(单词翻译:单击)
Stories about human spaceflight are usually full of heroism, math, and the triumph of human ingenuity over incredible odds.
人类航天的故事通常都是英雄主义、数学和令人难以置信的人类智慧的胜利。
The story of how an astronaut got the farts on Apollo 16 is no exception.
宇航员如何在“阿波罗16号”上放屁的故事也不例外。
It all started on the Apollo 15 mission, which landed on the Moon in 1971.
这一切都始于1971年登陆月球的“阿波罗15号”任务。
The mission was successful, but while they were in space, the astronauts experienced some arrhythmia, or irregular beating of the heart.
这次任务很成功，但在太空中，宇航员们出现了一些心律失常，或者心脏不规则跳动的症状。
Arrhythmia can signal all kinds of serious cardiovascular problems, like heart attack and stroke.
心律失常可能预示着各种严重的心血管疾病，如心脏病和中风。
So even though the astronauts made it back just fine,
所以即使宇航员平安返回，
NASA very much wanted to make sure that astronauts on future missions avoided arrhythmia while they were in space,
宇航局也非常想确保宇航员未来在太空执行任务时不出现心律失常的症状，
where humans have yet to establish any solid healthcare infrastructure.
人类在太空还没有建立任何硬性的基础医疗设施。
So NASA physicians did some bloodwork on the Apollo 15 crew when they returned to Earth,
所以，宇航局的医生们在“阿波罗15号”的宇航员返回地球后做了一些血液测试，
and found that they had too little potassium in their systems, a condition called hypokalemia.
结果发现他们体内的钾含量太少，患了一种叫做低钾血症的疾病。
Potassium is super important for your heart because it's a major part of nerve cell function.
钾对心脏非常重要，因为它是神经细胞功能的重要组成部分。
And your nervous system is what controls your heartbeat.
神经系统控制着心跳。
Specifically, potassium is used in the sodium-potassium pump, which is found in all kinds of cells,
具体地说，钾被用于钠-钾泵中，存在于所有类型的细胞中，
including those in every part of the nervous system.
其中包括神经系统的各个部分。
An enzyme separates out the sodium and potassium on either side of a nerve cell's membrane, building up voltage across the cell surface.
在神经细胞的细胞膜两侧，有一种酶将钠和钾分开，使得两侧产生电压。
For carefully timed bursts of cellular activity,
对于准时爆发的细胞活动来说，
you usually want the cell's membrane to reach a particular voltage before firing, called the action potential.
你通常想要细胞膜在细胞兴奋前达到特定的电压，这被称为动作电位。
Once you hit that voltage, the cell fires; otherwise, it just waits for the voltage to build up again.
一旦达到那个电压，细胞就会兴奋；否则，只能等到电压再次产生。
A network of nerve cells throughout the heart rely on the sodium-potassium pump, among other cell-signalling pathways, to time your heartbeat.
钠-钾泵支撑整个心脏的神经细胞网络，与其他细胞信号传导通路一起保证你的心跳有规律跳动。
If components of that system fall out of whack, like if you aren't getting enough potassium, your heartbeat can get off-kilter.
如果这个系统的成分不正常，如你没有得到足够多的钾，你的心跳就会失衡。
So be sure to eat your bananas, friends. But back to our astronauts.
所以，朋友们，要吃香蕉。我们回到宇航员身上。
To keep the Apollo 16 astronauts safe from the arrhythmia experienced by the Apollo 15 crew, NASA prescribed a ton of potassium.
为了让“阿波罗16号”的宇航员免受“阿波罗15号”宇航员曾经历的心律失常，宇航局开了一吨的钾。
Not enough to mess up the sodium-potassium pump in the other direction, but still a whole bunch.
虽然还不足以扰乱钠-钾泵的传导方向，但还是很多。
Potassium is typically very bitter, so it needs to be dissolved into something with a lot of flavor.
钾通常非常苦，所以它需要溶解到含很多味道的东西里。
NASA decided to use lots of citrus drinks.
宇航局决定使用大量的柑橘类饮料。
The crew had various citrus-flavored rehydratable drinks that they had to drink every day, multiple times a day.
宇航员们每天喝各种各样柑橘味的复水饮料，每天都要喝好几次。
As you can probably imagine, the astronauts got really tired of this.
你可以想象得到，宇航员得多厌恶它。
And the diet had some physical downsides, which we know because NASA records all its communication with astronauts and makes the transcripts publicly available.
饮食有一些物理缺陷，因为宇航局记录了宇航员之间的交流，并对外公开。
At one point, the mission commander, John Young, was unaware that he had a hot mic,
在这一点上，任务指挥官约翰·杨(John Young)没有意识到他的通话被播出去，
and well, I'll just let you listen to what he said to fellow astronaut Charles Duke.
好吧，我让你们听听他对同伴宇航员查尔斯·杜克说的话。
"I've got the farts, again. I got 'em again, Charlie. I don't know what gives 'em to me.
“我又放屁了。查理，我又放屁了。我不知道是什么导致的。
I think it's acid stomach, I really do.
我觉得是胃酸，真的。
I haven't eaten this much citrus fruit in 20 years. I'll tell you one thing, in another 12 days, I ain't never eatin' any more."
我已经20年没吃过这么多柑橘了。我要告诉你一件事，再过12天，我再也不会吃它们了。”
So of course the press reported this, and because farts are always funny, everyone had a good laugh about it.
当然，媒体报道这一点是因为放屁总是滑稽的，每个人都会开怀大笑。
That is, everyone except for Florida Citrus Mutual, the organization representing Florida's citrus industry.
也就是说，所有人都会这样，除了“Florida Citrus Mutual,”，它代表着佛罗里达的柑橘产业。
They issued some official statements saying that the astronauts were using artificial citrus drinks,
他们发表了一些官方声明，称宇航员们正在使用的是人造柑橘类饮料。
and not wholesome, Floridian OJ, part of this complete, balanced breakfast.
而不是健康的“佛罗里达OJ”，它是完整均衡早餐的一部分。
So citrus is not to blame, and they would like you to please continue to buy their products.
所以柑橘并不是罪魁祸首，他们希望你能继续购买他们的产品。
And that was true. The flatulence wasn't caused by fruit. It was the potassium.
这是真的。肠胃气胀不是由水果引起的，而是钾
See, potassium is used in another enzyme pump, in the digestive system. It's the hydrogen-potassium pump.
明白了吧，钾在消化系统中应用于另一种酶泵，氢-钾泵。
Your stomach acid is kept nice and acidic by an enzyme that pumps potassium in and hydronium ions out.
胃酸良好的酸性是由一种泵进钾离子和泵出水合氢离子的酶保持的。
The hydronium quickly dissociates to regular water and free hydrogen ions.
水合氢离子迅速分解成普通的水和游离的氢离子。
Having free hydrogen ions in a solution is what makes it acidic.
溶液中含有游离的氢离子会变酸。
In fact, pH stands for "power of hydrogen."
事实上，pH值是指酸碱度。
So all the extra potassium the astronauts were taking in caused the hydrogen-potassium pump to overwork, which gave them "the farts."
因此，宇航员们额外摄入的钾元素导致了氢-钾泵超负荷工作，这给了他们“屁”。
But their heartbeats were good and steady, so at least they solved that problem!
但他们的心跳良好平稳，因此他们至少解决了这个问题。
There has actually been a great deal of research into space farts by NASA, because they pose a safety hazard.
事实上，宇航局已经对太空屁进行了大量的研究，因为它们构成了安全隐患。
Methane is a flammable gas, so having a container of people emitting flammable gas on top of a rocket could conceivably pose some problems.
甲烷是一种易燃气体，因此，如果有人在火箭头上释放易燃气体，可能会带来一些问题。
But the amount of methane the Apollo 16 astronauts produced didn't cause a fire, and the astronauts didn't experience any arrhythmia.
但是“阿波罗16号”宇航员所产生的甲烷并没有引起火灾，而且宇航员也没有任何心律失常的症状。
So unfortunately for the Apollo 17 crew, NASA physicians required the potassium diet for them, too.
所以“阿波罗17号”的宇航员很不幸，宇航局的医生也要求他们吃含钾的饮食。
Thanks for watching this episode of SciShow Space.
感谢您收看本期的太空科学秀！
For more amazing stories from the history of space travel,
要想了解更多太空旅行的惊人故事，
plus all kinds of other fascinating space science, you can go to youtube.com/scishowspace and subscribe.
以及各种迷人的太空科学，可以登录youtube.com/scishowspace点击订阅按钮。
Not all of our episodes are about farts, I promise.
我保证，不是所有的剧集都是放屁的内容。
