Human Settlements on Venus
Exploring other worlds and inhabiting them is always a fun and interesting topic to talk about. There are so many possibilities when it comes to thinking about what life would be like living on another celestial body that isn’t Earth. In my past threads, I have talked about what it would take to live somewhere that isn’t Earth, including the process of terraforming Mars and living in giant metal tubes called O’Neill cylinders. But today, we’re going to be looking at another possible candidate, and it's just next door.
The planet Venus, named after the Roman goddess, is what people love to call “Earth’s twin”. They’re not wrong to call it that since everything about Venus is so similar. The two planets are similar in mass and size, and Venus even has a similar gravitational constant, around 90% that of Earth’s.
But, the planet is also very different in many ways. Venus is known as the living reincarnation of Hell because late in its planet formation, the planet continually got hotter due to the incoming radiation from the sun, and this has led to what we call a runaway greenhouse effect. The Venusian atmosphere that is composed of mostly CO2 has gotten so thick that it blocks any heat radiated from its surface from escaping. The trapped heat has caused the surface temperature to rise to around 700 degrees Fahrenheit, a temperature hot enough to melt lead. High in the atmosphere, there are clouds of sulfuric acid, which have a high albedo (measure of reflectivity) and makes remote sensing very difficult, and the atmosphere has led to a surface pressure of more than 90 times that of Earth’s. The majority of the surface of Venus is covered volcanic plains, some which are possibly active today due to measures of spikes in the amount of sulfuric acid in the atmosphere. No spacecraft that has landed on Venus has survived more than a few hours.
So yeah, Venus does not seem like the paradise planet people would like to move to. Despite that, there are continued efforts to learn how we can live on Venus, including terraforming efforts, and also the idea of cloud cities as a cool alternative.
Terraforming Venus was an idea first proposed by astronomer Carl Sagan in a 1961 article in Science. The fact that Venus is so similar to Earth, and that it once had liquid water oceans and reasonable surface temperatures makes it a very attractive candidate for terraforming. The main efforts in terraforming Venus are basically opposite to the efforts in terraforming Mars. We would need to
Thin out the dense CO2 atmosphere and make it breathable, and this would in turn eliminate the continuous runaway greenhouse effect currently happening on Venus
Reduce the very high surface temperatures, which follows directly from the first point
Establish a proper day/night cycle since currently, a day on Venus (243 Earth days) is longer than a year on Venus (~225 Earth days)
Help create a proper magnetic field that is much stronger than its current one
Scientists have thought of numerous ways to make the atmosphere thinner, some including introducing other volatiles that would produce chemical reactions to lead to it, freezing up some of the CO2 in the atmosphere, and using solar shades to prevent more heat from coming into the atmosphere. Once the atmosphere has changed, there will be less trapped heat, meaning much more reasonable surface temperatures.
Some people believe that although prominent, changing the day/night cycle on Venus is unnecessary because it wouldn’t really affect the creation of human settlements. But it would be something nice to have nonetheless.
Venus currently does not have an intrinsically produced magnetic field, and this could be due to a solidified core that would explain the lack of convection happening. Creating one would probably be similar to what I mentioned in my terraforming Mars thread, which would be to use superconducting magnets to artificially create one.
So those are the basics of terraforming Venus, and there is a lot more detail that goes into changing those specific characteristics of the planet in order to make it livable for humans. But, there is another possible and maybe even better solution to living on Venus, and that is the creation of cloud cities.
The upper Venusian atmosphere is a lot different from the lower section and the surface, and it can provide the necessary components we humans will need to survive there. It consists of the necessary building blocks and volatiles that people would need to live and produce food. Because of the previously mentioned high albedo of the sulfuric acid clouds, harmful ultraviolet (UV) radiation from the sun will be reflected out, protecting humans. It is also believed that extremophile microorganisms could be living in the Venusian upper atmosphere, which could possibly feed on UV radiation, and studying these organisms could provide useful information.
So, how exactly would we live here?
Between the altitudes of 50 and 60 km, there exists conditions that include reasonable temperatures suitable for living. This is where these cloud cities would exist. First proposed by Soviet scientists in the late twentieth century, we would live in these vehicles called aerostats, which are aircraft that are lighter than air. Breathable air, a mixture of oxygen and nitrogen, is light enough to have the aerostats float within the CO2 atmosphere, and people would inhabit ships carried by these envelopes of air. These floating cities in the Venusian atmosphere are a lot better than an orbiting space station because science can be done in real time, and orbiting Venus does not come with the same perks as living in the safety of the atmosphere.
Aerospace Engineer Geoffrey Landis of NASA Glenn Research Center has also put a lot of research into this, and published a paper, “Colonization of Venus” back in 2003. He stated that “At cloud-top level, Venus is the paradise planet”. Some interesting points from this paper includes
Technology to prevent acid corrosion from the sulfuric acid clouds is already well developed
The orbit of Venus puts it closer to the asteroid belt than both Earth and Mars, so resources can be gained from asteroid mining
As time goes on, more of these aerostats would be introduced into the atmosphere, establishing a permanent settlement on Venus. Getting the materials from Earth to Venus wouldn’t be difficult and would take less time compared to getting to Mars since Venus is pretty close to us.
Something that concerns me with cloud cities though is the potential for lightning within the Venusian atmosphere. A series of Soviet space probes called Venera with the goal of learning more about Venus detected these bursts of energy (along with some other cool things such as a layer of toxic chlorine right under the sulfuric acid clouds), but it isn’t confirmed. I wonder how this could possibly affect a settlement, or if the settlement would be too high up to be affected at all.
NASA themselves has actually done research on this topic as well, and the project is called the High Altitude Venus Operational Concept (HAVOC), and they have come up with a multi-step plan on how they would accomplish their goal. I definitely recommend reading up on it, the mission concept is super cool!
So with that, living in the deadly clouds of Venus sounds pretty great to me. It does solve a lot of the ethical issues that come with the long process of terraforming, though we probably shouldn’t expect this to happen anytime soon since it’ll take a lot of planning, money, and of course time. Either way, I’m looking forward to any human space settlement in the future!