Future Tense

How to Terraform the Moon

It’ll be habitable, if a lot like Florida.

A terraformed Florida moon.
The moon: Just like Florida.

Photo illustration by Juliana Jiménez Jaramillo. Images courtesy NASA and the Florida Division of Library and Information Services.

Space fans were startled—and perhaps a little skeptical—in May when the Russians announced that they intend to build a manned moon base. The Russians think the first stage of their project will cost about $800 million, maybe assisted by private-sector investors. Their goal: to dominate “a geopolitical competition for the Moon’s natural resources in the 21st century.”

According to the Russian press release, they’ll start by analyzing the physical and chemical composition of the future home of the base, in the deep cold of the moon’s south pole. (A foolish choice, in my opinion—think how readily machinery will seize up in shadows and the cost of heating the base.) In missions between 2016 and 2025, they’ll learn how to extract minerals such as aluminum, iron, and titanium. (Maybe they can also bring back some of the helium3 we know is there. Here on Earth we’re short on helium3, which would be a key ingredient for future fusion plants.)

Russia is on the right track. To deliver vast new resources to humanity, we must pioneer and occupy the moon, Mars, and perhaps even beyond.

And inevitably, we will shape those worlds, as we have shaped our own (though not always well, of course).

Mars often gets more attention as the second Earth, since it’s larger and has thick ice buried under its sands. But its distance means it will be hard to shape and hard to reach. When it comes to remaking a celestial body in Earth’s image—“terraforming” it—the moon has clear advantages: It gets twice the sunlight of Mars. It’s a three-day trip with current technology, while getting people to Mars would take six months. Furthermore, the moon is dead and it’s small, so it needs less work and investment to build an atmosphere. Mars has slightly less than the total area of Earth’s dry land; the moon has a quarter of it—a bit smaller than all Asia.

Still, engineering any planet or satellite, including Earth, is a huge job. We will probably encounter the true scale of it in this century, as we build defenses against climate change. Thinking through how we might thrive on other worlds, even in the far future, can make us reflect on how terraforming Earth or other worlds will alter the human perspectives.

So … how about the moon? With the right approach and some luck, it might make a decent place to live, so long as you enjoy Florida’s weather.

Terraforming our moon will take many decades and vast abilities. Before we can begin, we’ll have to master the resources of our solar system—especially transporting raw masses over interplanetary distances. That means nuclear thermal rockets (which we already developed by the 1970s), advanced robotics and communications, biotech, and sustainable closed environments. Once those come, we can reach higher. Here’s how the terraforming process might work.

Our moon was born too small to harbor life. It came from the collision of a Mars-sized world into the primordial Earth. From that colossal crunch spun a disk of rocks that condensed into a satellite. The sun robbed its gases, and that bully Earth slowly stole the moon’s spin, locking it so that one face always smiles at us.

The moon’s closeness is a huge advantage: To make it habitable, we would first have to bombard it with water-ice comets, a tricky endeavor best attempted with the many resources waiting on and near Earth. Using incoming comets will be worth the challenges, because they can deliver both an atmosphere and momentum.

The process begins by steering a comet nucleus, which some call an iceteroid, from the chilly freezer beyond Pluto. Nudge it from its slow orbit with a mile-per-second velocity change and swing it near any gas giant planet for a momentum swerve. By hooking the comet adroitly in a reverse swing-by around, say, Jupiter, we can loop it into an orbit opposite to the way that worlds orbit the sun. The grimy, mountain-size iceteroid soon will loom in the moon’s night sky.

Mere days before it strikes, scientists will have to blow it apart—brutally and carefully. Ice shards come gliding in all around the moon’s equator, small enough that they cannot free themselves from gravity’s grip. (We can’t let big chunks of comet scatter off the moon to rain down as celestial buckshot on Earth.) Within hours of the first incoming comet, the moon will have a crude atmosphere. With one-sixth of Earth’s gravity, it can hold gases for tens of thousands of years.

As more comets arrive and pellets pelt down, the moon spins faster. From its lazy “day” cycle of 28 days, it speeds up to a 60 hours—close enough to Earthlike, as they say, for government work.

For most of its life, the moon’s axial tilt has been a dull zero, robbing it of summers and winters. But if they are angled just so, the incoming ice nuggets can tilt the poles while shortening the days. From such simple mechanics we conjure seasons.

All told, we’ll need about 100 comets the size of Halley’s, which will bring water and carbon dioxide, with smidgens of methane and ammonia. We’ll need nitrogen, too, and some magic from the biochemists, who will pepper the moon’s old, gray rocks with blue-green algae that can exhale oxygen.

For centuries the moon’s dark plains had carried humanity’s imposed, watery names: Tranquility, Serenity, Crises, Clouds, Storms. Now, thanks to the “rain” of iceteroids, these lowlands of aged lava catch the rains and fatten muds into ponds, lakes, true seas. After billions of years, the ancient names come true.

Genetically engineered plants will create the first greenery. Like Earth’s tropics now, at the moon’s equator heat drives moist gases aloft. Cooler gas flow from the poles to fill in. The high wet clouds skate poleward, cool, and rain down.

On Earth, such currents are robbed of their water about one-third of the way to the poles, creating the worldwide belt of deserts. Not so on the moon. The new world has no chains of deserts, just one simple circulating air cell grinding away in each hemisphere. Moisture forges climate. Northerly winds sweep poleward, swerving toward the west to make the occasional mild tornado.

The moon, once “the lesser light that rules the night,” now shines five times brighter, casting sharp shadows on Earth. Because of the reflection of the seas, when the alignment is right, people on Earth’s night side gaze up at Earth’s image.

The moon has no soil, only the damaged dust left from 4 billion years beneath the solar wind’s anvil. Making soil from gritty grime is work best left to the biologists. Our moon can brew its own, in fast-forward. Bioengineered minions can till the dirt, massage the gases, build an ecology.

The gray sphere that the Russians may make into the realm of strip miners and rugged, space-suited loners can become a thin-aired habitat, in time—a world where humans might breathe free. We may walk alongside strange new life forms created by bioengineers. Perhaps we will see bovine gas-bags that patrol the skies, spindly zigzagging trees, birds swooping like manta rays, spindly ropes with shimmering green leaves bigger than buildings. Our moon can become not a replica of Earth, but an exotic realm we shape as we like, and come to love.

Sunsets will seem to happen in slow motion, the full pallet of pinks and crimsons and rouge-reds lingering for an hour. Pearly, blue-dot Earth will eclipse that sun, punching a dark hole in the middle of the day, for some on the half we’ll call Nearside. The deep air will covet heat, making the moon much like a cloudy Florida. In the one-sixth gravity, humans can fly, with flaps on arms and feet. At last we will be at one with the birds—big rude beasts who will challenge us among the thick decks of pewter cloud.

This exotic Floridalike globe with the land mass of Asia will have mostly cloudy days. It’ll be warmer, too, from greenhouse effects. Earth will still hold sway over a moon revolving much faster, making its presence felt even if you can’t see it most of the time. The tides will be 20 yards high—and so can be surfed. With lesser gravity, a boarder can skate over hundreds of miles, a daylong ride. Of course, when that tide slides up the shore of a lunar lake, there’ll be plenty of tourists scampering away from it.

This sobering step to a higher level could mark a defining role for an emergent humanity, securing its future with a new, distant habitat. We may finally become, millennia after the Old Testament commanded, true stewards of the Earth—and no doubt, more.

This article is part of Future Tense, a collaboration among Arizona State University, the New America Foundation, and Slate. Future Tense explores the ways emerging technologies affect society, policy, and culture. To read more, visit the Future Tense blog and the Future Tense home page. You can also follow us on Twitter.