Earth would have to turn into a lava planet for Mars to be a better option. Antarctica is more habitable than Mars and nobody's planning to set up self-sustaining colonies there. Every technology needed to survive on Mars could be implemented far easier here no matter how bad it gets.

As long as it’s on the same planet, it’s still all our eggs in one basket.

What kind of failure scenario would have a Mars shelter better than any post-apocalypse Earth shelter?

Mass political unrest, another pandemic, combined with overpopulation leading to complete collapse of food systems.

All of those scenarios combined are much more manageable than Mars.

All the problems on Mars are resolved through engineering.

The problems on Earth are the result of humans thinking their egoes are more important than the life support system of the spaceship they live on.

Eventually the people problems will ruin civilisation on Mars, but that will come after the “common foe” of simply surviving on Mars has been sufficiently cowed.

“any”? Just what did you have in mind?

There is a treaty prohibiting antarctic colonies that expires soon. We'll see then.

The reason nations were willing to sign a treaty agreeing not to colonize the antarctic is that none of them wanted to do it anyway.

Prior to the treaty, humans had already colonized every other continent, and had the means to travel to Antarctica for _thousands_ of years.

If colonizing Antarctica was in any way worthwhile, someone would have done it 100s (or 1000s, or 10,000s) of years ago.

The reason countries sign such treaties is that they don't want to spend money in a race to colonize the place (and a war to decide who owns it) that has no obvious economic return.

>If colonizing Antarctica was in any way worthwhile, someone would have done it 100s (or 1000s, or 10,000s) of years ago.

except technology has advanced since then.

And the global warming directly cuts costs regardless of technology level.

We've had the means and ability to colonize it since the end of WW2. Chile and Argentina have civilian towns there, since the 50s&60s. Very teeny tiny towns, but they exist.

As I understand it colonization in this context means self sufficiency. Are they without delivery of food and other essentials by ship and plane? Could they grow their food there in greenhouses?

Maybe that's why everyone signed the treaty in the first place. They didn't have the tech but now that they do, it's worth giving it another shot.

I can’t think of many things that make it better to be on Mars with no Earth support (even if your colony’s pretty well-developed and capable) than a survivor on Earth after a disaster other than something like a dwarf-planet-sized impactor. Climate change, nuclear war, and a dinosaur-killer asteroid combined wouldn’t do it. So-called “snowball Earth” is preferable. Earth with everywhere but the poles too hot and arid for crops is preferable. Mars is very hostile. Especially if you allow for your Earth-survivors having equipment like the Martian colonists do (far cheaper to provide, redundantly and distributed and hardened and with regular up-keep and replenishment, on Earth than on Mars). I can come up with some sci-fi scenarios, too, but as far as stuff that suddenly makes Mars better to be on than Earth and could happen today, it’s basically just super-huge impactors. Which isn’t nothing, but it’s a pretty small slice of the apocalypse pie.

I agree. This is why I am myself skeptical about settling Mars.

Maybe there are scenarios where an Earth disaster causes breakdown of physical and intellectual supply chains and expertise/components from Mars are essential to recovering industrial civilization on Earth.

To be clear I think settling Mars is cool and I’m not upset if someone tries—I’d love to watch that and cheer them on. I just think the “it’s a backup for humanity” angle is, at best, pretty weak.

While a K-T event might eliminate life on Earth, a Mars colony could be wiped out by a long dust storm or broken sewage system.

Why would a long dust storm wipe out a Martian colony? I don't think plants will be grown using sunlight (which is 25% Earth's sunlight). Nuclear reactors would provide energy for years after deployment, even though sourcing local fuel would require large industrial plants.

As for the broken sewage system, that's simple: build more than one. In fact, instead of one large colony, build a couple dozen smaller ones and never tax them to full capacity.

It's my assumption Martians will take birth control very seriously.

So you're assuming a Mars colony would have a nuclear reactor(s). Setting aside for a moment what a Herculean task that would be, how would you expect a nuclear reactor work on Mars? They require massive amounts of cooling, most of a nuclear power plant is essentially the core's cooling system. There's no ready sources of water to use and the atmospheric density is a tiny fraction of Earth's. A Martian cooling tower would have to be enormous. A cooling system might have other configurations but it would still be enormous.

Dust storms on Mars can last for months. While the overall wind energy isn't as high as on Earth thanks to much lower atmospheric density, Martian dust still gets everywhere.

So your Martian reactors would have their cooling systems constantly covered in insulating dust. While Reactor Cooling Maintenance Technician would be an in-demand job, a long or particularly bad dust storm would doom the colony.

Building a second sewage system, or any other infrastructure, isn't always practical or even possible. The problem with infrastructure on Mars is it must always work or people will die. If an infrastructure problem kills or disables enough Reactor Cooling Maintenance Technicians the colony is doomed.

A broken sewer line on Earth is inconvenient to dangerous but rarely an existential problem. A broken sewer line anywhere but Earth is an existential threat at best.

Ever heard of small modular reactors?

[1] https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...

As I understand it at least some of them are "walk-away-safe" in case of meltdown, which is conceptually unlikely, and don't need the big cooling towers you speak of.

I know they are not there yet because of materials science, regulation, but they are not science-fiction either.

Anyways, I don't see any reason to not bury them in mars ground, instead of doing so here on earth.

Getting them there would be difficult, but some big effing rockets in their freight configuration should do...

Edit: or some Sea Dragons [2] https://en.wikipedia.org/wiki/Sea_Dragon_(rocket)

SMRs don't solve the cooling problem with nuclear reactors. They're still producing megawatts of thermal energy that needs to be dissipated. Mars isn't known for its flowing rivers or deep cerulean oceans. So using massive amounts of water to carry away heat (like we do on Earth) Isn't an option for cooling. It's atmosphere is far less dense then Earth's so air cooling a reactor would take vast fields of radiators.

Burying a reactor underground is not a cooling solution. Rock is not a great heat conductor. So the reactor will stay cool for a little while, to the heat capacity of the surrounding rock, and then melt because the rock isn't effectively carrying heat away from the reactor.

But not to worry we'll launch them on fantasy rockets! So long as we make the rockets out of Impracticalium rather than Unobtanium we should be fine. We can start tomorrow.

It's entirely possible to conceptualize ways a Mars/Moon/orbital colony could work. The issue isn't coming up with ideas on paper it's the actual implementation of those ideas that is actually difficult. Handwaving implementation details and actual engineering challenges is just writing science fiction. It might be interesting and entertaining but it's not actionable.

I find your lack of faith disturbing!

> So you're assuming a Mars colony would have a nuclear reactor(s).

Yes. Or, at least, multiple power sources besides solar.

The same reactor designs that work for the Moon would work on Mars. Due to sandstorms, nuclear power is a necessity on Mars. Depending on the location of the colony, carbon dioxide ice deposits can function as heat sinks.

Martial dust gets everywhere, and that's why the colony will not place critical infrastructure on the surface.

Building redundant life-support infrastructure, however impractical, is a hard requirement for any off-planet colony. That's why any realistic approach will start by launching a massive amount of supplies and equipment before the first human is settled. That means there will always be enough water and food to supply the colony until another supply landing can arrive. Living on a planet where you can't open a window to the atmosphere is hard and dangerous, but also required if we want to survive in the long run.

Great plan. I hadn't thought of powering of powering a Martian colony with unicorns instead of basilisks. In retrospect that makes perfect sense.

The K-T event obviously didn't eliminate life on Earth.

For some values of life.

I share your puzzlement.

One could similarly say: "A co-pilot is, at best, no less likely to make a mistake than a captain. Why have two pilots in the cockpit then?"

The author writes:

> Of course, potentially halving our existential crises by doubling our presence in the solar system is not to be sniffed at [...]

Having a backup planet doesn't "halve" the risk of existential crisis, just like the second pilot doesn't halve the risk of plane crash or having a backup of your main HD doesn't halve the risk of you losing all your data. It reduces it much more (assuming, as you point out, that the risks are at least somewhat independent).

This is so obvious that I'm wondering whether the author just wishes to push this dream of an O’Neill cylinder habitat.

What's wrong with O´Neill cylinders?

The Moon is hundreds of times closer than Mars and pretty much all the arguments for spreading our risk among two heavenly bodies still hold if we were to target the Moon instead of Mars.

Why does Mars get so much more press than the moon? I guess it has a bit more gravity, 37% of Earth vs 17% for the moon. We can’t survive in either atmosphere. Temperature differentials on mars are less extreme? That seems like the least of the engineering problems however.

Mars has more Earth-like gravity (should be significantly better for humans). It has a lot more water. It has a 25-ish hour day instead of 4-week day. (The latter may not matter to humans since we'd have to be inside most of the time anyway, but it matters for things like solar power.) Mars temperature is much better.

I'm still not saying we should settle Mars first, but it does have some real advantages.

Why wouldn't space based solar power work for the moon, when the concept is discussed for earth?

[2] https://en.wikipedia.org/wiki/Space-based_solar_power

Only thing i can think of are decaying orbits because of irregular mass distribution.

But when thinking of such concepts, why not plan for some station keeping expendables? It's not like were talking about some feeble pebbles thrown into orbit there like we have done up until now...

That 9 month trip is a real killer, though. No dust storms on the moon, and solar power is way more efficient than on Mars. See, e.g. how weak rovers are overall, despite having the best engineered solar panels that money could buy. Solar energy is only about 600Wm^-2 there versus more than double that on Earth. The Moon also has no atmosphere to scatter blue and UV light.

Mars is a terrible idea for a long-term colony, IMHO.

Why does the moon get so much more press then Venus? Cloud cities. Basically Earth gravity. What's not to love there?

The rain of [1] https://en.wikipedia.org/wiki/Sulfuric_acid

But why is preserving humanity in that case even a goal? Everyone on Earth still dies in that disaster scenario. I understand wanting to prevent people from dying in the disaster, but just letting them die and then repopulating from somewhere else just doesn't seem like a worthy goal to me.

Better that half of humanity dies than all of it.