NASA在阿波罗1号的事故后,仍在使用纯氧的环境吗?Was pure oxygen still the environment of choice by NASA after the Apollo 1 tragedy?

https://www.quora.com/Was-pure-oxygen-still-the-environment-of-choice-by-NASA-after-the-Apollo-1-tragedy

【译注:Apollo 1 tragedy,阿波罗1号在地面测试时发生事故,驾驶舱起火,有宇航员遇难。wiki上有比较详细的记录。】

Yes, for several reasons:

对,有很多原因

  • A 100% oxygen cabin atmosphere means fewer tanks, less plumbing and altogether less weight. If you are thinking they could just use compressed air, you’re forgetting that life support on a spaceship works like a rebreather. You keep adding oxygen and scrubbing CO2, so you have to have a tank of oxygen. Using an oxygen nitrogen mix means you also have to have a tank of nitrogen with which to replace the air after venting for the EVA, etc.
  • 100%的氧气舱环境意味着数量更少的储气罐,更少的水管设备以及更轻的重量。如果您认为他们只能使用压缩空气,那么您应该是不知道飞船的生命维持就像循环呼吸器一样。您必须不断添加氧气并去掉二氧化碳,因此必须至少有一个氧气罐。但如果使用氧气-氮气混合物而非纯氧的话,意味着您还必须拥有一个氮气罐,以便在太空行走时用其替换宇航服中的空气。
  • Spacesuits of the era would have been impossibly stiff if inflated to normal pressure, but were usable at 4 psi. But at that pressure, they have to be pressurized with 100% oxygen, or you’ll pass out.
  • 如果膨胀到正常压力,那个时代的太空服就不可能变得硬邦邦,但仍然可以在4 psi下使用。但是在这样的压力下,必须用100%的氧气对它们加压,否则您就会昏倒。【??】
  • For the same reason, using an oxygen/nitrogen atmosphere in the cabin would force you to use higher cabin pressure (or the crew would pass out for lack of oxygen). And raising the pressure would increase the weight of the cabin.
  • 出于同样的原因,在机舱内使用氧气和氮气的混合会让您必须使用更高的机舱压力(否则机组会因缺氧而昏迷)。而且增加压力会增加机舱的重量。
  • Moving from a cabin with a normal pressure oxygen-nitrogen atmosphere to a low-pressure oxygen atmosphere requires the astronauts to pre-breathe pure oxygen prior to EVA to remove dissolved nitrogen from their tissues and prevent the bends.
  • 从具有常压氧氮气氛的机舱移动到低压氧气氛,需要宇航员在太空行走之前预先呼吸纯氧,以从身体组织中除去溶解的氮,以防止氮破坏身体组织。

There is nothing wrong with running a spacecraft at 100% oxygen at 3 or 4 psi. It’s the partial pressure of oxygen that determines its availability both to living things and to fire. 4 psi with pure oxygen is the same (in both cases) as 21% oxygen at sea level pressure.

在100%的氧气下以3或4 psi的压力下,运行航天器没有任何问题。氧气的分子压力保证了生命能够正常呼吸,火也能正常燃烧。4 psi下的纯氧(两种情况下)与海平面上的21%的氧气是相同的。

The mistake in Apollo 1 was not in using pure oxygen. It was in running a test that required the cabin to be pressurized a couple of psi above the ambient (sea level) pressure without considering that it was a pure oxygen environment. That produced an environment pressurized with pure oxygen at 16.7 psi, an environment in which you could build a campfire using soup spoons for kindling.

阿波罗1号的错误并非在于使用纯氧。在进行一项测试时,要求机舱增压至高于环境(海平面)压力几psi(磅/平方英寸),而忽视了纯氧气环境。这样就产生了一个纯氧气加压的环境,压力为16.7 psi,您在其中用汤匙就能点燃篝火。【??】

All that was needed was to use ordinary air in the cabin during all ground operations, then gradually vent it and enrich the cabin with oxygen while reducing the pressure during launch. That simple procedural change completely solved the problem, eliminating the elevated fire risk without adding weight or harming the crew. It’s just a damn shame nobody thought to do it in the first place.

那时所需要的就是在所有地面操作过程中,都使用普通的空气, 并且在发射期间降低压力的时候,逐渐排出空气并为机舱充氧。这种简单的程序更改完全解决了问题,消除了可能的火灾风险,而不会增加重量或伤害机组人员。他们之中从来没有人想过要这样做,太令人羞愧了。

Subsequent spacecraft (the shuttle and ISS) have operated with a nitrogen/oxygen mix at sea level pressure not because an oxygen atmosphere is inherently dangerous (it’s not if at low pressure) but because in larger craft, the weight and complexity penalty isn’t as material and because for missions of longer duration or with biomedical science in mind, a normal atmosphere is one less variable to worry about (that is, while a low pressure oxygen environment doesn’t harm the crew in the short haul, we don’t know what effect it might have over weeks or longer, and we don’t want it confounding our biochemistry experiments.

随后的航天器(航天飞机和国际空间站)在海平面压力下使用氮气/氧气混合物运行,并不是因为氧气本身具有危险性(如果不是在低压下的话),而是因为在更大的航天器中,重量和复杂度并不是重点,而且因为对于较长时间的任务,或考虑到生物医学的科学实验,正常的大气环境值得担心的变量较少。也就是说,尽管低压氧气环境不会在短期内损害机组人员,但我们不会我们不知道它可能在几周或更长时间内产生什么作用,我们不希望它扰乱我们的生物化学实验。

As a result of this mixed gas atmosphere, however, astronauts on the Shuttle and ISS (and cosmonauts on the Soyuz and Russian stations) have always had to pre-breathe oxygen prior to spacewalks, because the suits still use a low pressure 100% oxygen atmosphere to control ballooning.

然而,由于这种混合气体的气氛,航天飞机和国际空间站上的宇航员(以及联盟号和俄罗斯站上的宇航员)总是不得不在太空行走之前预先给氧,因为这些宇航服仍然使用100%的低压氧气气氛来控制膨胀。

NASA’s new spacesuit, just announced as I write this, may look a bit goofy, but it uses an improved type of constant-volume joint to eliminate the problem of ballooning without needing the internal restraining wires used in earlier suits (to keep convolute joints from lengthening under pressure). The new suit still operates under 100% oxygen, but permits the astronaut to climb inside and begin work at 8 psi—high enough pressure to prevent the bends, but not so high as to create a profound fire risk. The suit will then lower the pressure to 3 psi to save consumables, and in theory an astronaut can stay inside for up to six days.

我在撰写本文,美国宇航局的新太空服刚刚与大家见面,可能看起来有些愚蠢,但是它使用了改进型的等体积万向节来消除膨胀的问题,而无需使用早期西装的内部约束线(以防止回旋万向节在压力下延长)。新宇航服仍然在100%的氧气下工作,但允许宇航员穿上并以8 psi的压力开始工作——压力足够高以防止身体组织变形,却也不会高到能造成重大火灾隐患的地步。然后,该防护服会将压力降低至3 psi,以节省消耗品,理论上,宇航员可以在宇航服内呆最多六天。

It’s worth pointing out that there is no bathroom in a spacesuit. The astronaut is wearing a fancy diaper, so…yeah.

值得指出的是,太空服中没有浴室。宇航员穿着花哨的尿布,所以……是的。

【博主吐槽:NASA对尿布的发展作出了巨大贡献哦哦哦哦….】

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