For modularity it might make more sense to use nesting. A building inside a building has no seams. Doors only need footpaths between them, not hard structures. The inner building can be used for shelter in case of an accident, and can be run at higher pressures than it could in hard vacuum.
In the tinker toy model you would tend to have to keep repurposing buildings because while the size may be appropriate, the older structures may get pushed farther and farther from the center of the action, rather than staying in the center of the action.
When we get into the more utilitarian phase of space development, then I think you would want something like shipyards where there really is a big micrometeorite shield (yes, as a sphere) with the inside filled with scaffolding. Robots scoot around do work with old and new hardware.
If you think about nesting ROTATING structure inside of other pressure-envelope structures, then you're getting into some really crazy stuff. Are there designs that might make sense? Maybe, I don't know, I guess I wrote a blog about it
Windows are at a huge premium on cruise ships. It'll be much worse on space ships. But it's possible that inside windows will eventually look out onto something more interesting than the black void of space, so an inside window may be preferable. One of the reasons we look out the window in a car or on a boat is to establish the horizon and fight motion sickness. If you look 'outside' of a rotating space station - especially a rotating space station orbiting a planet or moon - you'll head rapidly in the exact opposite direction.
I think my train of thought makes a bit more sense for moon and asteroid bases rather than free-floating orbital structures. And asteroid bases - on the right asteroids - are probably going to house most of the people.
The ISS design definitely doesn't scale up. Everything off axis is a lever arm and the bigger you make it the more the whole thing tries to twist itself apart.
Another reason why it's not done is because one of the reasons why we have a space station is to do microgravity experiments, and having artificial gravity only hurts that.
That's what I thought until I started looking into it. The module has actually been built (several versions in fact), but never completed and launched.
It turned out during tests and simulations that the station's structural integrity was at risk and so it was decided not to attach a centrifuge to it.
Whether these concerns were warranted I cannot say, but engineers at NASA deemed it too risky to try.
https://blogs.scientificamerican.com/life-unbounded/watch-th...
We've also done some experiments already. There was, I believe, a Mercury mission where they spun the ship up. If I recall, it didn't go super well. But hey, we've had 50+ years to think of how to do it bette!
It’s don’t commonly on Earth. Most of the point of LEO space stations is to study microgravity so you wouldn’t even want it.
It is indeed pretty easy, but annoying to do for technical reasons (rotating joints, etc). Easier not to.
Having the whole habitable part of the station rotate may be fine most of the time, but it makes docking with ships more complicated. If the ship can't be spun, then you can either use some kind of rotating docking collar (which doesn't have to be perfectly airtight if it's only used once in awhile, but it still has to be pretty good) or you have put on a suit and do a spacewalk just to move things back and forth between the station and the ship which sounds kind of inconvenient.
(I guess there's actually another solution which is to stop the station spin whenever docking with a ship. That costs energy and/or reaction mass, though, and you'd have to deal with whatever disruption switching to zero-gravity brings.)
I can see why they might not have wanted to deal with this for ISS, but maybe for a bigger/more ambitious space habitat we'll want to do it.
Another possibility is to have the docking station completely disconnected from the outer ring atmosphere, and to use small "elevators cabins" attached to robotic arms to go from the ships to the rings and vice-versa.
Sadly, they do rather require "magical" technology....
From a radius of ~300m onward you'll see green lights (= good for people) for all considered parameters. RPM drops from 1.7 to 0.5 for a radius of 3000m.
If you made something like a gravitron ride on the moon, would it take a slower rotation speed to reach perceived 1g than if you spun up a ring station in orbit? This calculator makes it seem like you could get pretty close to 1g with just a bullet train running on a 3.14 kilometer loop.
It seems like the main thing stopping earth trains from being faster is that most of our tracks were built a really long time ago and it's not worth the effort replacing them, but if metal is readily available and you're laying new track already, designing for ~300km/hr wouldn't be that much of a stretch no?
The main thing stopping earth trains from being faster is politics, not engineering. Trains have been occasionally going over 300 km/h since 01955, decades before maglev. The Shanghai Maglev Train has been running at 430 km/hr since 02004. The Euroduplex regularly runs 320 km/hr on regular 1435mm standard-gauge rails and reached almost 575 km/hr in a test in 02007. 300 km/hr trains have been in regular service since 01989. There are several other train lines that run over 300 km/hr, in Taiwan, PRC, France, Belgium, Saudi Arabia, Japan, Germany, the UK, the Netherlands, Italy, Spain, Korea, and Switzerland. Soon India and the US will join them.
The big advantage of maglev is actually not smoothness or absolute speed but acceleration and deceleration.
https://en.wikipedia.org/wiki/Euroduplex https://en.wikipedia.org/wiki/High-speed_rail#Speed https://en.wikipedia.org/wiki/List_of_high-speed_trains https://en.wikipedia.org/wiki/Maglev#Comparison_with_convent... https://en.wikipedia.org/wiki/Taiwan_High_Speed_Rail https://en.wikipedia.org/wiki/Bombardier_Zefiro https://en.wikipedia.org/wiki/Centripetal_force https://en.wikipedia.org/wiki/Euclidean_vector#Addition_and_...
Being huge means less inner ear dizziness, spinning small and fast is stressful on materials and makes humans sick. And docking would be a major POA.
If we are talking km diameter structures holding station in system, making it rotate isn’t going to be a drama.
Other challenges include how to spin it up (and down) safely, how to dock with non-spinning things, how to deal with changes in mass distribution, and how to put thrusters on it for use when it's spinning. None of these is impossible, but together they create a serious engineering problem, and the size of the whole thing is ultimately the dealbreaker.
Docking would be via a central hub. Ships would have to match rotation to dock, but it shouldn't be too hard. My conclusion is that if the money and/or political will were there we could start doing this today, but the project would be hugely expensive (even with SpaceX cutting launch costs to a fraction of what they were only a few short years ago) and once you have it built it will be looking for a purpose. It would be cool for people to basically commute up to the central part (via elevator) to do zero-g research stuff, then commute back to the ring to live and avoid the various health problems with long term zero-g living like bone density loss.
You can even build a simple starter station that has only two segments on opposite sides of the central hub. This is less cool since you don't get the jogging path around the station. If stability is an issue you could also include a computer controlled mobile counterweight on the ends. I also had the concept of building it as a double hull with a layer of water between the inner and outer to reduce radiation flux and absorb micrometeorite impacts.
But in the end you are still talking about a hugely expensive project that solves problems that aren't all that bad yet. About the only way I could see this being built is if Elon decides to go all in on space and liquidates his fortune to build it. The instant some annoying bean counters ask the question "is this the best way to spend this money" the project is dead.
Basically, we would need to make something hundreds of meters in diameter to have any hope of a comfortable living situation. This is a huge amount of mass to get into space, which is notoriously expensive, but getting cheaper every year. Maybe one day we'll hit an inflection point where this is reasonable.
That would give you a circumference of around 628m. That sounds like a lot, but if you could build it in 80m segments by bolting each segment to the outside of SpaceX Starship (which is 120m tall) that would take 8 launches to get the ring in orbit. Plus some more launches for the hub and spokes and panels and everything else of course. Still, 15-20 launches is not outside of the realm of the feasible. If there were the political will (or personal fortune) to build this it could be done.
Split the initial station into two stations with a large number of cables connecting them securely. Now on your calculator, put in a 70m radius and a gravity of only 0.3g. All green dots.
But how do you get between the halves?" you ask? I think there's a simple answer to that: have cables complete the circle. A small car riding those cables can carry you around the radius. Then over time, you add more cells until the circle is complete!
The zipline would be trickier to make work, then. Probably you have a gadget that walks up the tether, and then you flip around and it walks down to the other end.
Non-popularized version https://space.nss.org/settlement/nasa/75SummerStudy/Table_of... (but that was the very first study iirc and made some known mistakes; I have no idea what the state of knowledge is now.)
Or, just extend everybody's cable a notch so there is room to shoehorn in the next pair of cans. As you add cans, the radius grows.
"Cans" is the only practical way to think of building a rotating station. Of course, the cans are really Starships, hanging by the nose. Passageways between cans are fabric tunnels. Each can has a mass on a column that is automatically raised and lowered as people and things move around, to maintain rotational stability, and keep the hub centered.
Realistically, you'd want to keep re-using the expensive parts of the starship rather than park them in space, which makes me wonder what's the best way to re-use a starship while leaving cylindrical body sections in space?
You could have a Starship body with sections that are removable -- like maybe you have a 50 foot section that unbolts from the nose and the tail which you leave in space, while the nose and tail get re-connected and return to Earth as a shorter version of Starship. Or maybe you could just launch two Starships, and in space remove the engine from one and place it inside the other as cargo, so you land one complete starship and the extra engine, but leave one complete body in space.
I doubt it's possible to have a disembodied engine land itself using its own thrust without a lot of clever and novel engineering, but maybe it can land by parachute? Or use thrust to slow its re-entry so it doesn't overheat, then parachute the rest of the way?
Maybe you vent the tanks and open a hatch on top, and there is a stairway inside with floors, ductwork, and places to clip on lights and electric outlets. Probably you roll out insulation onto the walls so you don't burn yourself or get frozen-stuck if you touch them, depending on what is going on outside.
If you instead make the rings "super-modules", you can connect as many as you like along a central axis of rotation. As long as the individual rings are balanced you're good to go. If they spin freely relative to each other, you could even build a super-modular ring in place and only spin it up after it is complete.
I'm pretty sure that phenomenon even kills the https://en.wikipedia.org/wiki/O%27Neill_cylinder, especially once you introduce liquids and soil to the interior. It's likely that we have to spin the cigar along the long axis to keep from killing everyone, which would greatly reduce the usable surface area and screw up the artificial lighting situation.
Not in my cosmic neighborhood.
What I'd prefer to see is a space construction that is continuous. Imagine a ring station, but one that is cellular in nature- lots of smaller modules that together form the huge station. This allows one to construct and add further modules over time, growing as needed.
The beauty of this design principle is that we could start today. Design the first iteration of these modules, with the intent to fit them into SpaceX's Starship (or whatever heavy rockets come next). Launch 10 or 20 of them, connect them, and spin them up to 1/5th gravity, something not too hard to do. Add modules in the centre of the ring that are zero-G, where zero-G things can be done- but allowing those who live on station to live in mild gravity at least.
All the while, you can dream big. You can plan for how this station goes from 10 or 20 small modules to thousands.