Hellish Venusian surface. Courtesy NASA.gov
(Note: this is a part of The Space Colonization Series)
When space colonization is mentioned many things come to mind: Mars, the Moon, the future, terraforming, and even occasionally asteroids. One thing that rarely comes to mind, however, is Venus. And why should it? After all, Venus is Earth's sister planet from hell, registering a spicy 450 degrees C average on the surface or, in other words, hotter than Mercury. As if the temperature wasn't enough incentive to destroy any thoughts of visiting Earth's closest planetary neighbor, reaching the surface is practically impossible to do safely. Atmospheric pressure reaches 90 times that of ours on the surface or equivalent to being under 1 km of water. Venus also has a relatively slow rotation, completing one rotation every 243 earth days. Thus nights would last a very long time--not that you could see the sun during the day anyway. So, if Venus seems so obviously irrelevant to the idea of space colonization why make an article connecting the two? Well, it is Venus' hellish properties that ironically make it so appealing. The common misconception about space colonization is that colonies are built on the surface. The key to a Venusian colony is it's incredibly dense atmosphere. Remember, "...or equivalent to being under 1 km of water?" Well, things float on water; don't they...?
The Idea
The concept is actually based on a rather simple premise--buoyancy. So, we all know lower density materials rise to the top but how could this apply to Venus? Simply put, breathable gas has the equivalent lifting power on Venus as half of Helium's lifting power on Earth (about 1 kg per cubic meter). This property allows for breathable air domes to lift a colony in addition to their own weight. Tweaking the lifting power could also easily be done by storing helium or hydrogen (both extractable from the atmosphere) filled tanks. The Colonies would float at an altitude of roughly 50 km where the air pressure is equal to Earth's. At this altitude the former problems encountered with a surface colony start to disappear. The temperature chills to a much more normal range of 0-50 degrees Celsius or liquid water temperatures. This altitude also happens to sit above the thick clouds providing abundant solar energy. The clouds themselves are so reflective that pointing solar panels downward would provide almost as much energy as they would pointing upward. The solar power available above Venus' cloud top is approximately 1.9 times that of Earth's providing plenty of power for a potential colony. Ah, that sounds great, but the issue of incredibly long dark periods still looms doesn't it? Fortunately, Venus' atmospheric winds bail us out of that situation giving us a manageable 50 hour solar day and likewise, a 50 hour solar night. Increase the latitude of the 'Bubble' and everything could be packaged into an Earth-like 24 hour cycle.
Bespin from the movie Star Wars: The Empire Strikes Back.
Other than the extreme density of Venus' atmosphere providing buoyancy, it also provides many important resources necessary for food and oxygen. Carbon dioxide and Nitrogen are very abundant in the atmosphere and could easily be harvested. Hydrogen can also be extracted from condensed sulfuric acid droplets, thus providing all of the basic elements required for human survival. Industrial minerals, also very important for maintaining an outpost or colony, could be mined from the surface. The hazards of reaching the surface drastically decrease in difficulty when making the attempt from an already established floating colony (or aerostat habitat). Large cables stretching the 50 km distance or less if the city lowers altitude temporarily could lift minerals from the surface directly to the habitat. Such a large habitat would have an incredibly large heat capacitance and thus be able to withstand momentary dips into much higher temperatures. So, it is starting to become clear how a floating city on Venus could theoretically become self-sustaining. That is great, but we are still left with a legitimate question: why should we want to go to Venus?!
The Reason
Obviously research of the planet is one simple and arguably lame reason to visit. That excuse could be made for practically anything. Everyone knows scientific research would take place. The type of research possible, however, could be highly relevant to our own planet. Global warming is currently a great debate across the globe and an in-depth look into Venus' extreme example of the greenhouse effect could open up many doors to explaining our own climate. Some other topics of interest include:
Before the runaway greenhouse effect, was early Venus temperate?
Did Venus once have an ocean? If so, did it ever have life?
What causes the geological resurfacing of the planet?
What is the nature of the atmospheric superrotation?
What are the aerosol particles in the atmosphere?
What is the —snow“ on Venus mountaintops?
What is the nature of the disequilibrium chemistry in the Venusian atmosphere? Could it indicate atmopsheric life?
View rest of paper [pdf]
[NOTE: pdf file is currently down so to view a transcript of the file I have decided to host it
here.]
There are many other reasons to colonize Venus. First and foremost, human survival is dependent upon our expansion and colonization of space as Stephen Hawking recently made so
clear. Venus is enticing for such a proposal for the three very important reasons: location, location, location. One, it is Earth's closest neighbor (excluding the Moon). Two, the colony is located in the dense atmosphere and thus it blocks harmful solar radiation naturally--problems that would be encountered on the Moon and Mars. The third is Venus' relative position to the coveted asteroid belt. It seems counterintuitive that Venus has a prime location for reaching the asteroid belt considering it is closer to the sun than Earth and the asteroid belt is even further than Earth but
astrodynamics says otherwise. Here is more from the previous
[pdf] explaining the concept in further detail:
In terms of flight time, Venus is closer to the asteroid belt than either the Earth or
Mars. This is shown in figure 3. For example, the minimum-energy trajectory to the largest main-belt asteroid, Ceres, takes 0.95 yeears from Venus, and 1.05 years from Earth. In terms of flight time, the closer you are to the sun, the more accessable the asteroids are. The asteroids are not actually close to each other, and hence if a habitat is to support prospecting and mining more than one asteroid, the asteroid belt is in some ways the worst location for it. An asteroid is as likely as not to be on the opposite side of the sun, and although the Earth is further from the sun, that does not put it closer, on the average, to any given asteroid. The higher orbital velocity of Venus actually makes transfer orbits somewhat faster, as well as increasing the number of transfer opportunities (that is, decreasing the synodic period).
View rest of paper [pdf]
Clearly, Venus presents a distinct advantage concerning mining asteroids, a potential 'gold mine.'
Establishing a floating city colony also gives humans much more 'practice' with inhabiting alien worlds. Learning to become air and land dwellers could prove to be a valuable asset in the future. Venus gives us a unique opportunity in regards to this because its gravity, at.904 G's, is only slightly less than Earth's. This means that colonists would not need to make frequent trips back to Earth to avoid bone loss or any other negative side effects of low gravity environments.
OK, but there are still problems right?Of course there are. Many obstacles face a floating colony on Venus, though not as many nor the type that most would expect. The atmosphere is filled with sulfuric acid and other corrosive particles. Ceramics or some other type of layer would be necessary to prevent corrosion. Sulfuric acid fortunately has many industrial uses and could also be harvested for use. Scooping raw materials would also require quite an engineering feet, not to mention the whole project itself being a gargantuan task. The hazards overall are similar to any ambition of colonizing a planet. One big concern would be leaks. Fortunately, since the pressure is approximately equal on the inside and out, leaks of even large proportions would be slow and manageable.
Personally, I wouldn't say that colonizing Mars or the Moon first is a better or worse idea. Clearly those two options get the most attention and seem the most viable options to many. A floating city may not be as easy or as difficult as what has been proposed but the idea deserves merit. I believe the proposal is worthy enough for deeper consideration and more research. Hopefully my spreading of this idea has sparked a few of you with your own ideas. If anyone has any questions feel free to post them and I will try my hardest to address them and find an appropriate answer.
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Titan
