为什么国际空间站具有如此怪异的形状? 为什么形状不均匀?Why does the ISS have such a weird shape? Why isn’t the shape uniform?

【翻译自Quora】

Robert Frost

Robert Frost Instructor and Flight Controller at NASA

的回答

Aww, I feel like a parent that was just told their child is ugly.

额,我就像那个被别人说自己孩子丑的父母。

As an engineer, I look at the ISS and think “of course it looks that way, why would it look different?”  Where a fictional spacecraft has the luxury of having its design dictated by style, real spacecraft are constrained by budget, tradeoffs, and practicality.  Every feature of the ISS can be explained by those words.

作为一名工程师,我看着国际空间站,认为“当然看起来是这样,为什么要变成其他的样子?”科幻小说中的航天器有着奢侈的设计,而实际的航天器则受到预算,平衡, 和实用性的限制。 这些话可以解释ISS的每个功能。

We don’t yet have the technology to do construction in space, so we have to assemble a large vehicle in space from launch-able components.  At the time of the ISS assembly, the two mechanisms for getting a large payload to space were the Space Shuttle Orbiter and the Russian Proton rocket.  Those two sentences explain a lot of the ISS appearance.  It had to be assembled from pieces that would fit in the Orbiter payload bay or the payload fairing of a Proton rocket.  This dictates a maximum length and diameter for each component.  We can therefore expect ISS to be composed largely of cylinders, linked together like sausages.

我们还没有在太空中进行建造的技术,因此我们必须使用可发射部件在太空中组装大型车辆。 在国际空间站进行组装时,将大型有效载荷送入太空的两种机制,分别是航天飞机轨道飞行器和俄罗斯质子火箭。 这两句话解释了ISS的许多外观。 它必须由适合轨道飞行器有效载荷舱或质子火箭的有效载荷整流罩的部件组装而成。 这规定了每个部件的最大长度和直径。 因此,我们可以预期,国际空间站将主要由圆柱体组成,像香肠一样连接在一起。

Those two delivery vehicles dictate other characteristics.  The Space Shuttle Orbiter could deliver a completely unpowered cylinder, remove it from the payload bay and attach it using the robotic arm and attach it to the ISS.  But, the Russian Proton rocket deposits its payload in low Earth orbit and that payload then has to fly itself to the ISS.  That means each of the Russian modules are self contained spacecraft.  They have to have thrusters and fuel tanks and navigation and communication sensors and antennae.  When we look at the Russian modules we see that equipment.

那两个运载工具也指定了其他的特征。 航天飞机轨道器可以提供一个完全没有动力的圆柱体,用机械臂将其从有效载荷舱中取出,然后将其固定在ISS上。 但是,俄罗斯质子火箭将其有效载荷放置在近地轨道上,然后该有效载荷必须自行飞向国际空间站。 这意味着俄罗斯的每个模块都是独立的航天器。 他们必须配备推进器和燃料箱以及导航和通信传感器以及天线。 当我们查看俄罗斯模块时,我们会看到该设备。

A space station with multiple labs operating at all times needs a lot of electrical power (a few kilowatts).  That’s going to require big solar arrays – enough to almost fill a football field.  And because the angle to the sun changes as the vehicle orbits the Earth, those solar arrays need to be able to rotate so that they constantly face the sun.  That dictates that those solar arrays need to have unobstructed paths – unobstructed not just in their rotation, but unobstructed in their line of sight to the sun.  That dictates that we mount the solar arrays off to the sides and that we keep the profile of the rest of the vehicle low.

具有多个实验室且始终在运行的空间站需要大量的电能(几千瓦)。 这将需要大型太阳能电池板-足以几乎填满一个足球场。 而且由于与太阳的角度会随着飞行器绕地球旋转而变化,因此这些太阳能电池阵列需要能够旋转,以便它们不断面对太阳。 这表明这些太阳能电池板需要具有通畅的路径-不仅在旋转时不受阻碍,而且在通往太阳的视线中也应不受阻碍。 这就要求我们将太阳能电池板安装在侧面,并保持空间站其余部分的轮廓较低。

Similarly, we need to be able to reject heat to space and thus need to have large radiators.  Those radiators need to be able to articulate so that they aren’t in direct sunlight.

同样,我们需要能够将热量排到太空,因此需要有大型散热器。 这些辐射器必须能够铰接,以免受到阳光直射。

To hold those solar arrays we need rigid structures that can handle the twisting torques of the solar array rotation and drag.  That’s the big horizontal bar across the vehicle.  The trusses are not pressurized modules, but they aren’t wasted space.  Those trusses are full of equipment like batteries and coolant pumps.  The ISS needs to stay powered during night passes, so several very large batteries are needed.

为了固定这些太阳能电池阵列,我们需要能够处理太阳能电池阵列旋转和拖动的扭转扭矩的刚性结构。 那是空间站上的大横杠。 桁架不是加压模块,但它们并不在浪费空间。 这些桁架充满了电池和冷却液泵等设备。 ISS需要在通行证期间保持供电,因此需要几个非常大的电池。

Now that we’ve accepted that our space station is going to be a series of linked cylinders, we might wonder how they would be arranged.  It took several years to assemble the ISS.  It needed to be a functioning and occupied vehicle during that time.  That puts restrictions on where components are put.  We need to have stable attitude control of the stack and we need to have power, data, and consumables connectivity.  We need to have unobstructed paths for docking vehicles along the v-bar (velocity vector) and r-bar (orbital radius vector).  We need to be able to reach all of the berthing ports with the robotic arm.  We can’t block communications antennae.  The GPS antennae need a clear path to the satellites.

既然我们已经接受了我们的空间站将是一系列连接的圆柱体,那么我们可能想知道它们的布置方式。 组装国际空间站花了几年时间。 在此期间,它必须运转良好。 这就限制了放置组件的位置。 我们需要对堆栈进行稳定的姿态控制,并且需要电源,数据和耗材连接。 我们需要让沿v形(速度矢量)和r形(轨道半径矢量)对接载具的路径畅通无阻。 我们需要能够使用机械臂到达所有对接端口。 我们不能阻挡通讯天线。 GPS天线需要一条通向卫星的畅通路径。

For example, one might wonder why the European Columbus module and the Japanese Kibo modules stick out to the side instead of being added to the front.  The reason is that they were delivered by the Space Shuttle Orbiter and the Orbiter needed to dock to the PMA (Pressurized Mating Adaptor) that is at the front of the ISS.

例如,您可能想知道为什么欧洲的哥伦布(Columbus)模块和日本的Kibo(基博)模块突出到侧面而不是添加到前面。 原因是它们是由航天飞机轨道飞行器交付的,并且轨道飞行器需要对接至国际空间站前端的PMA(加压配合适配器)。

The ISS is all about function over form.  When I watch science fiction, I find myself looking at the smooth, uniform, symmetrical ships and asking myself questions like “How do they reject heat?  Where are they getting their electrical power?  Where are the communications antennae?  How does a docking vehicle avoid pluming?  Why did they put the tanks on the inside where they are harder to replace?   Why are they using so much more material than needed?  Where the heck did they build that thing?” and so on.  But every little projection, every little change in color, every change in dimension on the ISS is for a explicit engineering reason.

ISS的样子完全是根据功能需要而设计的。 当我看科幻小说时,我发现自己看着光滑,均匀,对称的太空船,并问自己一些问题,例如“它们如何散热?它们从哪里获得电力?通信天线在哪里?对接时如何避免引擎废气喷到太阳能板上? “为什么要把水箱放在难以更换的内部?为什么要使用比所需更多的材料?它们在哪里制造的?” 等等。 但是,ISS上的每个小小的投影,每个颜色的微小变化,尺寸的每个变化都是出于明确的工程原因。

Here’s an animation showing how it was all put together:

这是一个动画,显示了它们如何组合在一起:

【评论区】

@ David Muccigrosso Scientist, Student, Grown-Up Child.

Robert: “How does a docking vehicle avoid pluming?”

What is pluming? I tried to look it up, but only got “plumbing”, even when I took off the search’s auto-suggestion.

什么是pluming?,我搜索只搜索到了“plumbing”,我关了自动搜索也是这样。

答主:

Pluming is when expelled propellants hit another surface. So, when the visiting vehicle is nearby and fires its engines, we don’t want those chemicals getting onto the surface of the solar arrays (because the prop is corrosive) nor do we want the force from that prop to bend the solar arrays.

当外部推进剂排出的废气喷到另一个表面时,就叫pluming。 因此,当来访的载具在附近并点火时,我们既不希望这些化学物质进入太阳能电池板的表面(因为该引擎废气具有腐蚀性),也不希望该引擎废气产生的力使太阳能电池板弯曲。

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