after nearly a year on the International Space Station.

在國際空間站工作近一年後。

But when he came back, he was 2 inches taller.

但是當他回來的時候，他又高了兩寸。

So, what exactly happened up there,

那麼，上面到底發生了什麼。

and what does that mean for the future of space travel?

這對未來的太空旅行意味著什麼？

If you're planning a trip to the International

如果你正計劃前往國際旅遊，那麼你就會發現，你是一個很好的選擇。

Space Station, be prepared to feel weightless.

空間站，要做好失重感的準備。

The station orbits the planet every 90 minutes,

該站每90分鐘繞地球一圈。

moving at more than 17,000 miles per hour.

以每小時17000多英里的速度移動。

That's 30 times faster than a commercial jet aircraft.

這比商用噴氣式飛機快30倍。

As a result, astronauts on board live in a constant state

是以，太空人在太空中的生活狀態是恆定的。

of free fall, or weightlessness.

的自由落體，或失重。

Garrett Reisman: Being up there in microgravity is awesome.

Garrett ReismanBeing up there in microgravity is awesome.

It's, like, the coolest thing,

這是一樣，最酷的事情。

because it's like you have the power to fly.

因為這就像你有飛翔的力量。

Narrator: That's Garrett Reisman,

旁白：那是Garrett Reisman

a former NASA astronaut who's logged 107 days in space.

前美國宇航局的太空人，在太空中呆了107天。

There are a few immediate side effects, he says,

他說，有一些直接的副作用。

when you first experience microgravity.

當你第一次體驗微重力時。

Reisman: So the first thing you really feel is

雷斯曼。所以你真正感受到的第一件事是

you feel kinda sick.

你覺得有點噁心。

You don't feel very good those first couple days.

前幾天你感覺不是很好。

It's kinda like being airsick or seasick.

這有點像暈機或暈船。

We call it space-adaptation sickness.

我們稱之為空間適應病。

Your vestibular system, your organs

你的前庭系統，你的器官

that provide information to the brain

向大腦提供資訊的

about your rotation and your acceleration,

關於你的旋轉和你的加速度。

they're not working that great without being in gravity.

他們在沒有重力的情況下是不會有那麼大的作用的。

Narrator: Without gravity working on your body,

旁白：沒有地心引力對你身體的影響

your bones and muscles start to break down, too.

你的骨骼和肌肉也開始分解。

In fact, bone density drops by over 1% per month.

事實上，骨密度每月下降1%以上。

By comparison, the rate of bone loss

相比之下，骨質流失率

for elderly men and women is around 1% to 1.5% per year.

老年男子和婦女每年約為1%至1.5%。

And, because it doesn't take much effort

而且，因為它不需要太多的努力。

to float through space,

漂浮在太空中。

your muscles lose strength and endurance pretty quickly.

你的肌肉很快就會失去力量和耐力。

Reisman: You have to work out every day.

Reisman你必須每天鍛鍊。

So, they scheduled two hours a day pretty much every day

所以，他們幾乎每天都會安排兩個小時的時間。

while I was on the space station for working out.

當我在空間站鍛鍊的時候。

What we found was, if you do enough resistive exercise,

我們發現，如果你做了足夠多的抵抗性運動。

you can halt the effects of the bone loss

你可以阻止骨質流失的影響。

and the muscle atrophy.

和肌肉萎縮。

Narrator: Without gravity pulling them down,

旁白：沒有地心引力把它們拉下來

fluids pool in the body, tricking it into thinking

液體在體內積聚，使其誤入歧途。

it's carrying too much water.

它承載了太多的水。

As a result, astronauts have to pee...

是以，太空人要尿... ...

a lot.

很多。

This makes it easy for them to get dehydrated

這樣一來，他們很容易脫水

and develop kidney stones.

並患上腎結石。

Reisman: So, you have a shift in your fluid.

萊斯曼所以，你有一個轉變 在你的液體。

A lot of the blood volume that normally is down in your legs

很多的血量通常是在你的腿部下降

ends up up here, and your chest kinda puffs up

最後在這裡，和你的胸部有點膨大了

and your face puffs up, and you can see it.

而你的臉腫起來，你可以看到它。

If you look at pictures of us on the space station,

如果你看一下我們在空間站的照片。

it looks like we put on some weight or something

它看起來像我們把一些重量什麼的

and we're all puffed up.

而我們都是浮誇的。

Narrator: Swelling in the upper body

旁白：上半身腫脹

puts pressure on the eyes as well,

給眼睛也帶來了壓力。

which can cause vision problems.

這可能會導致視力問題。

Reisman: A lot of us, including myself,

Reisman。包括我在內的很多人

had a shift in our vision while we're up in space.

我們在太空中的視野發生了變化。

You start out, everything was fine,

你開始的時候，一切都很好。

and all of a sudden things get blurry.

突然間，事情變得模糊不清。

We could see the effects of it.

我們可以看到它的效果。

We could see swelling in the optic nerve,

我們可以看到視神經的腫脹。

we could see folds in the cornea,

我們可以看到角膜上的褶皺。

but we're still not 100% sure

但我們還不確定

exactly what's causing it and how to stop it.

究竟是什麼原因造成的，如何阻止它。

Narrator: With all the challenges of space travel,

旁白：伴隨著太空旅行的種種挑戰

one benefit is you actually get taller.

有一個好處是你真的會變高。

Reisman: So, yes, you do get taller when you go to space.

Reisman:所以，是的，你確實會變高 當你去太空。

It's the whole reason I signed up for this job.

這也是我報名參加這份工作的原因。

Your spine is being compressed by gravity.

你的脊柱被重力壓縮了。

So, when you go into the microgravity environment

所以，當你進入微重力環境時... ...

and you no longer have any kind of compressive loads

而你不再有任何形式的壓縮負荷。

on the spine at all, it stretches.

在脊柱上，它伸展。

I grew about an inch.

我長了大約一英寸。

Astronaut: Woo-hoo!

太空人。Woo -hoo!

Narrator: Without gravity working against it,

旁白：沒有重力的作用

the heart doesn't have to work as hard

心有餘而力不足

to pump blood throughout the body.

以泵送血液到全身。

Over time, this could lead to the heart

久而久之，就會導致心

actually decreasing in size.

實際上是在減少。

Reisman: There is an effect on the cardiovascular system

里斯曼。對心血管系統有影響

about being up in space.

關於在太空中。

So you do get a reduced aerobic capability.

所以你的有氧能力確實有所下降。

You can be in great shape,

你可以有很好的狀態。

and after being up in space for a couple days,

而在上了幾天的空間後。

you might get on the treadmill, and you might be like,

你可能會得到在跑步機上， 你可能會喜歡，

"Man, I must not have been hitting the gym."

"夥計，我一定沒有去健身房。"

Narrator: The immune system also takes a hit.

旁白：免疫系統也會受到影響

Researchers discovered that a lack of gravity

研究人員發現，缺乏引力

weakens the functions of T cells,

削弱了T細胞的功能。

which play a crucial role in fighting off diseases.

在抵禦疾病方面起著至關重要的作用。

Another concern is cosmic radiation.

另一個關注點是宇宙輻射。

Astronauts on the station are exposed

空間站上的太空人被曝光

to over 10 times the amount of radiation

輻射量的10倍以上

that we get on Earth.

我們在地球上得到的。

Reisman: At a couple hundred miles,

萊斯曼。在幾百英里外

we're well above the atmosphere,

我們在大氣層之上。

but we're still well below the magnetic field of the Earth.

但我們仍然遠遠低於地球磁場。

But we still get a large bit of protection

但我們還是得到了很大的保護

from that magnetic field.

從該磁場。

In fact, you could tell, because when you close your eyes,

其實，你可以看出來，因為當你閉上眼睛的時候。

you see little lightning bolts,

你會看到小閃電。

and that's actually a result of some of the radiation

而這實際上是一個結果 一些輻射。

hitting your eyeballs and releasing photons.

打你的眼球，釋放光子。

Narrator: Artificial shielding on the ISS

旁白：國際空間站的人工屏蔽

only partially protects astronauts from harsh radiation,

僅能部分保護太空人免受惡劣的輻射。

leaving them more susceptible to cancer

使他們更容易患癌症

and other diseases later in life.

以及以後的其他疾病。

Finally, astronauts must also be able to handle

最後，太空人還必須能夠處理以下問題

the psychological challenges of confinement and isolation.

禁閉和隔離的心理挑戰；

Reisman: So, there is a psychological aspect

萊斯曼。所以，有一個心理方面

to being in space, both because of the fact

在太空中，既是因為有了這個事實，也是因為有了這個事實，才會有這樣的結果。

that you're isolated from the rest of humanity,

你和其他人類隔離了

it was really strange to be looking out the window

望著窗外的景色，真的很奇怪。

at billions of people down there

在下面幾十億人

that had no way to get to me.

沒有辦法讓我。

When I was there, I only had two crewmates

我在那裡的時候，我只有兩個船員。

at a time on the space station,

在空間站上一次。

so if you don't get along with somebody,

所以如果你不與人相處，

that could be bad, because you don't have

這可能是壞的，因為你沒有。

too many choices there in making new friends.

在那裡結交新朋友有太多的選擇。

Narrator: And, without a 24-hour sleep cycle,

旁白：而且，沒有24小時的睡眠週期

astronaut circadian rhythm is thrown off,

太空人的晝夜節律被打亂了。

which can cause more stress and lead to sleep disorders.

會造成更大的壓力，導致睡眠障礙。

Reisman: You're taking jet lag to a whole nother extreme.

Reisman你把時差帶到了一個全新的極端。

Well, the weird thing is that you go around the planet

好吧，奇怪的是，你繞著地球轉了一圈。

once every hour and a half.

每一個半小時一次。

So every 45 minutes, the sun is either rising or setting.

所以每隔45分鐘，太陽不是升起就是落下。

So you can't, like, tell what time it is

所以，你不能一樣，告訴它是什麼時候。

by looking out the window.

通過看窗外。

Narrator: So, what does all this mean

旁白：那麼，這一切意味著什麼？

for the future of space travel?

對於未來的太空旅行？

Well, a trip to Mars would expose astronauts

好吧，去火星旅行會讓太空人暴露在火星上。

to even more dangers than those

比那些更危險的

on the International Space Station.

在國際空間站上。

They would face higher levels of radiation,

他們將面臨更高的輻射水準。

shifting gravity fields, and longer travel times,

變化的重力場，和更長的旅行時間。

which would compound all of the negative effects

這將加劇所有的負面影響

of space on the human body and mind.

空間對人的身體和心靈的影響。

Reisman: I think the biggest issue we gotta deal with

雷斯曼：我認為我們要解決的最大問題是：1.

is the radiation.

是輻射。

We don't know precisely what that exact radiation

我們不知道確切的輻射是什麼。

does to human beings.

對人類的影響。

But what does gamma rays or what does heavy ions,

但什麼是伽馬射線，什麼是重離子。

what do they do human tissue?

他們做什麼人體組織？

We don't really know.

我們真的不知道。

Narrator: Right now, NASA and other research organizations

旁白：現在，NASA和其他研究機構

are working to develop better technology

正在努力開發更好的技術

that protects astronauts against these hazards,

保護太空人免受這些危害。

so maybe one day humans might make it to Mars.

所以也許有一天人類會登上火星。