By Dr. Gary Deel, Ph.D., J.D.
Faculty Director, School of Business, American Military University
This is the fifth article in a six-part series on the history of Venus space exploration and research, and the possibility of human colonization on Venus.
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In previous articles, we’ve thoroughly reviewed past, present, and future missions sent to explore and study Venus. This research is certainly interesting in its own right.
However, one of the key reasons why we explore the planets and celestial bodies within our solar system is to determine whether or not they have life and if they could potentially support Earth life. And on the subject of Venus, some very important questions remain to be answered: Could Venus in any way, shape or form be habitable for humans? If so, how? And would it make sense to do so?
Venus Colonization Could Be a Possibility
The short answer to the question of whether the habitability of Venus is at all feasible is maybe. However, a longer explanation requires quite a bit of unpacking.
Previous research has shown that the surface of Venus is absolutely inhospitable to human life. Even if we found a way to manufacture the oxygen needed for breathing there — something we’d need to do pretty much anywhere we go in the solar system — the temperatures and pressures on the surface of Venus would easily kill us in seconds.
No, inhabiting the Venusian surface is not a viable option. So what is the alternative?
Some experts have proposed that the best option for colonizing Venus would be to live in the upper layers of the atmosphere on floating habitats suspended by balloon-like structures. Although the temperatures and pressures on the surface of Venus are incredibly hostile, as one rises further toward space, the pressure goes down due to less atmosphere above pushing inward. Temperatures also go down due to thinner and thinner insulation from space.
It turns out that, at about 31 miles above the surface of Venus, the pressures and the temperatures are conveniently both very similar to Earth, so humans could survive without the need for any kind of insulated or pressurized suits. All that would be needed would be a supply of oxygen for breathing.
Sulfuric Acid Rain Could Be Converted into Potable Water
At this same altitude, human colonies would still potentially be exposed to sulfuric acid rain that falls on Venus. However, human habitats could be constructed out of materials resistant to such corrosive substances, such as Teflon.
The sulfuric acid could actually have a silver lining as well; it could serve as a source of water. Venus has very little water vapor in its atmosphere, but sulfuric acid is partly composed of hydrogen and oxygen atoms.
Consequently, a simple electrolysis process could turn the acid into water, with a supply of sulfur left over. This is really important given how much life relies on water for survival here on Earth.
Earth Plants Could Be Utilized to Create Oxygen Source
While Venus does not have much oxygen, it does have carbon dioxide and nitrogen in abundance. This mixture is perfect for growing Earth plants under artificial lighting.
Earth plants, in turn, give off oxygen as a byproduct. Hypothetically, we could satisfy both our sustenance needs and our oxygen needs by bringing seeds with us and cultivating plants within our floating colonies on Venus.
The plants would serve as a source of food, and the resulting oxygen from the Earth plants would then be used for breathing. This idea is essentially the flora/fauna symbiosis found on Earth, transplanted to another world.
Creating a Viable Human Habitat above Venus
This plant-based gas conversion process could have another key advantage for Venus colonies: buoyancy. One of the obvious challenges to the notion of a floating city around Venus is how one goes about making an entire city float.
Here on Earth, that would be difficult to do, due to the force of gravity. And causing an entire city to float above Venus wouldn’t necessarily be easy, either.
However, the key opportunity with Venus lies in the fact that its atmosphere is mostly carbon dioxide. Carbon dioxide is a heavier gas than oxygen or nitrogen.
As a result, some of the byproduct gases from plant farms could be used to inflate balloons that would provide lift for the colony. Because of the difference in density, a balloon filled with oxygen/nitrogen would float on top of thick layers of carbon dioxide below. In fact, humans could theoretically use the inside of such a balloon as the habitat itself, since the gas required for lift is the same gas required for respiration.
Scientists have done the math and determined that a single, spherical balloon, just 1 kilometer (0.6 miles) in diameter and filled with these lighter gases, could support more than 700,000 tons of habitat. Lifting capacity goes up exponentially with linear increases in diameter, so the possibilities for size and scale here are virtually endless.
The risk of balloon punctures would not be as concerning on Venus as they are here on Earth, since there wouldn’t be a significant pressure differentiation between the contents of such a balloon and the surrounding atmosphere. Buoyancy in the Venusian atmosphere does not require that such balloons be highly pressurized.
Instead, the balloons simply need to be filled with the lighter-weight gases that float atop the existing carbon dioxide clouds. Consequently, any holes suffered by the balloons could be easily patched before they threaten the viability of a Venusian habitat.
Creating Electrical Power from Wind Energy
In terms of electricity, a Venusian colony would have trouble harnessing solar power due to the thick cloud cover, but wind energy would theoretically be in abundant supply. Given its exposure to the currents within the Venusian atmosphere, wind turbines would be a natural choice for maintaining electricity within a Venusian habitat. As an alternative, spacecraft headed to Venus could simply bring along compact nuclear power generators.
Protecting Humans from the Effects of Venusian Radiation
As I mentioned previously, Venus does not have much in the way of a magnetic field, so radiation emanating from outer space could be particularly harmful to the health of space travelers. But Venus’s cloud cover would serve as a highly effective shield to prevent much of that radiation from reaching inhabitants. Even at an altitude of 31 miles, there would still be enough atmosphere above to provide substantial protection for Venus colonists.
Although Venus Colonization Seems Far-Fetched, Space Agencies Have Given It Serious Consideration
Some of this discussion about Venus colonization may seem far-fetched, but this idea is credible enough to have been given serious consideration by major space agencies. For example, NASA actually put the mission to paper under the name High-Altitude Venus Operational Concept (HAVOC), where the agency had proposed to send a manned crew on a 30-day mission aboard a blimp that would essentially float around in the Venusian atmosphere.
However, this mission’s current status is inactive. There is no indication that it will be revisited in the near future.
Colonizing the atmosphere of Venus is, at least, a viable idea. But how does it stack up against popular alternatives? In the last part of this article, we’ll look at how Venus compares with the other competitive option in the solar system: Mars.
About the Author
Dr. Gary Deel is a Faculty Director with the School of Business at American Military University. He holds a J.D. in Law and a Ph.D. in Hospitality/Business Management. Gary teaches human resources and employment law classes for American Military University, the University of Central Florida, Colorado State University and others.