Jump to content

10 years to evacuate Earth


Recommended Posts

5 hours ago, Dragon01 said:

With unlimited funding and no politics to interfere? Russia will build the world's biggest nuke, US will build the world's biggest launch vehicle (might use an Orion drive, a bit of fallout is nothing for humanity's survival), China will provide materials for all this, Europe and African countries will build an equatorial launch site in an unpopulated part of Africa, and we'll all send the nuke to meet whatever's coming for the Earth at a safe distance. :) 

In the present day, we're far better equipped for blowing up Earth-sized objects than for evacuating them. I'd say, if countries of the world banded together like that, it'd take more than flying space rock to stop us.

Yep, exactly.

There is no theoretical upper limit to the size of a multistage thermonuclear device. With just the US, Russia, and China working together we could easily build a dozen gigaton nukes. Throw in nuclear engineers from Israel, France, and the UK and we can probably double our output.

Ten years is a long time, even when you're dealing with interstellar velocities. I would say we could launch the first interceptor in under 24 months and send backup interceptors every six months thereafter.

Ten years is not enough time to develop off-world closed-loop life support for any significant segment of the human race, however.

On the other hand, if you specify that you already HAVE closed-loop life support available (moon or Mars base, for example), the hypo becomes much more interesting.

Link to post
Share on other sites

Nobody would build the launch site in the unpopulated part of Africa, because of logistic arm? leg? tail?

It would be built as close to the industrial base as possible. If necessary - with the population removal to any other place.

At least because they would have just ten years.

Unlikely China has some unique resources which others lack, and US could use the largest nuke as well.
Anyway, the nukes are being built by other people than rockets.

So, I would expect a close cooperation between US/EU/RF/JP and maybe some interaction with China and its own program.

Link to post
Share on other sites

If we're not limited by money, logistics can initially be handled by aircraft, and infrastructure build from scratch relatively quickly by military engineers. Equatorial launch site would be used to get a boost in dV, and it would have to be an unpopulated part, because an Orion-powered launch would create fallout within 80km of the site. 

Of course, depending on the size of the nuke, a stripped down BFR+Starship could be used. Tsar Bomba was just 27T, a nuke using full lifting capacity of an expandable Starship+BFR to get it to LEO, then another Starship derivative as a tug to aim it at the target, would be enough for all but the largest bodies. 

Link to post
Share on other sites

When you have 10 years till the total annihilation it's more preferrable to bring 1000 tonnes by trains than 10 tonnes by plane, and repeat this daily.

No known heavy launch sites are placed on the equator, and still work for decades.

A 80 km radius zone is nothing if compare this to the alternative.

Also, they always have Eurasian deserts and North to build it far from the most populated areas.

Novaya Zemlya, Central Asia, US deserts - all of them are by orders of magnitude better than Africa, even with some delta-V decreasing.

Link to post
Share on other sites

...or you could bring 100000 tonnes by ship (cargo ports are all over African coast), and build a railroad extension (because they do have railroads already) into an uninhabited area. Military can lay the tracks in weeks. If you want to maximize dV and have unlimited budget, that's the way to go. The warhead needed to move a celestial body that would otherwise warrant evacuating the Earth, and the chemical rocket module to aim it, would be quite large and likely need the extra dV.

With the Orion, and then the launch site needs to be placed away from any permanent infrastructure, because it launches by setting of a nuke. So we need to make sure the only thing that gets nuked is wilderness and temporary structures. Of all places on Earth that still have that much empty space, Africa is the closest to equator.

Edited by Guest
Link to post
Share on other sites
53 minutes ago, Dragon01 said:

If we're not limited by money, logistics can initially be handled by aircraft, and infrastructure build from scratch relatively quickly by military engineers. Equatorial launch site would be used to get a boost in dV, and it would have to be an unpopulated part, because an Orion-powered launch would create fallout within 80km of the site. 

Of course, depending on the size of the nuke, a stripped down BFR+Starship could be used. Tsar Bomba was just 27T, a nuke using full lifting capacity of an expandable Starship+BFR to get it to LEO, then another Starship derivative as a tug to aim it at the target, would be enough for all but the largest bodies. 

Tsar Bomba and the B41 were technically 4.5-stage devices: (boosted) fission primary for the first 1.5 stages, fusion secondary, fusion tertiary, and optional fission(able) tamper.

Both the two-stage W56 (MUCH smaller) and the B41 had a yield to weight ratio of approximately 5 kt/kg, although declassified documents suggest even potentially higher (and cleaner) yields. But whether you build a multistage device or just clustered smaller warheads, using that yield to weight ratio suggests you could potentially fit up to one gigaton TNT yield equivalent on a SINGLE expendable Starship.

Link to post
Share on other sites

i think you would be hard pressed to save the species, let alone every human. 10 years isnt enough time to set up a stable off world colony. bringing all the humans is just going to jeopardize the colony, you need food, water and air for everyone, and it only takes one being in short supply to have disastrous consequences. not just from the inevitable running out, but the panic caused by same. anyone declared a waste of space could easily find themselves butchered for meat, along with mass suicides and people killing each other over scraps simply because they don't know how to survive on mars or whatever.

Link to post
Share on other sites
19 minutes ago, Nuke said:

i think you would be hard pressed to save the species, let alone every human. 10 years isnt enough time to set up a stable off world colony. bringing all the humans is just going to jeopardize the colony, you need food, water and air for everyone, and it only takes one being in short supply to have disastrous consequences. not just from the inevitable running out, but the panic caused by same. anyone declared a waste of space could easily find themselves butchered for meat, along with mass suicides and people killing each other over scraps simply because they don't know how to survive on mars or whatever.

If you want to make it an interesting hypo, then say something like this:

"Assume the existence of stable, self-supporting bases on both the moon and Mars, capable of accepting the majority of human life between the two of them. Assume further that you are restricted to current technology in actually getting humans to the off-world bases. How do you do it in ten years?"

Because building a stable off-world colony is the work of a century, not a decade.

Link to post
Share on other sites
1 hour ago, sevenperforce said:

Both the two-stage W56 (MUCH smaller) and the B41 had a yield to weight ratio of approximately 5 kt/kg, although declassified documents suggest even potentially higher (and cleaner) yields. But whether you build a multistage device or just clustered smaller warheads, using that yield to weight ratio suggests you could potentially fit up to one gigaton TNT yield equivalent on a SINGLE expendable Starship.

If a gigaton is all it takes, sure, but if you want an impact that Earth wouldn't survive in a habitable state, we're talking a large planetoid. Blowing that up might take a lot more than 1GT. If that's all it took, then any of the major nuclear powers could do it alone, given 10 years and the others not objecting to them building, you know, a gigantic nuke. Building a one-off rocket that would match Starship in expandable performance is certainly well within capabilities of both China and Russia. It'd be larger and more expensive, but they both have engines sufficiently powerful for the task.

Edited by Guest
Link to post
Share on other sites

I was wondering how this would translate into a KSP challenge.

I mean, even in career, ten years is a long enough time to send and build crazy excrements in LKO and fil it up with tourists. And maybe we do not want to play the tedious part of running a space travel agency which basically takes people of KSC and send them to LKO for transfer aboard an ark or something that will go somewhere (I mean, refuelling run are tedious enough, sending a thousand or more kerbal in space will probably be boring), but maybe 2 years to get as many kerbals as you can in some habitable structure above the Mun orbit (just to not have everything sitting in 75km orbit waiting for the destruction of Kerbin at very close proximity. Even if it would be very kerbal).

No need to fly each runs, but is tehre a way to make it a playable ad interesting challenge ? in Stock and/or with mods ? Anyone interested to do it (worst case will be I'll give it a shot anyway :p)

Link to post
Share on other sites
3 minutes ago, Dragon01 said:

If a gigaton is all it takes, sure, but if you want an impact that Earth wouldn't survive in a habitable state, we're talking a large planetoid. Blowing that up might take a lot more than 1GT. If that's all it took, then any of the major nuclear powers could do it alone, given 10 years and the others not objecting to them building, you know, a gigantic nuke. Building a one-off rocket that would match Starship in expandable performance is certainly well within capabilities of both China and Russia. It'd be larger and more expensive, but they both have engines sufficiently powerful for the task.

Oh, blowing it up would be out of the question. The goal is to nudge it out of the impact zone. 

The hypo specified an interstellar object. Not sure how we'd have ten years lead time for something like that, but if we did, we're talking about rather high velocities. The Chicxulub impactor did enough damage to render the Earth uninhabitable for humans as we exist today and it was less than 80 km in diameter with an impact velocity of around 20 km/s. An interstellar impactor would have an impact velocity of easily up to 50 km/s or higher, meaning that it could mass only 1/4 the size of the Chicxulub impactor and delivery the same-size punch. Definitely not a large planetoid. 

Link to post
Share on other sites

Let's put it another way: we need something large enough to require the effort of the whole humanity. If it was 1/4th the size of the Chicxululb impactor (disregarding that a faster meteor would lose a lot more mass and energy in the upper atmosphere), it could be deflected by smashing a good-sized piece of scrap into it, North Korea could probably do that, if they figured out how to aim it in terminal phase. It'd be going at 50km/s, give the spent Uhna-X upper stage a 10km/s from escaping Earth, and you've got a KKV with a relative velocity of 60km/s. That'd suffice for turning an interstellar rock of that size into an expanding pile of gravel. It'd be quite small, so the biggest problem would be actually hitting it. It needs to be big and fast enough so that the biggest question wouldn't be which nation gets to do a free nuclear test in deep space. :) 

Link to post
Share on other sites

Interesting idea, but I see no way this could happen in ten, twenty, or maybe thirty years at present. In the future, we might even be able to get more than a couple hundred people off Earth.

If money or ecological damage aren't relevant, then maybe we build huge fleets of open-cycle nuclear liquid-core rockets and launch over the ocean; or perhaps relocate the population of equatorial Africa or South America and launch there? These would need to be mass-produced, though, which means a lot of nuclear material has to be mined.

As for where to put the people, we could haul a bunch of asteroids to lunar orbit and convert them into colonies. But none of this looks like it actually could move billions of people into space in just ten years. Would there be billions of people left on earth after an announcement of apocalyptic doom? Probably not; everyone would go mad.

I like the idea of intercepting the impactor better.

Link to post
Share on other sites
2 hours ago, Dragon01 said:

or you could bring 100000 tonnes by ship

then it's much faster to send it to Novaya Zemlya.

And even faster to skip the ship phase and deliver the cargo by trains right to the construction site rather than first to the ship, then to the site.

***

Also Africa is not a desert. It's overpopulated. The deserts are just somewhere, like everywhere.

Edited by kerbiloid
Link to post
Share on other sites

Well, the question is how many people would you save ? And how ?

I agree that there might be some limitation on how many fissile materials we can found, so mass Orion'ing our way out might not be doable easily, there might be a limit (I have no idea if uranium and/or thorium are rare materials or not).

And please, leave Africa alone. Or take them with you. There's already equatorial launch sites in remote-ish area (like Kourou, French Guyana. Ok population mangament in the jungle is near impossible to do, but still), but I think that if you want to evacuate a lot of people, you need to shorten the time of travel from where they live to the space center.

Or assume that most of the people you'll evacuate are people already living near the launch sites. I see no issue with turning Central Park into a mass evacuation center for instance. Yes, you'll have to work some orbital mechanics at some point, but having ships jumping from plane to plane to get all the evacuee on a better intercept course with the closest ark is something manageable. It's like flight control but for space. Plus were already doing it (with unmanned satellites, granted). So I really don't think that you want or need to be that far away from your home.

Ok, if your nuking your way out, you might want to have a no man's land around your launch center, but that should be like what, one hundred km radius ? People are going to take some Sivert anyway while they'll be in space so...

The getting the people up there is not really the hardest part of the plan, and you can probably spend your last year or two doing just that. Meaning that you need to have something to host them starting year 8. Probably a bit before, even if it's not complete. An habitat seeded with population and enough engineering tutoring can probably grow the habs to host more people, to grow the habs even further. That's skills and community building. We're good at that as a species. I do not think you really need to screen people before hand, just give the tools and training.

Maybe the first hardcore engineer who will have to live in cramped space doing the seeding would need to be screened somehow, but with a good enough education system that should not really be a requirement. Sure the work is harder, but the incentive is you'll be out of danger sooner, that should help kickstarting volunteers. And you need a lot of people. You need cooks to arrange for food from nutritious paste. You need social workers to help settle with things. You need designers which will try to pack more functions and more elegance in objects. You need arc wielder and drone operators. You basically need a lot of people to get that ark done.

Sending people in space is easy. Training them is easy. motivating them and having them coordinates is ... a bit harder, but it's easier than we can think of.

Really, the issue, for me, is the bootstrapping of things. The first seeds. What do you need to send up there first to host your first crew of habitats and community builders ? Yu'll still have Earth for ten years, so you can run supply run until biosphere are started up.

And you need multiple seeds too. In case some of them go bad. Also it allows to have more people working on growing living space at the same time. You'll connect the habs later on. Or not. But start a lot of projects, iterate and share the design, send regular people up there do the building, and gives them skills to do it.

Resources might be an issue though. But then you do not rely on a single space center. Or ten of them. Convert any airport into a space port, and every planes into a space fairing thing, You do not need planes anyway, everything you're building is sent up there. Convert the oceans into hydrolox, you'll have enough rocket fuel, batteries and electronics requires a lot of rare earth materials, but we're currently stock piling them in densely populated neighborhood where those rare earth are left to kills anyone living nearby.

That would be my plan

(After a long bike ride, my head got cleaner)

Link to post
Share on other sites
3 hours ago, sevenperforce said:

If you want to make it an interesting hypo, then say something like this:

"Assume the existence of stable, self-supporting bases on both the moon and Mars, capable of accepting the majority of human life between the two of them. Assume further that you are restricted to current technology in actually getting humans to the off-world bases. How do you do it in ten years?"

Because building a stable off-world colony is the work of a century, not a decade.

You're right that building a self supporting off-world bases is the real challenge. The question is, can this be achieved in 10 years? I doubt it.

Your hypo is indeed interesting but it is inconsistent. You assume gigantic collonies on the Moon and Mars but restrict to current technology. Such collonies are not possible with current technology.

Link to post
Share on other sites
3 hours ago, sevenperforce said:

If you want to make it an interesting hypo, then say something like this:

"Assume the existence of stable, self-supporting bases on both the moon and Mars, capable of accepting the majority of human life between the two of them. Assume further that you are restricted to current technology in actually getting humans to the off-world bases. How do you do it in ten years?"

Because building a stable off-world colony is the work of a century, not a decade.


So. Much. This.

It's also why I laugh uproariously at the fanbois who go about "getting off this rock so we can survive an extinction level event!"  Getting off this rock is the easy part.  Surviving Thriving after a complete loss of support from Earth (as opposed to merely prolonging the agony) - that's the hard part.   But they never talk about working on that part.  Just the easy, sexy parts.

Link to post
Share on other sites

Seeing as we're not even off this rock yet in any meaningful sense, of course they're talking about the "easy" part. We might start worrying about the rest when we get that done. There's no use talking about running before learning to walk.

Link to post
Share on other sites

Doing the math, we would need to launch ~22 people into space every second for the entire ten years, or ~80000 people per hour. If we waited till the last two years, it would be 111 people per second, or 400,000 people per hour. 

If our standard launcher can carry an ambitious number of 1000 people, then it has to fly seven million manned missions, or 80 launches an hour over ten years. Clearly we need a reusable vehicle.:lol:

And that's just the people...

Does anyone else think this qualifies for "non-trivial engineering problem" status?

Edited by SOXBLOX
Link to post
Share on other sites
8 hours ago, SOXBLOX said:

Doing the math, we would need to launch ~22 people into space every second for the entire ten years, or ~80000 people per hour. If we waited till the last two years, it would be 111 people per second, or 400,000 people per hour. 

If our standard launcher can carry an ambitious number of 1000 people, then it has to fly seven million manned missions, or 80 launches an hour over ten years. Clearly we need a reusable vehicle.:lol:

And that's just the people...

Does anyone else think this qualifies for "non-trivial engineering problem" status?

Well, the Federal Aviation Authority says they move 2.9 millions passengers per days. https://www.faa.gov/air_traffic/by_the_numbers/ On 45 000 daily flights. And that's for the US only, which is roughly 330 millions inhabitants. In a little bit under 113 days, the FAA can fly each and every american once.

It also gives us an average of 65 people per flight. Which is a little bit under the planned capabilities of a Starship. The USA currently already have the infrastructure to welcome, host, secure and have all of its population waiting in a time frame of three month. It also have the infrastructural capabilities of tracking all the necessary airship, to manage take off and landing and such.

Granted, a plane is not Starship, but if we can have as many Starship as there are plane, and launch them from airports (which would require some adaptation, especially fuel wise, but you've got ten years for that), the US can sen dits entire population in a little bit less than 3 month, without building really huge infrastructure. You can probably even recycle planes to make more Starships, you won't need them.

Sure there is engineering involved, but the logistics is something we already do on a daily basis (we need to track spaceship instead of planes, but besides that flight control should not be that tough to adapt). And yes, there's aprt of the world that have not developed that much of air traffic, but again, with mass production, funding and technology sharing, that's something that can be worked out in the five or six years that will follow.

The hard part is not really flying that many spaceship. It would be fueling them (and well, since you do not care about preserving the Earth anymore, that should make it easier). And docking them to something to transfer people to in a permanent way.

Link to post
Share on other sites
19 hours ago, EveMaster said:

You're right that building a self supporting off-world bases is the real challenge. The question is, can this be achieved in 10 years? I doubt it.

Your hypo is indeed interesting but it is inconsistent. You assume gigantic collonies on the Moon and Mars but restrict to current technology. Such collonies are not possible with current technology.

Right, it's unrealistic. We will not get colonies on the moon or Mars without Starship or a similar vehicle operating at high capacity. But it's much more realistic than supposing we could get anywhere close to constructing those colonies within ten years.

16 hours ago, SOXBLOX said:

If our standard launcher can carry an ambitious number of 1000 people, then it has to fly seven million manned missions, or 80 launches an hour over ten years. Clearly we need a reusable vehicle.:lol:

And that's just the people...

Does anyone else think this qualifies for "non-trivial engineering problem" status?

It's still the easy part.

Link to post
Share on other sites
This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...