宇航服需要两只脚符合逻辑吗?宇航员不行走,把双脚塞在一个袋子里,会不会更方便?

Is there a logical reason why astronauts’ space suits have legs? They don’t walk anywhere. Wouldn’t it make more sense to have a single pod for both legs, which would make it easier to put on and take off the space suits?

【翻译自quora, Jonathan Miller, 30+ Years NASA Engineer, Johnson Space Center, Houston 】

Believe it or not I’ve been asking that question for years. I call it the Dolphin or Mermaid suit.

不管你信不信,我被问这个问题很多年了。我叫它海豚服或者美人鱼服。

And finally I got another engineer’s attention long enough to explain why this is not such a good idea.

最后,我与另一位工程师讨论足够长的时间,以解释为什么这不是一个好主意。

First of all you are correct, in freefall (microgravity) of the ISS they are not walking. There are still stresses that have to be accounted for. When an astronaut is manipulating a massive object they must react those forces somehow. Most commonly that is done with foot restraints.

首先,您是正确的,在国际空间站(微重力)中,宇航员没有行走。但仍有压力必须解决。当宇航员操纵大型物体时,他们必须以某种方式反作用于这些力。最常见的做法是用脚约束力。

Now I can imagine designing a foot restraint that works with a single pod for both legs. But getting into and out of that would be very tricky. Not to mention we already have these in use all over ISS and they would need to be replaced.

现在,我可以想象设计一种把双脚放进一个裤带里的宇航服。但是穿上和脱下都将更加困难。更不用说我们已经在ISS上使用了它们,因此需要对其进行替换。【??】

More fundamentally there is a bigger problem. Suit sizing is not just a matter of convenience. The astronaut is actually floating within the spacesuit and when the crewmember moves, the suit has to move with him or her and the load path has to be consistent and understood for it to work properly.

从根本上说,并不是大不大的问题。宇航服尺码不只是为了方便。宇航员实际上是漂浮在宇航服内,当机组人员移动时,宇航服必须随他或她一起移动,并且载荷路径必须一致并能正常工作。【??】

In other words, you have this volume pressurized to 4.3 pounds per square inch and this large voluminous pod where your legs are, when you start torquing a bolt, how are your legs positioned within that pod? How do you react that load?

换句话说,您将如果你把双脚放在一个裤筒里,而加压到4,3磅每平方英寸,并拧紧螺栓,您的腿如何放置?您如何应对这一负担?

The current spacesuit is quite rigid in the lower torso and reacts much of that load for you. And that load is distributed across your entire lower torso.

当前的太空服在较低的躯干上非常坚硬,可以做出很大的反应。而且该负载分布在整个下部躯干上。

We don’t handle large satellites like this anymore, but if that satellite starts going sideways can you imagine the loads going through the crew member?

我们不再处理像这样的大型卫星,但是如果该卫星开始侧向飞行,您能想象机组人员的负载吗?

Finally, last but not least, in a large pod for both legs the hoop stress would be enormous. The hoop or circumferential stress increases in proportion to the radius. The spacesuit already has a large thick metal reinforcement at the waist to counter this. With a large pod for both legs this metal reinforcement would need to be extended all the way to the feet. This additional weight would negate any material savings from not having individual legs.

最后也很重要的一点,在双腿的裤筒中,环向应力将很大。环向应力或圆周应力与半径成比例增加。太空服在腰部已经有一个大的厚金属加强件来应对。由于双腿在同一个裤筒内,因此这种金属加固物需要一直延伸到脚。该额外的重量没有让两腿分开那样节省材料。

So there you have it, the Dolphin suit would actually be quite challenging to make.

所以记住,制作海豚服很有挑战性。

@ Mark Shulmann

Good answer, Jonathan. I’m sure you’ve hit all the major reasons, but I’m wondering about a minor reason: It seems to me that having your legs “tied together” in a single pod might give an astronaut a claustrophobic feeling. I’m sure if there were a big advantage to having a single leg pod, then you’d just suck it up and train until the feeling of being bound goes away, but I wonder if any of the astronauts have ever expressed a preference for separate suit legs. It seems like it would feel more natural, but maybe when you’re in free fall you really don’t care about your legs. Any idea?

好答案, Jonathan 。 我确定您已经写出了所有主要原因,但我想知道有一个次要原因:在我看来,双腿“绑在一起”到一个裤筒中可能会使宇航员产生幽闭恐惧感。 我敢肯定只有一个裤筒有很大的优势,那么您只需将把双腿放在一起并训练,直到被束缚的感觉消失,但我想知道是否有任何宇航员曾表示过喜欢分开双腿的宇航服,这样似乎感觉更自然,但也许当您飘来飘去的时候,您实际上并不在乎您的腿。 有什么想法吗?

答主:

I think if we had a spacesuit for tourists it would be acceptable to have a leg pod. The difficulty is when you need to use your upper body to do work. You need a stable lower body. For tourists you could imagine a pod for the entire body with no arms and legs. Kind of like the rescue ball.

我认为,如果我们为游客提供太空服,那么只有一个裤筒是可以接受的。 困难在于您当用上半身来做工作时。 您需要下半身很稳定。 对于游客来说,您可以想象包裹住手和腿的整个宇航服。 有点像抢救球。

@ Mark Shulmann

Wow, that does not look comfortable. The tourism thing is starting to lose some of its luster! Thanks for the reply, and for the thoughtful original answer.

哇,看起来不舒服。 旅游业看起来并不很好! 感谢您的答复和深思熟虑的原答案。

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