Practical for a civilian to build a space suit?

[CCWilson]

This is for a novel I'm writing. In it, the Earth has been separated from the Sun. At this point there is still an atmosphere (at perhaps 50% of normal pressure) but the temperature has fallen to somewhere around -150 centigrade. My question is this: Could a technologically savvy private citizen, after research, with a year's warning, build an insulated suit that would allow him to be outside for several hours? If so, what form would the suit take?

 

[Angry Citizen]

I'd probably think of multiple layers of thick cloth with some of the outer layers epoxied together, but it would restrict movement at the joints. The joints I'd probably think of some kind of metal slippage with a rubber-like seal, similar to the rubber you see on windshield wipers.

That's what I come up with from thinking about it for a few minutes. But one thing I don't know - is it even necessary to pressurize the suit against 0.5 atm pressure? It might be sufficient to develop a highly insulated suit. This I think would be much simpler, as you could epoxy the outer cloth layers in segments such that the joints aren't restricted, and you could add a wiring system to the bottom layer to create a "heated blanket" effect that would be nice and toasty, with battery power of course. And obviously a ventilation system would be necessary, but that's pretty trivial I think.

 

[marty1]

At .5 atm you may have to pressurize the houses too. Seems more challenging than the suit.

http://en.wikipedia.org/wiki/Mount_Everest

 

[Vadar2012]

At 0.5 atm, there are many moredifficult challenges than making a space suit.

 

[russ_watters]

At 50% of normal atmospheric pressure, the suit doesn't need to be pressurized!

 

[CCWilson]

At the time in question, the individuals are living underground and need a way to work and travel above ground for a few hours. The suit - which wouldn't need to be pressurized at half normal atmospheric pressure - would have to be pressurized later when the oxygen and nitrogen liquify, and at that point an oxygen supply would have to be carried, and the underground bunker would have to be pressurized.

 

[sadben]

Very practical actually

At 50% of normal atmospheric pressure, the suit doesn't need to be pressurized!

you don't need a space suit for this, people go to everest with just oxygen masks (~1/3 the pressure on the surface at 0m).

I recommend doing research on thermal materials (emergency foil blanket is a good place to start) and Scuba systems as well as CO2 scrubbing. Also a good starting point would be to build an underground base complete with hydroponics and what not. Good research material would be Mars bases and what not.

As for the suit i recommend you watch this :http://www.parabolicarc.com/2010/01/09/video-dava-newman-shows-flexible-spacesuit-design/

I really look forward to your novel, I am a sucker for a post-apocalyptic story

 

[Ryan_m_b]

Also a good starting point would be to build an underground base complete with hydroponics and what not. Good research material would be Mars bases and what not.

Long term survival of the human race without Earth would be far more complex; see the discussion in this thread https://www.physicsforums.com/showthread.php?t=625503

 

[onomatomanic]

The suit - which wouldn't need to be pressurized at half normal atmospheric pressure - would have to be pressurized later when the oxygen and nitrogen liquify [...]

More detailed explanation, please.

 

[ImaLooser]

This is for a novel I'm writing. In it, the Earth has been separated from the Sun. At this point there is still an atmosphere (at perhaps 50% of normal pressure) but the temperature has fallen to somewhere around -150 centigrade. My question is this: Could a technologically savvy private citizen, after research, with a year's warning, build an insulated suit that would allow him to be outside for several hours? If so, what form would the suit take?

Mountain climbers use low-tech goose and duck down. Use enough to look like the Michelin man, that might do it. Boots with cork soles a foot thick, maybe. You'd need some way to heat the air so it didn't freeze the lungs.

 

[Ryan_m_b]

Mountain climbers use low-tech goose and duck down. Use enough to look like the Michelin man, that might do it. Boots with cork soles a foot thick, maybe. You'd need some way to heat the air so it didn't freeze the lungs.

You seem to be missing the -150°C stipulation, that's 100° lower than the coldest place on Earth! I may be wrong here but a space suit has the advantage of the vacuum for insulation, in an atmosphere at half pressure convection and conduction will make it harder to maintain heat. In otherwords on the heat issue alone this may be harder than a space suit.

 

[chasrob]

You know, you could just buy one, from the folks who manufacture them for NASA. I don't have the link, but on a forum, a scientist familiar with government/industry commerce said that the manufacturing outfit would only charge $10,000 or so for a suit if you're a citizen, versus a million for NASA .

 

[Ryan_m_b]

That doesn't sound right at all. Are you sure they aren't just selling off used ones as novelty items?

 

[chasrob]

https://groups.google.com/d/msg/rec.arts.sf.science/gVESBWv0iSQ/WU60fl5LWa8J

It turns out he was talking about used, yes. Schilling was/is a long-time consultant for NASA and the military, AIUI.

 

[Ryan_m_b]

Hmm...thinking on this more it occurs to me that this scenario represents a significant plot hole in your story. Correct me if I'm wrong but your setting is:

- Due to an as yet undetermined catastrophe (black hole into sun, Earth flyby of massive object etc) the Earth is due to lose most/all the energy from the sun. This will result in temperatures plummeting until the Earth is back to something resembling the snowball of its early life.

- With the remaining decades/century left to them the peoples of Earth pour trillions of dollars and billions of manhours into the research and development of sustainable closed ecosystems and socioeconomic models so as to build minimally/optimally populated, self sufficient cities.

- Once research starts hitting deployable level they build/retrofit cities capable of keeping a few million people alive each even without the sun.

So long as I haven't got the wrong end of something the reason why I think this set up precludes your scenario is that in this situation there are not amateur survivalists. It's just not possible. You either live in one of the extremely high tech (note that does not necessarily mean nice to live in socially or aesthetically) cities maintained by their large population of specialist workers required to keep the technology/industry/ecology going or you're dead. If someone from the city needs to go outside they can use an extreme survival suit built in the city's internal factories. I can't think of a scenario where someone would have to cobble together bits and pieces to make their own.

 

[D H]

This is for a novel I'm writing. In it, the Earth has been separated from the Sun.

Somebody wrote this exact novel a long time ago. I can't remember the name of the novel or of the author. Synopsis: The Earth somehow became separated from the Sun. The atmosphere eventually froze. Almost everyone died. The book tracked one family that survived. They used layers and layers of blankets for insulation. These layers and layers of blankets also kept the air in their house from bleeding out too quickly. They had to occasionally venture outside in leaky home-made space suits to dig for water, oxygen, and nitrogen in the frozen-out atmosphere and to dig for food at a grocery store that escaped the worst of the apocalypse. At the end of the novel they were found by scientists who had the technology to build a sealed environment, make real space suits, etc.

 

[D H]

Found it. It was a short story, not a novel. A Pail of Air written in 1951 by Fritz Leiber.

 

[Ryan_m_b]

Found it. It was a short story, not a novel. A Pail of Air written in 1951 by Fritz Leiber.

Available here
http://www.baenebooks.com/chapters/0743498747/0743498747___6.htm

 

[CCWilson]

Ryan, the reason that our hero needs to build (or buy) a sort of space suit is that he and his family weren't selected as residents of the city. He buys property close to one of the cities and digs a hole and somehow (details to be worked out, but probably involving a generator and fuel hoarding plus canned food) manages to keep his family alive for six months or so, with a plan to trek to the underground city and show his pitiful entourage to the city's external cameras (originally necessary to prepare for the possibility of non-residents storming the barricades) in hopes that they need his particular skill set or let them in out of Christian charity.

 

[Ryan_m_b]

Ryan, the reason that our hero needs to build (or buy) a sort of space suit is that he and his family weren't selected as residents of the city. He buys property close to one of the cities and digs a hole and somehow (details to be worked out, but probably involving a generator and fuel hoarding plus canned food) manages to keep his family alive for six months or so, with a plan to trek to the underground city and show his pitiful entourage to the city's external cameras (originally necessary to prepare for the possibility of non-residents storming the barricades) in hopes that they need his particular skill set or let them in out of Christian charity.

Fair enough.

 

[CCWilson]

Ryan, thanks for that link to the short story. Very cool. Of course by the time the oxygen had frozen or liquified, a pressurized space suit would have been necessary to go outside. And geothermal power - which was just becoming reality in 1951 - is a better choice than nuclear for the long term.

One thing I'm still trying to clarify is what the surface would be like after the temperature drops enough to liquify and then freeze oxygen and nitrogen. My guess is that oxygen and nitrogen would flow like water when they liquify, seeking lower levels, perhaps collecting into rivers that reach the oceans, if snow and ice didn't impede them. So maybe there wouldn't be a thick layer of liquid or frozen gases everywhere. I'm having trouble figuring out what sort of scientific discipline might have already worked this out.

 

[Ryan_m_b]

Ryan, the reason that our hero needs to build (or buy) a sort of space suit is that he and his family weren't selected as residents of the city. He buys property close to one of the cities and digs a hole and somehow (details to be worked out, but probably involving a generator and fuel hoarding plus canned food) manages to keep his family alive for six months or so, with a plan to trek to the underground city and show his pitiful entourage to the city's external cameras (originally necessary to prepare for the possibility of non-residents storming the barricades) in hopes that they need his particular skill set or let them in out of Christian charity.

Out of curiosity can you think of a believable reason they would not get let in? I'm struggling...

 

[HallsofIvy]

I can't speak for Russia but all space suits used in the United States were made by civilians! Perhaps you mean something else?

 

[CCWilson]

Out of curiosity can you think of a believable reason they would not get let in? I'm struggling...

With five years or so warning, there would be a limit on how many underground cities could be built. So only a portion of the total population could be supported by the infrastructure. A lot of people would try to gain admission to the cities once the Earth was no longer in the solar system and the cold started to get severe. Initially the cities simply couldn't afford to let in people who didn't have a ticket, or the chances for survival for everybody would be diminished. At first they would turn everyone away who begged to get in, heart wrenching as it would be. But after a few months, they would no longer be in danger of being overrun, so those who had survived and were able to get to the bunker would probably be welcomed.

 

[CCWilson]

I can't speak for Russia but all space suits used in the United States were made by civilians! Perhaps you mean something else?

What I was asking was whether an individual person not associated with an engineering firm would be able to build outfits for his family that would allow them to walk around and breathe for several hours at temperatures well below -100 C.

 

[Ryan_m_b]

That's pretty much what I was thinking, given that this is very likely one of the only few solo survivalists there's little danger in letting them in.

How flexible are you on the time scale by the way? 5 years seems nowhere near enough. That might be just about enough time to work out what options should be researched but given the huge amount of R&D required still I don't see any chance of completion within decades.

 

[CCWilson]

The shorter the time frame, the more dramatic the situation, the fewer people who could be saved, the more concentrated the mental processes. It would be tight, but the mechanical construction of the underground cities would be relatively straightforward, and the hydroponic farms would draw on existing experience. There has been enough research on biospheric living and terraforming that I think the recycling of resources would be doable.

I'm not certain how much lead time an approaching black hole would give us in reality. I suspect that we would notice some deviations in the locations of objects in the Kuiper Belt as it passed through, which would put us in the general five year range. I don't know whether we would notice its passing through the Oort Cloud. I definitely didn't want warnings on the order of hundreds of years, which would be the case with a rogue star heading our way.

 

[skeptic2]

If I remember correctly the first high altitude suits and perhaps spacesuits were not pressurized. They were kind of like super spandex that applied pressure to the arms, legs and torso. The reason is, that pressurized spacesuits were difficult to make and still retain flexibility. Moving your arms or legs inside a pressurized spacesuit was kind of like bending a long balloon.

 

[Ryan_m_b]

Only time for a quick post but 1) hurrying cities seems pointless and a massive waste of resources. Just build sealed ones on the surface capable of taking the weight of frozen atmosphere. 2) you need to seriously look into closed ecological systems. There has never been a successful one and we don't have a good understanding of how to do it. It's not just a case of growing food! We require an ecology for everything from the development of our immune systems (growing up in a bubble will lead to severe allergies and probably death) to the processing of soil for nutrients.

 

[Ryan_m_b]

Also whilst I appreciate the need for tension a line must be walked between tension and believability (aside from the technological hurdles the social disruption is likely to be a massive headache for starting such a project). For inspiration I'd recommend the short story Meela's flowers by al Reynolds; essentially a society equivalent in technology to our 1930s is told that they have 70 years before their sun is destroyed. The main character (from a more advanced society) prints of a range of technical documents from his ship and gives them to them so that they can build their technology base and industry to the point where they can evacuate the planet. The protagonist then spends the story in and out of stasis skipping forwards a few decades as a time to track process. The tension is high throughout and their development (along with their hurdles) very believable.

 

[CCWilson]

If a black hole were discovered flying toward the Earth and was predicted to arrive in five years - a scenario which I believe to be scientifically plausible, though - whew! - unlikely, the question is what we residents of planet Earth would do. Obviously we'd scramble to figure out the best approach to keep homo sapiens and all other surface life from going extinct. We might not have a perfect answer, we might not be able to build a perfect closed ecosystem - but we wouldn't have a choice. Yes, there would be social disruptions, but those can be good fiction material.

I don't believe that allergies would be a big problem, because the cities would be fairly large and well populated. Plenty of allergens floating around to exercise the immune system.

I agree that structures could and would be built above ground, but underground would provide better insulation and would be easier to protect against meteorites when the atmosphere is gone after a few years. Seems to me that heavy equipment - bulldozers, backhoes, excavators - could dig large cities fairly quickly and efficiently compared to conventional aboveground construction. Sink posts, pour concrete, lay beams and joists, build roofs, cover with soil, and you'd have an enormous interior space within which you could construct streets, apartments, shops, hospitals, theaters and so on, as well as hydroponic farms, livestock barns, science and engineering research labs, and manufacturing facilities.

Keep those objections coming. I want the story to be scientifically credible, and I certainly haven't thought of all possible complications. By the way, I will look for that Meela's Flowers short story you recommended and hope to learn something from it. I will point out, however, that an approaching black hole is somewhat more believable than an advanced extraterrestrial society warning us that they plan to destroy the sun.

 

[Ryan_m_b]

Still short on time but I still really think you need to push the time scale further. Many tasks simply cannot be shortened by throwing more money or manpower at them. Simple illustration; 9 women cannot make a baby in 1 month. Building closed ecosystems that will work will take decades of study to observe the long term effects of isolation which will allow the next generation of experiments to try something new.

Regarding social upheaval I'm beginning to think this is more of a problem than the R&D. Human beings are not rational actors. It seems very unbelievable that in such a short amount of time the majority of the world will accept their fate and knuckle down to one purpose: saving a small amount of people. It's a nice idea but we're not like that. It's not that our species lacks the capacity for good but just look into phenomena like the tragedy of the commons. People will be motivated to try and help their loved ones more than some people they have never met.

Perhaps you could work that into the story; it would require a lot of work but the selection profess could include data mining social network sites so that when people get a letter that they aren't picked they have at least one friend or acquaintance that is. Then they are manipulated to be motivated by the thought of saving that friend.

 

[onomatomanic]

^ The standard plot device for adressing the humans-are-selfish issue is to allocate at least a fraction of the available places in the "lifeboat" by last-minute lottery. As long as the lifeboat in question offers significantly better survival chances than anything that could be accomplished individually, it seems very plausible that even a vanishingly small chance at winning that lottery would provide sufficient motivation for people to contribute to building it.

 

[CCWilson]

Ono, a lottery is among my plans for dying Earth. Probably half the population in the cities will be technical people - scientists, doctors, engineers, electronic technicians, hydroponic farmers, and so on - a labor force to keep civilization going. The remainder will be filled by a lottery - maybe a one in a hundred chance of being picked. The exclusion criteria would be tricky - mental illness or antisocial history or age over 40 might disqualify, since the future of our species must take priority. Would the families of each winner go along? That would reduce the chances to one in three hundred or so. The remainder of the population would get advice from the government for surviving as long as possible or ending their lives if desired.

 

[onomatomanic]

I'm not sure excluding the old makes any sense in this case.

It does if the impending disaster is only expected to last a time much shorter than a human lifetime, because then you want as many persons (women, really) of childbearing age as possible when things go back to normal, allowing you to repopulate the planet more rapidly. Unless I misunderstood the premise, though, this is for the long haul. The age distribution is going to normalize relatively soon anyway, so you might as well start out that way.

Or, to put it in even stronger terms, the space in the cities is obviously limited. If you only take young people, nobody is going to die for the first generation or so. So you'd either have to start with a half-empty city to accommodate the children being born in the interim, or start with a full city and ensure that no children will be born for a while. Neither seems like a appealing scenario.

 

[Ryan_m_b]

Space in the cities doesn't have to be limited after everyone else has died off. They can expand by digging and building

 

[onomatomanic]

Oh, true. I guess my mentally equating them with lifeboats wasn't really appropriate after all, because of that aspect. Thanks for pointing that out!

 

[CCWilson]

I'm not sure exactly where the optimal age cutoff would be, but the older the citizenry, the more medical problems. Significant disabilities would also disqualify. Political correctness has to go out the door when the survival of mankind is at stake.

I myself would not make the cut. Glad it's just a story.

 

[onomatomanic]

What about later on? There could be measures like enforced abortion if a fetus is showing any signs of abnormal development, and no medical care for those too old to productively contribute any longer, and so on. If the agenda is survival at any cost, those decisions should be made solely on the basis of material benefit versus impact on morale, with no ethical considerations directly taken into account. Examining these issues gives the story depth, but at some point can make it too "dark and edgy" to provide enjoyable escapism any longer.

ps: This is not "political correctness", though. That's a fad, whereas these are real ethical issues.

 

[Ryan_m_b]

I'm struggling with seeing this society to be honest. The majority of humans aren't purely rational and won't stand for what is essentially a totalitarian society in order for some abstract ideology of "continuing the species". I really don't see why people would dedicate the remaining time they have left when they know that there is a slim chance that their family is going to survive (hence my proposal earlier that the selection process needs to be made so that everyone knows at least one person who will be saved [ideally more] to make it personal and identifiable).

As for age and moderate disability I don't think it's too much of a problem. You're going to need very good social medicine anyway, it really isn't going to be much of an expenditure to keep the elderly and sick alive and aside from humanitarian considerations these people will likely have skills you need. Becoming an expert in a skilled field takes decades of training, you could try to include a cut off below retirement but especially for scientific fields you're going to be loosing a hell of a lot of tacit knowledge that your high tech survival cities are going to need.

Also political correctness is not a fad, though the term gets bandied about and abused quite a lot it will be an extremely important consideration in this scenario. Social tension in a closed environment will be something that is paramount to diffuse. A riot in a modern city IRL can lead to the death of hundreds, significant damage to infrastructure and cost a lot to repair. A riot in a city where the very ecosystem is in a tight balance and breaching the wall could kill thousands is not something you want. Standard cliche is to go overboard in the totalitarianism but that's just going to delay the problem and give you one heck of a revolution when the lid gets blown off the boiler.

 

[CCWilson]

The moral issues in this scenario are thorny, all right. Let's take the following individuals - a man in jail for assault, an undocumented worker, a mentally handicapped child, a thirty year old obese woman with diabetes and heart disease, a victim of cerebral palsy, and an eighty year old man. In our current politically correct society, we feel morally bound to help them all. We want to treat the first two fairly, at minimum, and the last four will be given all necessary government assistance. But if species survival is at stake, we must make difficult and repugnant decisions, and those six people should not become residents of the underground cities.

In order to limit public outrage, there will be a national referendum before the lottery in which the people will have a say as to how residents will be selected and what categories of individuals will be included in the drawing and how many political figures will get automatic selection to facilitate organizing life underground.

Of course every country will set its own rules and build its own shelters, and those with more autocratic regimes will not be concerned with fairness and therefore will be at huge risk of revolution by those with nothing to lose.

 

[onomatomanic]

The majority of humans aren't purely rational and won't stand for what is essentially a totalitarian society in order for some abstract ideology of "continuing the species".

I partly agree. If what people see is that an authoritarian government is murdering people they love and like, the impact on morale would be disastrous. However, if the situation is one in which people for the most part believe that such measures are necessary for their own survival, humans can also be remarkably callous.

t really isn't going to be much of an expenditure to keep the elderly and sick alive [...]

That depends entirely on what you mean by "keep alive". It's one thing to not letting an 80-year-old starve just because they can't work any longer, it's quite another to go to great lengths to try an cure them if they develop cancer.

Also political correctness is not a fad, though the term gets bandied about and abused quite a lot [...]

Maybe we're using the term differently. I understand "http://www.etymonline.com/index.php?term=politically+correct&allowed_in_frame=0" to be the fairly recent notion that anything that could possibly be perceived as offensive ought to be avoided at all costs. People don't riot because somebody offended them, they riot because they have concrete grievances.

 

[onomatomanic]

[...] an undocumented worker [...]

Why is an undocumented worker less likely to contribute to the survival of the species than a documented worker?

[...] those six people should not become residents of the underground cities.

What's the timeframe covered by your plot? I was assuming that it continues well into the future of the cataclysm, but you keep only talking about the initial stages, so maybe that's another unfounded assumption of mine?

 

[CCWilson]

Why is an undocumented worker less likely to contribute to the survival of the species than a documented worker?j

No country is going to include in its limited survival population someone who's in the country illegally. Certainly the US wouldn't, even aside from the practical fact that you've got to be on the books in order to be in the lottery.

What's the timeframe covered by your plot? I was assuming that it continues well into the future of the cataclysm, but you keep only talking about the initial stages, so maybe that's another unfounded assumption of mine?

Oh, it's long term, as in permanent. The Sun is gone forever. Of course anyone born in the bunker with a disability or reaching a ripe old age would be treated compassionately, but common sense says you stock your city initially with able-bodied, productive, healthy, good citizen types.

 

[onomatomanic]

No country is going to include in its limited survival population someone who's in the country illegally.

Pragmatically, that makes sense, but it makes the moral high-ground of any subsequent "the survival of the species requires it" justifications rather shaky, don't you think? That would be my perspective in such a situation, anyway.

 

[sshai45]

I'm not sure exactly where the optimal age cutoff would be, but the older the citizenry, the more medical problems. Significant disabilities would also disqualify. Political correctness has to go out the door when the survival of mankind is at stake.

I myself would not make the cut. Glad it's just a story.

So is it for some kind of "eugenics"-like "improve the gene pool while we're at it" kind of thing (pseudoscientific garbage), or more like "we just don't have the resources to care for the disabled & old, and crooks would be an obvious threat to the integrity of the society"? I.e. you want your society to *work* first of all, and with things this tight, there just isn't any way to be *able* to do the caring without jeopardizing that. E.g. medicine is going to be limited, so then you don't want to bring along medical liabilities.

And what else is required for them to "make the cut", beyond being not too old, not disabled, and not a crook or illegal immigrant?

 

[CCWilson]

That should be obvious; the only consideration is what gives us the best shot at keeping homo sapiens alive for long enough that the new generations can work out the kinks in closed ecological systems. As I said above, around half the population would be technicians - doctors, dentists, veterinarians, engineers, electricians, plumbers, scientists, medical technicians, computer and electronics guys, hydroponic farmers, manufacturing experts, and so on. Once those essential positions are filled, a lottery will be held among able bodied citizens of good mental and physical health and at least decent moral character between say 15 years and 45 years of age. In order to motivate those who work to design and build the underground cities, they will be given extra tickets to increase their likelihood of having their numbers drawn. Those selected would probably be allowed to bring in their family members who meet the criteria. There will be a national referendum where the public can choose the standards to be included in the lottery, and until that vote I can't say for sure what the final criteria will be.

 

[Ryan_m_b]

I don't think this lottery system will be that viable. You're going to need an optimum amount of every kind of skilled worker (as well as unskilled) to keep a technogivally advanced society going. Leaving it to chance won't be good enough.

As for medicine being limited I really don't see why. Just think of the scale of the industry this society is going to possess. You are proposing that they build closed underground cities for millions in a handful of years (something I think your readers will find unbelievable). Any society with that kind of industry isn't going to be short on medical devices or medicines.

 

[CCWilson]

If my scenario came to pass - if tomorrow we were told that a black hole or neutron star was approaching and would throw us out of orbit - what would we - specifically, our governments - do? I suspect it would be something like what I'm suggesting, since there would be no alternative. I will admit that I grossly misstated the lottery odds earlier. I envision building underground cities to house somewhere between 250,000 and 500,000 people in perhaps 20 sites in the US, but that figure is still being worked out by my crack team of architects, biospheric scientists, engineers, climatologists, and psychiatrists.

The concept of a lottery is to give all Americans at least a chance at surviving. Seems only fair. The last thing you'd want is for the public to think that the resources of the country are going to the benefit of a privileged elite.

 

[Ryan_m_b]

If my scenario came to pass - if tomorrow we were told that a black hole or neutron star was approaching and would throw us out of orbit - what would we - specifically, our governments - do?

Panic. Then spend years organising international conventions where they bring many of the worlds top experts in all fields. Honestly it's going to take a long time just to decide where to start. This isn't something that one country is going to pull off, even an economic giant like the US, China etc. Reason being that the world economy is going to have to be significantly put into this endeavour: think of all the factories in the far east, mines in Africa etc etc.

A really tricky thing to handle will be getting countries to agree on what method to take versus how they want to contribute their resources. That and deciding how much goes to what country. Imagine a scenario where smaller nations with less resources have nothing to contribute and aren't chosen as a site for a city. What are the people going to do? Probably hike to a neighbouring country as refugees (good luck building that city with hundreds of thousands of occupiers, you could turn the military on them but that could spark an international incident. Humans en mass aren't coldly logical, even if their lives are at stake).

I imagine that different cities would be built with different methods in an effort to appease this political problem and ensure a chance that some survive.

I suspect it would be something like what I'm suggesting, since there would be no alternative. I will admit that I grossly misstated the lottery odds earlier. I envision building underground cities to house somewhere between 250,000 and 500,000 people in perhaps 20 sites in the US, but that figure is still being worked out by my crack team of architects, biospheric scientists, engineers, climatologists, and psychiatrists.

I'd revise that number up to at least a million, though realistically it's likely to be more than ten million.

The concept of a lottery is to give all Americans at least a chance at surviving. Seems only fair. The last thing you'd want is for the public to think that the resources of the country are going to the benefit of a privileged elite.

I advise you start thinking of this internationally, one nation isn't going to do this alone. Certainly not if you're sticking to this 5-year-plan. Whilst a lifeboat lottery is a common trope it really doesn't seem likely to work. Are tickets going to go to families and close friends? If not you're not it doesn't sound like a system people will vote for but if so it limits who can win. My advice would be as I posted above. Think outside the box and chose a system designed so that everyone personally knows one or two people selected to survive, by making it personal most people have a very concrete reason to work and sacrifice: for whoever that friend is, rather than the abstract chance that they might win a ticket that will separate them from their friends and loved ones.