Construction Tips from a Type 2 Engineer: Collaboration with Isaac Arthur

Type 2 Civ Tips!

By popular request, Isaac Arthur and I have teamed up again to bring you a vision of the future of human space exploration. This time, we bring you practical construction tips from a pair of Type 2 Civilization engineers.

To make this collaboration even better, we’ve teamed up with two artists, Kevin Gill and Sergio Botero. They’re going to help create some special art, just for this episode, to help show what some of these megaprojects might look like.

I’d also like to congratulate Gannon Huiting for suggesting the topic for this collaboration. We both asked our Patreon communities to brainstorm ideas, and his core idea sparked the idea for the episode. You get one of my precious metal meteorites, which I guarantee will give you a mostly worthless superpower.

We’ll tell you the story of what it took to go from our first tentative steps into space to the vast Solar System spanning civilization we have today. How did we extract energy and resources from the Moon, planets and even gas giants of the Solar System? How did we shift around and dismantle the worlds to provide the raw resources of our civilization?

Lunar Rover Concept. Credit: Sergio Botero

Humanity’s ability to colonize the Solar System was unleashed when we harvested deposits of helium 3 from the Moon. This isotope of helium is rare on Earth, but the constant solar wind from the Sun has deposited a layer across the Moon, though its regolith.

Helium 3 was the best, first energy source we got our hands on, and it changed everything. Although other kinds of fusion reactors can produce more energy with more efficiency, the advantage of helium 3 is that the fusion reaction releases no neutrons. This means you can have a fusion reactor on your starship or on your base with much less shielding.

Multi-dome base being constructed. Credit: ESA/Foster + Partners

We still use helium-3 reactors when living creatures need to be close the reactor, or the ship can’t afford to carry around heavy shielding.

The Helium 3 is found within the first 100 cm of the lunar regolith. Harvesting it started slowly, but in time, our mining machines grew larger, and we stripped this layer completely off the Moon. There are other repositories across the Solar System, in the regolith of Mercury, other moons and asteroids across the Solar System, and in the atmospheres of the giant planets. We later switched to getting our Helium 3 from Uranus and Neptune, but the Moon got everything started.

A huge lunar miner, with astronaut for scale. Credit: Sergio Botero

One of our big problems with building in space was getting raw materials. Just about every place that has the supplies we needed was at the bottom very deep gravity wells which made accessing those materials a lot harder. Asteroid and moons offered us a large supply of material that was not locked inside such deep gravity wells.

These asteroids also gave us a big initial head start on developing space-based infrastructure as they contained a great deal of precious metals that we could bring home to help fund our endeavors.

For all that, the entire Asteroid Belt contains much less material than Earth’s own Moon. The ease of mining and transport on these bodies made them a critical source of raw materials for building up the early Solar Infrastructure and many of them became homes to rotating habitats buried deep inside the asteroid, where millions of people live comfortably shielded from the hazards of space and support themselves mining the asteroid around them.

Artist’s impression of the asteroid belt. Image credit: NASA/JPL-Caltech

These asteroids and moons often contained water in the form of ice, which is vital to creating life-bearing habitats in space, as well as fuel and propellant for many early-era spaceships.

However, even if the entire Asteroid Belt was ice, instead of it being a fairly smaller percent of the mass, that would still only be the approximate mass of Earth’s Oceans. There was a plentiful supply for early efforts but not enough for major terraforming efforts on places like Mars or creating many artificial habitats.

Water is incredibly scarce in the inner Solar System, but becomes more plentiful as we make our way further out, past the Solar System’s Frost Line. Deeper out past the planets we find enough water to make whole planets out of, as hydrogen and oxygen are the first and third most abundant elements in the Universe. Also, for the most part these come in convenient iceberg-sized packages, low enough in mass to have a small gravity well and to be movable.

Mastering the Solar System required moving very large objects in space. For the less massive objects, we could put a big thruster on it, but for the largest projects, such as moving planets with atmospheres (which we’ll get to later in this article), another technique was required.

Concept for a possible gravity tractor. Credit: JPL

To move large objects around, without touching them, you need a Gravity Tractor.

Want to move an asteroid? Use the gravity of a less massive object, like a spaceship. Hold the spaceship close to the asteroid, and their gravity will put them together. Fire your rocket’s thrusters to keep the distance, and you slowly pull the asteroid in any direction you like. It takes a long time, and does require fuel, but you can use this technique to move anything anywhere in the Solar System.

Put a massive satellite into orbit around an asteroid. When the satellite is on one side of the asteroid it fires its thrusters towards the satellite. And then on the other side of its orbit, it fires its thrusters away from the satellite. The satellite will have been pushed twice in the same direction. To an outside observer that satellite has moved, though on the asteroid it will seem to have been nudged closer than put back.

Don’t forget that the satellite pulls on the asteroid with just as much force as the asteroid exerts on the satellite. Earth pulls on the Sun just as hard as it pulls on us, but it’s more massive so it doesn’t move as much. But it does move, and so by pushing on the satellite towards the primary then pushing away on the opposite side, we move the primary body.

We can also take advantage of momentum transfers from gravity to alter the course of an object by making a close flyby. You can use this gravitational slingshot to use the gravity of a planet to change the move large objects into a new trajectory.

Over time, we put gravitational tugs into orbit around every chunk of rock and ice that we wanted to move, shifting their locations to the best places in the Solar System.

Artist view of an asteroid passing Earth. Credit: ESA/P.Carril

Some places gave us raw materials. Other places would serve as our homes.

Earth is the third closest planet to the Sun and it will always be the environment we’re trying to replicate. Earth is, well, it was… home.

For all the millions of other worlds across the Solar System, we made them capable of hosting life  with a little work. Often we could make them habitable just by increasing the amount of energy they received from the Sun.

Creating artificial gravity by spinning a habitat or breathable air by doming it over did us no good if there wasn’t enough light to melt ice into water or let plants grow.

The farther you get from the Sun, the less light you get, but we bounce light that would have been lost, concentrating it to let life flourish. The Sun gives off over a billion times the light that actually reaches Earth, so there’s no shortage in quantity, just concentration.

This was the first sunset observed in color by Curiosity on Mars. Credit: NASA/JPL-Caltech/MSSS/Texas A&M Univ.

To double the light reaching a planet like Mars, you would need a mirror surface area of twice the size of Mars. But not twice the mass of Mars. For every square meter of land on Earth, there’s about 10 billion kilograms of mass under our feet. A mirror on Earth wouldn’t weigh much more than a kilogram a square meter, but in space we can go far thinner. Any one of millions of small asteroids in the solar system contains enough material to make a planetary surface’s worth of mirrors.

Lenses or parabolic reflectors let us move light in from far more densely concentrated locations closer to the Sun. Reflecting light also allows us to remove harmful or less useful invisible wavelengths like ultraviolet or x-rays.

This allowed us to make almost any place warm and bright enough. We took distant moons and asteroids far from the Sun, and gave them a collar of thin mirrors bouncing light into a parabolic dish. By bouncing this light into rotating habitats safely buried inside the asteroid, we created warm, lush garden worlds in environments so cold that air itself would condense into a liquid.

Artist’s concept of a Venus cloud city — a possible future outcome of the High Altitude Venus Operational Concept (HAVOC) plan. Credit: Advanced Concepts Lab/NASA Langley Research Center

For most of the Solar System we wanted to warm planets up. But for Venus and Mercury, we needed to cool them down. We did this by placing shades between them and the Sun to reflect away some of the light hitting them.

The easiest way to do this was to position an opaque material between the planet and the Sun, at the L1 Lagrange point. At this point the gravitational pull of the planet counteracts the pull of the Sun allowing a large thin solar shade to remain in position with minimal energy. This way the planet is cooled.

A solar shade above Venus. Credit: Kevin Gill

But we did better than merely cool, we shaped the light to our needs. With a collection of many small shades, we avoided putting a visible dark spot on the Sun. Sunlight comes in many frequencies, from radio to x-rays; some were more valuable to us than others. Plants mostly use red and blue light, while green light doesn’t help with photosynthesis. So blocked a decent amount of green light, some blue, and no red, and cooled the planet without harming plant life and without really altering how the light looked to our eyes.

We engineered the perfect material for our shades which was mostly transparent to the wavelengths of light we wanted and mostly reflective or absorptive to the ones we didn’t.

Ultraviolet is a good example. We wanted some to get to our planet, as it does help as a sterilizing agent to biological processes and it helps make ozone, but we wanted to cut most of that out. Even better, about half of the light coming from the Sun is in infrared, which we can’t see and which plants don’t use.

We blocked most of that and seriously lowered temperatures on Venus and Mercury.

We set up shades to block the light from reaching our planets. And we did the same with dangerous radiation streaming from the Sun. We set up a concentrated magnetic shield at the Mars-Sun L1 Lagrange point, which catches and redirects high energy particles. This protects a world from the Sun, but it doesn’t prevent harmful cosmic rays, which can come from any part of the sky.

Our own planet Earth has a robust magnetosphere, and it’s the main reason we have air to breath and don’t absorb dangerous radiation from the Sun and space.

Places like Mars don’t. For this purpose, we created artificial magnetospheres. We considered trying to get Mars’ core spinning fast and hot so that rapid spinning molten ferromagnetic materials would generate a protective magnetosphere.

But that was too much effort. We didn’t actually care what generated the magnetic field, we just wanted the magnetic field. In the end we deployed a constellation of electromagnetic satellites around every world exposed to space. These satellites could do double duty, harvesting solar radiation and generating an artificial magnetosphere.

Mars used to have a natural magnetic field, but restarting it wasn’t worth it. Credit: NASA/JPL/GSFC

Cosmic rays and radioactive particles from the Sun were captured and redirected safely away from the world, allowing us to roam freely on the surface.

Once we had made acquired the resources of every world in the Solar System, we began our next great engineering effort. To move and dismantle the worlds themselves. To create the optimal configuration that gave us the most living space and the most usable energy. We began the construction of our Dyson swarm.

Moving planets is almost impossible. But not completely impossible. How do you get all that energy to move a world without melting it? The orbital energy of Earth around the Sun is approximately 30 million, trillion, trillion joules. That’s equal to all the energy the Sun puts out over a few months.

Of course, the Sun is slowly warming up, and while estimates vary, it’s generally accepted that in about a billion years it will have warmed up enough that Earth would be uninhabitable. Moving the Earth was inevitable.

To move the Earth outward to counteract the increased solar luminosity, we needed to add orbital energy. A lot of energy.

Earlier, we discussed using gravity tractors and gravitational slingshots to slowly and steadily move objects around the Solar System. This technique works at the largest scales too.

A gravity tractor could slowly and steadily move an entire planet if you had enough time and fuel. Because we already had mastery of all the asteroids in the Solar System, we put them into orbits that swept past worlds.

Credit: NASA/JPL-Caltech

Each gravitational slingshot gave or stole orbital momentum from the world, pushing it closer or farther from the Sun.

We also used orbital mirrors to bounce sunlight from the Sun. With enough of them, deflecting their light in the same general directional while maintaining an orbit around the planet, we could move worlds without touching them or heating them up from the light beams.

With enough satellites to keep the net gravitational force on the planet homogenous, we didn’t have to worry about tidal heating, allowing us to move a planet far faster.

In the future, we’ll use a king-size version of this to move the entire Solar System, using the star as the power source, called a Shkadov Thruster. We will push the Sun and every star we control into a constellation that matches our needs. But that’s a problem our Type III civilization engineers will have to worry about.

Like a cosmic lava lamp, a large section of Pluto’s icy surface in Sputnik Planum is being constantly renewed by a process called convection that replaces older surface ices with fresher material. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

We always needed ice. For water, for fuel and for air. And the outer Solar System had all the ice we could ever need. We brought comets and other icy bodies in from the outer Solar System to bring water to the planets we’re terraforming – Mars, Venus, and the large moons of the Solar System.

Pushing ice is a tricky process, but the comet itself is the source of fuel, either liquid hydrogen and oxygen as the propellants or using the hydrogen for a fusion torch drive. However we have an alternative trick we can use.

We just talked about using energy beams, focused sunlight, lasers, or microwave beams to push objects outward from the sun. You can also move inward by reflecting the beam off at an angle, removing orbital momentum. This lowers their orbit into the Solar System.

Credit: NASA/Denise Watt

By setting up energy collectors on comets, we could beam power out them, and use that energy to melt atoms into gas and accelerate them away with a magnetic field, just like an ion drive. This let us take high-strength lasers and microwave beams powered from the inner Solar System and use it to tractor comets inward. The propellant melted off the comets could carry away far more momentum than the energy beam added, though at the cost of losing some of your mass in the process.

One by one we identified the icy bodies in the Kuiper Belt and Oort Cloud, installed an ice engine, and pulled them inward, to the places we needed that water the most.

The day to day energy for our civilization comes from the Sun. Solar collectors power the machines, computers and systems that make day-to-day life spanning the Solar System possible.

Just as the ancient Earth civilizations used hydrocarbons as a store of fuel, we depend on hydrogen. We use it for our rocket fuel, to manufacture drinking water, and most importantly, for our fusion reactors. We always need more hydrogen.

Illustration Credit:© David A. Hardy/www.astroart.org, Project Daedalus

Fortunately, the Solar System has provided us with vast repositories of hydrogen: the giant planets, Jupiter, Saturn, Uranus and Neptune all made up of at least 80% hydrogen. But harvesting the planets for their hydrogen isn’t without its challenges.

For starters, the gravity on the surface of Jupiter is nearly 25 m/s2, which is nearly three times the surface gravity of Earth. On top of that, Jupiter’s magnetosphere produces intense radiation fields through its entire system. You can’t spend much time near Jupiter without receiving a lethal radiation dose.

Gas Giant Harvesting Concept. Credit: Sergio Botero

We deploy huge robotic scoopers to swoop down into Jupiter’s gravity well, skim across the upper cloud tops, funneling in as much hydrogen as they can. On board compressors liquefy the hydrogen, or refine it into the more energy dense metallic hydrogen. The fuel is then distributed across the Solar System through the interplanetary transport network.

For Uranus and Neptune, where the gravity well is less extreme, we have permanent mining stations which float in the cloud tops, harvesting raw materials for return back to space. These factories are a huge improvement over the more expensive scoop ships. Smaller cargo ships ferry the deuterium, helium-3 and hydrogen up to orbit, for an energy hungry Solar System.

Gas Giant Harvesting Concept. Credit: Gas Giant Harvesting Concept. Credit: Sergio Botero

In order to construct our Dyson Swarm, we will eventually need to dismantle almost all the planets and moons in the Solar System to provide the raw materials to house countless people.

This process has begun, and we we have a number of options. For some worlds, we plan to just keep mining and refining them with robotic factories until they are gone, but this can be quite time consuming and often we would rather do our refining and manufacturing elsewhere.

Instead, we have set up very large mass drivers running around the object to launch material directly towards its desired destination. To avoid building up angular momentum inside the shrinking mass of the planetoid, we run these giant cannons in both directions. This prevents it spinning so fast that it tears itself apart. There’s very little gravity holding these objects together after all.

For the smaller objects that’s actually just fine. When we want to disassemble a smaller asteroid or moon into rock and dirt for the inside of a cylinder habitat, we construct a cylindrical shell around the asteroid, and spray material from the asteroid onto the cylinder, giving it some spin and artificial gravity to hold the material up, or rather down to its surface. We spin the asteroid faster and faster until it flies apart, transferring its material and its angular momentum to the cylinder.

Credit: NASA.

With larger asteroids we send a series of cylinders past them in a chain, painting their interiors with the material we will turn into dirt later on, until we run out of asteroid.

For full blown minor planets and moons, which are much more massive but still fairly low in gravity and lacking an atmosphere, we pump matter up tubes to high above the planetoid to fill freighters, get compacted into cannon balls to be launched elsewhere, or simply pumped into rotating habitats being built nearby.

Mercury is already half consumed. In a few more generations, it will be a distant memory.

Perhaps our greatest accomplishment is the work underway at Jupiter and Saturn. We are now in the process of dismantling these worlds to harvest their resources.

Jupiter and Io. Image Credit: NASA/JPL
Jupiter and Io. Image Credit: NASA/JPL

The largest machines humanity has ever built, fusion candles, have been deployed into the atmospheres of Jupiter and Saturn. These enormous machines scoop up raw hydrogen from Jupiter to run their fusion reactors. One side of the fusion candle fires downward, keeping the machine aloft. The other end blasts out into space, spewing material that can be harvested from orbit.

Not only that, but these candles provide thrust, pushing Jupiter and Saturn slowly but steadily into safer, more useful orbits for our civilization. As we use up the hydrogen, their mass will decrease. Uranus and Neptune will follow slowly, from farther out in the Solar System.

Eventually, eons into the future, we will have dismantled them down to their cores. There is more than a dozen times the mass of the Earth in rock and metal down at the core of Jupiter. More raw materials than any other place in the Solar System.

Credit: Kevin Gill

The long awaited construction of our fully operational Dyson swarm will finally begin. We’ll miss the presence of Jupiter and Saturn in the Solar System, and remember them fondly, but humanity needs room to stretch its legs.

Of course, as huge as the gas giants are compared to Earth, the Sun is far bigger, and contains not just hydrogen and helium but thousands of planets worth of heavier elements, which are spread around the sun, not just concentrated deep down.

Trying to scoop matter off a star is much harder than out of gas giant, though conveniently, we can take advantage of all that energy the Sun is giving off to power our extraction.

The Sun loses mass via the solar wind, mass ejections and simply by emitting energy (Credit: NASA)

The material on the Sun is also ionized, so it reacts strongly to magnetic forces, and the Sun generates a massively powerful magnetic field too. In fact, our Sun ejects about a billion kilograms of matter a second as solar wind. We have a few ways to increase this flow and harvest it.

The first is called Thermal Driven Outflow. We hover mirrors over the surface, reflecting and concentrating light down on spots on the Sun’s surface to heat it up and increase the mass being ejected. This kicks up an eruption much like a solar flare, feeding more solar wind.

Credit: NASA/SDO, AIA

We then place a large ring of satellites around the Sun’s equator, connected to each other by a stream of ionized particles generating a huge current, themselves running that stream off solar power. This ring creates a powerful magnetic field pushing outward toward the Sun’s poles, and sending the super-heated matter in that direction.

Hovering over the poles further out, we have a giant ring sucking up sunlight and generating a huge toroidal magnetic field. All the matter we stir up on the sun and off the poles is sucked through that and slowed down for collection. It’s a lot like the VASIMR Drive, using a magnetic nozzle, so that nothing has to touch the ultra hot plasma. Giant Plasma Thrusters essentially acting as the pump to gather the matter, it stays in place using the momentum it’s stealing from the particles it is slowing down, again it’s a giant plasma thruster.

We will eventually build far more of these rings around the Sun, spaced up and down from the equator, and intermittently shut off the power beam holding them aloft. As all the satellites in that ring drop, building up speed, we switch the power for the beam back on and their plummet stops and they push back up to their original position. We do this with all the rings, in sequence, pushing much larger waves of matter toward the poles than the Thermal Driven Outflow method provides, and we call this option the Huff-n-Puff Method.

A montage of planets and other objects in the solar system. Credit: NASA/JPL

And there you have it, our tips and techniques to harvest all the resources from the Solar System. To push and pull worlds, to heat them up, cool them down and use their raw materials to house humanity’s growing, ever expanding population.

As we nearly achieve our Type II civilization status, and control all the energy from our Sun and all the resources of the Solar System, we set our sights on a new goal: doing the same thing for the entire Milky Way Galaxy.

Perhaps in a few million years, we’ll create another guide for you, to help you make this transition as efficiently as possible.

Good luck!

How Do We Terraform Venus?

Continuing with our “Definitive Guide to Terraforming“, Universe Today is happy to present to our guide to terraforming Venus. It might be possible to do this someday, when our technology advances far enough. But the challenges are numerous and quite specific. 

The planet Venus is often referred to as Earth’s “Sister Planet”, and rightly so. In addition to being almost the same size, Venus and Earth are similar in mass and have very similar compositions (both being terrestrial planets). As a neighboring planet to Earth, Venus also orbits the Sun within its “Goldilocks Zone” (aka. habitable zone). But of course, there are many key difference between the planets that make Venus uninhabitable.

For starters, it’s atmosphere over 90 times thicker than Earth’s, its average surface temperature is hot enough to melt lead, and the air is a toxic fume consisting of carbon dioxide and sulfuric acid. As such, if humans want to live there, some serious ecological engineering  – aka. terraforming – is needed first. And given its similarities to Earth, many scientists think Venus would be a prime candidate for terraforming, even more so than Mars!

Over the past century, the concept of terraforming Venus has appeared multiple times, both in terms of science fiction and as the subject of scholarly study. Whereas treatments of the subject were largely fantastical in the early 20th century, a transition occurred with the beginning of the Space Age. As our knowledge of Venus improved, so too did the proposals for altering the landscape to be more suitable for human habitation.

Venus is also considered a prime candidate for terraforming. Credit: NASA/JPL/io9.com
Venus is also considered a prime candidate for terraforming. Credit: NASA/JPL/io9.com

Examples in Fiction:

Since the early 20th century, the idea of ecologically transforming Venus has been explored in fiction. 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, owing to the beginning of the Space Age, 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.

Artist's conception of a terraformed Venus, showing a surface largely covered in oceans. Credit: Wikipedia Commons/Ittiz
Artist’s conception of a terraformed Venus, showing a surface largely covered in oceans. Credit: Wikipedia Commons/Ittiz

Proposed Methods:

The first proposed method of terraforming Venus was made in 1961 by Carl Sagan. In a paper titled “The Planet Venus“, he argued for the use of genetically engineered bacteria to transform the carbon in the atmosphere into organic molecules. However, this was rendered impractical due to the subsequent discovery of sulfuric acid in Venus’ clouds and the effects of solar wind.

In his 1991 study “Terraforming Venus Quickly“, British scientist Paul Birch proposed bombarding Venus’ atmosphere with hydrogen. The resulting reaction would produce graphite and water, the latter of which would fall to the surface and cover roughly 80% of the surface in oceans. Given the amount of hydrogen needed, it would have to harvested directly from one of the gas giant’s or their moon’s ice.

The proposal would also require iron aerosol to be added to the atmosphere, which could be derived from a number of sources (i.e. the Moon, asteroids, Mercury). The remaining atmosphere, estimated to be around 3 bars (three times that of Earth), would mainly be composed of nitrogen, some of which will dissolve into the new oceans, reducing atmospheric pressure further.

Another idea is to bombard Venus with refined magnesium and calcium, which would sequester carbon in the form of calcium and magnesium carbonates. In their 1996 paper, “The stability of climate on Venus“, Mark Bullock and David H. Grinspoon of the University of Colorado at Boulder indicated that Venus’ own deposits of calcium and magnesium oxides could be used for this process. Through mining, these minerals could be exposed to the surface, thus acting as carbon sinks.

A mass of swirling gas and cloud at Venus’ south pole. Credit: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA/Univ. Oxford.
A mass of swirling gas and cloud at Venus’ south pole. Credit: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA/Univ. Oxford.

However, Bullock and Grinspoon also claim this would have a limited cooling effect – to about 400 K (126.85 °C; 260.33 °F) and would only reduce the atmospheric pressure to an estimated 43 bars. Hence, additional supplies of calcium and magnesium would be needed to achieve the 8×1020 kg of calcium or 5×1020 kg of magnesium required, which would most likely have to be mined from asteroids.

The concept of solar shades has also been explored, which would involve using either a series of small spacecraft or a single large lens to divert sunlight from a planet’s surface, thus reducing global temperatures. For Venus, which absorbs twice as much sunlight as Earth, solar radiation is believed to have played a major role in the runaway greenhouse effect that has made it what it is today.

Such a shade could be space-based, located in the Sun–Venus L1 Lagrangian point, where it would prevent some sunlight from reaching Venus. In addition, this shade would also serve to block the solar wind, thus reducing the amount of radiation Venus’ surface is exposed to (another key issue when it comes to habitability). This cooling would result in the liquefaction or freezing of atmospheric CO², which would then be depsotied on the surface as dry ice (which could be shipped off-world or sequestered underground).

Alternately, solar reflectors could be placed in the atmosphere or on the surface. This could consist of large reflective balloons, sheets of carbon nanotubes or graphene, or low-albedo material. The former possibility offers two advantages: for one, atmospheric reflectors could be built in-situ, using locally-sourced carbon. Second, Venus’ atmosphere is dense enough that such structures could easily float atop the clouds.

Artist's concept of a Venus cloud city — a possible future outcome of the High Altitude Venus Operational Concept (HAVOC) plan. Credit: Advanced Concepts Lab/NASA Langley Research Center
Artist’s concept of a Venus cloud city – part of NASA’s High Altitude Venus Operational Concept (HAVOC) plan. Credit: Advanced Concepts Lab/NASA Langley Research Center

NASA scientist Geoffrey A. Landis has also proposed that cities could be built above Venus’ clouds, which in turn could act as both a solar shield and as processing stations. These would provide initial living spaces for colonists, and would act as terraformers, gradually converting Venus’ atmosphere into something livable so the colonists could migrate to the surface.

Another suggestion has to do with Venus’ rotational speed. Venus rotates once every 243 days, which is by far the slowest rotation period of any of the major planets. As such, Venus’s experiences extremely long days and nights, which could prove difficult for most known Earth species of plants and animals to adapt to. The slow rotation also probably accounts for the lack of a significant magnetic field.

To address this, British Interplanetary Society member Paul Birch suggested creating a system of orbital solar mirrors near the L1 Lagrange point between Venus and the Sun. Combined with a soletta mirror in polar orbit, these would provide a 24-hour light cycle.

It has also been suggested that Venus’ rotational velocity could be spun-up by either striking the surface with impactors or conducting close fly-bys using bodies larger than 96.5 km (60 miles) in diameter. There is also the suggestion of using using mass drivers and dynamic compression members to generate the rotational force needed to speed Venus up to the point where it experienced a day-night cycle identical to Earth’s (see above).

Atmosphere of Venus. Credit: ESA
Artist’s impression of Venus’ thick atmosphere, complete with lighting strikes and sulfuric acid rains. Credit: ESA

Then there’s the possibility of removing some of Venus’ atmosphere, which could accomplished in a number of ways. For starters, impactors directed at the surface would blow some of the atmosphere off into space. Other methods include space elevators and mass accelerators (ideally placed on balloons or platforms above the clouds), which could gradually scoop gas from the atmosphere and eject it into space.

Potential Benefits:

One of the main reasons for colonizing Venus, and altering its climate for human settlement, is the prospect of creating a “backup location” for humanity. And given the range of choices – Mars, the Moon, and the Outer Solar System – Venus has several things going for it the others do not. All of these highlight why Venus is known as Earth’s “Sister Planet”.

For starters, Venus is a terrestrial planet that is similar in size, mass and composition to Earth. This is why Venus has similar gravity to Earth, which is about of what we experience 90% (or 0.904 g, to be exact. As a result, humans living on Venus would be at a far lower risk of developing health problems associated with time spent in weightlessness and microgravity environments – such as osteoporosis and muscle degeneration.

Venus’s relative proximity to Earth would also make transportation and communications easier than with most other locations in the solar system. With current propulsion systems, launch windows to Venus occur every 584 days, compared to the 780 days for Mars. Flight time is also somewhat shorter since Venus is the closest planet to Earth. At it’s closest approach, it is 40 million km distant, compared to 55 million km for Mars.

On Feb. 5, 1974, NASA's Mariner 10 mission took this first close-up photo of Venus during 1st gravity assist flyby. Credit: NASA
On Feb. 5, 1974, NASA’s Mariner 10 mission took this first close-up photo of Venus during 1st gravity assist flyby. Credit: NASA

Another reason has to do with Venus’ runaway greenhouse effect, which is the reason for the planet’s extreme heat and atmospheric density. In testing out various ecological engineering techniques, our scientists would learn a great deal about their effectiveness. This information, in turn, will come in mighty handy in the ongoing fight against Climate Change here on Earth.

And in the coming decades, this fight is likely to become rather intense. As the NOAA reported in March of 2015, carbon dioxide levels in the atmosphere have now surpassed 400 ppm, a level not seen since the the Pliocene Era – when global temperatures and sea level were significantly higher. And as a series of scenarios computed by NASA show, this trend is likely to continue until 2100, with severe consequences.

In one scenario, carbon dioxide emissions will level off at about 550 ppm toward the end of the century, resulting in an average temperature increase of 2.5 °C (4.5 °F). In the second scenario, carbon dioxide emissions rise to about 800 ppm, resulting in an average increase of about 4.5 °C (8 °F). Whereas the increases predicted in the first scenario are sustainable, in the latter scenario, life will become untenable on many parts of the planet.

So in addition to creating a second home for humanity, terraforming Venus could also help to ensure that Earth remains a viable home for our species. And of course, the fact that Venus is a terrestrial planet means that it has abundant natural resources that could be harvested, helping humanity to achieve a “post-scarcity” economy.

Artist's conception of the High Altitude Venus Operational Concept (HAVOC) mission, a far-out concept being developed by NASA, approaching the planet. Credit: NASA Langley Research Center/YouTube (screenshot)
Artist’s concept of the High Altitude Venus Operational Concept (HAVOC) mission approaching the planet. Credit: NASA Langley Research Center/YouTube.

Challenges:

Beyond the similarities Venus’ has with Earth (i.e. size, mass and composition), there are numerous differences that would make terraforming and colonizing it a major challenge. For one, reducing the heat and pressure of Venus’ atmosphere would require a tremendous amount of energy and resources. It would also require infrastructure that does not yet exist and would be very expensive to build.

For instance, it would require immense amounts of metal and advanced materials to build an orbital shade large enough to cool Venus’ atmosphere to the point that its greenhouse effect would be arrested. Such a structure, if positioned at L1, would also need to be four times the diameter of Venus itself. It would have to be assembled in space, which would require a massive fleet of robot assemblers.

In contrast, increasing the speed of Venus’s rotation would require tremendous energy, not to mention a significant number of impactors that would have to cone from the outer solar System – mainly from the Kuiper Belt. In all of these cases, a large fleet of spaceships would be needed to haul the necessary material, and they would need to be equipped with advanced drive systems that could make the trip in a reasonable amount of time.

Currently, no such drive systems exist, and conventional methods – ranging from ion engines to chemical propellants – are neither fast or economical enough. To illustrate, NASA’s New Horizons mission took more than 11 years to get make its historic rendezvous with Pluto in the Kuiper Belt, using conventional rockets and the gravity-assist method.

Artist's impression of the surface of Venus. Credit: ESA/AOES
Artist’s impression of the surface of Venus. Credit: ESA/AOES

Meanwhile, the Dawn mission, which relied relied on ionic propulsion, took almost four years to reach Vesta in the Asteroid Belt. Neither method is practical for making repeated trips to the Kuiper Belt and hauling back icy comets and asteroids, and humanity has nowhere near the number of ships we would need to do this.

The same problem of resources holds true for the concept of placing solar reflectors above the clouds. The amount of material would have to be large and would have to remain in place long after the atmosphere had been modified, since Venus’s surface is currently completely enshrouded by clouds. Also, Venus already has highly reflective clouds, so any approach would have to significantly surpass its current albedo (0.65) to make a difference.

And when it comes to removing Venus’ atmosphere, things are equally challenging. In 1994, James B. Pollack and Carl Sagan conducted calculations that indicated that an impactor measuring 700 km in diameter striking Venus at high velocity would less than a thousandth of the total atmosphere. What’s more, there would be diminishing returns as the atmosphere’s density decreases, which means thousands of giant impactors would be needed.

In addition, most of the ejected atmosphere would go into solar orbit near Venus, and – without further intervention – could be captured by Venus’s gravitational field and become part of the atmosphere once again. Removing atmospheric gas using space elevators would be difficult because the planet’s geostationary orbit lies an impractical distance above the surface, where removing using mass accelerators would be time-consuming and very expensive.

Size comparison of Venus and Earth. Credit: NASA/JPL/Magellan
Size comparison of Venus and Earth. Credit: NASA/JPL/Magellan

Conclusion:

In sum, the potential benefits of terraforming Venus are clear. Humanity would have a second home, we would be able to add its resources to our own, and we would learn valuable techniques that could help prevent cataclysmic change here on Earth. However, getting to the point where those benefits could be realized is the hard part.

Like most proposed terraforming ventures, many obstacles need to be addressed beforehand. Foremost among these are transportation and logistics, mobilizing a massive fleet of robot workers and hauling craft to harness the necessary resources. After that, a multi-generational commitment would need to be made, providing financial resources to see the job through to completion. Not an easy task under the most ideal of conditions.

Suffice it to say, this is something that humanity cannot do in the short-run. However, looking to the future, the idea of Venus becoming our “Sister Planet” in every way imaginable – with oceans, arable land, wildlife and cities – certainly seems like a beautiful and feasible goal. The only question is, how long will we have to wait?

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!