the pressure at the surface is 92 times that of earth and the average surface temperature is 735 K (462 °C; 863 °F), higher than the melting point of lead. Not to mention that there are large clouds of sulphuric acid raining down corrosive droplets and winds on the surface that can reach 300 kilometres per hour (190 mph). Not exactly the most forgiving place.
With the recent fervor around the possibility of life on mars, fuelled by the landing of the Curiosity rover last summer, no one seems to remember that it would also be rather interesting to land a rover or a probe on the cloud planet.
In fact, humans have already landed probes on venus, but not many people in the first world (I use first world in the original sense of the word: allies of the United States) are aware of it, probably because it happened during the cold war and the probes were russian-made.
The USSR landed not one, but ten probes on the surface of venus between 1963 and 1985. Venera 4, launched in 1967, was the first ever man-made object to enter the atmosphere of another planet and to measure the characteristics of the atmosphere directly. The data sent back to earth included measurements of pressure, temperature and chemical composition proving that Venus was far hotter and its atmosphere far denser than it was thought at the time. Since Venera 3’s fate is unclear, it might also have been the first ever probe to crash-land on another planet.
Venera 7 was the first probe designed to soft-land on the surface of venus. It was built to withstand the enormous pressures at the surface and therefore did not have many experiments on board. It managed to land successfully and gave the first ever direct measurements of another planet’s surface.
The first images of Venus’ surface were relayed back by Venera 9, launched in 1975. Several other probes were launched with cameras on-board but not all managed to take pictures of the surface. In many cases the lens caps failed to come off.
The picture at the top of the article was taken by Venera 13 which managed to send back 14 colour pictures and 8 black and white ones in the 2 hours it survived on the harsh Venusian surface. That’s right, the extreme conditions on Venus caused the probes to break down after very little time. In fact, Venera 13 was one of the longest surviving ones. Most of the earlier ones failed after less than 20 minutes!
Quite interestingly, the probes that soft-landed on Venus did not have to use retrorockets or parachutes or a complex combination of both to slow down their descent. On Venera 11 a small parachute was used in the highest reaches of the atmosphere but it was jettisoned at an altitude of 50 km. The air is so dense that it slowed down the probes to 7-8 m/s, which is slow enough for a safe landing. In fact, if you were able to build a small plane on venus, you could achieve take-off at running speed! Of course, the plane would be on fire and the fuselage would be melting, but at least you’d be able to fly with just the power of your legs.
Time to go back
There have been several missions that have studied Venus from orbit like the Venus Express probe, launched by the European Space Agency in 2005, which is currently studying Venus’ atmosphere and clouds, but it’s been almost 30 years since humans last landed a probe on the cloud planet. It’s been long enough. The possibility of life in mars is undoubtedly exciting but we know so little about venus that there are bound to be many interesting and wonderful discoveries that are yet to be made.
References and further reading
- Venus: Overview – NASA
- Venera 13: First Color Pictures From Venus – Space.com
- Soviet Venus Images – Mental Landscape
- Colour Surface Photo – Venera 13 – NASA
- Venera 13 Descent Craft – NASA
- Venera 11 Descent Craft – NASA
- The Soviets and Venus, Part 1 – Larry Klaes – The Electronic Journal of the Astronomical Society of the Atlantic