Earth’s “Evil Twin” Will Get A Rover Of Its Own
By Judith E Braffman-Miller
From a distance, the planet Venus is a beautiful bright object, hanging like a twinkling diamond in Earth’s morning and evening sky. For this reason, Earth’s “twin” planet is often referred to as the “morning star”, as well as the “jewel of the sky”, because of its bewitching and beguiling beauty. Venus is certainly a lovely, sparkling object when it is observed from far away, but when it is examined more closely, it reveals itself to really be an almost Earth-size ball of hell–if it is Earth’s “twin”, it is an evil one. The surface of this extremely hot and inhospitable planet is enshrouded in an opaque and heavy blanket of thick, dense clouds that reflect the light of our Sun–and these spooky clouds drift around in the thick Venusian atmosphere, pelting this miserable world with sulfuric acid “raindrops”. In August 2017, a team of scientists, inspired by clockwork computers and World War I era tanks, announced that they have developed a design for a rover that can explore the long-veiled, hellish surface of Venus–and this project is now being investigated at NASA’s Jet Propulsion Laboratory in Pasadena, California.
Watches can suffer a bad beating, and still tell time. The rover that could one day roam the hostile environment that exists on the surface of searing-hot Venus, may be able to do likewise–just so long as it has the right parts.
This new project, that is being planned to give Venus a rover of its own, has been named the Automaton Rover for Extreme Environments (AREE). AREE is funded for study by the NASA Innovative Advanced Concepts program. This program provides small grants to be used for the development of early stage technology, which would enable engineers to develop their ideas.
AREE was originally proposed in 2015 by Dr. Jonathan Sauder, a mechatronics engineer at JPL. Dr. Sauder was inspired by mechanical computers, which use levers and gears to make calculations instead of electronics.
By eliminating electronics, a rover might be better able to roam the surface of Venus. This hellish second planet from our Sun is blanketed by an atmosphere that creates pressures that would smash most submarines. The average surface temperature of Earth’s “evil twin” is 864 degrees Fahrenheit–a temperature hot enough to melt lead.
No spacecraft has been able to survive the surface of Venus for more than an hour or two. The last visitors to attempt this feat were the Soviet Venera and Vega landers that, in the 1970s and 1980s, did manage to send back to Earth a handful of pictures that unveiled a heavily gas-laden and craggy surface.
“When you think of something as extreme as Venus, you want to think really out there. It’s an environment we don’t know much about beyond what we’ve seen in Soviet images,” noted Dr. Evan Hilgemann in an August 25, 2017 JPL Press Release. Dr. Hilgemann is a JPL engineer investigating high temperature designs for AREE.
Both Dr. Sauder and Dr. Hilgemann are planning to place some mechanical prototypes under the kind of searing-heat that broils the tragic Venusian surface. This will enable them to investigate how thermal expansion could influence the mechanical object’s moving parts. Some of the components of the two Soviet landers had been designed to take into account the expansion resulting from the intense heat. Indeed, the landers’ components would not be able to work properly until they were baked by the hellish Venusian temperatures.
Abandon Hope All Ye Who Enter Here
With its surface heavily blanketed by dense clouds, Venus has long been a source of mystery. Even though this second planet from our Sun is so bright in Earth’s sky that it has been known since prehistoric times, it has nevertheless managed to keep most of its secrets. This is because of the thick white clouds that veil its strange surface, hiding it from the prying eyes of curious Earthlings.
Venus is not a friendly “twin” by our planet’s standards–despite Venus’s superficial similarities to our own comfortable blue world. Earth is richly endowed with an abundance of life-sustaining liquid water, that swirls and shimmers around in its vast sloshing oceans and seas. In contrast, Venus is as dry as a bone, and its heavy atmosphere is composed mostly of carbon dioxide, with only tiny trace quantities of water vapor. Because Venus’s atmosphere is so dense and thick, the pressure on this planet’s tormented surface is 92 times that of Earth.
Earth’s indisputably weird sister-world is different from the other planets of our Sun’s family. This is because Venus rotates from East to West, and so it is (in a way) upside down. In addition, a day on Venus is longer than its year. If Venus were observed from high above its north polar region, it would look like it was rotating clockwise. If it were possible–which it is not–for an Earthling to stand on the surface of Venus, without being roasted and mashed, our Sun would rise in the West, take a leisurely and long trek across the sky, and then set in the East. This is, of course, precisely the opposite of what happens on Earth. Venus takes 225 days to finish one orbit around our Star. However, it requires 243 days to rotate only one time on its axis.
Carbon dioxide lets solar radiation in, but not out. This is the way a greenhouse on Earth operates. In fact, Venus is the tragic victim of a runaway greenhouse effect gone completely mad. This causes the temperatures that broil this miserable and tortured world to skyrocket to over 900 degrees Fahrenheit. While lovely life-sustaining liquid water does not exist on Venus, there may be pools of extremely strong sulfuric acid. Well hidden beneath the veil of Venus’s deceptively beautiful and benign wispy cloud tops, is an Earth-size horror that resembles Dante’s description of hell.
Venus is much hotter than it should be. The planet actually is located at a distance where its surface temperature should climb to no more than about 212 degrees Fahrenheit–which is the boiling point of water. Alas, for this tragic world, radio measurements collected from Earth reveal that Venus has the hottest surface of any planet in our Solar System–it is even hotter than the planet Mercury, the closest planet to our Star. Earth’s “evil twin” is also extremely volcanic, with a searing-hot surface that causes its rocks to emit a creepy red glow.
In the 1990s, a strange drizzle was detected by the Soviet Union’s two balloon probes, Vega 1 and Vega 2. The probes revealed that this weird drizzle was not a refreshing trickle of cooling water drops showering the Venusian surface, but was instead a “rain” of terror composed of tiny drops of corrosive sulfuric acid.
If there was ever a time, in the early days of our Solar System, when Venus sported lovely, life-sustaining, churning and frothing oceans of liquid water, the runaway greenhouse effect that broils this tragic planet would have heated these primordial seas to the point that they simply boiled away and evaporated. The existence of liquid water is necessary to support life as we know it on Earth. This is because liquid water triggers certain important chemical reactions on our planet, and these reactions snare unstable sulfur and carbon compounds–in this way keeping them imprisoned within rocks. On Venus, these volatile gases stay in the atmosphere and add to the runaway greenhouse effect.
The Venusian surface cannot be observed from Earth. Indeed, our secretive sister-world’s dense shroud of thick clouds reflect the light of our Star. However, the space probes dispatched to Venus were able to briefly unveil its surface, and showed that it possesses a surface pockmarked by many impact craters. The surface of Venus is also badly scarred by at least 1,600 major volcanoes. However, the Venusian volcanoes are smaller than those on Earth. In addition, the surface of Venus shows vast plains of lava, extensive mountain ranges, and highlands. Then, of course, there are those creepy clouds of sulfuric acid, floating around in the thick atmosphere, that ceaselessly shower this miserable nearby planet with sulfuric acid droplets.
As one of the quartet of relatively small, solid inner planets–the other three are Mercury, Earth and Mars–Venus is classified as a terrestrial planet. This means that it is a rocky world like our own Earth. Venus is about 7,512 miles in diameter–only about 404 miles smaller than Earth–and its mass is approximately 81.5% that of our own planet.
About 80% of Venus’s surface is composed of smooth, volcanic plains. Two highland “continents” make up the remainder of its surface area, one situated in the planet’s northern hemisphere and the other a bit south of the equator. The northern continent is named Ishtar Terra, after Ishtar the ancient Babylonian goddess of love, it is approximately the same size as Australia. Maxwell Montes, the tallest mountain on Venus, is located on Ishtar Terra. Its peak is 7 miles above the average surface elevation of Venus. The southern continent is named Aphrodite Terra, after the ancient Greek goddess of love, and it is the larger of the two highland regions at approximately the size of South America. A network of fault and fractures covers much of this region.
There is an absence of evidence of lava flows accompanying any of the visible calderas, and the reason for this is not known. Venus has few impact craters, indicating that its surface is relatively youthful–a mere 300 to 600 million years old. Venus also shows some unique features in addition to the impact craters, mountains and valleys frequently found on rocky planets. Among these strange features are flat-topped volcanic features called “farra”, which look something like pancakes and range in size from 12 to 31 miles across, and from 330 to 3,280 miles high. Indeed, much of Venus’s surface appears to have been shaped by volcanic activity. Venus has several times as many volcanoes as Earth, and it sports 167 large volcanoes that are over 62 miles across. The only volcanic complex on our planet of this size is the Big Island of Hawaii. However, this does not mean that Venus is more volcanically active than Earth. Instead, it indicates that Venus’s crust is older. This is because Earth’s oceanic crust is continually recycled by subduction at the boundaries of tectonic plates, and has an average age of only about 100 million years. In dramatic contrast, the Venusian surface is estimated to be approximately 300 to 600 million years old.
About 1,000 impact craters on Venus are evenly distributed across its surface. On other cratered worlds in our Solar System, such as Earth and its large Moon, craters show a range of states of degradation. On Earth’s Moon, degradation results from subsequent impacts, whereas on Earth it is caused by wind and rain erosion. On Venus, approximately 85% of the craters are in pristine condtion. The number of craters, along with their well-preserved condition, suggests that the planet experienced a global resurfacing approximately 300 to 600 million years ago. This global resurfacing was followed by a decay in volcanism. While our planet’s crust is in continuous motion, Venus is believed to be unable to sustain such a process. In the absence of plate tectonics to dissipate heat from its mantle, Venus alternatively experiences a cyclical process in which mantle temperatures rise until they reach a critical point that weakens the crust. Then, over a period of about 100 million years, subduction occurs on an immense scale, completely recycling the crust.
Venus’s extremely dense atmosphere is composed of about 96.5% carbon dioxide, 3.5% nitrogen, and traces of other gases, especially sulfur dioxide Studies have indicated that billions of years ago Venus possessed an atmosphere that was much more like Earth’s than it is now, and there may even have been large amounts of liquid water on the surface. Tragically, the runaway greenhouse effect on Earth’s sister-planet boiled away these frothing, churning, life-friendly seas, and left behind an Earth-size searing-hot world eerily similar to literary descriptions of Hell.
Earth’s “Evil Twin” Gets A Rover Of Its Own
Mechanical computers have been used for centuries, primarily as mathematical tools like adding machines. The best-known mechanical computer might be Charles Babbage’s Difference Engine, a 19th-century invention used to calculate algebraic equations. The oldest mechanical computer, known as the Antikythera mechanism, was used by the ancient Greeks to predict astronomical occurrences, like eclipses.
Works of art have also benefited from the development of mechanical computers. For centuries clockwork mechanisms were used to create automatons for wealthy patrons. In the 1770s, Pierre Jaquet-Droz, a Swiss watchmaker, created “The Writer”–an automaton that coud be programed to write any combination of letters.
Dr. Sauder commented in the August 25, 2017 JPL Press Release that analog technologies could prove to be useful where electronics normally fail. In extreme environments like the surface of Venus, most electrons would melt in the searing-hot temperatures or be corroded by sulfuric acid floating in the atmosphere.
“Venus is too inhospitable for the kind of complex control systems you have on a Mars rover. But with a fully mechanical rover, you might be able to survive as long as a year,” Dr. Sauder continued to comment.
Wind turbines in the center of the rover would power these computers. This would enable it to flip uside down and still keep running. However, the planet’s very hostile environment would still present a number of difficult challenges.
However, AREE includes some innovative design choices. One of the challenges that it addresses is mobility, because there are still so many unknowns about the surface of Venus. Dr. Sauder’s original idea was based on the “Strandbeests” created by the Dutch artist Theo Jansen. Strandbeests are spidery structures with spindly legs that transport their bulk across beaches–and are powered only by the wind.
However, these spidery structures appeared too unstable for rocky terrain. So, Dr. Sauder started combing through World War I tank treads as a possible alternative. These tanks, that roamed over our planet a century ago, were constructed to roll over craters and trenches.
A second challenge has to do with communications. In the absence of electronics, how could science data be transmitted? Current plans are inspired by yet another technology devised at an earlier era: Morse code.
An orbiting spacecraft could communicate with the Venusian rover using radar. The rover would sport a radar target which, if shaped just right, would behave like “stealth technology in reverse,” noted Dr. Sauder. Stealth planes sport special shapes that scatter radar signals. Dr. Sauder is studying how to shape these targets to brightly reflect signals instead. By adding a rotating shutter in front of the radar target, the rover could be turned to the bright, reflected spot on and off, communicating in a way similar to that of signal lamps on Navy ships.
Now in its second phase of development, the JPL scientists are selecting parts of the AREE concept to be refined and prototyped. The scientists hope to flesh out a rover concept that will eventually have the ability to study the geology of Earth’s “evil twin” world, and possibly even drill a few samples.
Judith E. Braffman-Miller is a writer and astronomer whose articles have been published since 1981 in various newspapers, magazines, and journals. Although she has written on a variety of topics, she particularly loves writing about astronomy because it gives her the opportunity to communicate to others the many wonders of her field. Her first book, “Wisps, Ashes, and Smoke,” will be published soon.
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