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Comment by bimmer44 | Hacker News Reader

I believe this post ignores the implications of increased surface level radiation (Mars does not have a protective magnetosphere). See the two articles I link below.

A structure like this might make sense for a shorter mission - but considering the thought experiment asks what structure would be suitable for a long term Musk-style settlement I don't think thin ETFE would be enough.

At least part of the radiation risk is temporary solar events, so perhaps you could use a slightly hardened version of ETFE as the author suggests but keep all human activity near regularly placed deep shelters to retreat to when radiation spikes are detected?

https://www.esa.int/Science_Exploration/Human_and_Robotic_Ex...

https://phys.org/news/2016-11-bad-mars.html

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The article's author points out that normal radiation on Mars is about the same as background radiation in Ramsar, Iran. Residents there have normal lifespans and cancer rates. Solar storms are a problem but fortunately, they give you enough warning to take shelter.

https://caseyhandmer.wordpress.com/2019/10/20/omg-space-is-f...

Thanks for this interesting link - I take back my criticism of the article! Based on your comment and that of t3hz0r it sounds like the martian colonists would be fine with this setup, as long as they mainly worked and lived in shielded habitats within the ETFE covered areas and also had underground shelters for emergency radiation protection.

I'll just point out that a Boring Co machine will fit inside a Starship.

Underground may be the only way to live, given that radiation dosage is cumulative, 24/7, it may not be possible to live on the surface at all in inflated domes. Maybe they're better suited for equipment storage and agriculture.

Why bother going then? I mean you can live underground on Earth much more easily.

Because it’s there. Some people like living in unusual places.

Read the link above. Aside from solar storms, radiation is at a level that humans survive just fine on Earth.

I do expect to see Boring machines on Mars anyway.

Also you could harden the ETFE with a specialized lead or other metallic layer, or perhaps incorporate it into polymer matrix.

Such a material would have other interesting uses, including spacesuits and spaceships.

I think the implication is that under this tented tensile structure you could build whatever radiation shielded (or not) structures you wanted, and this just contains the air.

Could the air become unsafe after exposure to radiation?

Radioactive particles (dust) in air are problematic. The gas in air does not become radioactive (at least in a dangerous way) from exposure to radiation.

If the surface of mars is exposed to radiation capable of making particles become radioactive, does that mean the surface is already radioactive? Or would this only happen to airborne dust particles, not to sand particles on the ground?

The dust itself would have to be something highly radioactive like uranium. Radiated silica isn't going to get into you and cause real issues.

Couldn't irradiated silica dust get into your lungs though?

If you're breathing silica dust you're going to get silicosis anyway, so there's not much point worrying about it.

Maybe the living area buildings inside the tent can have a vestible / "dustlock" for keeping the dust outside, and outside those it just becomes standard to wear a dust mask.

Dust is one thing but it’s the fines that really get you.

If you’re putting all of your eggs in the “shielded other structures” - why have the other structure in the first place? It’s not as if you can live outside those “other structures” if you’ll just die of radiation poisoning.

Or, to put it another way, any structure capable of shielding against cosmic radiation should be capable of also holding air (we’ve gotten really good at that).

> any structure capable of shielding against cosmic radiation should be capable

A thick roof without walls should protect you from cosmic radiations (some distance from the edges), yet wouldn't be airtight....

A large rubble pile would do the same.

You need much larger structures for growing food than for living. Food can handle the radiation.

The biggest problem of these artificial environments is the threat of sabotage from either disgruntled, suicidal or criminal minds.

You can vet people as much as you want but with the pop they are talking about someone’s bound to go crazy or be an agent of discontent. And then if they are settlers of course their children can be as varied as they are on Earth, which means the possibility of the same.

I don't see where criminal fits in aside from the fact that a sabotage of that sort would rightfully be hideously illegal. What is to gain personally from that destruction?

It might be a pedantic quibble but I can see power as the only "rational" sabotage motive. Which could include some disgruntlement. Either to oust management or rivals to gain control or possibly international politics where one thinks they can gain from the loss of the colony for the sake of their earth nation.

Suicidal can be taken as granted to be irrational and disgruntled relatedly as "so fed up they want to see everything collapse to make them suffer".

Imagine beeing sentenced to a desert prison, by your parents, a monastry of eternal work and little fun, where all the beauty of world, is that coming from another world, as videos, games and mail, which you can never reach.

> What is to gain personally from that destruction?

The promise of a ticket back to Earth and a shitload of money.

Maybe a part of the mission is to design a society to minimize or eliminate violence, mental illness, crime, etc. What would a society look like that depends on near-perfect harmony and peace for its very survival?

I would argue that it would be a dead society. It just takes one person who feels that being hurt themselves is worth it just to hurt others for whatever reason.

I think the membrane is only meant to pressurize a vast area, not to protect against solar radiation, which is what structures within would be for.

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