航海家2號如何在太空中精準穿梭：英語精讀講義

This is the Voyager 2 space probe approaching Neptune,

這是正在接近海王星的航海家2號太空探測器，

the furthest planet in our solar system.

海王星是我們太陽系中最遠的行星。

It was the first time that any spacecraft had made the 4 billion kilometer journey, 文法

這是太空船首次完成40億公里的旅程，

and very little was known about this gas giant at the time.

當時人們對這顆氣體巨行星知之甚少。

Neptune is so far away that it has only completed a single orbit of the Sun 文法

海王星距離我們非常遙遠，自1846年被發現以來，

since we discovered it back in 1846.

它繞行太陽的軌道才剛完成一圈。

The true scale of our solar system is impossible for us to comprehend,

我們無法想像太陽系的真實規模，

and due to the laws of physics,

而且由於物理定律的限制，

navigating this huge expanse is anything but straightforward. 慣用語

航行於這片廣闊無垠的太空中絕非易事。

Nevertheless,

儘管如此，

in August 1977,

在1977年8月，

the Voyager 2 space probe began an incredible lifelong journey

航海家2號太空探測器展開了令人驚嘆的畢生旅程，

that would take it all the way through our solar system and beyond. 片語搭配

這趟旅程將帶著它穿越我們的太陽系並飛向更遠的星際。

Today,

如今，

the space probe is some 20 billion kilometers from Earth,

這艘太空探測器距離地球約200億公里，

but how did it get to this point? 表達脈絡

但它是如何走到這一步的？

In this video,

在這支影片中，

we're going to look at the incredible physics behind Voyager 2's journey

我們將探討航海家2號旅程背後不可思議的物理學，

and the clever systems it used to navigate through space.

以及它用來在太空中航行的巧妙系統。

We'll also be giving away this awesome Saturn 5 framed print.

我們還將送出這幅超棒的農神5號裱框畫作。

So, stick around to the end of the video 片語動詞

所以，請留到影片最後，

to see how you could win.

看看你要如何贏得獎品。

In the mid-60s,

在60年代中期，

a NASA engineer discovered a rare alignment of our four biggest planets was about to take place. 講解

一位NASA工程師發現我們最大的四顆行星即將出現罕見的連線。

This alignment only happened every 175 years,

這種連線每175年才會發生一次，

and it would allow a spacecraft to visit all four of these giant planets in a single mission.

它能讓太空船在一次任務中造訪這四顆巨行星。

And so,

因此，

it was up to Voyager 2 to take on this challenge. 講解

航海家2號肩負起了這項挑戰。

But in order to get there,

但為了到達那裡，

Voyager 2 had to thread the needle through space, 慣用語

航海家2號必須在太空中穿針引線，

perform four gravity assists,

執行四次重力助推，

and escape the Sun's gravity.

並擺脫太陽的引力。

The planets in our solar system are constantly being pulled in by the Sun,

太陽系中的行星不斷被太陽拉扯，

but since they are also moving sideways very quickly,

但由於它們同時也以極快的速度橫向移動，

their motion fights against the Sun's pull,

它們的運動抵抗了太陽的拉力，

keeping them in a constant orbit.

使它們保持在固定的軌道上。

Without this velocity,

如果沒有這種速度，

objects in space would simply be dragged straight into the Sun.

太空中的物體就會直接被拉進太陽裡。

But if an object is traveling fast enough,

但如果一個物體的移動速度夠快，

it can outpace the Sun's pull,

它就能超越太陽的拉力，

allowing it to completely break free and travel beyond our solar system. 片語動詞

讓它完全掙脫並飛出我們的太陽系。

And so,

因此，

Voyager 2 needed to go fast enough to escape the Sun's gravity.

航海家2號需要達到夠快的速度才能擺脫太陽的引力。

The closer an object is to the Sun,

物體離太陽越近，

the more it will get pulled in.

受到的拉力就越大。

The Sun's gravity creates a deep well in the fabric of space,

太陽的引力在空間結構中創造了一個深谷，

which we can essentially think of as a hill. 片語搭配

我們基本上可以把它看作是一座山。

An object trying to escape from the bottom of the hill

一個試圖從山底逃脫的物體，

will need much more velocity than one escaping from the top.

會比從山頂逃脫的物體需要大得多的速度。

Since Earth is still relatively close to the Sun,

由於地球距離太陽相對較近，

Voyager needed a lot of energy to escape.

航海家號需要大量的能量才能逃脫。

None of the rockets around at the time were powerful enough to do this.

當時的火箭沒有任何一個的威力大到足以做到這一點。

But due to this incredible alignment,

但由於這次不可思議的連線，

Voyager could use gravity assists to slingshot itself from planet to planet, 用詞

航海家號可以利用重力助推，讓自己從一顆行星彈射到另一顆行星，

increasing its speed along the way.

沿途不斷增加速度。

In order to receive a gravity assist,

為了獲得重力助推，

it used these giant magnets.

它使用了這些巨大的磁鐵。

Just kidding.

開玩笑的。

But these magnets were used to hang up these awesome metal posters from Displate.

不過這些磁鐵是用來掛起Displate這些超棒的金屬海報。

Displates are designed to last with their sturdy, magnet-mounted, and durable build.

Displate的設計經久耐用，採用堅固、耐用的磁吸式結構。

They're customizable, collectible, and easy to adjust,

它們可客製化、具收藏價值，而且易於調整，

so you can experiment with different arrangements as often as you'd like.

所以你可以隨心所欲地嘗試不同的排列方式。

With just 20 seconds of setup time,

只要20秒的設定時間，

Displates can be mounted without power tools or damage to your walls.

Displate就能安裝完畢，無需使用電動工具，也不會損壞牆壁。

Whether you're in the market for James Webb artwork, 慣用語

無論你想買的是韋伯太空望遠鏡的藝術品、

Voyager artwork,

航海家號的藝術品，

or my current favorite,

還是我目前最喜歡的，

the Grand Tour from the official NASA collection,

NASA官方收藏的Grand Tour系列，

you're sure to find a design that speaks to you. 慣用語

你一定能找到引起共鳴的設計。

So, why not add a touch of interstellar flair to your home or office with Displate.

那麼，何不讓Displate為你的家或辦公室增添一抹星際風情呢。

Visit the link in the description to start your collection today

點擊資訊欄中的連結，今天就開始你的收藏，

and get up to 37% off.

並享有最高37%的折扣。

In order for Voyager to leave our solar system,

為了讓航海家號離開太陽系，

it had to exceed the Sun's escape velocity,

它的速度必須超過太陽的逃逸速度，

which at the distance of Earth was about 42 km/s.

在地球的距離，這大約是42公里/秒。

Despite launching on the most powerful rocket around at the time, 文法

儘管搭載當時最強大的火箭發射，

it could only provide a delta V of around 10 km/s.

它也只能提供大約10公里/秒的速度變化量（delta V）。

This may not sound like a lot,

這聽起來可能不多，

but Earth was already moving around the Sun at 30 km/s.

但地球本身已經以30公里/秒的速度繞著太陽運行。

So, by launching Voyager in the direction of Earth's travel,

所以，藉由朝著地球行進的方向發射航海家號，

it took advantage of this velocity, 片語搭配

它利用了這個速度，

allowing it to reach around 40 km/s relative to the Sun.

使其相對於太陽的速度達到了40公里/秒左右。

This was enough to escape Earth's gravity and place it into a very large orbit around the Sun,

這足以擺脫地球的引力，並將其送入一個非常大的繞日軌道，

one that would take it well past the distance of Mars.

這個軌道會把它帶到遠超火星距離的地方。

Under normal circumstances, 片語搭配

在正常情況下，

it would remain in this orbit indefinitely.

它將永遠留在這個軌道上。

But since it was trying to get a gravity assist from Jupiter,

但因為它試圖從木星獲得重力助推，

it aimed itself at the point where Jupiter was going to be by the time it arrived. 文法

所以它瞄準了它抵達時木星將會出現的位置。

However,

然而，

despite the sheer scale of the area around Jupiter,

儘管木星周圍的區域極其廣大，

Voyager had to thread itself through a very narrow 150 km wide corridor

航海家號必須穿過一條寬度只有150公里的狹窄通道，

and arrive at a specific point to the nearest second, 片語搭配

並且精確到秒地抵達特定地點，

all whilst traveling at 10 km/s.

而這一切都是在以10公里/秒的速度飛行時進行。

If Voyager missed this point or was a few seconds off,

如果航海家號錯過了這個點，或者差了幾秒鐘，

it would have ruined the gravity assist and its following gravity assist around Saturn.

它就會毀了這次重力助推，以及隨後繞行土星的重力助推。

In order to achieve such incredible accuracy,

為了達到如此驚人的準確度，

Voyager had to know its exact location in space and control its speed with great precision.

航海家號必須知道它在太空中的確切位置，並極度精準地控制速度。

Five sets of thrusters placed around the space probe would allow Voyager to rotate around all three of its axes.

配置在太空探測器周圍的五組推進器能讓航海家號繞其三個軸旋轉。

This was super important since its large antenna had to be constantly facing Earth

這非常重要，因為它的大型天線必須始終對準地球，

in order to send and receive signals.

才能發送和接收訊號。

These thrusters would fire tiny millisecond pulses,

這些推進器會發射毫秒級的微小脈衝，

rotating Voyager at around 0.3 degrees a second.

讓航海家號以每秒約0.3度的速度旋轉。

At this rate, 片語搭配

在這個速率下，

it would take an entire 5 minutes just to turn 90 degrees.

僅僅轉向90度就需要整整5分鐘。

Then,

接著，

there was another set of identical thrusters that could be fired for longer durations

還有另一組相同的推進器可以進行較長時間的點火，

to alter Voyager's speed,

以改變航海家號的速度，

allowing NASA to finely control its trajectory over time.

讓NASA能隨著時間微調它的軌跡。

But how did Voyager actually know where it was and where it was going?

但是航海家號實際上是如何知道它在哪裡以及要去哪裡的呢？

Located on Voyager's antenna was a device called a Sun sensor.

在航海家號的天線上，有一個叫做太陽感測器的裝置。

It detected the Sun as the brightest object in space

它會將太陽偵測為太空中最亮的物體，

and commanded Voyager to rotate until it locked onto it. 片語動詞

並指揮航海家號旋轉，直到鎖定太陽。

This would correctly align the x and y axes and ensure that Voyager's antenna was facing Earth.

這能正確對齊x軸和y軸，並確保航海家號的天線面向地球。

In order to sort out the roll axis, 片語動詞

為了處理滾動軸的問題，

a star tracker facing 90 degrees away from the Sun sensor

一個朝向與太陽感測器相差90度的恆星追蹤器，

would look for a specific star which had a known level of brightness.

會尋找一顆具有已知亮度的特定恆星。

Again,

同樣地，

Voyager would rotate around this axis until it locked onto the star.

航海家號會繞著這個軸旋轉，直到鎖定這顆恆星。

But Voyager couldn't always rely on these systems. 片語搭配

但是航海家號無法總是依賴這些系統。

Anytime Voyager passed by a planet, 文法

每當航海家號飛越行星時，

its Sun sensor would be temporarily blocked.

它的太陽感測器就會被暫時遮蔽。

Likewise,

同理，

when Voyager rotated to take pictures of specific targets,

當航海家號旋轉以拍攝特定目標時，

both sensors would no longer be facing their reference points.

兩個感測器就不再面向它們的參考點。

And so,

因此，

to keep track of how much Voyager had rotated, 片語搭配

為了記錄航海家號旋轉了多少，

it had an onboard gyroscope,

它搭載了一個機載陀螺儀，

which could be used for several hours at a time. 片語搭配

每次可以連續使用幾個小時。

This was a disc mounted on a three-axis gimbal.

這是一個安裝在三軸萬向節上的圓盤。

When activated, 文法

啟動時，

the disc would spin and its angular momentum would keep it perfectly stable.

圓盤會旋轉，其角動量會讓它保持完美的穩定。

As Voyager rotated,

當航海家號旋轉時，

the gimbals would rotate around this disc and a device would measure how much its orientation had changed.

萬向節會繞著這個圓盤轉動，一個裝置會測量其方向改變了多少。

Voyager then knew exactly how much it had to rotate in order to return to its Earth-facing position.

航海家號便能確切知道它必須旋轉多少才能回到面向地球的位置。

This entire system worked very well and gave Voyager a fixed orientation in space.

整個系統運作得非常好，為航海家號提供了在太空中的固定方位。

But knowing the orientation was only part of the problem. 表達脈絡

但是知道方位只是問題的一部分。

In order to plot its trajectory,

為了繪製它的軌跡，

NASA needed to know how fast it was going.

NASA需要知道它的速度有多快。

They did this by sending a signal out to Voyager 文法

他們藉由向航海家號發送訊號，

and timing how quickly it would respond.

並計算它回應的時間來做到這一點。

Since each signal traveled at the speed of light,

由於每個訊號都以光速傳播，

multiplying these two numbers would give them Voyager's distance.

將這兩個數字相乘就能得到他們與航海家號的距離。

Then,

接著，

they'd send another signal,

他們會發送另一個訊號，

which would give them Voyager's new distance.

藉此獲得航海家號的新距離。

By subtracting these distances,

將這些距離相減，

they could figure out how much Voyager had traveled in that time. 片語動詞

他們就能算出航海家號在這段時間內移動了多遠。

With this,

有了這個，

a simple calculation would tell them how fast Voyager was traveling.

一個簡單的計算就能告訴他們航海家號的飛行速度。

With all of these data points,

有了所有這些數據點，

NASA could continuously plot Voyager's trajectory and see how it compared to the desired trajectory.

NASA可以持續繪製航海家號的軌跡，並看看它與預期軌跡的差異。

If the space probe was a bit off,

如果太空探測器偏離了一點，

they could send a command to Voyager,

他們可以發送指令給航海家號，

which would fire up its thrusters to fix it. 片語動詞

讓它啟動推進器來修正。

With this incredible system,

憑藉著這套令人難以置信的系統，

Voyager arrived at its Jupiter target point

航海家號抵達了木星目標點，

just 1.4 seconds late and only 60 km off course. 片語搭配

僅晚了1.4秒，且航向僅偏離了60公里。

As Voyager 2 approached Jupiter,

當航海家2號接近木星時，

its speed had slowed considerably to around 10 km/s as it reached the top of its orbit.

由於到達了軌道的頂端，它的速度已經大幅減慢至約10公里/秒。

This was now well below the Sun's escape velocity,

這已經遠低於太陽的逃逸速度，

which at Jupiter's distance was around 18 km/s.

在木星的距離，逃逸速度大約是18公里/秒。

But as it got closer to Jupiter,

但是當它離木星越來越近時，

its gravitational pull started to have an effect on the space probe. 片語搭配

木星的引力開始對太空探測器產生影響。

Since Jupiter was already moving very fast in this direction,

由於木星在這個方向上的移動速度已經非常快，

it pulled Voyager in

它把航海家號拉了進來，

and essentially multiplied its current speed with Jupiter's speed,

基本上將它當前的速度乘上木星的速度，

sending it off at an even greater velocity.

以更快的速度把它送了出去。

Voyager was now going faster than the Sun's escape velocity,

航海家號現在的速度已經超過了太陽的逃逸速度，

and from this point onwards, 表達脈絡

從這時起，

it was destined to escape the solar system. 文法

它注定要飛出太陽系。

But the journey wasn't over yet. 表達脈絡

但是旅程還沒結束。

Voyager went on to complete two more gravity assists around Saturn and Uranus, 片語動詞

航海家號繼續完成了繞行土星和天王星的兩次重力助推，

making incredible discoveries along the way. 慣用語

並在沿途有了驚人的發現。

The final gravity assist would be around Neptune,

最後一次重力助推將繞行海王星進行，

but this gravity assist would go a little bit differently. 片語搭配

但這次的重力助推會有點不一樣。

Since there were no more planets to visit after Neptune,

因為海王星之後沒有其他行星要造訪，

Voyager didn't have to follow any particular path around Neptune.

航海家號不必沿著繞行海王星的任何特定路徑飛行。

However, scientists were very interested in flying as close as possible to Triton, 文法

然而，科學家對盡可能飛近海衛一（Triton）非常感興趣，

one of Neptune's moons.

它是海王星的衛星之一。

But Triton orbits at a steep angle,

但海衛一的軌道傾角很陡，

and so getting close would require a dramatic change of direction.

因此要靠近它需要方向上的劇烈改變。

And so,

所以，

instead of approaching from behind Neptune, 文法

航海家號沒有從海王星後方接近，

Voyager approached just a tiny bit in front,

而是從稍微靠前一點的地方接近，

heading over the planet's North Pole.

飛越這顆行星的北極上方。

This was enough to bend Voyager's trajectory downwards

這足以使航海家號的軌跡向下彎曲，

whilst also slowing it down. 片語動詞

同時也讓它減速。

5 hours later,

5個小時後，

Voyager flew past Triton.

航海家號飛越了海衛一。

And from then on,

從那時起，

began its lifelong journey into deep space.

開始了它前往深空的畢生旅程。

This epic journey took 12 years in total,

這趟史詩般的旅程總共花了12年，

and the discoveries that Voyager made along the way

而航海家號在沿途所做出的發現，

taught us an incredible amount about our solar system. 片語搭配

讓我們對自己的太陽系有了難以置信的了解。

And now,

現在，

for the moment you've all been waiting for, 表達脈絡

到了你們大家一直期待的時刻，

the winner of this awesome Falcon 9 framed print is Matthew Cole.

這幅超棒的獵鷹9號裱框畫作的得主是Matthew Cole。

Congratulations.

恭喜。

Sorry if you didn't win,

如果你沒有中獎，很抱歉，

but in the next video,

但在下一支影片中，

you'll get another chance.

你將會有另一次機會。

Next time,

下次，

we'll be giving away this epic Saturn V framed print.

我們將送出這幅史詩般的農神5號裱框畫作。

All you need to do is sign up at the link below 文法

你只需要在下方的連結註冊，

and leave a comment saying what you think will happen during Starship's first test flight. 文法

並留言說出你認為星艦（Starship）首次試飛時會發生什麼事。

Thank you very much for watching,

非常感謝你的收看，

and I'll see you in the next video.

我們下支影片見。