Remote controlled robots could do a lot of the work. By the time we are ready to start building this stuff, we’ll have robots that are capable of semi-autonomous action, and teams of people on Earth ready to step in if they encounter problems the tiny robot brains couldn’t solve. The moon is only a second away by radio message, so the response times should be quite good (compared to Mars, where commands take many minutes to arrive). Forget Mars, Mercury, Europa, Titan; they are all targets for the distant future. The moon is a near-future goal.
The only resources they have are all of the metals and organics and volatiles that they are sitting on. That’s not nothing.
Not all spinning cans are O’Neill cylinders. The only parts that would be under Earth Like gravity would be the areas where people live. Manufacturing can either take place in the middle, or even on a completely separate facility that is co-located with it. You are generally going to want to build these on or in asteroids for protection from radiation and space junk, (and for them being close to mine) so the way I see it playing out is that you have the habitat in a spinning cylinder that is buried under the surface, and most of the manufacturing, especially what benefits form zero g, on or around the surface.
The rocket equation is a real pain for getting off the Earth, or the moon for that matter. The rocket equation does not have the same effect when you are not escaping a gravity well. Moving materials from one asteroid mine/colony to another actually requires very little in the way of delta-V. If it is just materials, and nothing perishable like people, and it doesn’t matter how long it takes, it can be done with a few mere meters per second.
Exactly. We aren’t even talking about having to have this stuff move all that fast…not like the minerals or volatiles will spoil. I’m not sure what Sam was even thinking there, to be honest. Assuming…which is, of course, a huge assumption…that we could start mining a near Earth asteroid…you don’t need all that much delta V to get it back to an orbit with the Earth. And since we have already agreed there are volatiles there, then even conventional rockets, refued in situ, could do the trick, especially if you don’t mind waiting some time for them to come. We aren’t going to be building millions or billions of spinning tin cans tomorrow, after all…like Rome, this stuff is going to be built over centuries, not days or even years. We build one first…then another and another. Before you know it, you have populated a whole continent, or in this case, you’ve built out all the best spots in the various useful Earth/Moon orbits.
And this leaves aside nuclear propulsion, or things like fusion. This is just with what is plausible and current today. Of course, today we don’t need those resources or those habitats. The cost to benefit is no where near there for even the mining of the moon part. Today, we MIGHT do a moon base station for a few scientists and astronauts, and we MIGHT do a space station in orbit around the moon. But in 50 or 100 years? Costs might come down, and a need might be there. Eventually folks are going to look up at the huge profits that could be gotten from the levels of materials available and say, yeah…we could do that. You wouldn’t get the California Gold Rush in, say, 1000 AD because, even if they knew the gold was there it wouldn’t make any sort of sense to even try to go get it. Even in 1492, if the Spanish KNEW the gold was there they couldn’t plausibly go get it. It would have been impossible.
All of which had to be imported to the space colony, since it was built from nothing. And if any of it is sold, it has to be re-imported. The point is that there are no natural resources at a space colony to exploit. Unlike the moon, where there is essentially unlimited iron, aluminum, titanium, magnesium, silicon, oxygen, and water. These can be turned into rocket fuels (Aluminum-Oxygen, hydrolox, etc) and launched to low Earth orbit or lunar orbit for a fraction of the energy, and therefore could be highly profitable.
What is there on a space station that could generate enough profit to pay for its own maintenance and whatever the people need to import to stay alive and be happy? Maybe in a couple of hundred years there will be lots of things - maybe we’ll treat them like cruise ships and they’ll be filled with tourists. But they HAVE to have a reason for existing, measured in economic terms, or there is no reason to build them.
Maybe zero-g manufracturing will be a thing. Maybe we’ll make a bunch of discoveries of goods that are highly desirable but can only be made in zero-g. Maybe we’ll start building orbital manufacturing facilities in a decade after a huge discovery like that. But if we did, that would be even more reason to go to the moon, because we’ll need a lot of mass in orbit and it’s extremely expensive to send it from Earth.
Maybe. But we are so far from being able to hollow out asteroids and build bases in them that by the time we do that the economy will likely be so different that we don’t know what we’ll need and want at that time. Maybe we’ll have automated facilities and mass drivers shooting huge quantities of mass into lunar orbit, where robotic 3D printing robots spin it into huge floating complexes essentially for free.
That’s why I’m not too interested in talking about what a space colony might look like in hundreds of years. No one knows. No one knows what our needs will be then, what our tech will look like, how wealthy we are, or a host of other things that we need to know to be able to even remotely predict what the future of space will be like.
If you’re writing a science fiction story, all of this is fair game, and they are all good ideas. But if we are talking about things that should affect NASA policy now, or trying to debate where we should be investing our resources to make effective use of space, that stuff is all completely irrelevant. We have to start with economics, with what is do-able now, and with feasible plans to get there from here. That’s what I’m talking about. Practical plans, not speculation about a distant future that is probably no more accurate than random guesses. If you had asked people in 1800 how people will live in 2020, do you think any of them would have been even remotely close?
The basis of the rocket equation is the fact that rockets work by throwing mass out the back. So every mass you want to manipulate requires another mass to be accelerated to do it. If you want to do it quickly, it can require many multiples of the mass you want to manipulate. But even if you do it slowly, you still need extra mass to do it.
Where do you think taht we would be building these things, just in the depths of space? You’d be building them on or near asteroids, and that is where you would be getting resources.
What is there on the planet that does this? People make their own economies. In the short term, manufacturing satellites and other space structures that we are currently spending thousands of dollars a kilogram to get up there. If it’s worth that much to put it up there, if you can find a cheaper way to build it up there, then you have cornered the market.
Once you have a critical mass, the economy comes from people buying and selling things to other people.
Right, but I’m not talking about sending it from the Earth, I’m talking about getting it from the rock that you are sitting on.
You don’t need to “hollow out” an asteroid. Most asteroids are going to have the consistency of Mica at best. Unless quite a bit changes, then we will need goods and services, the same as we have always needed.
Looking out that far can be fun, but I agree, we are talking more near term here. That doesn’t change anything. Asteroids are still easier to get to, and from, than the moon.
Find a way to make crude metals out of asteroids, and use that as trusses in satellites, saving hundreds of millions a year in launch costs. Work your way up from there.
Right, but when we are talking about hohmann transfer orbits, we are talking about pretty tiny amounts of delta-v, probably more than an order of magnitude less than what is needed to get off the moon, much less the Earth.
No, we are talking about O’Neill colonies, which are literally metal cans built in space. The idea is that you build a mass driver on the moon, then start shooting material to the Lagrange points, where they will be stable for long periods of time. Then crews or automation take all that mass and turn it into giant enclosed cylinders. The cylinders rotate, and people live on the inside surface under artificial gravity provided by centripetal acceleration. Large mirrors are used to deflect light into the interior, and now you have a habitat for thousands of people. Repeat as needed.
This idea was big in the 1970’s and 1980’s, but the assumptions behind it are, IMO, no longer valid. And I never did understand what their economic benefit would be. I think originally the idea was that the Earth was going to be heavily overpopulated, leading to constricted living spaces, food rationing, etc. These colonies would then grow food, and would have limitless space (you just build more as needed), and you could ship food to Earth cheaply since you are sitting at the top of Earth’s gravity well.
None of those assumptions are true any more.
Earth has so much abundance that we take for granted how much we get for free. You can certainly have an internal economy in a space habitat, but you also are going to require huge amounts of very expensive imports. That means you have to have something to trade. Maybe some unique product can be made there, or tourism will be huge. But right now, we know of nothing a space colony could produce that would justify the massive expense and resources required to build one.
You still need to import a lot of things. Very expensively. A space colony will always need to buy and sell things. You can’t have a services-only economy when you need to import billions of dollars in stuff every year to stay alive.
Assuming an ‘asteroid colony’. And all asteroids are depleted in something. Unless you master the magic transmutation of materials, you’ll always be importing. A metal rich asteroid has lots of metal, but possibly no volatiles at all, or trace amounts. Now you have to find or buy water, nitrogen, sulfur, hydrogen, potassium, phosphorous… And the list goes on. And getting that stuff out to the asteroids will not be cheap.
I really don’t see people colonizing the asteroids. I think an asteroid mine would be a lot more like a deep-sea platform: A bunch of specialists in a facility running the machinery until the profitable stuff is used up, then the facility moves to the next one. Imagine a SpaceX Starship that is about to be retired because its engines are getting near their design life. So a company buys it, retrofits it with mining gear and living quarters, and sends it out to the asteroids. The crew can anchor on a candidate then explore it, take samples, and as much as 50 tons of valuables, then heads back to either a major depot in the asteroids where it drops its load and refuels, then goes out again. The engines only need to use a tiny amount of rated power, so they ladt for a long time.
But no one is going to live out their life on an asteroid. At least, not soon.
Totally disagree. A very few asteroids are easier to get to than the lunar surface in terms of energy, but that’s not the only criterion. With minimum energy transfer orbits they take years to get to. The distance means we can’t manually control robots from Earth as we can if they are on the moon. There is a lot less available solar energy.
The Moon doesn’t take much to land and take off from. SpaceX says that they can actually fly to the moon, land their Starship, and fly back with 50 tonnes of cargo both ways. It requires in-space refuelling, But the entire system is reusable so the cost of landing on the moon and taking off is very small - less than a million dollars.
Now consider a Starship mission to the outer planets or asteroids. First thing: you are tying up a $220 million dollar spaceship for years. That alone would make it far more expensive than going to the moon.
Satellites don’t need a lot of trusses, They are mostly as compact as they can be, and packaged with high tech materials.
Also, we have to consider the economic impact of the coming generation of reusable rockets. If Starship delivers on even most of its promise, We will eventually be at the point where the mass of a satellite and its launch cost will be a small fraction of what they are now.
Not even remotely true, except for a small subclass of near Earth asteroids.
Let’s assume Ceres, or a similar asteroid in the asteroid belt.
It takes about 11.8 km/s of Delta V to get from the surface of the Earth to Geostationary Transfer Orbit. You have to do that for both the Moon and Ceres. For the Moon, you then need to get into lunar capture, circularize and drop into LEO, then down to the surface. All of that takes about another 3.2 km/s, or 5.7 km/s from LEO.
For Ceres, you have to get to Earth Escape, then trans-Ceres injection, then when you get there you have to get into a capture orbit, then down to LCO. Here’s a NASA page showing the total Delta-V for Ceres from Low Earth Orbit: Hohmann Transfer to Ceres by Launch Window. You can see that the Delta-V is between 9 and 10 km/s. And the travel time is typically over three years. There’s a reason why NASA uses complex gravity-assist trajectories to get to the outer planets and asteroids. Because it takes a lot of energy to get there, even in a Hohmann transfer orbit. Almost twice as much as to land on the Moon.
So to get to Ceres, you need more Delta-V than getting to the surface of the Moon, and it takes three years instead of three days. So equivalent resources on the moon could be harvested and delivered to LEO cheaper than they could from Ceres.
Now, there are a handful of Near Earth Asteroids that are closer in terms of Delta-V. But they are all quite small and we have no idea if there is anything valuable there. All the rest of them are a LONG way away, and require huge amounts of energy to get there and back. Even more so than Mars, because at Mars you can use aerobraking. At an asteroid, not so much.
And when doing economics, that 3.5 year travel time is pretty daunting. Any money invested in the hardware is going to require seven years from launch at minimum to get anything back. Tying up a billion dollars for a decade would probably incur more in carrying costs than the entire fuel cost of flying to the moon, landing, and coming back.
Eventually, I imagine we could see facilities out there that never come back, but just keep sending back regular amounts of cargo. At that point, it might make sense. But until we are at the point of operational mining, just exploration and learning through iteration will take decades when every round-trip takes seven years or more.
Again, a lot of this stuff (and the O’Neill cylinders) were considered before the Moon because our view of the Moon post-Apollo was that it was a dry, dusty rock with nothing of interest and where everything people need would have to be imported. That’s no longer our view of the moon. We are increasingly seeing it as a relatively wet world with all sorts of potential resources. The existence of extensive water changes the entire game when it comes to the exploitation of the Moon. But it takes a long time for new data to make its way into the zeitgeist of an entire industry, so most people still dismiss the moon as uninteresting.
Those are a type of space habitat, but they are not the only ones. Since then, we’ve learned more about the hazards of space.
those are some of the possible benefits, but not all.
I agree we have plenty of room, but there are those who feel otherwise.
At some point, we are probably going to implement some sort of population control measures, whether we actually need them or not. One of the ways to get around having the govt tell you how many kids you can have would be to leave the Earth and go where you are allowed to have as many as you like.
I agree that just going out and building one for no reason is a bad idea. But, building up to it is what we should be working on, and at some point, it will become a cost effective proposal.
Before we even start doing this, we do need to have fairly extensive space manufacturing capabilities. Those can be developed for other economically viable purposes.
High tech items, like high end CPUs and the like, sure. It’s going to be a while before a space colony can produce the next Intel Processor. But those are lightweight and easy to transport from Earth, unlike bulk materials like iron or water.
Why?
If the rock you are on is short on something, you don’t have to get it from Earth, you can trade with another rock that has an abundance of what you need and a shortage of what you have an abundance of.
That would be how I would see things starting too.
Agreed, but soon is relative. And soon comes much sooner if we actually work towards it, rather than consider it beyond our current reach.
That’s why I said you have to be choosy about your windows. They do pass close enough to the Earth, from time to time, to take a reasonable amount of time. It would certainly be longer than a moon mission, but still shorter than to Mars.
Two things, I was proposing a manned mission here, so light lag isn’t an issue, and I do think that AI has more than advanced enough that things can operate with only minimal inputs, for autonomous missions.
There would only be less solar energy if you chose an NEA that had a very eccentric orbit. And, in any case, one of the technologies we need to develop is nuclear power in space. Assuming we don’t have fusion (or it’s just 50 years away, really, really this time), fission should still be perfectly viable, with plenty of uranium and thorium in asteroids to use, though it will be interesting engineering to build them to deal with varying gravitational situations.
Considering that a big body airliner costs in the same ballpark as the Starship, I’m not all that worried about it. We’ll build a bunch of them, and they will have some specializations to them. Once we start building them, the company that is building them wants to keep building them, or it loses money.
I’m not too sure how much longer SpaceX is gonna make it though. They’ve done some impressive things, even if rarely holding to timelines or budgets, but space is definatly in one of those “second mouse” industries rather than “early bird”.
They have quite a number of structural parts. They are made a compact as they can be in order to fit inside the fairing they are launched from, not because they want to be compact. In fact, many satellites have very complex mechanisms to unfold solar panels and equipment that had to pack into the launch vehicle. You can have a perfect launch, perfect telemetry, but one stuck hinge can endanger the whole project. You know how close we came to not having a Galileo mission because of some stupid mechanical failure? It still was not the mission that they really wanted, with the loss of the main antenna.
How nervous will the James Webb team be after a successful launch, and now they get to see if their mirror unfolds correctly?
Send up the stuff that can’t be built in space. At first, you are only going to be building the basic frame out of in situ resources and slapping on the parts that were launched up. Then, as you develop capabilities, more and more of the satellite is sourced from resources that did not need to be launched from earth, until the only thing that is coming up is electronics and optics and other high end products that require larger supply chains. Even if you can’t build high end electronics in space for quite a while, making simpler control chips is something that can be done in a basic university EE lab, and so should have little difficulty transferring to space.
What I am talking about here is specifically asteroid to asteroid travel. The whole part of your equations involving breaking out of gravity wells does not apply, as that is the entire point of staying away from gravity wells.
Do your math on Ceres to Vesta, and see if it’s that expensive.
Well, we check out the ones that are easiest to get to first, then use the resources and technology that we develop to get out to further ones. Delta-V is far less important if you don’t have to lift your fuel out of a gravity well. No matter what the NEA’s are made of, we can turn it into fuel. It is guaranteed to have a decent amount of oxygen in it, and so we split that oxygen out, and then just recombine it with what we separated it from, if nothing else. Probably the best would be aluminum, as that is likely to be very common, and it is easy to make a simple rocket out of. If you didn’t lift it out of a gravity well, it’s practically free. We don’t have to restrict ourselves to the lowest energy orbits if we don’t want to.
Once you have things established, you can slap a little rocket pack on a big pile of semi-processed ore, and it doesn’t matter if it takes a decade or more to work its way to its destination. People and valuable goods may want a shorter trip, though.
It takes that long to build any of our giant industrial machines right now, at about the same cost. Planes, cargo and oil ships, oil drilling platforms, power plants; these all take years and decades before they are available to start returning on investment.
Now, you can argue that those all have guaranteed returns on investment, unlike asteroid prospecting, but then, I’d remind you that the airline industry as a whole is out over a billion dollars over a faulty sensor on a couple 737 MAXs. Deepwater Horizon should have cost BP far more than it did, but it still lost a couple asteroid probes worth of money in damages and cleanup.
These are not daunting numbers in terms of cost or time on return. What is daunting is the unknown parts of the risk. There are too many unknowns involved for the underwriters to okay such an undertaking in any publicly traded company. SpaceX is getting away with some pretty risky bets that would not be allowed by shareholders, and ultimately, I think that they will end up losing one of them, but hopefully not until they’ve gotten far enough to show others the way.
That’s why the govt really needs to do more of the deep space stuff while allowing private industry to take over the areas that have already been well developed. It needs to be the first mouse so the second gets the cheese.
My point is that we should be working towards operational mining. We won’t just get there without pushing to get there.
The moon is not useless, but it is in a gravity well, and gravity wells are for suckers. 
There is science to be had on the moon. Just from what we brought back with Apollo, we learned quite a bit about the Earth. If we could drill down hundreds of feet, or explore lava tubes, or whatever the lunologists can come up with. It could also be used as a launcher for deep space probes. It has enough mass that it’s not going to notice when you use accelerators to fire something out at greater than solar escape velocity. Maybe a giant radio telescope on the far side, where it is shielded from the EM pollution of the Earth.
There may be resources on the moon. I don’t know about using the water for fuel, that seems wasteful, it is going to be a limited resource, and if you are planning on colonizing the moon at some point, you may want to keep it around. Helium 3? Sure, show me a fusion reactor that can use it though. That’s farther off, IMHO, than full scale space manufacturing. What else does the moon have that asteroids do not?
Not saying we shouldn’t visit the moon, and maybe even set up shop there to some extent. But when it comes to colonization, actually creating settlements to grow and become largely independent, the asteroids is where it’s at.
If we really would have all the needed things for a living then Mars was the best planet for colonization - it is similar to the Earth more than any other planets from the solar system. Besides, even NASA is gonna colonize Mars cause Moon is like a test place before Mars.
We have been, for decades. Female empowerment, mostly. They do work.
Mercury has not been mentioned yet (well, once but I think the poster meant to type Venus). I think it deserves a vote.
A solar day on Mercury lasts 157 Earth days. You stay out of the sunny side (yes it’s quite hot there) by moving your base camp at walking speed at the equator, slower at other latitudes, which is not conceptually impossible. Try racing against the sunrise on the moon.
There’s also ice in permanently shaded craters near the poles. No atmosphere, but the moon has the same disadvantage so in that regard it’s a wash.
Let’s go there!
Though the locals may be a problem I’d go with the planet Mongo.
Fun topic, and ultimately I think best can vary.
Luna itself is probably going to win initially because of distance, cost and technology that’s not too far from present. Trying to build a permanent lunar base is a step beyond the International Space Station, but man has walked on the moon and it doesn’t seem totally beyond our capabilities at present. As an aside, Luna also has the fortunate quirk that caves or tunnels deep underground would average out at roughly Earthlike temperatures.
Mercury may be the most profitable. Light elements are more common than heavy elements, but Mercury would seem to have an overshare of these heavier elements. Although Mercury is obviously too hot, with only a trace of a trace atmosphere, it’s possible to exploit its super long days and find permanent shade.
Farther in the future, I suspect Venus has the best potential to be another Earth. Venus’ problems are many, but they stem from a problem which humanity needs to fix now–climate change can destroy the world. Trying to reduce CO2 levels, trying to cool a planet that’s getting too hot, and basically getting a school of hard knocks version of terraforming together is probably not enough to flip Venus into the sci-fi steamy jungle world of yore, but it does start to suggest some answers. If humanity gets to the point where it can start fixing planets, Venus’ atmosphere wouldn’t leak into space and it does have enough oxygen for a familiar ecology.
Finally, icy dwarf planets like Ceres, Pluto, and similar moons (Triton, Rhea) may be a good compromise between a deep space station and requiring large amounts of fuel to depart. Worlds like this don’t ‘WIN’ the best sweepstakes, but if we wanted to poke around the minor moons of giant planets and the Asteroid and Kuiper Belt, wouldn’t some kind of hub colony make sense?
It’s the Moon first, Mars second. I don’t see how there’s any doubt about that. The Moon is orders of magnitude easier to get to than anywhere else, and Mars is the second-easiest place to get to (more or less tied with Venus) and doesn’t have a 400 degree atmosphere filled with sulfuric acid.
One problem with dumping heat into the ground is a similar issue with all the ‘geothermal anywhere’ or closed loop geothermal projects that are being bounced around on earth. The thermal diffusivity of rock is awful , so if you don’t have some fractured system to pump the fluids away you just end up heating the rock around your heat sink system very quickly without taking away a lot of energy because of the low specific heat capacity of the rock, then that heat wont conduct away very fast because of poor thermal conductivity so overall it’s not a very effective heat sink.
That may not be a killer problem, but it is one of note.