Are there fundamental limits to mechanical reliability?
Towards the end the article talks about how the initial startup period for the colony will be the hardest.
If the startup process were automated, no one would be at risk. Send the first colonists once the tomatoes are ripe. But is there a practical limit on how much can be automated, remotely?
Are we approaching (or have we already passed?) a singularity in the human race based on our ability to product fault tolerant ball race bearings and machine screws that never snap?
> Are we approaching (or have we already passed?) a singularity in the human race based on our ability to product fault tolerant ball race bearings and machine screws that never snap?
I guess not [0]. I don't know of any artificial autonomous self-diagnosing and self-repairing mechanism either. The current approach is to hope that either nothing breaks or that built-in redundancy is sufficient to compensate for mechanical failures.
Yup, and notice that the autonomous voyage was "interrupted by a small mechanical problem" and "no one on board to repair".
It doesn't take much to shut down mechanical devices.
The problem with the "machine screws that never snap" is that we are still dealing with physical materials - everything is a trade-off; we could spec a screw with 100x the strength of the max expected load instead of a standard 2.4x margin, but we've probably blown both the weight and dollar budgets, and/or merely shifted the failure point to another component. And this doesn't even count for disasters to the mission from unexpected events.
Seems that we'll need to get well into the realm of self-repair and self-replicating devices before such massive remote autonomous are reasonably feasible.
B. Sun is close, and huge objects like sun tend to clear their neighbourhood of small rocks. (There are comets coming your way, though.)
C. Even if something hits Mercury, there are no oceans, so zero risk of a tsunami wreaking havoc 1000 km from the original point of impact. This is one of the disadvantages of having a liquid ocean on our surface.
That said, asteroids are not the main problem. The radiation on the surface of Mercury would be a challenge. Humans wouldn't be able to work outside during Mercury day at all, unless we can construct much better protective suits. Even getting there would be a challenge, you would get a lot of exposure during the flight.
But Mercury is rich in minerals, so perhaps we can find something of value in mineable concentration there. And building a space elevator on Mercury should be possible with current materials.
You'd also need to get anything you mined on Mercury to where it's needed. Probably a lot further out in the solar system. That sounds like a lot of delta-v.
True, but when moving stuff away from the Sun, perhaps you could use solar sails. Pressure of solar radiation is significantly higher at Mercury's orbit than in proximity of the Earth, so solar sails should be more efficient there.
Cargo, unlike humans, can take its time on the way. In case of minerals, it likely won't be damaged by vacuum or radiation exposure. The only thing that really interests you is that it arrives on schedule.
Wait, that's not how gravitation cleaning works, sorry. The density of «stray» debris is approximately same as at Earth's but they are have v-squared energy. I'd say, not big deal for Mercury just as for Earth.
"us humans will consume the Earth's non-renewable energy and mineral resources almost completely within the next 50-100 years, severely reducing our discretionary income for costly activities such as space travel."
I know this is an old article. Perhaps written in the hype of peak-oil days or something like that.
Old, as in ~2019~ 2013.
It mentions four, not five mars rovers.
So its from before 30. Juli 2020.
It might have been writing during the fourth mission, so from 2004-2018 any date might be valid. But i would guess it is very new.
FYI, Kim Stanley Robinson's book '2312'[1] has a large chunk of the story set on Mercury - with a novel concept for the colony. (Small story spoilers in the link below)
Caution, the author is communist and it severely affects his social sci-fi imaginations, almost to revolting notch. That made me to ditch martian trilogy at ⅔ despite of absence of other sci-fi reading.
If you want an insurance policy against a large asteroid strike, then the best bet would still be on Earth - but perhaps deep under the ocean, or deep underground. The arguments for this project (and against) are largely the same (e.g. it's not likely to be economically viable because of trade).
"Air is for birds and gods. Ground is for people." -- unknown person, AD 1000
Why are we so shortsighted? The future is an incredibly long time. If self-sufficient human settlements on, say Mars, are out of the question with our current level of technology and are unlikely in the next few centuries, does that imply they'll be just as unlikely in 10,000 years? Will our descendants be so stupid they won't be able to solve new technology challenges?
Bad impression of announcer voice: Will humanity survive long enough to find out the answers to these questions and more? Tune in next time to find out! Same Bat-Time, Same Bat-Channel!
given that humans took less than 100 years to get powered flight, less than 50 yrs to get rocketry, i expect interplanetary colonization to not be in the too distant future...
I'ma have to see a viable colony on Earth's moon before I'ma able to even consider the possibility we have a snowball's chance in Hell of surviving someplace like Mars. Problem is… Can humanity survive itself long enough to even get a colony on the Moon?
Yes, well, that's the trouble with analogies - they are misleading. "After all, we broke the sound barrier, so breaking the light barrier is only a few years away!" I'm sure people made that argument. Just as they made the same false-generalizing in the early days of X-rays - imagining Vita-rays and superpower rays and so on.
You can do the same thing with digging. Well, we can dig 10m down, why not 100m? Why not 10000m? Why not all the way through? I mean it's easy physics to show you can move between any two points on a planet through an evacuated tunnel with no energy price, so why don't we do it? Is it because the downers like me don't think we have the materials to actually build the tunnels, and that we'd have to spend a great deal of energy to cool them because the Earth's core is really hot, and if only we'd shut our cynical traps the dreamers would get 'er done?
I blame science-fiction for really and truly warping our intuition of what is physically possible. A small moon base is certainly possible, but does that mean a sun base is possible? No. Cars revolutionized transportation, and phones communication. Does that mean teleportation is possible? No. Do insights about spacetime make time-travel possible? Except in the Ted Chaing sense (where time-travel has a lovely, inevitable symmetry to it), no. Chemistry - so we can create matter from nothing? No. Theoretical physicists play games with math - so free energy from vacuum? No.
But nanotechnology? Yes. AI? Yes. Full control over the genome? Yes. It's not that I think history is over, it's just that our stories are misleading about which branches of history we can travel. No ancient thinking person really ever doubted the earth was round (because there are easy experiments anyone can do), and they didn't think that heavier-than-air flight was impossible (because birds). It's true a few believed faster-than-sound travel was impossible, but I don't think that was ever a majority view (could be wrong on that, though).
Back to space. Space sucks. I don't want to live there. The Expanse was/is a great show, and it's certainly more realistic than most space-faring SF -- but it is still deep fantasy. The impact of living outside of gravity and outside of the magnetosphere is enormous and even with perfect medicine it would be uncomfortable because of the atmospheric constraints. The Epstein drive is fantasy. It is admittedly more plausible than most SF drives, but still non-physical. Of course, the alien stuff is pure fantasy.
Places like Mars suck even more than space, IMHO. Mars is a lifeless, cold rock without atmosphere or light, or proper gravity. I mean, Mars right now is still infinitely worse off for supporting life than Earth in the worst case, struck by a 20km asteroid. Or post-Yellowstone caldera. Another way to put it, Mars could take 100 meteor strikes like that and be no worse off. That's how bad it is. (There wouldn't even be much of a nuclear winter since there's no atmosphere to keep ejecta suspended. Although maybe if you strike it just right and with the right rocks you could give it an atmosphere of sorts?)
So, there is hope for exotic effects! Quantum phenomena at scale is basically magic. Black holes are quite mysterious! So is the origin of the universe - and I believe, contrary to most, that cosmological questions could very well have practical applications. "Metamaterials" (a kind of cousin to nanotech) can open up a lot of cool options for building things. And so on.
But yeah I wish people would give up the childish Star Trek/Star Wars fantasies about the possibilities of technology and embrace the reality of what we know. I too want FTL, teleportation and sexy humanoid aliens to seduce as much as the next guy, but despite the aesthetics its fantasy. And while shows like The Expanse seem more real, they still sneak in enough fantasy to invalidate it. (I do appreciate them not aband...
Here's a reason I think humans will embrace space habitats and colonizing other planets: we can't let go of the idea of infinite growth, and we want to preserve life and nature(and biodiversity). Those two facts are incompatible with each other if we remain only on earth.
So we'll build carbon-neutral space launch platforms. We'll figure out asteroid mining and space manufacturing. We'll grow beyond Earth because we will never, as a whole, accept death.
Thanks for taking the time to elaborate. I mostly agree with both this and your GP comment, and that's just it: I don't think we can at this point imagine how the future (tech) will look or what will be possible.
Any attempt is at best speculation and at worst a fantasy. As you said, extrapolation from current trends quickly gets us into unbelievable territory.
I'm definitely not a religious person, but I do have faith they (future humans) will figure something out, if there's any incentive (survival, profit, ... fun?) to do so - unless our species goes extint first.
That's also why I do believe things SpaceX and others are doing are important. Not because we'll have a colony on Mars in a few decades (I don't think we will). But if we don't even start trying, it'll be awfully long before we get anywhere.
I like politely disagreeing conversations - they are more productive! So, thanks.
I get your gist, but I don't agree. The analogy I think of in this case is ancient Greece - let's say Athens. Imagine a precocious boy who discovers he can walk on the ocean floor by fitting an inverted bowl over his head and breathing the trapped air there for a time. He continues to innovate, and attaches a hose. He makes discoveries!
Thrilled by his success, he pitches the idea of making an underwater map of the entire Mediterranean! The benefits would be vast, to all the sciences, and would make the sea safer to travel. All the problems can be solved: too deep? Longer hose! With enough ships, enough diving bells, and divers, there is nothing physically impossible about doing this.
But of course, it's not worth doing. Such a project could have consumed an entire economy indefinitely. To attempt it prematurely would have been folly - a folly we call pride. The Mediterranean Sea is not that big compared to other bodies of water on Earth, but it is still truly vast, effectively infinite, on a human scale. Even with modern equipment a full mapping of the Med is a truly daunting task.
SpaceX is doing excellent work changing the economics of delivering goods to orbit by a factor of 10x or 100x. But even so, we are still at the diving bell level - or even worse - when it comes to space exploration and colonization. I DO NOT believe it makes sense for us, the modern Athenians, to even start spending enormous sums mapping the Med with sailboats and diving bells.
The nature of the future seems obvious to me, but what I envision, I don't often see mentioned in these sorts of discussions.
The engineering people talk about won't get us to self-supporting colonies on other celestial bodies.
What will, someday, is re-engineering ourselves until we become the extraterrestrials we've failed to find in the rest of the solar system.
It's analogous to how life emerged from the water on Earth. Every cell in our bodies (I'm plagiarizing a little, but I don't recall what) carries a bit of primordial ocean with just the right saltiness, because we really are still sea creatures with built in life support. But at the same time, we aren't adapted to the open sea and can't go back.
Some day there will be creatures descended from us, maybe called human and maybe not, who have changes at the cellular level or lower to deal with the harsh environments on other planets. That carry their own atmosphere and ozone layer with them. And they probably will not be able to return to Earth.
The litmus test will be whether a place is survivable with stone-age technology. Otherwise it's only a matter of time until a colony is wiped out due to some unforeseen technology failure.
It's an interesting point. I don't think we can get away with just re-engineering ourselves, though - Life is effectively one big phenomena. We'd need to produce an entire ecosystem.
And to do that we could start with the smallest thing that could make a living on the moon. The moon is a good placeholder for "space" - and is arguably a lot kinder than most places. (If the OP is right about Mercury, then it would be somewhere between Earth and the Moon in terms of friendliness.)
Earth's moon is far more extreme than the most extreme life we know of could endure[1]. Look at that table of extremophiles - and recognize that the Moon is easily 10x worse than the worst environments.
There are only two resources available to potential life on the Moon: rocks and sunlight. There are indeed some interesting atomic elements in the rock[2], but you'll notice two elements not in the list: no hydrogen, no carbon. I don't see a feasible way to bioengineer the Rockeaters from "The Neverending Story" but even if you could you'd have to make sure they didn't need to breath or stay warm. And I'm pretty sure that such creatures would be closer to robots than biological life, anyway.
(Note that life in empty space is about as harsh as you can get - you have sunlight, but without mass you can't grow or reproduce, and without gravity you can't move effectively or sustainably. You are forced to lose mass with every movement. As you move away from a star you lose even sunlight, and it's not clear what you could do out there except cool down to ~4K in equilibrium with cosmic background radiation and hope that you warm up enough to come back to life someday.)
I definitely agree that gravity, some sort of ecosystem, probably some kind of atmosphere, and a source of heat are needed in any case.
The idea of "stone age" tech being enough to survive implies an ecosystem that maintains itself.
A rogue planet could have heat and water if it was reasonably large or part of a multiple body system with tides. C.f. Enceladus and Io. Then there's Titan.
We didn't know what electricity was 300 years ago. And the best way to get around was riding on the backs of other animals.
We're maybe 70 years away from being a multi planet species if technology keeps advancing at the same rate.
We just need better ways to get into space. If the Sabre program works out or we figure out fusion power we'll be ready to roll in 20.
Or we could figure out self replicating robots. Nature has been doing it a billion years so we already know it's possible.
Or, just create a robot species in our image to explore for us. And hope they keep their meaty parents around and happy
There's multiple paths for humans to get off the planet. Out of the solar system, maybe not. But it's damn hard to predict farther than 100 years into the future
>Or, just create a robot species in our image to explore for us. And hope they keep their meaty parents around and happy
Indeed, I think this is the most plausible scenario. And I think a robot civilization would want to keep Earth living and breathing for reasons other than sentiment. Life has been around a long time, and has solved problems a robot civ hasn't thought of yet. Also, there are certain catastrophes that could wipe out a robot civ, but not Earth (and vice-versa) so we could be each other's backups. Of course, Earth is just an absolutely beautiful place, worth maintaining for that reason alone. And the bots might even choose to maintain pockets of life elsewhere in the solar system, just in case, but that is a very different scenario to the one in the OP's article.
Getting there is requires almost twice as much delta v as to Mars or Venus. Also, since you are going deep into Sun's gravity well, getting from there to practically anywhere is going to be very expensive. Setting a base on Mars actually helps further colonization as you are setting further from Sun on a planet with less gravity.
Though my understanding is that future of space exploration is going to be swarms of robotic factories that can replicate itself from minerals from asteroids.
The potential trick for dealing with this is sundiving with a solar sail.
That is, you set out of earth orbit for Venus, and while there, do a gravity assist to drop your perihelion very low. Then, you use the sail to brake (lower aphelion) the whole way in, and as the thrust you get from the sail goes up the closer you get to the sun, by the time you reach your perihelion you have sufficient thrust to be in complete control of your orbit, with infinite Δv. Then you can match your aphelion to Mercury at your leisure, and arrive with a slow constant raise of your perihelion to make entering low orbit very cheap.
The math works out so far as thrust is concerned, even with relatively conservative solar sail designs. The bigger question is how much risk does unpredicted solar activity cause. (On the other hand, you might have the ability to just dodge any you encounter... Solar sails very close to the sun operate more like cartoon spaceships than any other real spacecraft.)
Solar sails might be acceptable for unmanned probes, but for an actual manned mission so close to Sun you need a huge vessel, which would require proportionately gigantic sail.
While you can deal easily with heat by reflecting the light, you need to contend with a lot of shielding necessary to deal with solar winds that are much more stronger and frequent so close to the sun.
It might be possible to run a train of supply missions this way, I would have to check the math but I am too lazy today to do it:) IN general it does not matter a lot how long it takes for a supply mission to reach the planet, you can have as many of them in flight as you want (and your budget allows).
It could actually be interesting to see if it would be possible to have a fleet of these vessels constantly moving between Earth/Mercury, taking cargo by randezvous at Earth's orbit and dropping it off at Mercury's orbit to come back for more cargo. Kind of light-powered conveyor belt.
> for an actual manned mission so close to Sun you need a huge vessel, which would require proportionately gigantic sail.
It will be big, but a lot less so than you'd think. Solar sails need to be a huge proportion of the mass of the vessel they are moving if you are near earth. However, the thrust provided by the sail scales by 1/(distance to sun)². Near Mercury's perihelion, solar sails are stronger than they are near earth's orbit by a factor of ~10. But that's not where it ends. The plan calls for sundiving, or going <1 million km from the surface of the sun, where sails have tens of thousands of times the thrust they have near earth.
> While you can deal easily with heat by reflecting the light, you need to contend with a lot of shielding necessary to deal with solar winds that are much more stronger and frequent so close to the sun.
Solar wind is charged, which means it's just extra thrust with the right kind of sail.
> It might be possible to run a train of supply missions this way, I would have to check the math but I am too lazy today to do it:) IN general it does not matter a lot how long it takes for a supply mission to reach the planet
This would actually be a lot faster than going to Mercury with a traditional Hohmann transfer, assuming you leave earth with a burn towards Venus (you could also slowboat with the sail there, but that would probably take years). The route is circuitous, but the speeds would be much, much higher.
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[ 4.8 ms ] story [ 91.0 ms ] threadUniverseToday 2016: "How Do We Terraform Mercury?" [https://www.universetoday.com/128531/terraform-mercury/]
Towards the end the article talks about how the initial startup period for the colony will be the hardest.
If the startup process were automated, no one would be at risk. Send the first colonists once the tomatoes are ripe. But is there a practical limit on how much can be automated, remotely?
Are we approaching (or have we already passed?) a singularity in the human race based on our ability to product fault tolerant ball race bearings and machine screws that never snap?
I guess not [0]. I don't know of any artificial autonomous self-diagnosing and self-repairing mechanism either. The current approach is to hope that either nothing breaks or that built-in redundancy is sufficient to compensate for mechanical failures.
[0] https://safety4sea.com/autonomous-vessel-prototype-pauses-at...
It doesn't take much to shut down mechanical devices.
The problem with the "machine screws that never snap" is that we are still dealing with physical materials - everything is a trade-off; we could spec a screw with 100x the strength of the max expected load instead of a standard 2.4x margin, but we've probably blown both the weight and dollar budgets, and/or merely shifted the failure point to another component. And this doesn't even count for disasters to the mission from unexpected events.
Seems that we'll need to get well into the realm of self-repair and self-replicating devices before such massive remote autonomous are reasonably feasible.
Earths atmosphere protects us from all but the biggest rocks. Micrometer impacts on Mercury are a real danger, but that's also true in space/moon/mars
A. Mercury is small.
B. Sun is close, and huge objects like sun tend to clear their neighbourhood of small rocks. (There are comets coming your way, though.)
C. Even if something hits Mercury, there are no oceans, so zero risk of a tsunami wreaking havoc 1000 km from the original point of impact. This is one of the disadvantages of having a liquid ocean on our surface.
That said, asteroids are not the main problem. The radiation on the surface of Mercury would be a challenge. Humans wouldn't be able to work outside during Mercury day at all, unless we can construct much better protective suits. Even getting there would be a challenge, you would get a lot of exposure during the flight.
But Mercury is rich in minerals, so perhaps we can find something of value in mineable concentration there. And building a space elevator on Mercury should be possible with current materials.
So in my case, the jury is out.
Cargo, unlike humans, can take its time on the way. In case of minerals, it likely won't be damaged by vacuum or radiation exposure. The only thing that really interests you is that it arrives on schedule.
I know this is an old article. Perhaps written in the hype of peak-oil days or something like that.
So its from before 30. Juli 2020. It might have been writing during the fourth mission, so from 2004-2018 any date might be valid. But i would guess it is very new.
Update: Appeared on HN in 2013.
---
[1] https://en.wikipedia.org/wiki/2312_(novel)
Space is for robots. Earth is for life.
Why are we so shortsighted? The future is an incredibly long time. If self-sufficient human settlements on, say Mars, are out of the question with our current level of technology and are unlikely in the next few centuries, does that imply they'll be just as unlikely in 10,000 years? Will our descendants be so stupid they won't be able to solve new technology challenges?
Today is not the end of history.
You can do the same thing with digging. Well, we can dig 10m down, why not 100m? Why not 10000m? Why not all the way through? I mean it's easy physics to show you can move between any two points on a planet through an evacuated tunnel with no energy price, so why don't we do it? Is it because the downers like me don't think we have the materials to actually build the tunnels, and that we'd have to spend a great deal of energy to cool them because the Earth's core is really hot, and if only we'd shut our cynical traps the dreamers would get 'er done?
I blame science-fiction for really and truly warping our intuition of what is physically possible. A small moon base is certainly possible, but does that mean a sun base is possible? No. Cars revolutionized transportation, and phones communication. Does that mean teleportation is possible? No. Do insights about spacetime make time-travel possible? Except in the Ted Chaing sense (where time-travel has a lovely, inevitable symmetry to it), no. Chemistry - so we can create matter from nothing? No. Theoretical physicists play games with math - so free energy from vacuum? No.
But nanotechnology? Yes. AI? Yes. Full control over the genome? Yes. It's not that I think history is over, it's just that our stories are misleading about which branches of history we can travel. No ancient thinking person really ever doubted the earth was round (because there are easy experiments anyone can do), and they didn't think that heavier-than-air flight was impossible (because birds). It's true a few believed faster-than-sound travel was impossible, but I don't think that was ever a majority view (could be wrong on that, though).
Back to space. Space sucks. I don't want to live there. The Expanse was/is a great show, and it's certainly more realistic than most space-faring SF -- but it is still deep fantasy. The impact of living outside of gravity and outside of the magnetosphere is enormous and even with perfect medicine it would be uncomfortable because of the atmospheric constraints. The Epstein drive is fantasy. It is admittedly more plausible than most SF drives, but still non-physical. Of course, the alien stuff is pure fantasy.
Places like Mars suck even more than space, IMHO. Mars is a lifeless, cold rock without atmosphere or light, or proper gravity. I mean, Mars right now is still infinitely worse off for supporting life than Earth in the worst case, struck by a 20km asteroid. Or post-Yellowstone caldera. Another way to put it, Mars could take 100 meteor strikes like that and be no worse off. That's how bad it is. (There wouldn't even be much of a nuclear winter since there's no atmosphere to keep ejecta suspended. Although maybe if you strike it just right and with the right rocks you could give it an atmosphere of sorts?)
So, there is hope for exotic effects! Quantum phenomena at scale is basically magic. Black holes are quite mysterious! So is the origin of the universe - and I believe, contrary to most, that cosmological questions could very well have practical applications. "Metamaterials" (a kind of cousin to nanotech) can open up a lot of cool options for building things. And so on.
But yeah I wish people would give up the childish Star Trek/Star Wars fantasies about the possibilities of technology and embrace the reality of what we know. I too want FTL, teleportation and sexy humanoid aliens to seduce as much as the next guy, but despite the aesthetics its fantasy. And while shows like The Expanse seem more real, they still sneak in enough fantasy to invalidate it. (I do appreciate them not aband...
So we'll build carbon-neutral space launch platforms. We'll figure out asteroid mining and space manufacturing. We'll grow beyond Earth because we will never, as a whole, accept death.
Any attempt is at best speculation and at worst a fantasy. As you said, extrapolation from current trends quickly gets us into unbelievable territory.
I'm definitely not a religious person, but I do have faith they (future humans) will figure something out, if there's any incentive (survival, profit, ... fun?) to do so - unless our species goes extint first.
That's also why I do believe things SpaceX and others are doing are important. Not because we'll have a colony on Mars in a few decades (I don't think we will). But if we don't even start trying, it'll be awfully long before we get anywhere.
I get your gist, but I don't agree. The analogy I think of in this case is ancient Greece - let's say Athens. Imagine a precocious boy who discovers he can walk on the ocean floor by fitting an inverted bowl over his head and breathing the trapped air there for a time. He continues to innovate, and attaches a hose. He makes discoveries!
Thrilled by his success, he pitches the idea of making an underwater map of the entire Mediterranean! The benefits would be vast, to all the sciences, and would make the sea safer to travel. All the problems can be solved: too deep? Longer hose! With enough ships, enough diving bells, and divers, there is nothing physically impossible about doing this.
But of course, it's not worth doing. Such a project could have consumed an entire economy indefinitely. To attempt it prematurely would have been folly - a folly we call pride. The Mediterranean Sea is not that big compared to other bodies of water on Earth, but it is still truly vast, effectively infinite, on a human scale. Even with modern equipment a full mapping of the Med is a truly daunting task.
SpaceX is doing excellent work changing the economics of delivering goods to orbit by a factor of 10x or 100x. But even so, we are still at the diving bell level - or even worse - when it comes to space exploration and colonization. I DO NOT believe it makes sense for us, the modern Athenians, to even start spending enormous sums mapping the Med with sailboats and diving bells.
The engineering people talk about won't get us to self-supporting colonies on other celestial bodies.
What will, someday, is re-engineering ourselves until we become the extraterrestrials we've failed to find in the rest of the solar system.
It's analogous to how life emerged from the water on Earth. Every cell in our bodies (I'm plagiarizing a little, but I don't recall what) carries a bit of primordial ocean with just the right saltiness, because we really are still sea creatures with built in life support. But at the same time, we aren't adapted to the open sea and can't go back.
Some day there will be creatures descended from us, maybe called human and maybe not, who have changes at the cellular level or lower to deal with the harsh environments on other planets. That carry their own atmosphere and ozone layer with them. And they probably will not be able to return to Earth.
The litmus test will be whether a place is survivable with stone-age technology. Otherwise it's only a matter of time until a colony is wiped out due to some unforeseen technology failure.
And to do that we could start with the smallest thing that could make a living on the moon. The moon is a good placeholder for "space" - and is arguably a lot kinder than most places. (If the OP is right about Mercury, then it would be somewhere between Earth and the Moon in terms of friendliness.)
Earth's moon is far more extreme than the most extreme life we know of could endure[1]. Look at that table of extremophiles - and recognize that the Moon is easily 10x worse than the worst environments.
There are only two resources available to potential life on the Moon: rocks and sunlight. There are indeed some interesting atomic elements in the rock[2], but you'll notice two elements not in the list: no hydrogen, no carbon. I don't see a feasible way to bioengineer the Rockeaters from "The Neverending Story" but even if you could you'd have to make sure they didn't need to breath or stay warm. And I'm pretty sure that such creatures would be closer to robots than biological life, anyway.
(Note that life in empty space is about as harsh as you can get - you have sunlight, but without mass you can't grow or reproduce, and without gravity you can't move effectively or sustainably. You are forced to lose mass with every movement. As you move away from a star you lose even sunlight, and it's not clear what you could do out there except cool down to ~4K in equilibrium with cosmic background radiation and hope that you warm up enough to come back to life someday.)
[1] https://en.wikipedia.org/wiki/Extremophile
[2] https://en.wikipedia.org/wiki/Moon_rock#Composition : mostly: Aluminum, Iron, Magnesium, Calcium, Silicon, Oxygen, Titanium
The idea of "stone age" tech being enough to survive implies an ecosystem that maintains itself.
A rogue planet could have heat and water if it was reasonably large or part of a multiple body system with tides. C.f. Enceladus and Io. Then there's Titan.
We're maybe 70 years away from being a multi planet species if technology keeps advancing at the same rate.
We just need better ways to get into space. If the Sabre program works out or we figure out fusion power we'll be ready to roll in 20.
Or we could figure out self replicating robots. Nature has been doing it a billion years so we already know it's possible.
Or, just create a robot species in our image to explore for us. And hope they keep their meaty parents around and happy
There's multiple paths for humans to get off the planet. Out of the solar system, maybe not. But it's damn hard to predict farther than 100 years into the future
Indeed, I think this is the most plausible scenario. And I think a robot civilization would want to keep Earth living and breathing for reasons other than sentiment. Life has been around a long time, and has solved problems a robot civ hasn't thought of yet. Also, there are certain catastrophes that could wipe out a robot civ, but not Earth (and vice-versa) so we could be each other's backups. Of course, Earth is just an absolutely beautiful place, worth maintaining for that reason alone. And the bots might even choose to maintain pockets of life elsewhere in the solar system, just in case, but that is a very different scenario to the one in the OP's article.
Getting there is requires almost twice as much delta v as to Mars or Venus. Also, since you are going deep into Sun's gravity well, getting from there to practically anywhere is going to be very expensive. Setting a base on Mars actually helps further colonization as you are setting further from Sun on a planet with less gravity.
Though my understanding is that future of space exploration is going to be swarms of robotic factories that can replicate itself from minerals from asteroids.
That is, you set out of earth orbit for Venus, and while there, do a gravity assist to drop your perihelion very low. Then, you use the sail to brake (lower aphelion) the whole way in, and as the thrust you get from the sail goes up the closer you get to the sun, by the time you reach your perihelion you have sufficient thrust to be in complete control of your orbit, with infinite Δv. Then you can match your aphelion to Mercury at your leisure, and arrive with a slow constant raise of your perihelion to make entering low orbit very cheap.
The math works out so far as thrust is concerned, even with relatively conservative solar sail designs. The bigger question is how much risk does unpredicted solar activity cause. (On the other hand, you might have the ability to just dodge any you encounter... Solar sails very close to the sun operate more like cartoon spaceships than any other real spacecraft.)
While you can deal easily with heat by reflecting the light, you need to contend with a lot of shielding necessary to deal with solar winds that are much more stronger and frequent so close to the sun.
It might be possible to run a train of supply missions this way, I would have to check the math but I am too lazy today to do it:) IN general it does not matter a lot how long it takes for a supply mission to reach the planet, you can have as many of them in flight as you want (and your budget allows).
It could actually be interesting to see if it would be possible to have a fleet of these vessels constantly moving between Earth/Mercury, taking cargo by randezvous at Earth's orbit and dropping it off at Mercury's orbit to come back for more cargo. Kind of light-powered conveyor belt.
It will be big, but a lot less so than you'd think. Solar sails need to be a huge proportion of the mass of the vessel they are moving if you are near earth. However, the thrust provided by the sail scales by 1/(distance to sun)². Near Mercury's perihelion, solar sails are stronger than they are near earth's orbit by a factor of ~10. But that's not where it ends. The plan calls for sundiving, or going <1 million km from the surface of the sun, where sails have tens of thousands of times the thrust they have near earth.
> While you can deal easily with heat by reflecting the light, you need to contend with a lot of shielding necessary to deal with solar winds that are much more stronger and frequent so close to the sun.
Solar wind is charged, which means it's just extra thrust with the right kind of sail.
> It might be possible to run a train of supply missions this way, I would have to check the math but I am too lazy today to do it:) IN general it does not matter a lot how long it takes for a supply mission to reach the planet
This would actually be a lot faster than going to Mercury with a traditional Hohmann transfer, assuming you leave earth with a burn towards Venus (you could also slowboat with the sail there, but that would probably take years). The route is circuitous, but the speeds would be much, much higher.
Better to strip mine Mercury and use the metals for building a Dyson swarm.