Photo credit: Michael Lionstar
There is a place in our solar system, beyond Earth, where, if you could get there, you could live in an inflated plastic building and go outside without a pressure suit.
You could go boating there. You could watch a rain storm. You could even strap wings on your back and fly.
Titan, a moon of Saturn, is by far the best place in the solar system for human beings to live other than the Earth. We think it’s the only practical place for a permanent human space colony, as we argue in our new book, Beyond Earth: Our Path to a New Home in the Planets
We are a planetary scientist (Hendrix) and an environmental writer (Wohlforth). We’ve considered the growing body of research on Titan and the needs of human beings in any home. Our book examines the reasons why we would build a space colony, considering our own planet’s history and prospects, and a scenario for how such a project could actually take place.
Current technology can’t get people to Titan, but we will someday be able to get there and set up a colony. We will need faster propulsion to make the trip safely, robots with artificial intelligence to prepare the way, and biotech to produce food.
All that is possible. Eventually, if human beings ever need to send a human ark into space, this will be our destination.
The people would find a strange world, but one more like the Earth than anywhere else in our solar system.
Titan is no Garden of Eden. Surface temperatures are typically 290 degrees below zero, Fahrenheit. But Titan has special qualities that make life there viable and sustainable like nowhere else in the solar system other than our origin.
Human beings have non-negotiable needs. We need protection from space radiation. We need an abundant source of energy. And we need resources that can be readily manufactured into shelter and other material needs.
The Moon and Mars do not meet those criteria. Considering radiation alone, neither has an atmosphere adequate to shield us from the cancer and/or brain damage likely to result from space radiation, without finding shelter far underground.
If we want to live underground, we can do it on Earth. There aren’t many advantages to living in a deep cave on Mars instead.
But on Titan, the atmosphere provides radiation shelter, and an extraordinary weather cycle of organics exchanges an inexhaustible supply of hydrocarbons.
That’s right, hydrocarbons, like the fuel we currently use on Earth. They fall from the sky, filling lakes and building dunes. Liquid methane, like the liquefied natural gas carried in tankers, evaporates and rains down like the water in the cycle of our own climate system. Waves travel cross methane seas to carve hydrocarbon beaches.
Titan’s hydrocarbons don’t burn because the atmosphere lacks oxygen. But much of Titan’s mass is water ice. Where the Earth has an iron core and rock mantle, Titan’s core is rock and its mantle is water. Human colonists could use the water for many purposes, but the most important would be to obtain oxygen.
The process of electrolysis — exposing water to an electric current — can break its hydrogen and oxygen components apart. On Titan, it would be simple to harvest water, produce oxygen, and use that oxygen to burn hydrocarbons, yielding more than enough energy to repeat the process.
With energy and hydrocarbons, everything necessary to make plastic is at hand. In Titan’s atmosphere, a plastic building could easily be inflated by warm, breathable oxygen and nitrogen. In fact, an inflated building would need firm anchors to keep it from floating up into the atmosphere.
We imagine robots going ahead to build the infrastructure for human beings who would follow, arriving to occupy warm buildings already erected.
The people would find a strange world, but one more like the Earth than anywhere else in our solar system. Titan is extremely cold, but we wouldn’t need pressure suits, thanks to the thick atmosphere. Very warm or heated clothing and respirators would keep us safe.
The atmosphere is somewhat thicker than Earth’s and the gravitational force is similar to the Moon. Astronauts on the Moon made giant leaps, but that was in the absence of an atmosphere. On Titan, the thick atmosphere and weak gravitation would allow people to fly, like birds or, more practically, with personal propellers.
If your wings fell off, you would be fine. On Titan, terminal velocity — the maximum rate at which objects fall — is 15 miles per hour.
The sky would be dim, but not black. The atmosphere is hazy, so you wouldn’t clearly see Saturn filling the sky, but its light would give Titan’s landscape a constant red glow. The moons of Saturn are tidally locked, so the same side always faces the planet. As Saturn tilts through the seasons Titan also tilts and so goes its weather, with patterns of wind and methane rain and possibly snow changing during the course of the 29 Earth years of a single Titan year.
Why would people go there? Logically, the environment on Titan would have to offer an advantage over the Earth.
Most likely, fear of a deteriorating environment here would come first, motivating investment in a colony as a backup or safety net. But once the colony was in place, it could be self-sufficient — in fact, it probably would have to be so — and could grow on its own, as another home for humanity to develop in a new way.
In thinking about these issues, we’ve brought a new mixture of skepticism and open-mindedness to the subject of where humanity will go and why.
On the one hand, we hear leaders and industrialists talk about the prospect of colonizing Mars as if it will be easy. We don’t buy that vision.
On the other hand, investments in the stretch research that will make a trip to Titan or even Mars possible have received little attention. Commercial space companies are lowering the cost of launching payloads into orbit, which is important, but NASA also should be developing much faster spacecraft to get astronauts to other planets before radiation does them too much harm.
In Beyond Earth
, we’ve considered these issues with a mix of hope and realism. We don’t expect a space colony to develop just because it would be cool and interesting. But we do expect one to develop.
And when it does, Titan is the most reasonable destination.
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is the author of more than 10 previous books. He writes a column for Alaska Dispatch News
, hosts a weekly interview program for public radio stations in Alaska (where he lives), and has won the Los Angeles Times
Book Prize for Science and Technology, among many other awards.
Amanda R. Hendrix
, Ph.D., is a planetary scientist who worked for 12 years at NASA’s Jet Propulsion Laboratory. She has been a scientific investigator on the Galileo and Lunar Reconnaissance missions, a principal investigator on NASA research and Hubble Space Telescope observing programs, and is the author of many scientific papers. As an investigator on the Cassini mission to Saturn, she has focused her research on the moons of Saturn.