(This is a re-write of a much earlier post of mine on Medium.)
I’m going to write something shocking here that I need to prepare you for first. Bear in mind that this comes from a total sci-fi geek – I have, at various times in my life, owned not only a toy phaser, but a tricorder and communicator to boot. I have seen every episode of Star Trek ever made (really) and love Battlestar Galactica. I can have an informed discussion about the relative merits of visions of the future embodied by the Foundation series, the Culture, or the Hegemony of Man. I love this stuff.
Yet any way I approach it, one conclusion seems inevitable: manned spaceflight is mostly a waste of resources, and we should put a stop to it. Hear me out.
We’re experiencing a newfound fever pitch of exuberance about space exploration these days. Elon Musk keeps insisting that we must go nuke and colonize Mars, and his devoted audience of dittoheads cheer. In fact, so many people rush right past the “exploration” part of the space discussion in their hurry to get to “so when can I board a shuttle to Europa?” that a reality check is in order.
In short: space exploration is great, and we should do more of it. But there are vanishingly few good reasons for shooting humans into space, other than to show off that we can.
What humans do (and don’t) in space
Today, a big reason we send humans into space at all — besides flag-waving politics — is to see how human beings fare in space. Unfortunately, it turns out that humans are squishy, fragile little bags of mostly water that burst pretty easily and fry up fast.
Every time a human is sent into space, it is with a whole cocoon of life support that is 100x more complicated than just sending a machine. The obvious requirements for humans are tricky enough as it is: oxygen, pressurization, climate control, food and water, rest, heavy radiation shielding, somewhere for the poop to go, etc. Keeping humans up in space for very long, or sending them anywhere interesting, presents even greater challenges. Human bodies actually disintegrate without gravity, for example. 15% of our waking hours in space must be spent just exercising enough to stave off permanent disability.  Once you get beyond the Earth’s magnetic field, the harsh radiation of deep space is enough to require hardened shielding – and we’re actually not really sure what would happen to humans exposed to even that residual amount for very long. (Like, say, on a trip to Mars.)
(Side note: one reliable sign of good science fiction is that it deals with radiation in space.)
Indeed, it turns out that robots can do pretty much everything humans can in space, except more easily, faster and far, far cheaper.
This is such a completely obvious point that almost no one denies it , but it’s worth pointing out anyway. Robotic probes like Cassini, Curiosity and the Solar Dynamics Observatory (among many others) have already done some amazing scientific research which is simply impossible for humans. Not only can robot probes operate for far longer and collect more data, but they also have far greater latitude in adjusting their mission agenda on the basis of new discoveries. And because politics is never far from space exploration, it’s fair to mention that catastrophic loss of a robot spacecraft does not engender anywhere near the same political heat that losing humans does.
Just getting into outer space is extremely expensive — staying there is way, way more so. By low estimates, just keeping the lights on in the International Space Station costs $350,000 per hour — and it’s already there, and built! Even in a permanent structure on the Moon, Mars or anywhere else — which will be terrifically costly to construct, with tech we don’t have yet — just generating enough water, oxygen, food, heat, pressure and radiation protection to sustain human life will remain expensive. It will always cost more to support a human in space than on Earth, our natural habitat, and this fact is probably all but immune to advances in technology . That being true, there needs to be a pretty compelling reason for having them out there.
This is why the most realistic vision for humans in space is more like a North Sea oil platform, or McMurdo Station in Antarctica, than anything else; incredibly remote and expensive bases where humans can be temporarily based for strictly utilitarian ends (economic or scientific), with perhaps the odd self-funded bazillionaire visitor now and then. And their inhabitants can’t stay there very long, or they will die.
What all of those bases also have in common, by the way, is the need for constant resupply. There are undoubtedly large mineral resources to be found on Mars, the asteroid belt and elsewhere, but a truly self-sufficient outpost in any of those places is inconceivable with any technology even imaginable yet today. We haven’t even developed the propulsion technology necessary to get a manned mission to Mars and back.
Look, we all know that new technological advancement inevitably makes things possible that used to be impossible, so you can never say “never” to almost anything. Indeed, in the long run, all predictions about the future whatsoever are mostly void because the premises will change. So hey, sure — maybe, one day in the distant future, mass migration off-world will be a thing. But for now, it sure isn’t, and it’s not likely to be for a couple of centuries yet. The big reason isn’t just technological (though it’s that, too). It’s economics.
Every single mass migration in the history of human civilization has been fundamentally economic in motive. It seems unlikely to me that the future will be so different. With the big built-in costs of supporting any human off-world (let alone getting them there in the first place), it would take a curiously powerful economic impetus to convince any significant number of people that it was in their own economic self-interest to move. That human settlement in space would need to be surplus-generating in the long term, after all — otherwise, it’s a net cost. So what do humans do up in space that creates all that surplus to justify their existence there?
Of course, if you go back before human civilization, you had another reason for mass migration — existential threats to the species, which is one of the big justifications offered for why mankind simply must become a multi-world species.
But that’s a silly rationale too.
The Earth in peril?
Elon Musk is only the most recent proponent of interplanetary colonization as a sort of “insurance policy” against catastrophic threats to humankind — say, a massive asteroid impact, climate change, war, etc. In the long run, the argument goes, Earth is toast. We must eventually become a multiplanetary species to survive.
It is true that, in about 5 billion years, our sun will eventually grow into a red giant and fry the Earth and the other inner planets in the process. (Contrary to popular belief, it probably will not go supernova — not massive enough.) Before that happens, though, we’ll almost certainly get hit multiple times with the kind of massive asteroids that strike Earth every few tens of millions of years. The latest one created the Chesapeake Bay, so you can imagine they’re not good for life on the planet. And, of course, there are lots of other reasons why massive extinction events happen too. They’ve happened at least five times since animal life appeared on Earth:
Everyone panic! To the lifeboats! To Mars!
Not really. The most obvious problem with this argument is that it relies on galactic time scales. In the history of the just the Earth itself, a million years isn’t even a rounding error. Human ancestors have only been around for 6 million years, and the modern form of Homo sapiens are only about 200,000 years old.
(Think about that! That’s insane! We went from evolving into humans to lolcats in just 200,000 years!)
This is another way of saying that planet-killing extinctions, or asteroids, are extraordinarily rare events on human timescales. We easily can wait another 100,000 years without much cause for alarm. What’s more, deflecting or destroying an asteroid that was on course to strike Earth is almost certainly a much more realistic plan for saving the species than… well, anything else.
The same is true of war or climate change. While these are both certainly Big Problems to learn to deal with, it is surely many orders of magnitude easier to stop or mitigate either one and figure out how to live sustainably here than it is to colonize Mars (or anywhere else).
The elitism of escape fantasy
You’ll notice that virtually all of the theorizing about how humans could escape a blighted Earth doomed by poverty, disease, climate change or war is done by people who, tacitly or not, assume they’ll be among those permitted on the lifeboats. Occasionally, this is done under the guise of pursuing the “greater good” of preserving the species, but just as often it’s justified as: “let those other idiots deal with the mess while we, the clever ones, get out of here.”
This is essentially the motivating ideology of Elysium, not Star Trek. It’s an unattractive and narrowly self-interested philosophy that reflects the understandable, but unavoidable, frustration with getting lots of humans to agree on how to live together. The Earth has billions of people whose poverty and lack of opportunity are the result of a complex global political and economic system and a distribution of resources that allows a very tiny portion to indulge fantasies about leaving the others behind, and that’s sad. We can do much better — and we are, slowly but surely. Leaving our human bretheren who never even had a chance behind is not a vision I find very compelling.
In short: you cannot “tech” your way out of politics. Anyone who claims you can is trying to sell you something. Don’t buy it.
Keeping things in perspective
At the end of the day, supporters of space exploration — like me — always have to point out that NASA is a total bargain. Leaving aside the truly enormous second-order benefits of the technology space exploration has spun off, everything NASA does today it accomplishes for roughly one half of one cent of every U.S. tax dollar. By contrast, fifty cents go straight to entitlement programs, eighteen to defense, and seven to interest on the federal debt.
When you start thinking about what our society actually spends real money on – like the $1 trillion dollar F-35 Joint Strike Fighter boondoggle or a trillion and a half to fight a fruitless war in Iraq – cutting space exploration as a means of saving money is an absurdity.
Space exploration is mostly the domain of governments who can fund it, which makes it also a matter of public policy. Like any policy decision, its merits must inevitably be weighed in terms of dollars spent and benefits gained. In that context, the case for sending humans into space just does not hold up at all. Given that NASA’s budget will, unfortunately, probably not be doubled, tripled or otherwise in the foreseeable future, robots are an obvious, and better, answer for our exploration of the cosmos than shooting humans into the stars.
Is this all a total buzzkill? I don’t think so. If you really believe the Earth is too boring, or doesn’t offer the opportunities for exploration and wonder and awe that you crave — well, you clearly haven’t seen enough of it yet. We have an amazing planet here that only a very tiny minority of people will ever get to see a lot of. If you’re one of them, take advantage of it. I promise you will not be disappointed.
 — This is not hyperbole – the human body literally disintegrates in outer space. ISS astronauts are assigned 2.5 hours of rigorous weight and aerobic exercise every single day just to stave off the atrophy of zero-G that would make them all but helpless back on Earth (or any other significant gravity environment). Interestingly, astronauts’ eyesight also erodes, apparently irrevocably, after a few months in orbit, a problem for which NASA still has no clue how to answer.