Because only in science fiction are space programs funded to the level needed to build such impressive space stations.
The idea of simulated gravity caused by rotation comes from substitution of the reaction force to centripetal force in place of the force of gravity. To provide this simulated gravity, the spacecraft would be rotated, causing the inner contents to be pushed against the outer edge, giving a sensation of weight.
The formula for this force is:
Meaning we are putting an angular velocity (ω) on the vehicle. At a distance (r) from the center it will result in a force equivalent in impact of mg (weight).
From that equation, you can see that the two ways to influence the amount of simulated gravity that would result from rotation are to either spin faster (ω) or make the circle bigger (r)。
A complication that arises is that for a person standing on the “floor” of such a space station, the value of “r” is different for their feet than it is for their head. That means the feet and head experience different velocities and accelerations and that can be disconcerting in the mild case, nauseating in the medium case, and debilitating on the extreme cases.
有一个很复杂情况是，对于站在一个空间站的“地板”上的人来说，“ r”的值对于他们的脚而言与对于他们的头部而言是不同的。 这意味着脚和头将会有不同的速度和加速度，如果这个差值很小可能会令人不安，在差值变大时会令人恶心，在差值非常大时会使人虚弱。
To avoid that, we need a very big “r”. The bigger “r” is the less the deviation between the feet and head.
为了避免这种情况，我们需要一个很大的“ r”。 “ r”越大，脚和头之间的偏差就越小。
These factors have to be considered when planning such an environment. In general, it is felt that we should limit the angular velocity to no more than 2 rpm (0.209 rad/s) to minimize the gradient between foot and head.
规划此类环境时必须考虑这些因素。 通常，我们应该将角速度限制为不超过2 rpm（0.209 rad / s），以最小化脚和头之间的差值。
If we plug that upper number into our formula, we can determine a minimum radius for a space station that simulated Earth equivalent gravity.
That’s a BIG space station. We simply don’t have the funding to build such a large vehicle.
In addition, the primary purpose of a space station like the International Space Station (ISS) is to provide a laboratory where gravity is removed from the experiments. We send experiments to the ISS explicitly because to achieve the goal of the experiment requires removing gravity from the equation. An example of this is crystal growth experiments. We know that gravity on Earth limits that growth. Doing the experiment in space provides results that can’t be seen on Earth. If the laboratories were rotating, then there would be simulated gravity and there wouldn’t be a point of doing those experiments – because they would have the same results they have on Earth.
此外，像国际空间站（ISS）这样的空间站的主要目的，是提供可以无视重力的实验室。 有些实验我们要交给ISS去做，因为要达到实验目的需要消除重力的影响。 晶体生长实验就是一个例子。 我们知道地球上的引力会限制这种增长。 在太空中进行实验可以提供地球上无法看到的结果。 如果实验室在旋转，那么将有模拟的重力，那就没有必要进行这些实验了——因为它们的结果与地球上的结果相同。
So, some might then suggest that we build a space station in which the laboratories don’t spin but the crew quarters do. To those people, I say read the first sentence of the answer.
@ Matthew Bates 一楼
Could a cheaper, smaller space station be designed such that it cork-screwed its way through space, as if it were attached to an imaginary axle at some fixed point in space outside of the ship?
I.e. – a giant tether with a counterweight? That is theoretically possible – but would require massive technology development and would have a very awkward challenge in “how would one dock to such a space station?”
即 -带有配重的巨大绳索？ 从理论上讲这是可能的-但将需要进行大规模的技术开发，随后衍生出的问题“如何让火箭对接到这样的空间站上”，也非常难以解决。
@ Matthew Bates 三楼，回复二楼
I was thinking more like perpetual, giant barrel rolls in space. But I suppose it’d need multiple, always-firing rockets to pull that off.
Back to the part of the answer about small radius + fast rotation = bad for the crew.
回到答案，小半径 + 快速旋转 = 宇航员感到很不舒服
@ Matthew Bates 五楼，回复四楼
Sorry I’m not describing what I mean very well. So here’s a picture instead. Like the path this roller coaster is taking, but without the track of course. Self-propelled around an imaginary center point, which could be miles away from the ship itself. If there were a no-fuel or very-low fuel propulsion system that could keep the station moving like that on its own, without being physically tethered to the center point or counter-weighted or anything.
抱歉，我可能没说清楚，我在下面放了一张图片。我想象中的空间站就像这个过山车所走的路径一样，当然是没有轨道的。 在假想的中心点附近自行推进，该中心点可能距空间站本身数英里。 如果有一个无燃料或极低燃料的推进系统，它就可以自己移动，而不必在物理意义上用绳子拴系到中心点或配重或其他任何东西。
Anyway, just something interesting to think about. I’m sure it’s already been thought about by much smarter people than me.
@Peter Kruger 六楼，回复五楼
Oh, I see what you’re going for now!
Yeah, that would probably be a lot less practical than just a spinning drum. You could get the same effect from just a straight rocket thrust out the back and a “flying office tower” design. By flying in a big looping/corkscrew pattern like that, you’re not only trying to add momentum in one direction, you’re also trying to change that direction. It would basically take 2–3x the energy to do it as opposed to just constant forward thrust. It works for the roller coaster train because there’s a rail for it to push back against, creating a “downward” force from the perspective of the occupants. Without a rail in space, it wouldn’t have anything to push back against.
是的，但空间站不仅仅只是一个波浪鼓。 您可以让空间站用向后方喷射的直火箭和“飞行办公塔”设计中获得相同的效果。 但在像空间站这样的半径巨大的循环/螺旋模式飞行，您不仅要在一个方向上增加动量，还要改变方向。 由于不仅仅是恒定的向前推力， 这样做大概需要2到3倍的能源。您说的这种方法适用于过山车，因为有一条轨道可以将其向后推，从而从乘员的角度产生“向下”的力。 太空里没有轨道，就不会有任何可推倒的东西。【？？这段没看懂】
Not a bad thought, though!
@ Stephen Merkel 七楼，回复五楼
This is kind of like applying a constant thrust of 1 g to the rocket. if the decks are perpendicular to the rocket thrust, so that your body is aligned with the thrust, you experience normal gravity until the rocket stops firing. Of course, the tether and counterweight idea would also kind of work, where you spin things like a bolo. To dock, you’d need a small zero g “knot” in the middle that could split in half and load crew and supplies into, and you’d put half the weight on the side that approaches on half of the station, and another that slides over and out from the center. Kind of like this:
这有点像对火箭施加1 g的恒定推力。 如果发射台垂直于火箭推力，从而使火箭向上的速度方向与推力在一条直线上，则您将一直感到1g重力的影响，直到火箭引擎关闭。 当然，系绳和配重的想法也可以奏效，您可以像滚球一样旋转东西。 要对接其他火箭，您需要在中间有一个零重力的小“结”，该结可以一分为二，将机组人员和补给物装入，然后将一半的重量放在接近一半站台的那一侧，另一半放在另一端。 从中心滑出。 有点像这样：
So, no rigid structure is needed other than some cables for a reactionary tension, and potentially the lab in the middle and the dock could be zero g for research, and act as a hub for the wheel. You would just have a ton of time spent docking and undocking cable guided elevator modules to the stations, and any mass imbalance would require some thrusters to balance out, so it pays for both sides to be equal weight. The whole thing could also have rocket engines to fly “up” in the image, so it could be a spaceship instead of a station. This would make its motion approximate your “barrel roll” idea, but it would really be more of a “double barrel roll” or “double helix motion path.
因此，除了一些用于反作用张力的电缆外，不需要其他刚性结构，并且中间的实验室和对接装置也是零重力环境以方便研究，并充当轮毂。 您只需要花费大量时间将电缆导向的电梯模块对接和对接，任何质量失衡都将需要一些推进器来平衡，因此，最终两侧有相等的重量。 整个过程还可能使火箭发动机“飞起来”，因此它可能是飞船而不是空间站。 这将使其运动近似于您的“桶身滚动”构想，但实际上它实际上更像是“双桶身滚动”或“双螺旋运动路径”。
It might even be cheaper than the ISS, since it is only 3 modules, but it would have lots of frequent use out of its airlocks, so that may be the most difficult part. (Though I will defer to Robert Frost’s knowledge on the subject)
它可能甚至比ISS便宜，因为它只有3个模块，但是它需要大量的 airlock 结构【译注： airlock 不知道怎么翻译qwq】，因此这可能是最困难的部分。 （尽管我会参考罗伯特·弗罗斯特在该主题上的知识）
@Gareth Rowlling 八楼，回复七楼
Maybe the airlock problem could be averted by connecting the ends with the lab in the middle by a lightweight human-diameter flexible hose, adjacent to the load-bearing tether?
也许可以通过在承重系绳附近用一根轻便的，直径与人身高差不多的的软管，将两端与实验室连接在中间来避免 airlock 问题？
The need for equal weights could perhaps be mitigated with weights that move along the tether cables, but given the expense of getting weights into orbit this might be limited to fine adjustments for trim rather than anything more substantial (which could in an case cause stability problems.
@ Stephen Merkel 九楼，回复七楼
Maybe. I think that Robert Frost pointed out that any such solution with a tube connection between the counterweights would be too expensive at the radius needed for the rotation to not cause nausea and inner ear problems in the astronauts. But, I suppose it is certainly a way of doing it. I think that maybe there could be a water tank some hoses and a pump as a way of dynamically adjusting the load to keep things balanced, and maybe the hose runs along the tether with a nice insulated layer and heater, but, can’t say for sure.
也许吧。 我认为答主所指出的，在配重之间使用管连接的任何此类解决方案， 为了不引起宇航员的恶心和内耳问题。 在旋转所需的半径范围内都太昂贵， 但是，我想这肯定是一种方法。 我认为也许可能会有一个水箱，一些软管和一个泵，以动态地调整负载以保持平衡，也许软管沿着系绳延伸，并带有一个很好的绝缘层和加热器，但是，不能说 当然。
@ Jim Kolter 十楼，回复七楼
If you’re using this as a space craft rather than an orbital station there would be an additional vector of the artificial gravity during acceleration due to the force applied by the engine in the hub. Of course when terminal velocity was reached and rocket or whatever was turned off, then only the rotation would have to be taken into consideration. But gravitational slings arojund celestial bodies would again alter the direction of the artificial gravity. You would need some sort of gimbal at the ends to accommodate these effects.
如果您将把这个想法用在太空飞船上而不是轨道空间站，则由于引擎在轮毂中施加的力，在加速过程中会存在一个附加的人工重力矢量。 当然，当达到最终速度并且火箭或其他任何东西都关闭时，则仅需考虑旋转。 但是，围绕着天体的重力吊索将再次改变人工重力的方向。 您可能需要在末端安装一些万向架来适应这些效果。
@ Michael Elmore 十一楼，回复五楼
Matthew, I understand what you’re describing. I think that this would work. It is analogous to the Zero-G training flights where an airplane simulates weightlessness by increasing its descent rate.
马修，我明白您在说什么。 我认为这个有用。 它类似于零重力训练飞行，其中飞机通过增加下降速度来模拟失重。
The only problem with this technique as you describe it, as I see it, is the fact that you would need to constantly expend fuel to keep this going, because you are constantly changing the velocity of the spacecraft. The nice aspect of the designs that spin around a centre, is that theoretically the centre of mass doesn’t move and such a station, once set in motion, would keep spinning around forever.
@ Jennifer Sittinger 十二楼，回复五楼
That’s the other kind of ‘artificial gravity’ we know of – gravity simulation via thrust. Moving in a straight line wouldn’t cause the same sort of nausea as too tight of a spin would; moving in a loop like you suggested would be mechanically simpler and require no tether.
这就是我们所知道的另一种“人工重力”-通过推力进行重力模拟。 直线移动不会像旋转太紧一样引起恶心。 像您建议的那样循环移动会在机械设置上更简单，并且不需要系绳。
The problem is that the only ways we know to apply that force in space are tension (i.e. counterweight) or reaction (which means thrust). A lot of thrust. There is a very short list of theoretical spacecraft engines that can provide that kind of thrust over anything longer than a spacecraft launch, and none of the fuel is cheap.
问题是，我们知道在太空中施加力的唯一方法是张力（即配重）或反作用力（即推力）。 很多推力。 理论上，可以提供比航天器发射时更多的推力的航天器引擎很少，而且燃料都不便宜。
@ Wavion Noivaw 十三楼，回复五楼
I still see docking as an issue though…
@Peter Kruger 十四楼，回复三楼
Once it was going, it wouldn’t take much to maintain. Getting it rotating would be the energy intensive part. But, as Robert points out, without a very wide radius “barrel,” the Coriolis would make everyone pretty sick.
空间站一旦发射，将不需要太多维护。 使它旋转将是耗能的部分。 但是，正如答主指出的那样，如果没有非常宽的半径， Coriolis 会使每个人都感到恶心不舒服。
@ Michał Bruchwalski 十五楼，回复十四楼
you can put gian electro magness and weight in the midle and just rotate it to give a spin, also I think you could use this counterweight multiple of times for diferent spaceships, Electricity is ccheap because all you need is Sun to produce it
您可以将 gian electro magness 【？？】和配重放到中部，然后旋转它就能让空间站旋转，同样，我认为您可以将这种配重多次用于不同的宇宙飞船，电很容易获得，因为可以通过太阳能来产生
@Max Williams 十六楼，回复三楼
The ISS doesn’t have the fuel to keep firing rockets all the time. It does a “burn” every two weeks (I think) to compensate for its orbital decay but not something like what you are suggesting. If a spaceship wanted to simulate gravity by doing a constant burn then it should just accelerate forwards. This would make it feel like being in a building, where the back of the ship is the “ground”.
国际空间站没有燃料来一直打开火箭引擎。 （我认为）它每两周进行一次“燃烧”以补偿其轨道衰减，但它并不像您所建议的那样。 如果一艘太空船想通过不断燃烧来模拟重力，那么它应该向前加速。 这将使其感觉就像在建筑物中，而船的背面是“地面”。
@ Santos Eichmann 十七楼，回复三楼
And even then, the tether-counterweight solution is waaaaaay more feasable and economical. The barrel-roll maneuver is only possible in aircraft because wings moving through an atmosphere provides lift into the center of the roll.
The “rocket solution,” you proposed is akin to something called a “forced orbit,” where a vehicle uses reaction mass to maintain an orbit outside of conventional orbital mechanics.
@ Robert Schuh 十八楼，回复三楼
You’d need rockets firing at 1G acceleration 24/7, if you had that good rockets you could fly to Saturn and back in a month.
@ Peter Murias 十九楼，回复二楼
You could have two identical spacecraft instead of the dead mass of a counterweight. Maybe a central module with the fuel and propulsion system, and the two craft are reeled back in for orbit changes.
@ Drew Nemeth 二十楼，回复十九楼
That would then mean the center module with the pieces reeled in would be spinning very fast. Still somewhat unhelpful.
@ Lee Jacobson 二十一楼，回复二楼
Couldn’t there be a ‘stationary’ docking station mounted on the tether half way between the station and the counterweight (or an opposing station)? A pod could run out on the tether from the central dock to the station.
@ Petri Haikio 二十二楼，回复二楼
The counterweight could be another living quarter.
Even better, have two of these rotating opposite directions to keep it balanced and dock at the center of the rotating axis.
@ Jim Kolter 二十三楼，回复二十二楼
I agree about living areas at both ends. The teacher could be a tube with “elevators” moving people or goods to the ends and external sliding counter balances to equalize the loads.
@ Tim Meiwald 二十四楼，回复二楼
Theoretically, you could have it spinning in say the x-y plane(which is obviously arbitrary) and then dock in the middle approaching from the z axis. What I’d be concerned about is how angular momentum is being conserved while it’s also orbiting Earth. Though maybe it would work dunno.
从理论上讲，您可以让它在x-y平面（显然是任意的）中旋转，然后停在从z轴开始的中间位置。 我要担心的是，当空间站在绕地球运行时，角动量是如何守恒的。 这个也许可以解决问题。
Dock in the middle to what? There’s nothing but a space station, a long tether, and a count weight at the opposite end.
@ Kemp Stephens 二十六楼，回复二十五楼
Why does a “tether” have to be something thin like a cable? Could you not have a tether that is actually a 10ft + diameter steel “pipe” connecting two habitation pods at either end (“useful” counter weight)? Docking would be at the center of rotation of this steel tunnel. Experiments where gravity is not desired, could also be done at the center of such a setup.
为什么“系绳”必须像电缆一样细？ 您是否可以使用实际上是一根10英尺+直径的钢制“管子”的绳索来连接两端的两个居住舱（“有用的”配重）？ 对接在该钢隧道的旋转中心。 不需要重力的实验也可以在这种设置的中心进行。
Now I direct you back to the first sentence of the answer.
@ Klas Färd 二十八楼，回复二十七楼
Would a tube that long (220+ meters) really be that expensive ? It doesnt have to be steel of course, and since none would “live” in it you wouldnt need radiation shielding etc. You could even have at least a partially lower air pressure in it, which could give you a very lightweight tube. Of course if you were to put a lab and docking station in the middle you would at least have strength enough to support that
这么长（220米以上）的管真的那么贵吗？ 当然，它不必一定是钢，由于宇航员不一定需要生活在其中，所以您不需要辐射屏蔽等。甚至可以在其中至少地部分降低空气压力，这可以使您的管非常轻巧。 当然，如果您要在中间放置一个实验室和对接口，则至少要有足够的力量来支持。
Yes, likely more expensive than the ISS. No one has ever built such a massive, airtight, load bearing structure.
@ Klas Färd 三十楼，回复二十久楼
Sure, but such an undertake would be much more expensive in itself, so the addition of a load bearing tube wouldn’t be a major component, although probably a substantial one I’ll admit…
@ Paul Cattalini 三十一楼，回复三十楼
I have often thought of such a system, using spent solid fuel boosters as the tubes. Just a thought.
@ Pavel Drotár 三十二楼，回复二十六楼
But even that central point would be rotating (at the same angular speed, but much lower circumferential speed). The docking vessel would then have to align itself with that exact point (difficult to do) AND start rotating at the same rate. Which means any course correction maneuvers would be a simple “left” or “right”, but would constantly change their vector due to the rotation.
但是，即使该中心点也会旋转（以相同的角速度，但线速度要低得多）。 然后，对接船必须将自身与该精确点对齐（很难做到），并以相同的速度开始旋转。 这意味着任何航向校正操作都变成了简单的“向左”或“向右”，但是矢量会由于旋转而一直变化。
Otherwise, if the non-rotating vessel would dock to the rotating docking port, the screeching sound of metal-to-metal would be very annoying, and the moment you’d try locking the system would result in transfer of momentum from one of the objects to the other, probably breaking your metal pipe due to torque.
@ Rudolph Jensen 三十三楼，回复三十二楼
Why would you need anything rotating in the center? There could be a docking port that is not rotating and connected to the station that is rotating. When the pod docks it would start rotating with the rest of the structure then lock into an airtight seal.
为什么您需要在中心旋转的东西？ 可能有一个不旋转的对接口，并已连接到正在旋转的工作站。 当其他的火箭对接上来时，它将随结构的其余部分开始旋转，然后锁定到气密密封中。
There is no reason a small ring could not have zero angular momentum in the center (just enough to make a docking target for the pod). If the docking ring was frictionless a tiny electrical motor could stop its rotation when a pod is docking while the rest of the space station rotated around it.
I don’t think this is complicated at all. Much better than spinning the docking craft.
@Pavel Drotár 三十四楼，回复三十二楼
Kemp Stephens described the “tether” to be a 10′+ steel tube. That’s what I was arguing against.
肯普·斯蒂芬斯（Kemp Stephens）将“系绳”描述为10’+钢管。 这就是我所反对的。
@ David Smerdel 三十五楼，回复三十二楼
I’m pretty sure that it would be rather trivial to program a docking computer to align the docking vessel and match the rotation.
Hahahahahaha right now, every docking flight controller just had an aneurism. “Trivial” – Oh my God!
@ David Smerdel 三十七楼，回复三十二楼
By the time we have the technology to build a functioning giant rotating space station, programming a computer to fire thrusters to match rotation to a station will indeed be trivial.
I’m quite sure that if there was a need for it, we would already have it.