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  • When you picture a spaceship, you probably think of something like this,

    想到太空船,你可能認為長成這樣

  • or this, or maybe this.

    或這樣,或者是這樣

  • What do they all have in common?

    以上太空船的共通點是什麼?

  • Among other things, they're huge because they have to carry people, fuel,

    綜合以上是其體型巨大,因為要搭載人員、燃料

  • and all sorts of supplies, scientific instruments,

    各類物資、科學儀器

  • and, in rare cases, planet-killing lasers.

    甚至罕見情況下,足以摧毀行星的雷射

  • But the next real-world generation of spacecraft may be much, much smaller.

    但是,新一代真實世界的太空船實際上可能很小

  • We're talking fit-inside-your-pocket tiny.

    這裏講的大約是可以放進你口袋的大小

  • Imagine sending a swarm of these microspacecraft out into the galaxy.

    想像發射一群這麼小的微太空船進入銀河

  • They could explore distant stars and planets

    它們可探索遙遠的恆星及行星

  • by carrying sophisticated electronic sensors

    攜帶著複雜的電子感應器

  • that would measure everything from temperature to cosmic rays.

    能從溫度、宇宙射線等測量各種資料

  • You could deploy thousands of them

    你可部署上千台這樣的微太空船

  • for the cost of a single space shuttle mission,

    其成本和一次太空梭任務相當

  • exponentially increasing the amount of data

    卻可大量增加

  • we could collect about the universe.

    我們從宇宙蒐集的資料量

  • And they're individually expendable,

    個別而言,每台微太空船是消耗品

  • meaning that we could send them into environments

    其意謂我們可將之送到高風險環境

  • that are too risky for a billion dollar rocket or probe.

    這比發射數十億元的火箭或探測器還划算

  • Several hundred small spacecraft are already orbiting the Earth,

    目前,已有數百個小太空船圍繞地球軌道

  • taking pictures of outer space,

    拍攝外太空照片

  • and collecting data on things,

    蒐集各種資料

  • like the behavior of bacteria in the Earth's atmosphere

    例如,地球大氣層內細菌的行為

  • and magnetic signals that could help predict earthquakes.

    和電磁信號,以幫助地震預測

  • But imagine how much more we could learn if they could fly beyond Earth's orbit.

    想像微太空船若能飛越地球軌道 我們將可獲得更多

  • That's exactly what organizations, like NASA, want to do:

    這正是許多機構,例如NASA,想作的事

  • send microspacecraft to scout habitable planets

    送出微太空船偵察可居住的行星

  • and describe astronomical phenomena we can't study from Earth.

    和觀察一些地球無法研究的天文現象

  • But something so small can't carry a large engine or tons of fuel,

    但是,這麼小的太空船 無法攜帶大引撆或數噸燃料

  • so how would such a vessel propel itself?

    所以太空船要如何推動自己?

  • For microspacecraft, it turns out, you need micropropulsion.

    顯然,微太空船需要微推進器

  • On really small scales,

    在很小尺度上

  • some of the familiar rules of physics don't apply,

    一些熟悉的物理定律並不適用

  • in particular, everyday Newtonian mechanics break down,

    尤其是日常的牛頓力學不再有效

  • and forces that are normally negligible become powerful.

    平常可忽略的作用力變得強而有效

  • Those forces include surface tension and capillary action,

    這些力包括表面張力和毛細管作用

  • the phenomena that govern other small things.

    這些現象支配一些小物質的運作

  • Micropropulsion systems can harness these forces to power spacecraft.

    微推進系統可駕馭上述作用力而驅動太空船

  • One example of how this might work

    一種可能的運作方式

  • is called microfluidic electrospray propulsion.

    稱為微流體電噴灑推進法

  • It's a type of ion thruster,

    這是一種離子推進器

  • which means that it shoots out charged particles to generate momentum.

    作法為噴出帶電粒子,以產生動能

  • One model being developed at NASA's jet propulsion laboratory

    NASA的噴射推進實驗室開發出一種模型

  • is only a couple centimeters on each side.

    每邊只有幾公分寬

  • Here's how it works.

    其工作原理如下

  • That postage-stamp sized metal plate is studded with a hundred skinny needles

    此郵票大小的金屬面板配有一百根細針

  • and coated with a metal that has a low melting point, like indium.

    其表層塗有低鎔點金屬,例如銦

  • A metal grid sits above the needles,

    一個金屬網格置於細針上方

  • and an electric field is set up between the grid and the plate.

    再於網格及面板之間設立電場

  • When the plate is heated, the indium melts

    當面板受熱,銦開始鎔解

  • and capillary action draws the liquid metal up the needles.

    毛細管作用將把液態金屬吸上細針

  • The electric field tugs the molten metal upwards,

    一方面電場牽引鎔化金屬上升

  • while surface tension pulls it back,

    另一方面表面張力將其拉回

  • causing the indium to deform into a cone.

    造成銦變形成圓錐狀

  • The small radius of the tips of the needles

    針尖的小半徑

  • makes it possible for the electric field to overcome the surface tension,

    可讓電場克服表面張力

  • and when that happens,

    一旦實現

  • positively charged ions shoot off at speeds of tens of kilometers per second.

    帶正電離子的噴離速度可達每秒數10公里

  • That stream of ions propels the spacecraft in the opposite direction,

    此離子束可將太空船往相反方向推進

  • thanks to Newton's third law.

    這是受牛頓第3定律影響之故

  • And while each ion is an extremely small particle,

    雖然每個離子為一極小粒子

  • the combined force of so many of them pushing away from the craft

    眾多離子推離太空船的總合力量

  • is enough to generate significant acceleration.

    足以產生有效加速度

  • And unlike the exhaust that pours out of a rocket engine,

    不像排出火箭引撆的廢氣

  • this stream is much smaller and far more fuel efficient,

    此離子束比較小,而且燃料效率高

  • which makes it better suited for long deep-space missions.

    更適合長途的深太空任務

  • These micropropulsion systems haven't been fully tested yet,

    這類微推進系統尚未完整測試過

  • but some scientists think that they will provide enough thrust

    但是,一些科學家認為可提供足夠動力

  • to break small craft out of Earth's orbit.

    讓小太空船脫離地球軌道

  • In fact, they're predicting that thousands of microspacecraft

    事實上,他們預估上千台微太空船

  • will be launched in the next ten years

    將在10年內發射

  • to gather data that today we can only dream about.

    蒐集眾多我們今日只能想像的資料

  • And that is micro-rocket science.

    此稱為微火箭科學

When you picture a spaceship, you probably think of something like this,

想到太空船,你可能認為長成這樣

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B2 中高級 中文 美國腔 TED-Ed 太空船 離子 金屬 地球 蒐集

【TED-Ed】未來的太空船會變口袋般的大小? (Will future spacecraft fit in our pockets? - Dhonam Pemba)

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    稲葉白兎 發佈於 2015 年 06 月 28 日
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