Mercury, Venus, Earth and Mars

We’re Going the Wrong Way

Mars Mars Mars. Everyone always going on about Mars.

But I’m here to convince you that we have another neighbor that might be a better candidate for human colonization: Venus.

Venus gets a bad rep. It is known as the “hell planet” due to surface temperatures hot enough to melt lead but it wasn’t always that way. In fact, until the Soviet Venera missions in the 1960s, the planet was largely a mystery, shrouded in dense yellow clouds.

Quite a bit of science fiction was written about Venus in the early 1900s. Many stories were written about a wet, tropical paradise of a planet. The reason the Soviets sent so many probes to Venus was that the world believed that Venus could be a suitable planet for colonization. Venus has had more probes sent to it than Mars at 40 to 38 respectively.

Number of probes to different celestial locations

There was a real hope that Venus could be terraformed to a more Earth-like place but that hope vanished in 1967 with the data from Venera 4 and Mariner 5 which confirmed without a shadow-of-a-doubt that Venus was a hot, dry, desert planet. The science fiction community responded to this news with the publication of Farewell Fantastic Venus in 1968, a collection of hopeful short stories about the planet before the real Venus was known. This essentially put an end to the popular opinions about Venus and a slowdown in scientific probes being sent to the planet.

Currently there are only two proposed probes for Venus, Venera-D and the Venus In-Situ Explorer, but there are five proposed probes for Mars. When the public opinion shifted away from our sister planet, it shifted towards our red neighbor Mars.

But what if we were wrong to throw Venus out the window? What if, in our Earth-centric idea of terraforming, we tossed aside a perfectly good candidate for space colonization?

A terraformed Venus. src:

Now we can’t talk about Venus and Mars colonization without discussing terraforming. Terraforming is the act of changing a planet to be more Earth-like. However, in colonization the aim is to not “terraform” a planet because that may not be in the best interests for the human species or the most economical. The phrase planetary engineering is used to describe the tools and processes used to change a planet in such a way that humans can live on it. The last part of that statement “such a way that humans can live on it” could be a range of environments that is much dependent on the initial state of the planet and the constraints set upon the settlers on adapting to that environment. Chemical volatiles, temperature, pressure, radiation, gravity, economics and psychology all need to be taken into account when planning for human habitation of a place beyond Earth.

Planetary engineering is an unbiased approach to the act of changing a planet. The planet can be taken as is, without the need to change it just so that it becomes more Earth-like. Certain qualities, despite not being what we’re used to, would still fall well within human limits for livability. For example, we don’t have to live in a 24 hour day/night cycle. We also don’t need to live on the surface of a planet.

Venus has a lot of good things going for it making it a better prospect than Mars. It’s closer than Mars (4 month trip vs 6 month trip), has a similar gravity (0.9g vs 0.38g), has a longer window of time to potentially launch (every 19 months vs 26 months), has an atmosphere and an induced magnetosphere from it’s ionosphere. Here’s the real kicker: 50 to 55 kilometers above the surface of Venus, the planet has a similar pressure and temperature to Earth. In fact, Venus might be one of the only places in the entire solar system where you can find a similar gravity, pressure and temperature as Earth. The problem is that it’s high up in the clouds.

Pressure and Temperature on Venus

But here’s where things get interesting: because Venus has an atmosphere of 95% CO2, and the density of pure CO2 is 1.96g/L as opposed to Earth air density of 1.25g/L. This means that a spacecraft filled with normal air would have an effect similar to helium on Venus.

A properly designed spacecraft could float on top of the clouds. Think of it as a flying submarine. In addition, there wouldn’t need to be any concern for explosive decompression as the ambient pressure is equal to the internal pressure. Any leak in the craft would be a slow exchange of gases.

Currently there’s a bit of “surfacism” in the scientific community. Humans are so used to living on the ground that any idea to the contrary is greeted with skepticism. Since we can’t live on the ground on Venus, we can’t live there at all.

It would be far easier to set up a colony in the upper atmosphere of Venus than it would be to colonize Mars.


Because the colony is in the upper atmosphere, it takes less energy for an orbital insertion into the gravity well. The atmosphere allows for quicker aerobraking and the deployment of spacecraft. This is important because it means that less energy is needed to escape from the gravity well of the planet, thus enabling return trips.

The window of launch (every 19 months) and the length of the voyage (4 months) is also lessened, this means that supply ships can come and go faster and more frequently, ensuring constant support for the initial colonists.


On Venus, there is a minimized risk of radiation due to the weak induced ionosphere. This is vastly different than Mars which has no magnetosphere.

Venus also has two times the solar insolation as Earth which means that any solar panels used on Venus would have a much better efficiency. In addition, the reflective cloud cover allows solar panels to be placed on any surface of the craft and still receive a similar amount of solar energy.

Image of a potential Venusian airplane

There are a number of problems with Venus that may actually provide an advantage to living on the planet.

First, Venus rotates in retrograde. It is thought that a catastrophic collision caused Venus to flip its rotation. The planet spins clockwise very slowly, once every 243 Earth days. It’s day is longer than it’s year (116 days).

This could actually be an advantage to Venus. The slow rotation means that a powered aircraft could stay in constant sunlight with very minimal effort. In addition, this allows for plants to grow with maximum sunlight. The CO2 atmosphere would also help immensely with plant growth.

VIRTIS measurements of the south pole wind speeds of Venus:

Secondly, Venus has wind speeds of over 200 miles/hour in the upper atmosphere. However, this is limited to the equator; close to the poles and at greater than 55 degrees in latitude, the wind speed decreases to less than 22 miles/hour above the cloud cover, a much more manageable amount. you would only have to fly at the same speed as a slow-moving car to stay in the same location. In addition, in the polar regions the temperature is much more stable with swings of less than 27 F (15 C), well within Earth-normal.

Lastly, the problem that Venus has is the lack of water and the abundance of sulfuric acid. Although difficult to deal with, this is not an insurmountable problem. The corrosive acid could be an essential source of hydrogen ions in order to make water, and with the proper coatings of PIBO, surfaces can be protected against the acidic clouds.

Due to the high density of CO2, properly attired colonists could fly around the clouds of Venus with relative ease. Also, the colony could be a good testing ground for carbon-fixing technology that would have the effect of reversing global warming on Earth.

Certain microorganisms would do incredibly well in the Venusian atmosphere. Geobacter sulfuredducens is a microbe that reduces sulfur in order to generate electricity. Modified geobacter could generate the constituent components of liquid water while also producing electricity for the colony.

Additionally the carbon source in the atmosphere makes a perfect substrate for the growth of carbon-based structures. Mycological growth could be tailored to build constantly expanding, lightweight platforms that support the expansion of Venusian colonies.


Venus > Mars

All-in-all Venus seems like a much more likely prospect of prolonged human habitation than Mars. Let’s move away from wanting to transform other planets to be exactly like Earth. If we refocus our efforts on our sister planet, pretty soon we could be living among the clouds in eternal sunlight. ER.

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