Space six crew, dragon capsule and the astronauts inside safely reentered Earth's atmosphere on August 2nd.

8月2日，航天六號機組、龍艙和裡面的太空人安全返回地球大氣層。

Welcome back to planet Earth.

歡迎回到地球。

Thanks for flying space.

謝謝你的飛行空間。

Six.

六、

The world nervously watched the historic launch, the first from US soil in almost a decade on May 30th 2020.

世界緊張地注視著2020年5月30日的歷史性發射，這是近十年來首次從美國本土發射。

But it's this landing that Elon Musk most feared.

但埃隆-馬斯克最擔心的就是這次登陸。

Here's what had to go right in order to bring Bob Benk in and Doug Hurley home.

為了讓鮑勃-本克和道格-赫利回家，必須要做的事情是這樣的。

There are two main reasons why reentry is the most dangerous part of the mission.

再入是任務中最危險的部分，主要有兩個原因。

Extreme speed and temperature.

極端的速度和溫度。

Space six And NASA had to think about these factors in three key ways.

空間六 而NASA不得不從三個關鍵方面考慮這些因素。

The first pain point was finding the precise angle for reentry.

第一個痛點是找到準確的再入角度。

Not steep enough, the crew dragon would have bounced right off the atmosphere and back into orbit to sharp or too fast, And the astronauts could have faced fatal gravitational forces, and the spacecraft could have caused enough drag to break up and disintegrate.

不夠陡峭，乘員龍會直接從大氣層彈回軌道，太尖銳或太快，而太空人可能面臨致命的引力，航天器可能造成足夠的阻力而破裂解體。

Then, even at the correct angle, moving at about 25 times the speed of sound through the atmosphere creates extreme friction, which produces superheated plasma.

然後，即使以正確的角度，以大約25倍的音速在大氣層中運動，也會產生極端的摩擦力，從而產生過熱的等離子體。

A heat shield has to deflect and absorb the energy created by the plasma.

隔熱板要偏轉和吸收等離子體產生的能量。

At 3500 degrees, the shield gets hot enough to glow.

在3500度的時候，防護罩就會熱得發亮。

But Musk said, due to the crew dragons asymmetric design, the craft could have over rotated during reentry and diverted plasma into launch escape pods on the side.

但馬斯克表示，由於乘員龍非對稱設計，飛船在再入過程中可能會過度旋轉，並將等離子體轉入側面的發射逃學生艙。

If that happened, the ship could have overheated in some parts or started wobbling, causing the crew to lose control.

如果發生這種情況，飛船可能會在某些部位過熱或開始晃動，導致船員失去控制。

The plasma caused a six minute communications blackout between the crew dragon and Earth Dragon Space six com check.

等離子體造成了船員龍和地龍空間六號通訊檢查的六分鐘通訊中斷。

So if anything went wrong in that moment, remote control would have been impossible.

所以，如果那一刻出了什麼問題，遠程控制就不可能了。

In 2019 auditors listed parachute problems as a key risk to NASA's commercial crew program and the physics turbulence.

2019年，審計人員將降落傘問題列為NASA商業乘員計劃和物理湍流的關鍵風險。

A space capsule parachute goes through is one of the most difficult calculations for researchers.

一個太空艙降落傘所經歷的是研究人員最困難的計算之一。

Space six and NASA had to design a completely new system for the crew dragon.

太空六號和NASA不得不為乘龍號設計一套全新的系統。

After multiple versions and dozens of tests, the Mark three design was approved.

經過多個版本和幾十次測試，馬克三的設計得到了認可。

Even so, Musk's worry was that they might not deploy correctly, or that the system would guide the crew dragon to the wrong splashdown location.

即便如此，馬斯克擔心的是，它們可能無法正確部署，或者系統會將乘員龍引導到錯誤的濺落位置。

All these risks were assessed and calculated six ways to Sunday, as Musk told Aviation Week.

馬斯克告訴《航空週刊》，所有這些風險都是經過評估和計算的，到週日的六種方式。

But they could never be fully done away with.

但它們永遠不可能被完全消除。

NASA estimated that there was a one in 276 chance of this mission being fatal.

美國宇航局估計，這次任務有276分之一的概率是致命的。

But both Banken and Hurley told us they were comfortable with those odds.

但班根和赫爾利都告訴我們，他們對這些賠率很滿意。

Luckily, that bet paid off.

幸運的是，這個賭注得到了回報。

We can officially call this historic mission a success, and Space six is set to fly the same crew dragon back into space with four astronauts in spring of 2021.

我們可以正式稱這次歷史性的任務是成功的，航天六號將在2021年春天帶著4名太空人飛回太空，同樣是乘龍。