There are reasons why one might dispatch humans into space. Many are inspired by intangibles (quest for pure knowledge! prestige!) that have historically failed to convince large corporations and nations to invest the resources needed to support a significant human presence in space. Of course, one could pin hopes on bitterly divorced multibillionaires who might in space colonization find the personal validation their pitiful love lives will forever deny them … but really, how many of those guys could there possibly be?
Space colonization being terribly cool (if currently impractical), pundits and enthusiasts have over the years searched for tangible justifications for large-scale efforts in space. They have enjoyed mixed success, in the sense they did come up with a few somewhat convincing arguments, all of which have failed in their short-term goal (funding) for reasons I will discuss below.
(On the plus side, however, SF novels require far less capital investment than Moon bases. Real world discussions about space settlement have cost SF authors nothing and have resulted in some spiffy stories and novels.)
But back to the proffered reasons, and the reasons they failed.
Oddly, space colonization has been suggested both as the means to better conduct nuclear war and the means to better survive it. A nation in sole possession of a lunar missile base could be confident their base would see enemy missiles launched from Earth long before they arrived, giving the base time to launch its weapons before its inevitable destruction. As well, a missile from the Moon would take long enough to reach the Earth that such missiles would only be useful as a second-strike weapon. Win! Win!
However, there are a lot of drawbacks. Nations generally want the option of striking first, even if a proliferation of first-strike weapons would increase insecurity. Nuclear weapons require regular maintenance and doing anything on the Moon is hella expensive. Plus, once more than one nation has lunar nukes, the advantage of seeing counter-force attacks days in advance vanishes.
Orbiting missiles have the maintenance issue in spades, plus they would force enemy nations to decide once per missile per orbit if they are under attack. I’d like to say it’s the second issue that killed orbiting nukes, but it’s probably the first. It’s just much cheaper and much more convenient to stick the missiles in some expendable terrestrial region.
On the flip side, the best-known defense against nuclear attack is distance. A 100 MT strike on Boise won’t directly hurt someone living in the Asteroid Belt. As well, a sufficiently determined space-based civilization could (as Cole and Cox suggested in their Kennedy-era Islands in Space) increase human living space by the same factor that nuclear weapons increased our ability to kill. Whereas purely terrestrial exchanges might be brief spasms, space-based civilizations could conduct entirely sustainable nuclear wars. Good or bad, they would at least be survivable.
However, the evidence that people can be sufficiently motivated purely by collective survival is meagre at best; the case that personal survival is a sufficient motivation isn’t much better. I am reminded of Canada’s Cold-War-era Continuity of Government programs, which were intended to ensure that the handful of Canadians who survived WWIII would have a full roster of functionaries to govern them. Even though the people signing off on the funding might well have benefited personally from COG programs, COG programs were generally underfunded and many of the planned facilities simply never got constructed.
(Pamela Sargent’s Venus series has as part of its background the establishment of space colonies—the Habbers—who appear to have sat back and let the Earth suffer through and recover from a planetary collapse, which did nothing to endear the Habbers to the people of Earth.)
Human populations expanded greatly in the 20th century, fueling concerns that a Malthusian crisis loomed. One proposal for dealing with the crisis was exporting the surplus population to space habitats. It was argued that even if the habitats didn’t bleed off enough of the surplus, at least the habitats had a good chance of surviving the coming crash.
This argument failed to convince for many reasons, not least of which is that if one assumes exponential population growth cannot be checked, all space colonization could do is buy a little time before every bit of mass in the solar system was either human flesh or the means to support it. Even interstellar programs only defer doom, rather than preventing it. At the same time, if there were means to prevent Malthusian doom IN SPACE, the same methods could be used on Earth, more cheaply and more conveniently (which is what happened).
(Dave Duncan had a depressing variation of Malthusian doom in Hero!, which featured a shell of recently colonized worlds well on their way to Malthusian doom, a shell which surrounded a sphere of older dead worlds that had already bred their way to total planetary collapse).
As the dinosaurs discovered, having an Everest-sized object hit the Earth at tens of kilometers per second is a global catastrophe. Smaller impacts compensate for lack of severity by increased frequency. Surely, avoiding asteroid doom demands a vast space-based network of observers/asteroid tractors and the usual off-planet backup in case they miss one!
Once again, human ingenuity is the enemy. Earth-based astronomers have done sterling work over the last four decades documenting the smaller bodies of the Solar System. The population of potential impactors is far better characterized than it was when scientists realized the significance of Chicxulub crater.
As astonishing as this revelation may sound to younger readers, there was a time known as the Energy Crisis, when for various geopolitical reasons gas prices soared and caused all manner of undesirable economic side-effects. Given that oil reserves are finite, the future could well feature a larger and permanent repeat. Space-based solar power stations exploiting 24/7 access to sunlight could offer a way to avoid future energy crises.
Solar power is enjoying enormous growth right now but the usual “everything is much more expensive in space” has limited it to the surface of Earth. At least thus far.
(Ben Bova’s 1978 Colony features space-based solar power facilities, monopoly of which gives the World Government some, but not sufficient, ability to address the world’s pressing issues.)
Perhaps in an effort to avoid the “we can get it on Earth cheaper and more easily” issue, later pundits suggested mining the Moon for helium-3 to use in fusion reactors. There are many reasons why this will never happen, but the one that matters right now is that we don’t have commercial fusion reactors and we don’t seem likely to have them any time soon.
That’s four fear-based reasons and I like these to be lists of five. Have a fifth!
The laws of thermodynamics mean that every joule used in our economy becomes heat. There is a limit to how much heat you can directly dump into a planetary atmosphere before extremely bad things happen. Not just mild stuff, like the increasingly violent weather, sea level rise, and mass extinctions we see from garden-variety greenhouse gas pollution, but undesirable events like the oceans literally boiling, the crustal carbonates being baked out, and the resulting runaway greenhouse effect raising the planetary temperature to the melting point of tin. At the risk of sounding like an extremist, I must point out that lifeless, uninhabited planets tend to have under-performing GDPs.
Happily, for humanity, we won’t get to total planetary collapse through direct heat radiation unless we raise the planetary heat level to something three orders of magnitude greater than current levels. We can avoid this by moving some of our more energy-intensive activities off the planet before we Venusform it. But humans being humans, what we will probably do is either
- work out some better way to pipe heat from Earth into space;
- or more likely, end up living in balloon habitats fifty kilometers above an incandescent surface.
But at least it won’t be in my lifetime.
In the words of fanfiction author Musty181, prolific book reviewer and perennial Darwin Award nominee James Davis Nicoll “looks like a default mii with glasses.” His work has appeared in Publishers Weekly and Romantic Times as well as on his own websites, James Nicoll Reviews (where he is assisted by editor Karen Lofstrom and web person Adrienne L. Travis) and the 2021 and 2022 Aurora Award finalist Young People Read Old SFF (where he is assisted by web person Adrienne L. Travis). He is a four-time finalist for the Best Fan Writer Hugo Award, and is surprisingly flammable.