10 Interesting Facts about the Missions to Venus

Venus Probes
Image Credit: HistoricSpacecraft.com

Despite being named after a goddess of love and beauty, Venus is a harsh, hellish place that does not inspire warm and fuzzy feelings. Temperatures on its surface are hot enough to melt lead, and its atmosphere is so dense and massive that a visitor might think he is at least one km under the surface of an ocean on Earth. As if that’s not bad enough, a visitor to Venus might have to dodge rain made of iron and sulfuric acid, and always be wary of being blown over by the gentle surface breezes that move the dense, treacle-like atmosphere around.

On March 1, 1966, the Soviet space probe Venera 3 crash-landed on the planet Venus, making it the first spacecraft ever to reach the surface of another planet. Following a few failed attempts, Venera 7 became the first successful probe to land on Venus on December 15, 1970, followed by Venera 8 (1972), and Venera 9 and 10 (1975). In 1978, Venera 11 and Venera 12 then dropped descent vehicles with cameras and other equipment on the planet, while in 1981, the Venera 13 and Venera 14 landers carried out further research. In 1983, Venera 15 and Venera 16 subsequently entered orbit around Venus, and analysed the planet’s upper atmosphere and surface geology.

It’s not just the Soviets/Russians that have been studying Venus, however, with the US Mariner 10 probe passing within 5,768 km of the planet Venus during a flyby on its way to Mercury in 1974, and probes that have been placed in orbit around the planet for a period of time including the American Magellan probe (1990) which collated data in for four years, and the European Space Agency’s Venus Express mission (2006). Needless to say, despite the hostile conditions, Venus remains a fascinating world, which is why we have compiled this list of 10 interesting facts about the Horned Planet you may not have known.

First close-up view of Venus’ surface

Venera 9 Mission
Image Credit: Government of the USSR/Venera 9 mission

The image above, taken by the Russian Venera 9 lander on October 22, 1975, is the first picture taken of surface features of Venus, and it shows un-eroded rocks that are between 30 and 40 cm in diameter. The absence of shadows is because the picture was taken while the Sun was close to the zenith, and the vertical lines across the image were caused by the simultaneous transmission of atmospheric data to an orbiter that relayed data back to Earth. The lander survived the measured 485 °C (905 °F), temperature at the landing site for 53 minutes before losing contact with the orbiter.

First view of Venus’s surface in color

Venus in Color
Image Credit: USSR Academy of Sciences

The image above, taken by the Russian Venera 13 lander on March 1, 1982, shows the surface of Venus in color, using blue, green and red filters. As well as part of the spacecraft, the image shows flat rock slabs and the planet’s soil, although their true color is hard to discern due to the Venus’ atmosphere which filters out blue light. In this image, the camera focused on a spring-loaded landing pad to measure the compressibility of the soil at the landing site, hence the prominent view of the landing pad. The Venera 13 lander also took a soil sample, which it analyzed in an on-board laboratory, and which turned out to be a form of solidified lava, similar in composition to terrestrial basaltic lava. As a testament to Russian engineering skill, the Venera lander survived the measured 457 °C (855 °F) temperature at the landing site for a full 127 minutes, despite having had a design life of only 32 minutes.

Is this proof of complex life on Venus?

Life on VenusDespite the extreme conditions on Venus, a Russian contributor to the Venera program used the small shiny semi-circular object depicted in the image above to suggest that the Venera lander was positively surrounded by a “rich diversity of life”. The scientist, Leonid Ksanfomaliti of the Space Research Institute of the Russian Academy of Sciences, described the object, and others such as the one shown here, variously as “disks”, “black flaps”, and “scorpions” that “emerge, fluctuate and disappear”, in reference to their seemingly changing positions as indicated by “traces on the ground” observed in multiple photographs.

However, engineers familiar with the design of the lander were at pains to point out that the object shown next to the spacecraft was actually just a lens cap that automatically popped off the camera that took this picture. Moreover, careful analysis of all pictures taken by the landers’ cameras revealed that the “scorpions” and other signs of life were just image processing artifacts produced by subsequent processing of the original photographs, in which there is no sign of complex life on Venus.

Venus has currently active volcanoes

 Maat Mons on Venus
Image Credit: NASA/JPL

While it has been known for a long time that volcanism had been the primary driving force behind the run-away greenhouse conditions on Venus it was only in 2008-2009, during the Venus Express mission, that it was discovered that volcanoes are still active on the planet. The craft detected four transient, but localized hotspots near Maat Mons, a huge shield volcano in the Ganis Chasma, an extended rift zone. Other evidence of active volcanism is the decline, and subsequent 10-fold increase in the levels of sulfur dioxide in the planets’ atmosphere, which can only be explained by coinciding large volcanic eruptions. Note that the image above is a Venera-era radar-generated image of a recently active volcano, and does not relate to the data obtained by the Venus Express mission.

Venus has really strong winds

Various Russian and American probes have discovered that wind speeds in Venus’ middle cloud layers can exceed 450 km/h (280 m/h), which is considerably higher than the wind speeds in even the most powerful terrestrial storm systems. However, things are different at the surface; here, winds are gentle breezes that generally do not exceed a few km/h. Nonetheless, Venus’ atmosphere is so thick that even these gentle breezes have the power to move around relatively large rocks.

Venus has few impact craters

Venus CraterOnly about 1,000 large impact craters are known to exist on Venus, and about 85% of them are in virtually pristine condition, as can be seen in the radar-generated image above. The absence of weathering is taken by most investigators as evidence that Venus had undergone a sudden, and total resurfacing event between 300 million and about 600 million years ago. Moreover, there are no known craters on Venus that are smaller than 3 km (2 mi), and the biggest are about 280 km (174 mi) or so in diameter. The absence of small craters is because small impactors break up in the dense atmosphere before they can reach the surface.

Venus does have an ozone layer, after all

It was long thought that Venus’ atmosphere did not include an ozone layer. However, during 2011, the Venus Express probe identified a distinct layer of ozone about 100 km (62 mi) above the planets’ surface, which is about four times higher than the height at which Earth’s ozone layer exists. The ozone was discovered when the craft’s instruments noticed that the UV light from stars on the planet’s limb was being absorbed by ozone in Venus’ atmosphere. While the existence of ozone in Venus’ atmosphere is helpful in understanding the chemistry of the planets’ atmosphere better, some astronomers are touting the discovery as a means to detect life on exoplanets. However, as with the ozone on Mars, the ozone in Venus’ atmosphere has a non-biological origin, a fact that could yet produce many false positives in the search for extraterrestrial life.

…and lightning, too

As with ozone that was thought not to exist in Venus’ atmosphere, it was long thought by most investigators that Venus’ atmosphere cannot produce lightning. The controversy started when the Russian Venera probes spotted what could have been lightning, and the dispute was only settled when the Venus Express probe confirmed the existence in 2006-7 of a form of electromagnetic waves that only occurs in the presence of lightning. The probe also revealed that lightning on Venus occurs at a rate of about half the lighting strike rate on Earth, as well as the existence of an enormous double atmospheric vortex at the planets’ South Pole, which indicates that weather exists in the Venusian atmosphere.

Acid rain on Venus will dissolve landers made of ferrous metals

On Venus, the acid rain consists primarily of ferric chloride hydrocarbons and mercury with a measure of sulfuric acid mixed into a cocktail that forms the most corrosive form of precipitation in the entire solar system. Therefore, apart from the high surface temperature on Venus that can melt a lander, and the high atmospheric pressure that can crush the remains, the acid rain that occurs on Venus can dissolve what little is left of the lander. However, NASA is working on a lander, provisionally dubbed AREE (Automaton Rover for Extreme Environments- see image above), that can withstand all of the above. Moreover, this lander will have a wind-powered mechanical computer, and it will use old-fashioned Morse code to transmit data to balloons high in the planet’s atmosphere, which balloons will relay that data to Earth.

How not to build a Venus-bound probe

During May of 2010, students from several Japanese universities worked to build and launch a probe bound for Venus called UNITEC-1 (UNISEC Technology Experiment Carrier 1), as a means to test the effects of interplanetary space flight on computers inside spacecraft. However, this craft had no means to control or maintain its attitude, nor did it have a means to stabilize itself during flight. Power was supplied by means of solar panels stuck to the outside of the craft. Given these serious design flaws, is it to be wondered at that communications with the craft was never established, and that control of the craft was lost less than a day after launch? Perhaps not.

Related Articles