A Realistic Way to Make Space Habitats From Asteroids 

So many space puns, all the time. I'm numb at this point.

Good analysis. I worked in Motorola in assembly, then technician work keeping machines going I didn't totally understand. Even after looking at schematics ...but they work.... I'll bet an honest Doctor will say the same thing.

Had me at Roci...

Many of our common items were likely inspired by & considered to be science fiction. I went from dreaming of a Star Trek communicator to having something infinitely more capable in my hand right now to both watch this video and discuss it in real time with people on the other side of the planet. It blows my mind when I really think about it...🤔

Hard science fiction is obtainable fantasy for our descendants.

Yeah, the mismatch between the wide angle upward facing foreground camera and the less wide straight back view of the backdrop is jarring, especially when he moves forward and back.

Are you talking about the rocinante interior shot?

I was thinking the same. Bore out a nickel-iron asteroid and fill it with bags of water. Use solar mirrors to melt a plug. Spin the asteroid and start heating it up with solar mirrors. Once it's fully molten, the water boils and expands to blow it up into a solid shell. Let it cool, and you have a hab.

Do the math about how much energy is required ... and how long it will take to cool.

@@AndrewBlucher Energy is free; a row of solar mirrors concentrates heat along the length of the asteroid. Not sure how long it would take to cool, but there would be ways to speed it up if necessary.

@@septegram Free mirrors? Seriously, do the math. And explain what the volatiles are going to do when heated.

@@AndrewBlucher The mirrors aren't free, obviously, but if we're at the technological and economic point that we can mine asteroids, a series of mylar mirrors will be trivial. The mirrors aren't free, and I didn't say they were. I said the _energy_ was free; concentrated sunlight.

Wouldn't it be a kick in the pants that we find out we are actually the von Neumann probes?

Basalt fiber could definitely be made from asteroid rock. Typical tensile strength for basalt fiber is about 1000 MPa, which is much stronger than Dr. Frank's paper suggests is needed for even a 3km radius hab (not considering atmosphere pressure).

​@@olawlor Cool, thx! So a solar-powered, basalt fiber producing robot (if that's feasible) could convert one rubble pile after the other into cylinders.

@@hodor3024 I've melted basalt into (neat black) glass with a 0.4 x 0.6 meter solar concentrator, so it sounds plausible to me! The hardest part is making the autonomous robotic control system reliable, especially given the unknown geology and abrasive dust.

to an informed roman, we are already "living almost like gods" i will call it the "theory of informatics relativity". sufficiently vague? surviving with style may be necessary to motivate humans to go away from earth. perhaps full on luxury if space farers are too reckless. i like the inflatables and the underground habitats best. self healing of course

And don't forget your Larry Niven library.

It's kind of fun to think about possibilities for instructions for nanobots as in #2 would look like. I imagine that somewhere you'd have a bunch of information describing the manufacturing techniques and materials available in 1967, engineering drawings for the individual parts, images of the model of car, etc., and software that would take all that in and run a simulation of manufacturing the vehicle to produce a model of the part to be built, including details like the grain structure of a forged crankshaft, imperfections in upholstery stitching, etc., and the nanobots would build from that so the final artifact could be as indistinguishable from an original as possible.

A lot of asteroids are just loose agglomerations of rubble--they'd have to be tested first to be sure they're solid, so a tether would actually hold on to them.

@@rikk319 No, I said "bag each". The tether connects the bags together. Rubble inside each bag.

This would solve the issue of the energy required to rotate the mass to a speed fast enough to create at least partial gravitational force equivalent. The energy required to create spin in millions of tons of material is just incredible. So much easier if it is already embodied in the system. While being drawn together, the material in the bags could be spread out to either side of the tether along the orbital plane with new tethers until a ring is formed that rotates at the desired speeds. A big question is the number of binary asteroid systems available with the needed compositions to make it work.

Love this idea.

The cost "savings" in using Kevlar could be lost in increased launch costs to lift more of it. I haven't checked but I'm guessing latest CT designs are about 10x - 20x stronger than Kevlar. I could be wrong there..just illustrating a point lifting costs are a factor as well as simple cost of material.

​@@user-pf5xq3lq8i It's not about cost savings, it's about simple tensile strength and materials that exist. Sure, a carbon-nanotube filament could allow you to make giant space cities, but we're many decades away from being able to create such materials at scale, if ever. It's a fundamental consequence of rotation and mechanics that the larger the diameter of a spinning object, the greater the tensile strength needed to hold it together. Thus, while these future materials may allow multi-km scale objects, I'm more interested in what we can do with materials that already exist. Maybe we can't build something the size of a city, but something the size of a stadium in Earth orbit would still be pretty neat. Moreover, as was noted in the video, asteroid distributions are logarithmic, with smaller objects being much greater in number. What I'm imagining is something a bit more near-term. Think using a small existing near-Earth asteroid, bagging it and spinning it up into a station the size of a stadium. If the target object were chosen correctly, it could be placed into Earth orbit with only a small expenditure of delta v. Now we have a massive industrial hub in orbit, with lots of raw materials and space to build out manufacturing facilities. I'm considering this as a way to jump up a few rungs on the space industrialization ladder, not as a habit for millions to live on.

translucent aluminum

Interstellar probes?

Alternatively, the habitable portion could be roofed. The roof would form a secondary ring, and thus would form a Stanford torus

You wouldn’t want to arrest the spin, because that is what generates an artificial “gravitational” force that’s really centrifugal forces that “sticks” objects to the inside of the cylinder.

Interesting. Perhaps building large subterranean cities would also be an effective option. Although, I'm sure in 4-5 billion years from now, we'll be able to convert our consciousness into energy and into statis for long term trips to other worlds where we'll be able to create customized bodies and other life suitable for any planet of the many planets we'll be settling by then.

@@00dfm00 Closest to that might be uploading you brain to a robot in which you can then underclock or overclock your brain for hibernation or heavy computing.

@@pazitor If we're talking about the journey to another system, I'd rather go to sleep and let AI handle the day to day. Interstellar travel would be boring af. It's the destination that's interesting. At the rate we're advancing in our understanding of life, how it forms and how the brain works, I'm sure we could do much better in millions of years than anything we consider robots today.

@@00dfm00 "I'm sure in 4-5 billion years from now," " I'm sure we could do much better in millions of years" I'm NOT sure, 100 years, or one billion years. That's the whole thing about the future. We discover some things we never expected we could do (internet), but we learn other things are impossible due to physics (faster than light travel). And "uploading" or "transferring" your consciousness isn't a thing in reality. You'd be making a copy of your personality, not moving some "soul" within you to another human or android body. What make you, you, would still be in your original body until you die. Sure, a copy of you would go on living, and could copy itself numerous times, but for the original you, that's not the key to immortality.

@@rikk319 While uploading or transferring may not be a thing now, it's reasonable to think we could completely understand how our brains work and replicate it in the future. And no, I'm not suggesting a soul or anything supernatural as that's far more fetched than replicating our neural activity. Also, outside of your brain, there are no original cells left in your body since everything is replaced several times in your life, so the concept of 'original you' is dubious.

A similar technology (albeit more of a brute-force approach) was developed back in the 1950s-1970s, using white-hot tungsten "drill faces" instead of spinning tunnel-boring bits. It was powered by a compact nuclear reactor in its first iterations, but later smaller commercial applications used umbilical power cables to connect to any handy (and high-amp) power source. Can't remember the name of that technology right now, but there's a funny story about how the public funding was provided for it... I'll try to look it up

Konstantin Tsiolkovsky mentioned it before 1910. Noordung sketched a wheel station in the '30s. Von Braun in the early '50s. The NASA Ames / Stanford studies and Gerard O'Neill laid out hard numbers nuts & bolts studies that showed that no new inventions are needed to mine asteroids and moons and to build for virtually Earth like conditions anywhere in space. "Ringworld" is space-tech fantasy.

I don't know which one of y'all to trust more(Don't really know enough about physics), but I definitely had my own doubts about the cylinder plan

True

Stop it, get some help.

It depends on the solid rocket motor or the liquid-fuel rocket engine you're talking about, and where exactly the spacesuited crew member is, and their relative velocity compared to the rocket. Oh, it also depends on whether this "close encounter" takes place in an atmosphere or in the vacuum of space (since I suppose a crew member could don a space suit on Earth or Mars, hoping it will protect them from a nearby exhaust plume) Scenario A: the rocket nozzle is pointed directly at the astronaut. Answer: Hella far away. Far AF. Especially in a vacuum, where there's no atmosphere to slow down and cool down the superheated exhaust particles that are being blasted at the astronaut at [insert specific impulse of the rocket here]. But even in an atmosphere, the rocket plume will create a pressure wave powerful enough to pulverize concrete. The exact answer depends on the size and the thrust of the rocket motor or rocket engine, but if it were me in that space suit, I would be unhappy and nervous about standing in the path of the exhaust plume when a rocket engine lit off if I was any less than three miles away. The further the better. Scenario B: the rocket nozzle is pointed slightly away from the astronaut, enough so that the direct exhaust plume will miss them, and the astronaut and the rocket are stationary relative to one another (sharing the same orbit, or the rocket is on a test stand and the astronaut is standing to one side nearby, etc.) Answer: again, the exact answer depends on the size and power of the rocket, but if you're in the vacuum of space, you're probably going to be fine. Unless the radiant heat from the passing plume or from the bell nozzle begins to cook you, if you're close enough and the rocket is powerful enough for that to happen. Scenario C: the rocket is firing and the spacesuited astronaut passes through the rocket plume momentarily. Answer: again, it depends on the size and power of the rocket, how close the astronaut is to the combustion chamber/bell-and also on how fast the astronaut is moving. Think of the old children's game of passing your finger through the flame of a candle: as long as you are moving your finger at a certain speed, or faster, you feel nothing, or maybe just a bit of warmth. But dawdle in that candle flame and you'll be crying for your mama pretty quick. Same situation here but the stakes are much much higher. Outlier variables: If by "other engine types" you want to include electric ion thrusters, you could probably hold your bare hand right in front of them for half a minute before you felt any pain, maybe longer (and the pain would be from ionization not actual heat-more like a sunburn than an actual flame against your hand). But if by "other engine types" you want to include nuclear salt-water reactor rockets, I'm not sure there is a "safe space" for that astronaut anywhere in the detectable plume of that rocket. Rather than superheated water vapor (from H2/O2 and methalox rocket engines) or heavier superheated carbon-compound molecules and particles (from solid rocket motors), you'll be blasted with super-superheated radioactive salts possibly mixed with microscopic depleted-uranium droplets, traveling at three times the speed (iSP) of most rocket exhausts. Remember, it isn't just the visible flame and immediate heat of a rocket plume that can do damage. The pressure wave is tremendous too, compared to the size of the rocket motor: ask yourself how much mass that rocket motor is able to push, and how fast that rocket motor can accelerate it. If it's a cold-gas reaction thruster that is meant to gradually turn a modest little space capsule or satellite, that's one thing. But if it's a main engine for a big orbital-class rocket, either first or second (or even third!) stage, it imparts a hell of a kick to a very heavy payload-and sends an equally powerful kick in the opposite direction, in the form of an exhaust plume. The content of the exhaust plume matters, too. If it is composed of tiny cold xenon atoms, even if they are accelerated to insanely high speeds by an ion thruster's magnetic fields, they are just xenon atoms. Individually they don't have enough mass to penetrate your spacesuit or even your skin, even if they are expelled from an ion thruster. A good ion thruster will offer about the same thrust as one hummingbird. The ionization of the xenon atoms, not their speed or mass or toxicity, is what you need to worry about. On the opposite end of the exhaust plume scale you have solid rocket motors and concepts like the NSWR. Those emerge at insanely high temperatures and velocities, and many of the exhaust particles have a lot more mass than mere xenon atoms. And the particles themselves can be toxic: bits of unburned solid rocket fuel, flinty flecks of carbonized fuel, and in the case of the NSWR, it's all insanely radioactive too, and only some of the uranium is "depleted" or transformed into less-radioactive heavy metal particles in the combustion chamber. Enough to sustain the combustion chamber's criticality of course, and that's enough to give you a bad day a mile away. Or ten miles away, if you're in outer space where nothing is slowing those exhaust particles down, and they are cooling off more slowly too.

Kind of ok with extending a 'doughnut', as long as you avoid the two-axis ratios, then you'd get the problem of it either switching rotation modes (cylindrical/end-over-end) or it flips to 'end-over-end' permanently. If you have difficulty imagining it, think of what happens to a free-hanging long cord if you start rotating it along its length; it soon forms nodes and anti-nodes in resonance with its mass and rotation rate. A similar problem happens with power-shafts known as 'whirl-speed'.

@@bikerfirefarter7280 Yeah, I know this effect. I think it can be counteracted by adding this consideration to the water flow (whether for cooling or all the other uses, we have for plumbing), or ultimately by setting up aligning thrusters in plenty of places. A long cylinder which would ever need a change in orientation would need many points working in concert, anyway: If you only have them at nose and tail, the whole thing would collapse like a tower of empty cans at the smallest alteration.

@@Smo1k no collapse, self gravity insufficient. Fluids wouldn't solve it either. Thrusters wouldn't work either. The momentum exchange goes up to really high values at certain ratios. Check out 'shaft whirl speed' and 'axis flipping' on 'Net.

An object with a long center of mass, rotating around that long axis is inherently, disastrously unstable. It wants to spin end-over end. Yes, you can apply active stabilization, but a good engineer doesn't design to defy real-world materials and physics and apply complexity to try to overcome the inherent design flaws. (the Space Shuttle was an example of that) O'Neill never proposed the "Island 3" huge 30km long cylindrical habitats as an actual design, but as an extrapolation of what they'd found that real-world engineering could do. The NASA Ames / Stanford studies found that well-known methods (in the '70s) could build a torus or drum shape up to 30km diameter.

I know about the effect that causes end-over-end rotation out of axial rotation, but one of the answers I've found in SF is a cylinder where the hard parts (basically, the cylinder "proper") rotates one way, while all liquids and gases rotate the other in their systematic circuit, so that from a mass perspective, the cylinder isn't rotating. One of the things often overlooked is the amount of water you need to have on board, if you're to grow your food on the station, and that food isn't to be dystopian in its lack of diversity. Add to this that you'll need to move heat around, and that nobody wants to live in a place with no green things, and you'll quite quickly reach a couple of tons of water which needs cycling, per human inhabitant. And since we're dreaming, I don't see why we can't add more water to the equation, so that the difference in speed to maintain equilibrium between fluids and solids doesn't get out of hand...

For a first go, I think this is the sort of idea we'll have to use. There will likely be a trade off for launch costs vs how quickly you can get something useful out of the asteroid. Balancing the costs of running the operation, particularly if/when humans are going there.

While I do agree that current mass production tech would surely have something strong/light enough to make a first go of it worthwhile, I don't think latex or neoprene (weather balloon material) would be enough. Something like Kevlar seems much more likely as an option. Having a too small asteroid will result in one or more of the issues: of not enough gravity to stave off permanent physiological issues, or too small a diameter resulting in Coriolis effects that humans can't handle, or too thin a crust providing insufficient radiation shielding, or too small an area to have it be worthwhile.

😂

You place thrust generation at points that compliment each other to induce a spin instead of moving it Ina direction.

Not really , the material science is already here. Only application and funding would be required to carry this out. This is unlikely to be soon though due to the Economic Great Adjustment in progress from 2019-2039.

Because of a comet's highly elliptical orbit you'd have to constantly deal with incredible fluctuations in temperature and the resulting outgassing when approaching the sun.

Inside the solar system, this will be important. Between the stars, though... Once you hit 0.25 c, the energy required to maintain a fixed acceleration makes like a hockey staff. You're going to need other means to get a gravity.

Whatever material you use has to be suitable for space, withstand the temperature range and dehydration of space as well as hazards such as uv, gamma-ray and micrometeorites.

For ethical reasons generation ships will be banned. People would riot and cause a mutiny all the time. Instead the ships will be loaded with embryos stored inside birthing pods, ready for growing on arrival at the colony.

Most likely high probability destinations will first be explored with robotic micro ships. It will take an enormous amount of earths resources to get to another solar system, so we would need to be sure of a place to live when we get there.

z"a semi simple idea of hollowed out ASTEROID, and then ?

I don't think such a thing would be so large as to be able to block out the sun if it was in orbit around the Earth.

@@zombieshoot4318 I don't mean completely, or for long. More akin something like Phobos eclipsing the sun on Mars. But if it were pretty big, and in LEO... and there were a lot of them. Well, I could see that being a potential nuisance.

You are thinking in terms of the force of a high speed centrifuge providing much more than one g of force. Your bed requires very little structural strength to overcome earths gravity, and a rotating space habitat does not have to be very strong to provide earths gravity equivalent, let alone less than earths gravity. This type of system is more like how a rope on a swing provides more than enough strength to support your weight against gravity, or a how the cable on a crane can lift tons of material against gravity. Just take that same rope or cable, and make it into a giant loop where it can support that same force all along its length. Likely a bigger challenge is stabilizing the habitat to prevent harmonic imbalances that might cause catastrophic flexing leading to its destruction.

​@@GoCoyote- I agree about imbalance, but it would never get to that point. The large boulders in the rubble pile would hit the mesh with a lot of force, on opposite sides and other random places, almost all at once, producing a lot of large *shock loads*. High RPM is not required in order to get those devastating blows. It is a function of the high-ish speed needed to overcome mutual attraction when all the boulders are close together, compared to the much lower speed needed when they are no longer in contact with each other. BUT the boulders will still have most of the higher speed when they reach the mesh, IF the plan discussed in the video is carried out. Your analogies do not involve shock loads, so they do not really apply here.

Mars has 0.376 of earth’s gravity, and Martians, Belters & others who live their lives in space could train in earth gravity for 2 hours a day while living in space if their jobs require transit to earth or “spin-up” to earth gravity while in route if they need to visit earth &/or use exoskeletons while on earth.