A think piece for today:
If you want to get a rise out of space nerds, bring up Mars colonization1. These days it’s the subject of countless op-eds and heated Facebook discussions. The Elon Musks and Robert Zubrins of the world are fierce proponents, viewing the expansion of humanity as a matter of survival; on the other side, many doubt the feasibility of the whole project, or wish to keep other worlds pristine for ethical or scientific reasons. There are complicated issues at play, bound to become even more prominent as the Starship project brings us closer to realizing the vision.
I myself lean towards the Musk/Zubrin camp, and as the (halfway facetious) title of this blog would indicate, I am a true believer in the spacefaring dream. Yet, my views have definitely softened since I wrote my last post on the subject. There are technical, economic, and biological problems which need to be seriously examined before we attempt anything rash. And when civilization does grow on Mars—sure to be a long and arduous process—it will be no replacement for the one we have on Earth. Even as we undertake these magnificent adventures far afield, the best thing we can do to ensure the ultimate flourishing of our species is to improve and beautify our home planet.
Now, I may sound like a bit of a hippie, but I promise that I don’t believe in any kind of planet-wide life force or mystical “Mother Earth.” The Earth is, however, one of our greatest birthrights as a species. We have rolling fields and forests and coral reefs2 , so many ferociously alive landscapes, and the rocky vistas of the Moon or Mars—while beautiful in their own unique ways—just aren’t a substitute. In aesthetic terms alone, a cramped settlement on Mars could not make up for the loss of Earth’s natural wonders.
There are practical reasons, too. Earth is a place where you can breathe, walk around, and grow crops with minimal technology. To conduct the same activities on Mars is orders of magnitude more difficult and reliant on numerous advanced technologies—not a reason not to go, but certainly a limiter on how much we can reasonably accomplish there in the near future. A hostile environment will necessarily slow the economic development of any colonies on Mars or elsewhere. Since Earth can house far more people, at far less expense, it is always going to be the economic powerhouse of the Solar System, and any space colonization project will depend on it as a foundation—a foundation that won’t exist if climate change gets out of control.
Which brings me to my next point. The current drive to colonize Mars gains much of its urgency from the chaos happening on Earth. As Elon Musk usually puts it: if climate change doesn’t do us in, it will be a nuclear war or a runaway AI, so we’d better settle millions of people off-world in a desperate gamble for self-sufficiency. This is actually a bad reason, and here’s why:
- I’ve seen space skeptics point out that Earth, even after ten degrees of climate change or a nuclear war or whatnot, would remain much more habitable than Mars. They’re right on this one. No known process is going to obliterate Earth’s oxygen atmosphere or oceans of liquid water—even if something catastrophic happened, there would remain a strong potential for the return of civilization on Earth. And humans are so adaptable that extinction is very unlikely within the next thousand years or so.
- A rogue AI3 could more effectively wipe out Earth-dwelling humanity, since it might actively hunt us down. The issue is that such an AI could follow us to Mars with relative ease. If we want to contrive a way for an AI to neutralize Earth while leaving Mars alone, it would have to be some sort of grey goo scenario, which would consume the planet and then passively stay there.
- Self-sufficiency is much harder than Elon Musk claims. Think about all the countries throughout history that have aspired to autarky, and failed—how self-sufficient is North Korea, for instance? Prospects are even bleaker when you propose to build a hyper-advanced civilization from the ground up on a hostile planet with dubious natural resources. Casey Handmer did an excellent run-down of the subject in this book; it is indeed possible, but there is a severe risk that the colony would struggle economically and demand imports from Earth far into the future.
- We don’t know how a large community of humans will react to living in low gravity and a totally closed ecosystem. I’m not saying that we can never do it successfully—just that we don’t know. The first generations of Martians will be guinea pigs in an incredibly risky experiment. It’s dubious not just on ethical grounds, but practical ones: the colonization of Mars will not get very far if the colonists all suffer horrible birth defects, or straight-up starve to death after a crop blight. While these risks are unavoidable, it does not help to drop a million people on another planet and hope for the best.
- It does admittedly make sense to have multiple homes for the species, long-term. In the very long-term—four billion years—Earth will be rendered uninhabitable by the expansion of the Sun, and by that point whatever post-humans still exist will need to relocate. However, this does not suggest anywhere near the urgency that would have us pour hundreds of billions into settling Mars within the century.
There’s also the issue of cost. Yes, you’re probably groaning, and I am too—various killjoys love to talk about space exploration wasting resources that would be better spent on Earth. Virtually all of the time, it’s bunk, because NASA’s activities are a blip on the financial radar—0.48 percent of the federal budget. Perseverance was capped at $2.75 billion, against $50 billion for agricultural subsidies in 2020 alone4. But when we look at the SpaceX proposal, with staggering quantities of people and material ferried to Mars three times a day atop an utterly vast rocket fleet, we’re not exactly talking about exploratory probes anymore. To build a self-sustaining civilization from scratch is an unbelievable investment, a project of decades or even centuries. It would require utter commitment from Earth. When we face potentially huge upheavals here on the homeworld, on account of the climate and other crises, can we really assume that the money will keep flowing?
I, personally, would advocate for a slower and more cautious approach, to be undertaken in tandem with a far larger program of climate engineering here on Earth. After all, Earth’s stability is the rock upon which any large-scale expansion into space must rest. So in the next few decades we would see a steady, measured escalation of probes, rovers, and then manned flights. These would ascertain the presence or absence of any life, and on the manned missions test colonization methods—farming, radiation shielding, low-gravity biology—in situ. Only around the 2050s or 2060s would colonists embark to stay, supported by regular but relatively low-mass flights from Earth. Self-sufficiency would come later, with the slower landing schedule, but there would be plenty of time.
So—do I think we shouldn’t settle Mars in the near future? Not necessarily. Elon Musk has a vision, and I support his grand endeavor to make life multiplanetary. If SpaceX ships do land a million people on Mars it will be a glorious thing. I just question the pace—and want to stress that while we must embark for the wider cosmos, we cannot forget the necessity of preserving civilization right here, on this truly irreplaceable planet.
- A note on terminology: Some in the spaceflight community have raised objections to the use of the term “colonization” for human expansion offworld. I stand by that word’s validity, especially because there aren’t any others that succinctly describe the transplanting of human civilization to other planets, but I insist that it should be used mainly in the biological sense. Going to Mars won’t be anything like the settlement of the Americas, marked by long, complicated, and violent interactions between Europeans and the civilizations already living there. It will be much more like bacteria spreading to a new petri dish, or birds flying to a new island, or even the epic Polynesian voyages across the Pacific. People going to a place without people; the peaceful expansion of life and knowledge, creating new cultures uniquely adapted to their environments. So when we talk about Mars, it does not help to reference Columbus and the New World.
- For now. <Cries>. With the immense sensitivity of corals to hotter, more acidic oceans, and the warming that is already baked into the climate system, our best hope at this point is to actively engineer ecosystems to survive the new world.
- For the record, I am skeptical of the idea of the Singularity or supposedly godlike artificial intelligence. We don’t know what an advanced AI would look like, but it would still be subject to the laws of physics, and that would put a pretty big damper on its ambitions of controlling everything.
- Not to knock agricultural subsidies—I appreciate having food. It’s just that they’re not what you first think of when you hear “billions in government spending.”