Welcome back to our series on Settling the Solar System! Today, we take a look at Earth’s “sister planet”, the hellish, yet strangely similar planet Venus. Enjoy!
Since humans first began looking up at the skies, they have been aware of Venus. In ancient times, it was known as both the “Morning Star” and the “Evening Star”, due to its bright appearance in the sky at sunrise and sunset. Eventually, astronomers realized that it was in fact a planet, and that like Earth, it too orbited the Sun. And thanks to the Space Age and numerous missions to the planet, we have learned exactly what kind of environment Venus has.
With an atmosphere so dense that it makes regular surface imaging impossible, heat so intense it can melt lead, and sulfuric acid rain, there seems little reason to go there. But as we’ve learned in recent years, Venus was once a very different place, complete with oceans and continents. And with the right technology, colonies could be built above the clouds, where they would be safe.
So what would it take to colonize Venus? As with other proposals for colonizing the Solar System, it all comes down to having the right kinds of methods and technologies, and how much are we willing to spend.
Examples in Fiction:
Since the early 20th century, the idea of colonizing Venus has been explored in science fiction, mainly in the form of terraforming it. The earliest known example is Olaf Stapleton’s Last And First Men (1930), two chapters of which are dedicated to describing how humanity’s descendants terraform Venus after Earth becomes uninhabitable; and in the process, commit genocide against the native aquatic life.
By the 1950s and 60s, terraforming began to appear in many works of science fiction. Poul Anderson also wrote extensively about terraforming in the 1950s. In his 1954 novel, The Big Rain, Venus is altered through planetary engineering techniques over a very long period of time. The book was so influential that the term term “Big Rain” has since come to be synonymous with the terraforming of Venus.
In 1991, author G. David Nordley suggested in his short story (“The Snows of Venus”) that Venus might be spun-up to a day-length of 30 Earth days by exporting its atmosphere of Venus via mass drivers. Author Kim Stanley Robinson became famous for his realistic depiction of terraforming in the Mars Trilogy – which included Red Mars, Green Mars and Blue Mars.
In 2012, he followed this series up with the release of 2312, a science fiction novel that dealt with the colonization of the entire Solar System – which includes Venus. The novel also explored the many ways in which Venus could be terraformed, ranging from global cooling to carbon sequestration, all of which were based on scholarly studies and proposals.
Proposed Methods:
All told, most proposed methods for colonizing Venus emphasize ecological engineering (aka. terraforming) to make the planet habitable. However, there have also been suggestions as to how human beings could live on Venus without altering the environment substantially.
For instance, according to Inner Solar System: Prospective Energy and Material Resources, by Viorel Badescu, and Kris Zacny (eds), Soviet scientists have suggested that humans could colonize Venus’ atmosphere rather than attempting to live on its hostile surface since the 1970s.
More recently, NASA scientist Geoffrey A. Landis wrote a paper titled “Colonization of Venus“, in which he proposed that cities could be built above Venus’ clouds. At an altitude of 50 km above the surface, he claimed, such cities would be safe from the harsh Venusian environment:
“[T]he atmosphere of Venus is the most earthlike environment (other than Earth itself) in the solar system. It is proposed here that in the near term, human exploration of Venus could take place from aerostat vehicles in the atmosphere, and that in the long term, permanent settlements could be made in the form of cities designed to float at about fifty kilometer altitude in the atmosphere of Venus.”
At an altitude of 50 km above the surface, the environment has a pressure of approximately 100,000 Pa, which is slightly less than Earth’s at sea level (101,325 Pa). Temperatures in this regions also range from 0 to 50 °C (273 to 323 K; 32 to 122 °F), and protection against cosmic radiation would be provided by the atmosphere above, with a shielding mass equivalent to Earth’s.
The Venusian habitats, according to Landis’ proposal, would initially consists of aerostats filled with breathable air (a 21:79 oxygen-nitrogen mix). This is based on the concept that air would be a lifting gas in the dense carbon dioxide atmosphere, possessing over 60% of the lifting power that helium has on Earth.
These would provide initial living spaces for colonists, and could act as terraformers, gradually converting Venus’ atmosphere into something livable so the colonists could migrate to the surface. One way to do this would be to use these very cities as solar shades, since their presence in the clouds would prevent solar radiation from reaching the surface.
This would work particularly well if the floating cities were made of low-albedo materials. Alternately, reflective balloons and/or reflecting sheets of carbon nanotubes or graphene could be deployed from these. This offers the advance of in-situ resource allocation, since atmospheric reflectors could be built using locally-sourced carbon.
In addition, these colonies could serve as platforms where chemical elements were introduced into the atmosphere in large amounts. This could take the form of calcium and magnesium dust (which would sequester carbon in the form of calcium and magnesium carbonates), or a hydrogen aerosol (producing graphite and water, the latter of which would fall to the surface and cover roughly 80% of the surface in oceans).
NASA has begun exploring the possibility of mounting crewed missions to Venus as part of their High Altitude Venus Operational Concept (HAVOC), which was proposed in 2015. As outlined by Dale Arney and Chris Jones from NASA’s Langley Research Center, this mission concept calls for all crewed portions of the missions to be conducted from lighter than air craft or from orbit.
Potential Benefits:
The benefits of colonizing Venus are many. For starters, Venus it the closest planet to Earth, which means it would take less time and money and send missions there, compared to other planets in the Solar System. For example, the Venus Express probe took just over five months to travel from Earth to Venus, whereas the Mars Express probe took nearly six months to get from Earth to Mars.
In addition, launch windows to Venus occur more often, every 584 days when Earth and Venus experience an inferior conjunction. This is compared to the 780 days it takes for Earth and Mars to achieve opposition (i.e. the point in their orbits when they make their closest approach).
Compared to a mission to Mars, a mission to Venus’ atmosphere would also subject astronauts to less in the way of harmful radiation. This is due in part to Venus’ greater proximity, but also from Venus’ induced magnetosphere – which comes from the interaction of its thick atmosphere with solar wind.
Also, for floating settlements established in Venus’ atmosphere, there would be less risk of explosive decompression, since there would not be a significant pressure difference between the inside and outside of the habitats. As such, punctures would pose a lesser risk, and repairs would be easier to mount.
In addition, humans would not require pressurized suits to venture outside, as they would on Mars or other planets. Though they would still need oxygen tanks and protection against the acid rain when working outside their habitats, work crews would find the environment far more hospitable.
Venus is also close in size and mass to the Earth, resulting in a surface gravity that would be much easier to adapt to (0.904 g). Compared to gravity on the Moon, Mercury or Mars (0.165 and 0.38 g), this would likely mean that the health effects associated with weightlessness or microgravity would be negligible.
In addition, a settlement there would have access to abundant materials with which to grow food and manufacture materials. Since Venus’ atmosphere is made mostly out of carbon dioxide, nitrogen and sulfur dioxide, these could be sequestered to create fertilizers and other chemical compounds.
CO² could also be chemically separated to create oxygen gas, and the resulting carbon could be used to manufacture graphene, carbon nanotubes and other super-materials. In addition to being used for possible solar shields, they could also be exported off-world as part of the local economy.
Challenges:
Naturally, colonizing a planet like Venus also comes with its share of difficulties. For instance, while floating colonies would be removed from the extreme heat and pressure of the surface, there would still be the hazard posed by sulfuric acid rain. So addition to the need for protective shielding in the colony, work crews and airships would also need protection.
Second, water is virtually non-existent on Venus, and the composition of the atmosphere would not allow for synthetic production. As a result, water would have to be transported to Venus until it be produced onsite (i.e. bringing in hydrogen gas to create water form the atmosphere), and extremely strict recycling protocols would need to be instituted.
And of course, there is the matter of the cost involved. Even with launch windows occurring more often, and a shorter transit time of about five months, it would still require a very heavy investment to transport all the necessary materials – not to mention the robot workers needed to assemble them – to build even a single floating colony in Venus’ atmosphere.
Still, if we find ourselves in a position to do so, Venus could very become the home of “Cloud Cities”, where carbon dioxide gas is processed and turned into super-materials for export. And these cities could serve as a base for slowly introducing “The Big Rain” to Venus, eventually turning into the kind of world that could truly live up to the name “Earth’s sister planet”.
We have written many interesting articles about terraforming here at Universe Today. Here’s The Definitive Guide To Terraforming, Could We Terraform the Moon?, Should We Terraform Mars?, How Do We Terraform Mars? and Student Team Wants to Terraform Mars Using Cyanobacteria.
We’ve also got articles that explore the more radical side of terraforming, like Could We Terraform Jupiter?, Could We Terraform The Sun?, and Could We Terraform A Black Hole?
For more information, check out Terraforming Mars at NASA Quest! and NASA’s Journey to Mars.
And if you liked the video posted above, come check out our Patreon page and find out how you can get these videos early while helping us bring you more great content!
Sources:
-
Geoffrey A. Landis, “Colonization of Venus“, NASA Glenn Research Center
- V. Badescu, K. Zacny (eds.), Inner Solar System: Prospective Energy and Material Resource, Springer.com
- Wikipedia – Colonization of Venus
- M.J. Way et al. “Was Venus the first habitable world of our solar system?“, Geophysical Research Letters.
- D. Arney, C. Jones. “HAVOC: High Altitude Venus Operational Concept – An Exploration Strategy for Venus“, NASA Technical Reports Server, Langley Research Center.
A few corrections.
1) Landis’s statement about the temperatures at 50km is not correct. HAVOC is correct in their analysis, where they refer to the temperature at around 70°C during the daytime. Landis’s reported temperature range might be appropriate for the poles, but then you’re in the polar vortex. 50km is just too low for a Landis-style habitat (HAVOC, by contrast, uses an enclosed, insulated habitat slung as a gondola… much smaller and less appealing, however). However, it works out rather well at about 1/2 ATM in the cold collars, around 70° latitude.
2) We don’t actually know that there is “acid rain” on Venus; we don’t know whether there’s any precipitation in the middle cloud layer at all. The data from VEGA is conflicting on the subject. There are acid mists, like a smog/vog, but their density shouldn’t be overstated; visibility is a couple kilometers and densities are between a couple and a couple dozen milligrams per cubic meter, depending on the layer (US workplace environmental regulations allow *breathing* of H2SO4 mists up to, if I recall correctly, 3 mg/m^3). That said, Venus’s H2SO4 is a higher concentration and there’s also anhydrous acidic compounds. But it’s not like taking a bath in acid.
3) Water, in the state of H2O, is indeed nearly absent on Venus. But in the form of H2SO4 droplets, is not at all. The concentration is estimated at 70-85%, so right there that’s 15-30% H2O, liberated by heating. Further heating decomposes….
… H2SO4 into H2O and SO3. SO3, heated further in the presence of a catalyst, decomposes into SO2 and O2. So right there, you have H2O and O2, your two most important resources for life, from a rather simple industrial process. As for collection, there’s a wide range of techniques I could get into, but we really need to get a better sense of the middle cloud environment, answering basic questions like “does it rain?”, “what sort of surfaces will mists accumulate onto and at what rate?”, “what is the exact composition of the droplets and anhydrous compounds?”, etc before we lay out specific designs. But just to pick a random example, habitat thrust could be directed through a dust with a packed bed absorber.
A challenge that as far as I’m aware nobody has raised thusfar in the literature is that Venus’s hydrogen is incredibly deuterium rich, with estimates ranging from about 150x to 240x that of Earth. While humans can certainly survive deuterium concentrations of that level, there’s been relatively little study on long-term health effects, and that which has been done suggests potential problems (such as depression) at far lower levels. Variations in deuteration levels of plastics can ruin transparency (although highly deuterated plastics often have improved transparency), deuterated drugs can have different magnitudes of effects on the body, etc. There is however a readily available solution: if nighttime power storage is done through a reversible fuel…
… cell (for example, hydrogen-chlorine), you can exploit the high separation factor of electrolysis by plumbing the fuel cell layers as a cascade. Indeed, deuterium could be a potential export product.
Robots don’t come into play. The size of the envelope required packs even into a Falcon-sized payload shroud, let alone SLS. The habitat can readily be launched as a preassembled stage, with the transfer stage(s) boosted separately. HAVOC calls for entry by traditional aeroshell, but it probably pays to raise the TRL for ballute capture/entry (HAVOC notes that traditional parachutes probably won’t work for deceleration and ballutes might be needed anyway; you might as well go all the way with it).
The real big issue, the one thing that’s unusually difficult with Venus, is return stages. In HAVOC, the vast majority of the mass is the return stage. As Venus is nearly as large as Earth, it’s also difficult to get off of. But sending a fully assembled, Pegasus style return stage, as in HAVOC, is clearly not long-term sustainable; you need something that can repeatedly cycle. A SSTO would probably be possible, but marginal, and very likely require a hydrogen-rich fuel, which is production-limited on Venus. Probably a more realistic option is a reusable core stage with simple, locally produced drop tanks. Early on, the drop tanks would need be delivered along with incoming crews, until local production capabilities can meet that need.
The other issue with…
… cycling to and from orbit is docking. I went through analysis a lot of different variations, most unsatisfactory, and eventually came to the conclusion that there’s really only one that works: having the empty return stage deploy a reusable balloon, and docking to the underside, as was done with the U.S.S. Macon and Akron with small aircraft. A very significant amount of engineering work, but it actually works and provides a dramatically better margin of safety than other options. And unlike the Macon and Akron, you don’t need to dock directly – a drone could make the connections, allowing the two craft to keep their distance until securely moored.
Yet another rocketry concern (did I mention that’s the really big issue? 😉 ) is abort scenarios. On Earth, you do a test firing first; then on the day of launch, you do a hold down to make sure all systems are nominal, then release. None of this is workable with a rocket hanging right next to an airship. There is however an abort option, if you budget the mass for a large winch and several hundred meters of cable: drop the rocket while attached to the winch, up to near its terminal velocity, then fire the engines. If everything is nominal, detach from the winch, angle away from the habitat, and ascend. In case of an abort scenario, shut off the engines, brake the winch to a stop, and reel the rocket back in. Keep in mind however that you’re looking at a rocket that’s at least tens of tons in mass….
Well that takes care of everything _I_ was going to say… ^_^ Thanks, karenrei!
Actually I did have one minor nit:
“One way to do this would be to use these very cities as solar shades, since their presence in the clouds would prevent solar radiation from reaching the surface. This would work particularly well if the floating cities were made of low-albedo materials. Alternately, reflective balloons and/or reflecting sheets of carbon nanotubes or graphene could be deployed from these.” (emphasis mine)
I assume that since we’re trying to reflect heat back to space, you want something with a high albedo, rather than a low one?But Venus’ albedo is already pretty darned high, which means it maintains its heat balance despite reflecting the lion’s share of TSI back into space (per Fraser’s article on the subject here [http://www.universetoday.com/36833/albedo-of-venus/], and a short-sweet discussion of the principle here [http://astronomy.swin.edu.au/cosmos/A/Albedo]). I wonder just how much we can realistically expect to increase the cloud deck’s already high reflectivity with just a few hundred, or even a few tens of thousands of square meters of ~100% reflective material?
Personally, I’m still a fan of using a giant solar shade orbiting at the Sun-Venus L1, to induce a near constant total/annular eclipse, and letting Venus’ albedo take care of the rest.
Wait, we’d have to PAY for that? I prefer Jamaica. =D
Better review of words used to describe technical things is in order in Terraforming Venus.
For instance: The word is “apposition” NOT “opposition” when intended to describe nearness.
Apposition – the positioning of things or the condition of being side by side or close together.
Opposition: resistance or dissent, expressed in action or argument.
And, “albedo” is a measure of reflectivity. So when describing high reflectivity, as I believe the following two paragraphs are trying to say, it is inappropriate to say “low-albedo” when “high-albedo” is apparently meant:
“These would provide initial living spaces for colonists, and could act as terraformers, gradually converting Venus’ atmosphere into something livable so the colonists could migrate to the surface. One way to do this would be to use these very cities as solar shades, since their presence in the clouds would prevent solar radiation from reaching the surface.”
“This would work particularly well if the floating cities were made of low-albedo materials. Alternately, reflective balloons and/or reflecting sheets of carbon nanotubes or graphene could be deployed from these. This offers the advance of in-situ resource allocation, since atmospheric reflectors could be built using locally-sourced carbon.”
I believe the context of the paragraphs intends to describbe high reflectivity and the word “high-albedo” should have been used..
Great article. After reading a lot about settling Mars, I have convinced myself that Venus presents a much better opportunity for a permanent settlement. The technical difficulties of Mars have led enthusiasts to adopt a the one-way-to-mars concept. This would save resources spent in returning the crews to earth, but it requires the settlements to be either self sustainable or constantly resupplied, likely a indefinite combination of the two, which would be easier for Venus. In almost every aspect that I can imagine, living on Venus atmosphere beats Mars surface. Depressurization, unreliability of aerobraking (for arrival and vital resupply shipments) by Mars atmosphere, radiation and dust problems are the biggest fears for me if I were to spend the rest of my life in Mars, all of which do not seem to be a problem in Venus. I am cautiously optimistic about the chances Venus present for humans over Mars because we know less about Venus than Mars, but still optimistic. I would like to add a couple of ideas that would make Venus even more appealing than Mars for a one-way-mission….. please read on (in newest order)
Skadi Mons are located at 64° 0? 0? N, 4° 0? 0? E?in Venus. At 10k meters above the mean planetary radius and higher latitude above the equator, the peak of Skadu Mons might make the surface accessible by at least unmanned probes assuming that at higher altitude, latitude and at night time the temperature and pressure at the peak is lower(how much?). Anchoring to this mountain would provide a fixed location for the settlement so that resupply ships can find the settlement. It would require a 40 to 50 kilometer cable for the anchor which do not have to hold its own weight if the cable if partially lifted by aerostatic balloons at different altitudes. The cable could be made by stronger nano-carbon materials also. I am not an expert on the technologies, so I post the ideas here hoping that some one can help me evaluate them, or provide more insight. Thanks.
Skadi Mons are located at 64° 0? 0? N, 4° 0? 0? E?in Venus. At 10k meters above the mean planetary radius and higher latitude above the equator, the peak of Skadu Mons might make the surface accessible by at least unmanned probes assuming that at higher altitude, latitude and at night time the temperature and pressure at the peak is lower(how much?). Anchoring to this mountain would provide a fixed location for the settlement so that resupply ships can find the settlement. It would require a 40 to 50 kilometer cable for the anchor which do not have to hold its own weight if the cable if partially lifted by aerostatic balloons at different altitudes. The cable could be made by stronger nano-carbon materials also. I am not an expert on the technologies, so I post the ideas here hoping that some one can help me evaluate them, or provide more insight. Thanks.
I do believe someone is talking Space Elevators! You, my friend, are speaking my language! 🙂
As WE (the infallible homo sapiens sapiens) have managed to slowly destroy earth with many of its species, it is ample time to look for habitable and/or transformable planets…. and not make the same stupid mistakes we have made here.
Earth has reached a point of no return. The really bad things will not happen in my lifetime, but surely pose a problem for later generations.
We must therefore start right now to look for intelligent ways to Terra-form Mars and Venus, maybe find a way for parts of Mercury to make it livable. At the same time scan the heavens for earth like planets in the vicinity. Robotic probes should be sent out to those systems chosen.
Let’s do it NOW 😉
Let’s not forget, the methods used to terraform/colonize these planets could be used to rescue our own. And given that no one lives on these planets, we can screw up all we like and not have to worry about carelessly killing millions of people 🙂
Replace the word “colonize” with “infect”.
Only if you consider yourself a pathogen.