And just how high is that? Let's take a look...

那到底是個什麼樣的概念?我們舉個例子...

The Karman Line is generally considered to be the start of outer space.

卡門線通常被認為是外太空的起點

The International Space Station orbits here.

國際太空站就運行在這個高度

Most satellites orbit between here...

多數的衛星運行軌道都介於從這裡開始

...and all the way out here.

一直到這個高度

It's called a parking orbit because

它之所以被稱為停駐軌道

it's not high enough to stay in orbit for a long time.

是因為物體在這個軌道仍無法永久停留在軌

But don't worry, we'll only be here for about 2 hours.

不過別擔心，因為我們只會停駐約兩小時之久

After orbiting the Earth 2 or 3 times and confirming all systems are good

在繞行地球兩至三圈，並確認所有系統都正常後

it's time to ignite the 3rd stage one more time for about 6 minutes.

就必須再次點燃第三級火箭約六分鐘時間

We call this the Translunar Injection.

這階段稱之為「逾月軌道嵌入」(TLI)

This is what sends us away from the Earth and towards the Moon.

這階段將讓太空人脫離地球並前往月球

The S-IVB is now completely useless.

這時S-IVB火箭已經耗盡

Remember that's the 3rd stage at the top of the Saturn V.

還記得這是農神五號火箭的第三級吧?

The Spacecraft Lunar Module Adapter panels detach

這時「太空船登月艙結合器」面板張開

exposing the Lunar Module.

讓內部的登月艙外露

The Command and Service Module do a complete 180 degree turn around.

指揮/服務艙接著進行180度迴轉

The Command Module must dock with the Lunar Module and pull it out.

指揮艙必須與登月艙對接後將它從第三級火箭中拉出

In space, temperatures are a lot more extreme.

在太空中，溫度差異十分巨大

There was a real danger of parts of the spacecraft freezing

太空船可能有部分處於極低溫

or other parts getting too hot.

而另一部份卻處於極高溫狀態

To prevent this, the spacecraft was now put into a slow roll

為了避免危險，太空船會處於慢速滾轉狀態

so that there was an even heat distribution.

這樣才能使太空船的熱分布達到均衡

This was called Passive Thermal Control

這種方法稱為「被動熱控制」

but also nicknamed the "Barbecue Roll"

不過也被戲稱為「翻烤肉」

If we ignore the moon, this is what our flight path will look like

如果不考量月球的話，這就是實際的飛行軌跡

we're still orbiting the Earth but we're in the shape of an elipse

我們仍繞著地球運行，只不過變成了橢圓軌道

heading all the way out into the middle of nowhere.

一直漫無目的地飛去

With the Moon however, everything starts to make a little more sense.

但當把月球放進去時，這個飛行軌跡就有了意義

At the time of launch, the Moon is about here.

在發射之時，月球大概在這個位置

During the next 3 days, their paths converge.

接下來的三天裡，它們的軌跡將會交會

Just to be clear, this is the Earth and Moon drawn to scale.

為了明確起見，這是地月依實際比例繪製

I animate it out of scale so it's easier to see the flight paths.

我在示意圖中沒有依照比例，是為了展示飛行軌跡

So, the Moon's gravity changes where the spacecraft flys.

接著月球引力將改變太空船的飛行方向

This is called a "Free Return Trajectory"

這被之稱為「自由返回軌跡」

If something were to go wrong with the engines

這樣如果火箭發動機發生故障

the astronauts would still be able to get home.

太空人仍然有機會能夠回到地球

On the other hand, if all systems are go

但如果一切系統都正常的話

it's now time to enter Lunar orbit.

這時就要準備進入月球軌道

This is called the Lunar Orbit Insertion.

這階段稱之為「月球軌道嵌入」(LOI)

As the spacecraft passes behind the Moon

當太空船航行到月背時

the Service Module engine was fired up for about 6 minutes to slow the spacecraft down.

服務艙發動機開始點燃六分鐘，以便進行減速

At times like this they would loose contact with mission control

太空人在這個階段是會與管制中心暫時失去聯繫

because they are on the far side of the Moon.

因為他們這時正位於月球背面

Unfortunately, this is where a lot of important events happened.

碰巧這階段正需要進行多項重要操作

The guys at mission control just had to sit tight until the astronauts came around the other side.

管制中心的人也只能乾等太空船從月背出現

Now it's time for the main event.

現在重要階段上場了

When the astronauts are ready

當太空人準備完畢後

two of them get into the Lunar Module

其中兩位會轉移至登月艙中

and get ready to land on the Moon.

並準備登陸月球

One of them stays behind and continues to oribit the Moon.

而另一人則會留守指揮/服務艙並繼續繞行月球

Side note: the Lunar Module was usually just called the LM.

另外一提，通常會直接把登月艙簡稱為LM

And when the Command Module and Service Module were together

而當指揮/服務艙結合在一起時

they were usually referred to as the CSM.

兩者則通常會被簡稱為CSM

The LM now extends it's legs.

這時登月艙的起落架張開

After making sure everything still checks out

在確認一切系統就緒的同時

the LM separates from the CSM.

登月艙會與指揮/服務艙分離

The LM must get to a safe distance of about 2 miles away

登月艙必須遠離約兩英里的安全距離後

before firing the descent engine.

才會點燃它的下降發動機(LMDE)

The engines fire up for about 30 seconds.

發動機燃燒約30秒時間

This is called the Descent Orbit Insertion.

這個階段稱之為「降落軌道切入」(DOI)

This puts the LM down to about 50 thousand feet above the surface.

這會讓登月艙下降至離月面五萬英呎高度

Now the engine fires up again for Powered Descent Initiation.

接著再次點燃發動機進行「動力下降起始」階段

The windows are initially pointed down.

原本機窗是處於朝下狀態

But as we get closer to the surface

但隨著越來越接近月面

the windows will be facing forward

機窗會開始朝著飛行軌跡前方

to give the astronauts a good view of the surface they'll be landing on.

好讓太空人能清楚確認著陸地點的狀況

The landing site needs to be on level terrain

著陸地點必須選擇平坦地形

and away from any big boulders.

並遠離任何巨石

There's a limited amount of fuel so the astronauts can't take too long to land.

因為燃料有限，所以太空人的降落窗口很小

And finally...touch down.

直到最後...著陸成功

Now it's time to step down the ladder, say some historic words,

接著就是要爬下階梯，發表歷史性宣言

plant the American Flag, get some rock samples

插下美國國旗，採取岩石樣本

and do some science.

然後進行數項科學實驗

After the Lunar stay was over, it's time to take off from the surface.

月面活動結束後，便要從月面升空

but, let's save that for part 3.

不過這部分要留待第三部影片再說

Thanks for watching and I'll see you in the next video.

謝謝觀賞，下部影片再見