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Forged From Fire

by Perry Pezzolanella

A silvery star has been shining like a beacon in the evening sky far brighter than any star. It is the planet Venus, named for the Goddess of Love, but beauty is only skin deep, or in this case, cloud deep. Beneath the innocent looking clouds is one of the most fearsome environments imaginable.

Before the dawn of the Space Age there were many theories about what the surface of Venus might be like. Because Venus is shrouded in thick clouds and closer to the Sun than Earth, it was assumed that Venus was warmer, had heavy rains, was a steamy, swampy world with lush vegetation thanks also to the high levels of carbon dioxide, and the poles were cold enough for snow. It was even theorized that creatures similar to dinosaurs might roam the surface! Another theory was that Venus was covered with oil which would explain the high levels of carbon dioxide. Still another theory had Venus wrapped in a global ocean of seltzer water and raging storms with towering waves. A final theory nearly had it correct, that Venus was a scorching hot vast desert with huge dust storms. There is no evidence of dust storms on Venus as the surface winds are too low in the dense atmosphere to kick up large clouds of dust. Mariner 2 was the first successful flyby of another planet when it flew by Venus in 1962 revealing a true inferno with temperatures of at least 800ºF. Gone were the romantic visions of oceans, lush jungles, and dinosaurs.

Venus is a tough planet to explore, but the Soviet Union was successful after several failed attempts. The intense atmospheric pressure crushed spacecraft while still far above the surface. Success came with Venera 7 in 1970 when it landed and confirmed the searing heat of nearly 900ºF and an air pressure 90 times Earth’s. It only survived for 23 minutes, but became the first spacecraft to transmit data from the surface of another planet. Following in 1972, Venera 8 survived a little longer and confirmed that it was bright enough on the surface for photography. Veneras 9&10 landed on Venus during October 1975 and transmitted the first black and white pictures from the surface of another planet. The historic photos revealed a vast, desolate, rocky desert where Venera 9 landed on the slopes of a volcanic mountain. Venera 10 landed in the lowlands showing a vast plain of flat, plate-like volcanic rocks. Conditions were as hostile as ever with Venera 9 recording a temperature of 851ºF and Venera 10 recording 867ºF! Veneras 11&12 detected lightning and thunder while landing in December 1978, but failed to return pictures as the intense atmospheric pressure prevented the lens caps from jettisoning. Venera 13&14 were a huge success when they landed in March 1982 returning the first color photos from the surface. The scenery was bathed in orange light from the dense carbon dioxide atmosphere that effectively absorbs the blue component of sunlight and scatters the red. No lander has lasted more than 127 minutes on the surface.

NASA launched the Venus Pioneer Orbiter and Multiprobe missions in 1978. Three small probes and one large probe descended through the clouds to the surface sampling the atmosphere. One of the small probes survived 67 minutes on the surface even though they were not designed to survive impact. None of them were equipped with cameras. Pioneer Orbiter remained in orbit into 1992 and made the first crude map of Venus. NASA launched Magellan in 1988 and orbited Venus well into 1994 creating the first detailed map of Venus. The European Space Agency (ESA) orbited Venus Express from 2006-2014 and discovered possible volcanic transient hot spots on Venus. Venus Express and Venus Pioneer Orbiter detected a large spike in atmospheric sulfur dioxide that subsided in a few years adding suspect for active volcanoes. Japan’s Akatsuki orbiter arrived at Venus in 2015 and is still there today studying the clouds and atmospheric dynamics.

The challenge of exploring the surface of Venus remains high, but technology is advancing far enough along where it will soon be possible for a probe to survive on the surface for weeks or months, and even rovers are a possibility. The problems with high pressure and acid have been solved using a bathysphere design made of titanium. The spherical shape and the titanium both give it added strength and titanium is resistant to acid. Windows and viewing ports made of industrial grade diamonds and sapphires are also resistant to heat and acid. Still it is the heat that is the villain as electronics cannot withstand such intense heat, until now. Silicon carbide is the answer and electronic chips made from them have been tested in a lab using a real live Venus chamber. The chamber is filled with the exact chemistry of the Venus atmosphere and pumped up to 100 times Earth’s atmospheric pressure and heated to 500ºC (932ºF). The results are amazing as the chips still function after 60 days in the chamber and probably longer since the trial run was limited to two months. It is now possible to design a lander that can last at least half a Venus day, or 58.5 Earth days. This opens up a whole new era of Venus exploration. It will soon be possible to have long-lasting landers and rovers that can monitor the weather, seismic activity, change in lighting and local geological changes during a full Venusian day (117 Earth days).

What would it be like if we could find a way to safely take the plunge to the blistering surface? As we approach Venus, we are greeted with a dazzling creamy white globe with only a few faint cloud streaks visible. We plunge into an endless sea of clouds and are buffeted by winds over 200 mph and temperatures of -40ºF. We soon find out that the creamy tint is due to sulfur, actually sulfuric acid, and it is everywhere as a mist and drizzle. Lightning flashes and thunder booms as we plunge through the 15-mile deep triple cloud decks. We emerge beneath them about 30 miles above the surface with an acid rain falling as virga into the superheated depths below. The wind slows to 100 mph as temperatures soar past 200ºF; the atmospheric pressure here reaches five times Earth’s. Everything around us is bathed in a sickly yellowish light and the scorched surface below ripples in a deeper orange murk. As we fall below 20 miles we begin to see the ground quite clearly as the hot air is very dry and clean. We see towering mountain ranges and an erupting volcano on the distant horizon, gaping canyons far below mightier than the Grand Canyon, and sprawling plains of hardened lava with scattered dune fields and an occasional large crater. As we descend and drift along in the slowing wind we see a long river channel carved long ago by runny lava. At 12 miles above the surface strange things begin to happen. The atmosphere feels and behaves more like a fluid than a gas. The temperature rises relentlessly as we descend, now 600ºF and air pressure 20 times Earth. Daylight now shifts to a strong orange cast, adding to the feeling of the intense heat.

We land at last and kick up a cloud of dust. The temperature is 892ºF with an air pressure 94 times Earth. A fiery breeze at 3 mph feels like a strong current. The rocks around us are split from the intense heat and everything is bathed in an eerie orange light. The sun struggles to shine through the clouds with lightning flashing in the distance and thunder rumbling. Nighttime is no cooler than daytime and it is no cooler at the poles. The highest mountain peaks are a great place to cool off as they are a chilly 700ºF while the air pressure is cut in half, only 45 times Earth’s! The peaks glisten in the dull sunlight and we discover that they are frosted in metal! Lead and bismuth sulfides are cooked out of the hotter lowlands and condense onto the cooler peaks as frost! If you like it really hot, then head for the deep basins and canyons which broil at nearly 1000ºF with air pressures 100 times Earth’s. Lead, tin, and zinc melt and it is so hot that the surface of Venus may glow a faint red at night in the deepest lowlands.

It is hard to imagine Venus being any hotter than it already is, but during periods of intense volcanic activity, such as what was suspected 500-750 million years ago, the increase in carbon dioxide and sulfur dioxide from volcanoes may have increased surface temperatures as high as 1200ºF. At that temperature the ground would glow a dull red and alter the atmosphere. The clouds and haze would clear and the Sun would blaze down upon the fiery landscape. At night stars would sparkle above the vast field of red-glowing rocks and the Milky Way might actually be visible in areas where ground glow is not too intense. Anyone looking at Venus from Earth would, for a brief time, see the bare surface before it cooled back down below 1000ºF and clouded over again.

As hostile as Venus is, it is important that we explore it as it may hold important clues to how Earth’s climate works and its fate. A whole new era of Venus exploration is coming with a fleet of spacecraft that will be able to withstand the heat on a planet forged from fire.