From Earth to space. 从地球到太空
There's no tougher 50 miles to cross. 这是最艰难的50英里
Fewer than 600 people have ever traveled it. 不到600人曾经穿过
But that number... 但是这个数字...
Liftoff--the Falcon 9 takes flight. 起飞--猎鹰9号升空了
..maybe about to get a whole lot bigger... ..也许会有巨大的增长...
Competition will drive the prices down. 竞争将使价格下降
And we can enter a space age,a space 2.0. 我们将进入太空时代，太空2.0
...Powered by entrepreneurs with bold, new ideas. ...由具有大胆、创新的企业家推动
Landing on a pillar of fire, 喷着火焰降落，
that last five feet can be critical. 最后五英尺可能很关键
Elon Musk set himself up 埃隆·马斯克让自己去做
to do something that no one else says he can do. 别人说他做不到的事情
If he delivers,it might change the world. 如果他成功了，可能会改变世界
...And NASA daring to dream big once again. ...美国宇航局又一次大胆的设想
We're working on the next heavy-lift rocket 我们正在研制下一代重型火箭
that will take us farther than we've ever gone before. 这将使我们比以前走得更远
It's giving the nation what it wants 它给了这个国家想要的东西
in a very exciting,next-generation space program. 一个非常激动人心的下一代太空计划
Space-- 太空--
it's never been closer for humans and machines. 人和机器从来没有这样融洽合作
It's the "Rise of the Rockets," 这是“火箭的复兴”
lifting off right now,on "NOVA." 现在起飞，就在“NOVA”
(loud bang) （爆发）
♪ ♪
T minus one minute 35 seconds on the Apollo mission, 阿波罗任务倒计时1分35秒
the flight to land the first men on the moon. 首次的人类登月任务
Kennedy Space Center,Cape Canaveral, Florida. 肯尼迪航天中心，卡纳维拉尔角，佛罗里达
Launch Complex 39. 39号发射台
T minus 17. 倒数17
Final guidance released. 最后导臂释放
From here,every Saturn V Apollo mission 从这里，所有的土星5号阿波罗任务
and every space shuttle lifted off. 和所有的航天飞机发射
Liftoff. 起飞
Liftoff on Apollo 11. 阿波罗11号升空
♪ ♪
But after the final space shuttle landing in 2011, 但是在2011年，最后的航天飞机返回之后
NASA tore down its Pad 39 launch gantries. NASA拆除了39号发射架
And since then, 之后，
no American astronaut has flown into orbit from U.S. soil. 美国宇航员再没有从美国本土飞上轨道
♪ ♪
The one hole in U.S. space capability 目前美国太空能力的一个漏洞
right now is the ability to transport humans 是运输人类的能力
into orbit or beyond. 进入轨道或者更远
The U.S. has spent more than $100 billion 美国已经花费了超过1000亿美元
building and operating the space station, 建造和运营空间站，
and we can't even get there 我们甚至自己到不了那里
unless we pay, and overpay,the Russians to do it. 除非我们付钱，而且付得很多，俄国人才肯送
♪ ♪
It's not where we want to be as a country, 这不是我们作为国家想处的位置，
it's not where we want to be as an agency. 也不是我们作为一个机构想处的位置
♪ ♪
But now Launch Complex 39 is back in business, 但现在39号发射台又开始运作了，
rebuilt with the goal of flying astronauts once more. 以再次运送宇航员为目标重建
Three, two, one. 3,2,1
And this time, 这一次
the rockets are not only NASA-owned and operated. 这些火箭不仅是美国宇航局拥有和实施
Private company SpaceX is already launching 私人公司SpaceX已经在发射
its Falcon rockets, 自己的猎鹰火箭
ferrying supplies 运送物资
to the International Space Station. 到国际空间站
(crowd cheering) （人群欢呼）
Eventually, 最终，
they hope to become a major provider 他们希望成为一个主要的供应商
of human flights to the station as well. 提供飞往空间站的航班
And SpaceX isn't alone. SpaceX并不孤单
A number of private companies have stepped up 一些私营公司已加快步伐
and started providing economical, reusable, 开始提供经济的，可重复使用的，
recyclable launch capabilities to deliver to space. 可回收的发射能力，以到达太空
(rocket roaring) （火箭声）
♪ ♪
But what about NASA? 但美国宇航局呢？
♪ ♪
They're focusing on pure exploration, 他们专注于纯粹的探索
with a new rocket to take humans into deep space. 用新型火箭把人类送进深空
We're working on the next heavy-lift rocket 我们正在研制下一代重型火箭
that will take us farther than we've ever gone before. 将使我们比以前走得更远
It will be the most powerful rocket ever built. 这将是有史以来最强大的火箭
♪ ♪
The landing burn has started. 着陆反推已经开始
(radio chatter, crowd cheering) （无线电，人群欢呼）
At the same time, 同时，
the audacious technical achievement 大胆的技术成就
of SpaceX's reusable rocket SpaceX可重复使用的火箭
and their stunts, 还有他们的噱头
like launching a car and dummy driver out of earth orbit, 就像把汽车和模型司机送出地球轨道，
have ignited new public enthusiasm. 激发了新的公众热情
If you believe the hype, 如果你相信炒作，
then we're on the brink of a new era of space flight. 那我们就快到太空飞行的新时代了
But great uncertainties lie ahead. 但未来仍有很大的不确定性
The demand for seats remains tiny, 对载人任务的需求仍然很小，
with only governments and a handful of private citizens 只有政府和少数人
willing to pay for an expensive ride to space. 愿意为昂贵的太空之旅买单
So will this lead to a renaissance in space travel? 那么这会导致太空旅行的兴起吗？
Or fizzle out... 或者落寞...
nothing more than a flash in the pan 只不过是昙花一现
that fails to take the next giant leap for humankind? 不能为人类带来下一个巨大的飞跃？
火箭的复兴
(helicopter rotors droning) （直升机旋翼声）
Liftoff--the Falcon 9 takes flight 起飞--猎鹰9号升空
with the Dragon spacecraft 带着龙飞船
destined for the one-of-a-kind laboratory in microgravity-- 为独一无二的微重力实验室服务--
the International Space Station. 去国际空间站
We're in the midst of a revolution; 我们正处于一场革命之中；
a surge of commercial rocketry 激增的商业火箭
that could make space more accessible 可以使太空更容易进入
and usher in a new chapter of exploration. 开启探索的新篇章
And liftoff. 起飞
It's a revolution that was started by NASA. 这是一场由美国宇航局发起的革命
In 2005, the agency decided 2005年，该机构决定
to commercialize the task of flying cargo and crew 将运送货物和乘员的任务商业化
to the International Space Station, 去国际空间站
freeing NASA to take on bigger challenges. 解放美国宇航局，承担更大的挑战
It allows NASA to focus 它使美国宇航局能够集中精力
on bolder expeditions for deeper space exploration, 进行更大胆的探索，更深入的太空探索，
putting human beings on Mars and other worlds; 把人类送上火星和其他星球；
pushing beyond the envelope 超越极限
and giving the nation what it wants 给国家想要的
in a very exciting,next-generation space program. 一个激动人心的下一代太空计划
♪ ♪
NASA's next-generation space program 美国宇航局的下一代太空计划
calls for a big, new rocket, 需要一个新型的大火箭，
capable of carrying humans beyond earth orbit once again-- 能够再次将人类送出地球轨道--
to the moon or even Mars. 去月球甚至火星
It's a return to NASA's roots. 这是回到美国宇航局的本源
NASA is recreating a 21st-century 美国宇航局正在重现
version of the Saturn V 21世纪版的土星五号
as an exploration vehicle, 作为探索的工具，
a heavy-lift vehicle 重型运载火箭
intended to enable the resumption of human exploration 旨在恢复人类探索
beyond low Earth orbit. 超越地球低轨道
We're developing the Space Launch System 我们正在开发太空发射系统
to carry crew and heavy cargo, 运送乘员和重型货物，
first to the moon or in near-lunar orbit 先到月球或在月球轨道附近
and eventually to Mars and, and the outer planets. 最终到达火星和外行星
(machinery humming) （机械声）
Already eight years in development, 已经研发了八年，
NASA's Space Launch System--or SLS, as it's known-- 美国宇航局的太空发射系统，也就是众所周知的SLS--
is designed to carry 50 tons of spacecraft and human cargo 设计用于运载50吨航天器或载人飞船
beyond Earth orbit. 到达地球轨道之外
♪ ♪
It will be able 它将能够
to take the large systems that we need to land to an outpost, 把我们需要的大型系统带到一个前哨站，
to do the exploration in deep space, 去进行深空探索，
and to deliver payload and humans necessary to do 运送有效载荷和人类
the research on the moon. 在月球上进行研究
♪ ♪
If all goes well,in the early 2020s, 如果一切顺利，在20世纪20年代初，
NASA's new rocket will send a human-rated spacecraft 美国宇航局的新火箭将发射一艘载人航天器
around the moon-- 进入绕月轨道--
the first since the days of Apollo. 阿波罗时代之后的第一次
The second mission will follow a similar flight path, 第二次任务将沿循类似的飞行路线，
with humans on board, 这是载人任务
the first such voyage in over 50 years. 50多年来第一次这样的航天任务
Its initial target mission 它最初的目标任务
is to bring astronauts in orbit around the moon, 把宇航员送到绕月轨道上，
in order to lay the groundwork 为了奠定基础
for a new space station that will orbit the moon 建一个环绕月球运行的新空间站
and an eventual return to the moon 最终能够重返月球
by U.S. astronauts and robots. 送美国宇航员和机器人上去
The SLS is the latest SLS是最新的成员
in a long line of NASA's human-rated rockets, 排在美国宇航局的载人火箭系列，
starting with the one that carried Alan Shepard 从1961年搭载艾伦·谢泼德的
on his famous 15-minute flight in 1961. 著名的15分钟飞行开始
♪ ♪
(engines ignite) （发动机点火）
All right now, liftoff and the clock has started. 好了，升空了，计时开始
These liquid-fueled rockets all share common features: 这些液体燃料火箭有共同特点：
engines at their base, 尾部的发动机，
fed by powerful pumps 由强力泵供给
that draw propellant from the tanks above. 从上面的燃料箱中抽取推进剂
Perched above all this is the payload, 在所有这些之上的是有效载荷
the cargo to be delivered to space. 将要运送到太空的货物
As payloads got bigger, 随着有效载荷越来越大，
so did the rockets required to launch them, 对发射火箭的要求也是如此，
culminating in the Saturn V, 最终到土星五号那么大，
capable of carrying over 48 tons to the moon... 能够运载超过48吨到月球...
Two minutes, 30 seconds and counting. 2分30秒，倒数
We're still go on Apollo 11 at this time. 现在阿波罗11号准备就绪
...and the space shuttle, ...还有航天飞机，
built to routinely haul up to 32 tons to orbit. 通常可将高达32吨的货物送入轨道
One, zero... 1,0...
And liftoff, the final liftoff of Atlantis, 起飞，亚特兰蒂斯的最后升空，
the shoulders of the space shuttle... 这次航天飞机搭载着...
NASA's new rocket, the SLS, 美国宇航局的新型火箭，SLS，
will be even larger than the Saturn V. 会比土星五号还要大
But rather than designing from scratch, 但与其从头开始设计，
NASA has borrowed technologies that have flown before. 美国宇航局还是借用了以前的技术
SLS is a cross between the Apollo, SLS有阿波罗任务的经验，
which had the capsule at the top, 飞船在最顶端，
and the shuttle, 还有航天飞机，
which had the two solid-rocket boosters 有两个固体火箭助推器
on each side. 在左右两侧
So if you look at Apollo and shuttle, 如果你看看阿波罗和航天飞机，
you can see the similarities of both of them 你可以看到与他们两个的相似之处
coming together to form SLS. 结合形成了SLS
♪ ♪
The SLS has not yet flown, SLS还没有起飞，
but as these aspirational NASA animations suggest, 但正如美国宇航局雄心勃勃的动画，
it will be quite a sight at liftoff. 升空时会很壮观
The minute the SLS launches off the pad, 一旦SLS从发射台起飞，
it will be the most powerful rocket ever made. 这就将是有史以来最强大的火箭
♪ ♪
Building the most powerful rocket in history 建造史上最强大的火箭
is full of challenges-- 充满挑战--
not least,the size of the rocket. 尤其是火箭的大小
Even a single fuel tank,like this one, is enormous. 即使是一个燃料箱，像这个，也是超大的
A building big enough 大型的建筑
to put this giant rocket together inside is so vast, 能在其中组装这么大的火箭
the engineers use bicycles to get around. 工程师们需要骑自行车来往
(bell chimes) （铃声）
Even the tools they're working with to assemble the rocket 甚至他们用来组装火箭的工具
are gigantic. 也是庞大的
I'm a weld and metals engineer here for NASA. 我是美国宇航局的金属焊接工程师
This is the vertical assembly center, 这是垂直装配中心，
and it's the largest weld tool in the world, 这是世界上最大的焊接工具，
and it's the only one of its kind. 这是唯一的一个
♪ ♪
The weld tool, a giant tower, 焊接工具，一座巨塔，
tackles the tank in sections called barrels, 用圆筒部件组装燃料箱，
welding them together vertically. 垂直焊接在一起
When we're assembling a tank, 当我们组装燃料箱时，
it's done in different stages. 这是分阶段完成的
So one barrel is welded to the dome, 一个圆筒焊接到箱顶，
and then once that's been welded and checked and verified, 焊接后经过检查和验证，
then another barrel is brought in. 然后下一节圆筒运过来
And so to assemble a hydrogen tank, 这样装配一个氢罐，
and you have five of those barrels. 你需要5节这样的圆筒
And the very last piece is the bottom, the aft dome. 最后的一节是底，尾部圆筒
♪ ♪
The tanks are welded 燃料箱的焊接
using friction to melt the metals together, 用摩擦把金属熔化在一起，
generated by spinning the toolhead at high speed. 通过高速旋转工具头完成
(whirring) （摩擦声）
It looks easy, 看起来简单，
but in reality the construction of this first hydrogen tank 但实际上第一个氢罐的建造
has been plagued by problems, 就遭遇棘手问题，
putting the rocket far behind schedule. 使火箭远远落后于计划
It's a very troubled program,basically. 总的来说，这是一个非常麻烦的计划
The SLS will cost SLS将花费
at least $8.9 billion through 2021, 到2021年至少89亿美元，
which is double the amount initially planned. 是最初计划的两倍
♪ ♪
It's now ten years later, 已经过了10年，
a couple billion dollars a year. 每年花费20亿美元
It's continuing to be delayed. 仍然在继续推迟
♪ ♪
Overruns aside, 除了超支，
it's an ambitious new rocket. 这是个雄心勃勃的新火箭
But why does it have to be so big, 但为什么一定要这么大，
larger than any other? 比其他的都大？
The answer lies in the fundamentals 答案在于基本的
of rocket science. 火箭科学
♪ ♪
At its heart, rocket science is all about propulsion 本质上，火箭科学的核心是推进
and a principle that was first described by Isaac Newton, 艾萨克·牛顿率先描述的原理，
whose third law of motion states, 他的第三运动定律，
"For every action,there is an equal “对每个作用力，都有大小相等
and opposite re-action." 方向相反的反作用力”
So the principle behind a rocket is actually really simple. 所以火箭背后的原理其实很简单
All we really have here is what's called a mass engine. 我们这里拿的是所谓的质量发动机
If we have enough mass inside, 如果我们有足够的质量，
and we push it out fast enough, 推出的速度足够快，
then what we are going to be able to do-- 那我们能做到的--
through Newton's law,action and reaction-- 通过牛顿定律，作用力和反作用力--
is to propel this rocket,I hope, skywards. 能把火箭推动，我希望，能上天
First, mass. 首先，质量
We're going to pour water into a tank inside our rocket 我们要把水倒进火箭里的水箱里
to add mass. 增加质量
And as we fill it up, 当我们填满它的时候，
I can feel the rocket actually getting heavier. 我能感觉到火箭确实变重了
That's good sign, 这是个好现象，
because that gives us more mass, more propulsion 因为这给了我们更多的质量，更多的动力
to get the rocket to go that much further. 让火箭走得更远
Second, a source of energy 第二，能量
to push the water out of the back of the rocket 把水从火箭后面推出来
as fast as possible. 越快越好
For that, we're going to use high-pressure air 为此，我们用高压空气
from this compressor. 就是这台压缩机
And so now all I need to do 所以现在我要做的就是
is to release the compressed air into the rocket itself. 就是把压缩空气释放到火箭里
(hissing) （嘶嘶）
Pressurizing. 加压
The compressed air raises the pressure 压缩空气使压力升高
in the rocket's water tank, 火箭的水箱，
which is prevented from escaping. 现在的口是封上的
Until... 直到...
Five, four, three, two, one. 5,4,3,2,1
Go! 发射！
Yay! 耶！
♪ ♪
When released, 释放时，
the high-pressure air pushes the mass of water 高压空气推动水
out of the nozzle at high speed, 高速冲出喷嘴，
producing thrust that propels the rocket 产生推力使得火箭
in the opposite direction--skywards. 冲向相反方向的天空
That's why it's called a mass engine. 这就是为什么它被称为质量发动机
And so there we are, 就是这样，
the principle of action and reaction. 作用力和反作用力的原理
As we push the water out the bottom, 当我们把水从底部推出时，
the rocket goes up. 火箭向上升
And so the question is, 所以问题是，
how much fuel and how fast do you have to eject it 你需要多少燃料，喷射多快的速度
in order to get a rocket into space? 才能让火箭进入太空？
This question is at the heart of all rocket science. 这个问题是所有火箭科学的核心
The combination of the mass of propellant-- 推进剂质量的组合--
in this case water-- 在这里是水--
and the speed you're pushing it out the back 你把它从后面推出的速度
is what propels you into the air. 是把你推向空中的动力
But you can't get to space using cold, relatively slow water. 但是你不能用相对缓慢的冷水到达太空
Propelling a rocket fast enough to reach space 为了达到足够快的速度推进火箭到达太空
requires something much lighter moving much faster-- 需要轻得多的东西，移动快得多--
like rapidly expanding hot gas. 就像快速膨胀的热气
The idea of using such a hot gas rocket to reach space 用这种热气体火箭到达太空的想法
was first published in 1903 by Russian mathematician 1903年由俄罗斯数学家和科学家
and scientist Konstantin Tsiolkovsky. 康斯坦丁·齐奥尔科夫斯基首次发表
He worked out the best way 他想出了最好的办法
of generating a lot of hot gas expanding very rapidly. 产生大量快速膨胀的热气
Gunpowder-- or "black powder"-- 火药--或“黑火药”--
seemed like a good way to do that. 似乎是个好办法
(gunshot) （枪声）
It's what humans used for centuries 这是人类几百年来使用的东西
to fire everything from arrows 射出所有的包括箭
to cannonballs and rifle bullets. 炮弹和步枪子弹
And it's one of the main fuels in fireworks. 它是烟花的主要燃料之一
I've got a small jar of it here. 我这儿有一小罐
And what we'll do is we'll just quickly 我们要做的就是很快
take a look at what happens when it lights. 看一眼当它着火时会发生什么
Here we go, let's go. 我们开始，开始了
Oof! 哦！
It's pretty fast. 很快的
♪ ♪
When ignited, 点燃时，
the gunpowder reacts with oxygen, 火药与氧气发生反应，
releasing a lot of energy 释放大量能量
and turning it into a rapidly expanding hot gas. 把它变成快速膨胀的热气
Seems like an ideal fuel for a rocket. 似乎是火箭的理想燃料
But there's a problem with solid fuel like gunpowder. 但像火药这样的固体燃料也有问题
Once ignited, 一旦点燃，
it burns until the reaction is over. 它会一直燃烧直到反应结束
But in a rocket, 但在火箭里，
it's preferable to have a fuel 燃料最好是
that can be controlled. 可以控制的
Tsiolkovsky's crucial insight 齐奥尔科夫斯基的重要见解
was the fact that if you light a solid fuel, 如果你点燃固体燃料，
then the burn kind of goes on until it runs out. 燃烧会一直持续到燃料用完
If, on the other hand, 另一方面，如果，
he were to use liquid fuels, 他要用液体燃料，
then he would be able to control 然后他就能控制
how much liquid was being poured into the flame. 有多少液体被送入燃烧的火焰
In other words, 换句话说，
he would be able to exert even greater control 他将能够进行更有余地的操作
over his rocket. 控制火箭
Tsiolkovsky started casting around 齐奥尔科夫斯基开始四处挑选
for the right liquid fuel to use. 合适的液体燃料
At the time, 在那时，
high-quality liquid fuels like kerosene and gasoline 煤油、汽油等优质液体燃料
were becoming available, 逐渐可以利用，
thanks to the emerging petrochemical industry. 多亏了新兴的石化工业
Here on earth, 在地球上，
these fuels burn by reacting 这些燃料通过燃烧
with oxygen in the atmosphere. 与空气中的氧气反应
But in space, there is no air, 但在太空，没有空气，
so Tsiolkovsky proposed carrying a supply of oxygen 所以齐奥尔科夫斯基建议携带氧气
along with the fuel. 与燃料一起
It would take an American scientist, 这个想法要靠一位
also obsessed with the idea of space flight, 痴迷太空飞行的美国科学家，
to build such a rocket. 造出这样的火箭
His name was Robert Goddard. 他叫罗伯特·戈达德
So what Robert Goddard came up with 罗伯特·戈达德想出了
was the idea of combining liquid kerosene 结合液体煤油
with liquid oxygen, 和液氧，
and by burning the two together, 这两者在一起燃烧，
he would get a fierce flame that he could control 他会得到他能控制的烈焰
and that would really push his rockets skyward. 这会把他的火箭推向天空
When the kerosene reacts with the oxygen, 当煤油与氧气反应时，
the result is a very hot rapidly expanding gas. 结果是非常热的快速膨胀的气体
And if channeled through a nozzle, 如果通过喷嘴，
that hot, fast-moving gas produces thrust 热的、快速移动的气体产生推力
that can push the rocket in the opposite direction. 会把火箭推向相反的方向
What we get is an enormous expansion 我们得到的是极大的膨胀
and enormous push. 和极大的推力
But above all,we can control it. 最重要的是，我们还可以控制它
With just such a design, 有了这样的设计，
on the 16th of March 1926, 1926年3月16日，
Robert Goddard finally launched 罗伯特·戈达德终于发射了
the very first liquid-fueled rocket in history. 历史上第一枚液体燃料火箭
The flight was brief. 飞行时间很短
The rocket didn't go far or fast, 火箭不远也不快，
but the potential was clear. 但潜力是显而易见的
Carrying liquid oxygen on board 火箭携带液氧
meant rockets could fly beyond the Earth's atmosphere. 意味着火箭可以飞出地球大气层
And with that, 有了这个，
Robert Goddard imagined we could go to the moon. 罗伯特·戈达德想象我们可以去月球
Goddard might have dreamed of reaching the moon, 戈达德可能梦想到达月球，
but his liquid rockets never even reached two miles 但他的液体火箭从来没有飞到两英里高
into the sky. 的天空
And that's because of something 那是因为所谓的
called Tsiolkovsky's rocket equation. 齐奥尔科夫斯基火箭方程
When Tsiolkovsky 齐奥尔科夫斯基
was thinking about how to power a rocket, 考虑如何为火箭提供动力，
one of the things that he realized 他意识到一件事
was that you're not just moving the payload, 你不只是推动负载，
you've also got to move the fuel. 你还得移动燃料
And the fuel itself has weight. 燃料本身就有重量
Now, you can imagine putting more and more fuel, 现在，你想投入越来越多的燃料，
in order to power your rocket more, 为了给你的火箭提供更多动力，
but at the same time, 但同时，
you're adding more and more weight. 你增加了更多的重量
Tsiolkovsky tried to describe this "Catch-22" problem 齐奥尔科夫斯基描述这个“第22条军规”的问题
by considering things 考虑到了一些关系
like the mass of the rocket,the fuel, and the payload, 火箭的质量、燃料和有效载荷，
and the velocity it would need to reach 它需要达到的速度
to get to orbit. 才能到达轨道
The longer the engine burns, 发动机燃烧的时间越长，
the more velocity the rocket will have. 火箭的速度越快
But longer burning means more fuel, 但燃烧时间越长意味着燃料越多，
making the rocket heavier and harder to push. 使火箭更重更难推动
It's a vicious cycle 这是一个恶性循环
and still bedevils rocket scientists today. 今天仍然困扰着火箭科学家
To travel fast enough to deliver a payload into space, 以足够快的速度将有效载荷送入太空，
most of the rocket has to be fuel. 火箭的大部分组成必须是燃料
♪ ♪
The critical consequence of the Tsiolkovsky equation 齐奥尔科夫斯基方程的关键结果
is the fact that,really rather depressingly, 事实上，真的很令人沮丧，
only a tiny percentage of a rocket can ever be payload. 火箭中只有很小一部分可以作为有效载荷
And when you think back 当你回想起来
to the lunar missions of the Apollo space program, 阿波罗太空计划的登月任务时，
those enormous rockets were used to fire just three men. 那些巨大的火箭只用来发射三个人
♪ ♪
NASA's giant Saturn V-- 美国宇航局巨型的土星五号--
the largest,most powerful rocket ever to fly. 有史以来最大最有力的火箭
Built in a hurry to race to the moon, 为了赶往月球而匆忙建造，
engineers hacked the rocket equation 工程师们破解了火箭方程式
by building the Saturn V in a series of disposable stages, 通过一串可抛段建造土星五号，
where each set of tanks and engines were discarded 每套燃料箱和发动机都会被丢弃
as they ran dry, 在燃烧完之后，
shedding weight and allowing the next rocket stage 减轻重量，让下一级火箭
to accelerate even faster. 加速更快
But even a giant staging rocket the size of the Saturn V 但即使是像土星五号那样巨大的火箭
wouldn't be large enough to carry the Apollo spacecraft 也并不足够大，能运送阿波罗飞船
all the way to the moon without the right fuel. 到月球，如果没有适当的燃料
Kerosene wouldn't do. 煤油不行
In fact, 实际上，
there's only one fuel that packs enough punch. 只有一种燃料能产生足够的冲击力
A fuel that Tsiolkovsky himself had also proposed. 齐奥尔科夫斯基自己也提出的燃料
Tsiolkovsky's focus 齐奥尔科夫斯基的注意力
on the chemistry that's available to us, 在我们能得到的化学物质上，
and its crucial role in being able to push a rocket, 它在推动火箭方面的关键作用，
led him, inescapably,to the conclusion 使他不可避免地得出了结论
that he needed the lightest 他需要最轻的
and yet most energetic fuel possible. 但是最有力的燃料
And that had to be hydrogen. 那必须是氢
The power of hydrogen compared to other fuels 氢的能量与其他燃料相比
is easy to demonstrate, 很容易证明，
using a homemade cannon and some sacrificial potatoes. 用自制的大炮，牺牲一些土豆
First up, regular gasoline. 首先是普通汽油
We're really using the same sort of fuel 我们真的在用同样的燃料
that, you know, you might put in a car or in an airplane. 你知道，你可以把它用在汽车或飞机上
Here we are. 准备好了
Now, we'll screw the end over the barrel. 现在，我们把炮筒的末端拧上
Okay, right, so here we go. 好了，可以开始了
And now all it needs is that vital spark. 现在它所需要的就是关键的火花
♪ ♪
When ignited, the highly reactive gasoline vapors 当被点燃时，高活性的汽油蒸汽
are converted into a very hot, fast-expanding gas 转化成非常热的，快速膨胀的气体
that pushes the potato out of the cannon. 把土豆推出大炮
(plunking) （砰）
Whoa! 哇！
Gasoline has carried the potato just over the bushes 汽油把土豆送到了灌木丛那边
into the next field. 的田野里
Now, the same experiment-- 现在，同样的实验--
but instead of gasoline, 但不是汽油，
we'll try the same mass of hydrogen, 我们将尝试同样质量的氢，
an invisible gas. 一种看不见的气体
And so I've got the hydrogen here
in these monster syringes, 所以我这里有氢气
which we've preloaded 我们已经预装了
with a little bit of hydrogen in each one. 每个里面都有一点氢
We're going to cap the whole thing up. 我们要把这些都封住
Now, I tell you, 现在，我告诉你，
this thing is a really pretty scary explosive mixture. 这是一种非常可怕的爆炸性混合物
This one is going to be really loud. 这个会很响的
Here we go. 可以开始了
Ready, aim, fire! 预备，瞄准，发射！
Whoa! 哇！
Hydrogen is the lightest element in the universe, 氢是宇宙中最轻的元素，
so you can pack a lot more atoms into each pound of fuel. 所以你可以在每磅燃料中装入更多的原子
And when it reacts with oxygen, 当它与氧气反应时，
it burns with a near invisible flame, 它燃烧着几乎看不见的火焰，
producing a very familiar substance: water, 产生出非常熟悉的物质：水，
which expands rapidly as a hot vapor. 以热蒸汽的形式迅速膨胀
Whoa! 哇！
That was the biggest distance yet. 这是迄今为止最大的距离
Whether you're launching potatoes across fields 无论你是向田野发射土豆
or big, heavy payloads into deep space, 或是又大又重的载荷送上太空，
there's no more efficient fuel to use. 没有更高效的燃料可供使用了
♪ ♪
And that's why the Saturn V's upper stages 这就是为什么土星五号的上层
also used hydrogen fuel to get it to the moon. 也是用氢燃料把它送到月球上
The main engines of NASA's new SLS rocket NASA新型SLS火箭的主发动机
will also be powered by hydrogen. 也将由氢提供动力
♪ ♪
It's an engine called the RS-25. 这是一个叫RS-25的发动机
This model powered all 135 space shuttles to orbit. 这一型号推动了135班次航天飞机，进入轨道
It's an incredible record 这是一个不可思议的记录
that makes the RS-25 one of the most reliable rocket engines 使RS-25成为最可靠的火箭发动机之一
in history-- 有史以来--
and NASA wants to repurpose them for the SLS. 美国宇航局希望将它们稍加改动用于SLS
It's built by a company called Aerojet Rocketdyne. 它是由一家名为洛克达因的公司建造的
Tom Martin works at their world-class engine test facility 汤姆·马丁在他们的世界级发动机测试机构工作
here at NASA's Stennis Space Center in Mississippi. 在密西西比州的美国宇航局斯坦尼斯航天中心
The RS-25 RS-25
was originally developed in the 1970s and '80s, 最初是在1970年代和80年代发展起来的，
throughout the shuttle program. 通过航天飞机项目开发
Five, four... we've gone for main engine start... 5,4...我们启动主发动机...
We have main engine start. 主发动机启动
Some of these engines have been 其中一些发动机
in multiple flights in space. 曾多次在太空飞行
You know, very reliable,very high-performing. 非常可靠，表现非常出色
There were three of these RS-25 engines located 有三台RS-25发动机安装在
at the tail end of each shuttle. 每架航天飞机的尾部
At launch, they were supported 在发射时，它们有两个可抛的
by two detachable solid-fuel boosters. 固体燃料助推器帮助
Good speed now,320 miles per hour. 现在速度很好，每小时320英里
But the three main engines were part of the shuttle itself 但3个主发动机属于航天飞机的一部分
and returned to Earth each time to be used again and again. 每次都回到地球，被一次又一次重复使用
♪ ♪
But will they work on NASA's new rocket? 但它们能用在美国宇航局的新火箭上吗？
Today they're going to simulate 今天他们要模拟
a full SLS eight-minute launch to space 一次完整的SLS八分钟太空发射过程
on one of the engines, 用其中一个发动机，
to test the control of its flight computers. 来测试飞行电脑的控制
♪ ♪
You can see the A2 test stand, 你可以看到A2测试台，
and then further off in the distance, 然后在远处，
the A1 test stand. 是A1测试台
The A1 is where the RS-25 is going to be tested here A1是RS-25在这里测试的地方
in just a couple of minutes. 仅仅几分钟以后
♪ ♪
Close to the test engine 靠近测试发动机的
are 300,000 gallons 是30万加仑
of highly explosive liquefied hydrogen and oxygen. 高爆炸性的液化氢和氧
A crew will go in right before test 一组人员在测试前进去
and verify that there aren't any leaks, 确认没有任何泄漏，
everything looks good. 一切都很正常
And we are standing by for the RS-25 engine test. 我们准备进行RS-25发动机测试
Okay, it sounds like we're two minutes away, all right. 好，听起来我们还有两分钟，好吧
♪ ♪
Nothing's 100% guaranteed, 没有什么是100%保证的
so there's always a little bit of nerves before a test. 所以测前总有些紧张气氛
We do everything we can 我们竭尽所能
to make sure the test and the flights are going to go off, 确保测试和飞行顺利进行，
but, you know, there's always unknowns that creep up. 但是，你知道，总有一些未知的事情从哪儿冒出来
We'll evacuate the area to at least a quarter mile, 我们会疏散至少四分之一英里，
so if anything bad does happen, 所以即便发生意外，
we want everybody to stay safe. 我们希望大家都安全
Most of the test crew is in the Test Control Center. 多数测试人员都在测试控制中心
That's where they control and monitor the engine. 那是他们控制和监视发动机的地方
♪ ♪
Keeping a safe distance is crucial, 保持安全距离至关重要，
because when an engine fails, 因为当发动机出故障时，
the results can be often catastrophic, 结果往往是灾难性的，
as seen in this early Apollo engine test. 在阿波罗早期的发动机测试中可以看到
(explosion) （爆炸）
(siren blaring) （警笛）
So you can hear the siren. 你听到了警笛
That means we're one minute away. 意味着还有一分钟的时间
Sounds like auto-sequence has started. 自动程序已经开始了
At this point the computers take over, 现在计算机接管了，
it's kind of under the computer command. 就像是在电脑的指挥下
The engine actually goes from zero thrust to full thrust 发动机实际上从零推力到全推力
in, in about five seconds. 只需要5秒钟
♪ ♪
And we have ignition. 我们点火
♪ ♪
(rocket roaring) （发动机声）
As the engine hits full power, 当发动机达到最大功率时，
the temperature reaches 6,000 degrees, 温度达到6000度，
accelerating the exhaust out at 13 times the speed of sound. 以13倍音速排出燃烧的废气
Guzzling 1,500 gallons of propellant each second, 每秒消耗1500加仑的推进剂，
it's now generating just over half a million pounds of thrust. 它现在产生的推力刚刚超过50万磅
The heavy steel structure of the test stand 测试台的重型钢结构
keeps it firmly grounded, 使其牢固的接地，
while the exhaust is diverted 当排气被分流时
out to the side using enormous flame buckets. 使用巨大的火焰挡槽
These billowing clouds of combustion gas 这些滚滚的燃烧气体
are just water vapor, 只是水蒸气，
formed as the hydrogen burns in oxygen; 当氢在氧气中燃烧时形成；
and like naturally formed clouds, 就像自然形成的云，
sometimes they make rainbows. 有时它们会产生彩虹
You don't really get a sense for what these machines are doing 你真的不知道这些机器在干什么
until you're on the ground seeing a test, 直到你在地面上看到这个测试，
and then you get the full impact of how powerful this stuff is 然后你就能充分感受到这东西的威力
and how hard it is to get things into space. 把东西送上太空有多难
It never gets old seeing a test. 看这样的测试永远不会厌倦
I could see it every day. 每天看都行
♪ ♪
The 535-second test 535秒的测试
of the RS-25 engine has concluded. RS-25发动机已经测试结束了
The engine's flight computer has performed flawlessly, 发动机的飞行电脑表现完美，
controlling the throttling of the rocket 控制火箭的节流
through the simulated ascent to space. 完成了模拟升空
It gives me goose bumps 它让我起鸡皮疙瘩
every time I hear the engine start. 每次听到发动机启动
I mean,it's a visceral experience 我说，这是震撼内心的体验
to, to, to see an engine test. 看到发动机测试
♪ ♪
If it all goes as planned, 如果一切按计划进行，
the engine they've tested today will power the first SLS rocket 他们今天测试的发动机将为第一枚SLS火箭提供动力
in the early 2020s. 在20世纪20年代初
And like the Saturn V,this engine-- 就像土星五号，这个发动机--
along with most of the rest of the rocket-- 和火箭的其他部分一起--
will be dropped into the ocean,never to be used again, 会掉进海里，再也不用了，
after just one flight. 仅仅飞一次
That's at least part of the reason 这至少是部分原因
why getting huge, heavy payloads into deep space 为什么把巨大而沉重的有效载荷送入深空
is still so expensive. 仍然这么昂贵
But is that the only solution? 但这是唯一的解决办法吗？
(radio squawking) （无线电）
Why not reuse your rocket like an airliner? 为什么不把你的火箭像飞机一样再用呢？
♪ ♪
That question poses an array of new challenges. 这个问题提出了一系列新的挑战
(jet engine roaring) （喷气发动机轰鸣）
The airplane, if you threw it away after every flight, 飞机，如果你每次飞行后都把它扔掉，
would be a very expensive way to travel. 会是一种非常昂贵的旅行方式
(suitcase wheels clacking) （手提箱轮子作响）
In the beginning of aviation, 在航空业的初期，
we created vehicles to be reused. 我们创造了可重复使用的飞行器
For rocketry,we somehow forgot that, 对火箭，我们不知怎么忘记了，
and we're not benefitting from reusability. 没有从可复用中获益
We threw away everything when we were done. 用完后我们把所有东西都扔掉了
And that's because 那是因为
making a landing from space by reentering the atmosphere 重返大气层从太空着陆
at a speed of five miles a second, 每秒5英里的速度，
is much harder than landing a plane 比降落飞机难得多
from a cruising speed 飞机的巡航速度
of over 800 feet per second. 每秒800多英尺
After the Apollo mission, 在阿波罗任务之后
NASA tried to build a reusable space plane 美国宇航局试图制造可重复使用的太空飞机
through the 1970s-- 在1970年代--
the iconic space shuttle. 标志性的航天飞机
And the shuttle has cleared the tower. 航天飞机已经离开了发射塔
But there were problems from the start. 但从一开始就有问题
The space shuttle was supposed to travel every other week, 航天飞机应该每隔一周飞行一次，
40 times a year was their proposal, 他们提议一年40次，
which would have dropped the cost significantly. 这将大大降低成本
♪ ♪
We thought if you're reusing an engine, 我们想如果重复使用发动机
it's going to be less expensive, 会比较便宜，
but they again had to pretty much take apart 但他们又不得不拆开
and rebuilt the shuttle main engines 再重建航天飞机的主发动机
after every flight. 每次飞行之后
♪ ♪
The space shuttle never was able to launch regularly, 航天飞机从来就不能正常发射，
and it was very, very expensive, 它非常非常昂贵，
about a billion a flight. 一次飞行大约10亿美元
Footing that kind of bill was not sustainable for NASA. 对美国宇航局来说这种费用是不可持续的
And in the early 1990s 在1990年代初
the agency started funding research 该机构开始资助研究
into other ways of making rockets reusable. 以其他方式使火箭可重复使用
Engineer John Garvey was on the team. 工程师约翰·加维参与其中
There are different ways to do reusability, 有不同的方法来实现可复用性，
and many advocates believe that a vertical lander 许多提倡者认为垂直着陆器
is, is the way to go 是可行的办法
if you can just come down on the same engines that you launch on. 如果你用发射的引擎来降落
♪ ♪
They developed an experimental rocket 他们研制了一种试验火箭
known as the Delta Clipper. 被称为“三角快帆”
It was a radical departure, 这是一次彻底的颠覆，
as this rarely seen footage shows. 正如这段罕见的录像所显示的
The Delta Clipper Experimental,or DCX, 三角快帆试验，或DCX，
was an experimental vertical take-off, 是试验性的垂直起飞，
vertical landing rocket. 垂直着陆火箭
Unlike the space shuttle, 不像航天飞机，
which was designed to fly back to earth, 设计上是飞回地球，
the Delta Clipper would land on its tail. 三角快帆是以它的尾部着陆
♪ ♪
Test flights of the DCX began in the early 1990s DCX的试飞始于20世纪90年代初
at a desert testing ground out in New Mexico. 在新墨西哥州的沙漠试验场
Nothing like this had ever been attempted before. 以前从未尝试过这样的事情
♪ ♪
We took it out to White Sands, 我们把它带到白沙，
a missile range out in New Mexico, 新墨西哥州的导弹试验场，
and launched it multiple times. 进行多次发射
This footage looks like outtakes from a science fiction movie. 这段录像看起来像是科幻电影的片段
It flew, you know,maybe 10,000 feet, 它飞了，你知道，大概一万英尺高，
but it was demonstrating 但它在展示
that it was possible to get the rocket back 有可能把火箭返回
and fly it with minimum refurbishment, 用很少的整修来再次发射它，
reduce costs. 降低成本
♪ ♪
The engineering team was on top of the world. 工程师团队兴高采烈
But their fortunes were about to change. 但他们的命运即将改变
There was a line that was not hooked up, 有一条线没有接通，
and as a result,as it was landing, 结果，当它降落时，
only three of the landing legs deployed, 只有三条腿展开了，
the fourth one did not, 没有第四条腿，
so it actually landed successfully, 所以它成功着陆了，
and I was like, "Yep, let's go!" 我说，“好，我们去吧！”
Landing small negative. 着陆有小差错
Engine out. 发动机关闭
She's going over. 她倒了
(explosion) （爆炸）
Then you turn around,and then the rocket's gone, 转身的功夫，火箭就不见了，
and it's on the side, 侧面着地，
and the tanks are rupturing. 燃料箱破裂
(explosions) （爆炸）
Yeah, it was a tough day. 是啊，很难过的日子
But, you know, that's how...that's... 但是，你知道，就是这样...就是...
If you're in this business, 如果你是做这行的，
you, you've got to get used to it, 你，你得习惯它，
you've got to roll with it and just say, 你必须接受，然后说，
"That's part of the deal." “这就是生意。”
And if you can't handle it,don't do it. 如果你应付不了，就不要做
♪ ♪
Losing the entire vehicle 失去整个的火箭
before it reached space 还没有到达太空
led NASA to cancel the program to pursue other avenues. 导致美国宇航局取消了计划，另辟蹊径
(radio squawking) （无线电声）
But there was one person who saw the potential: 但有个人看到了潜力：
a South African-born entrepreneur 南非出生的企业家
who'd made his first fortune disrupting the banking industry 他扰乱了银行业，挣到第一桶金
with a company called PayPal-- 用一家叫贝宝的公司--
Elon Musk. 伊隆·马斯克
Musk had always been a science-fiction fan 马斯克一直是科幻小说迷
and interested in the possibilities 他很感兴趣的是
of colonizing other planets. 殖民其他星球
And after he became wealthy as an entrepreneur, 当他作为企业家致富后，
he had some money 他有了钱
he could put toward this kind of scheme. 他可以实施这种计划
And that's how SpaceX was born. SpaceX就是这样诞生的
There have to be reasons that you get up in the morning, 你早上起来一定有原因，
and you want to live. 你想活下去
Like, why do you want to live? 比如，你为什么想活下去？
What, what's the point?What, what inspires you? 重点是什么？什么在激励你？
What, what do you love about the future? 什么，你喜欢怎样的未来？
And if we're not out there... 如果我们不去那里...
if the future does not include being out there among the stars 如果未来不是在星际文明之中
and being a multi-planet species, 成为一个多行星物种，
I find that...it's incredibly depressing 我觉得...真是令人沮丧
if that's not the future that we're going to have. 如果那不是我们的未来
♪ ♪
In the early 2000s, 在21世纪初，
there was little business incentive 没有什么商业激励
in building rockets to take people to space, 在制造火箭把人们送上太空的过程中，
let alone Mars. 更不用说火星了
But that was about to change. 但这种情况即将改变
♪ ♪
GNC, are you ready? GNC，准备好了吗？
Flight max, we're ready. 任务指挥，我们好了
GNC is go. GNC准备好了
I think we're ready,no deltas. 我们准备好了，没有变化
On the first of February 2003, 2003年2月1日，
NASA's oldest space shuttle,Columbia, 美国宇航局最老的航天飞机哥伦比亚号，
was returning from orbit. 从轨道返回
Columbia, Houston,UHF comm check. 哥伦比亚，休斯顿，特高频通讯检查
Loss of voice communication is always expected 语音通信的中断总是意料之中的
for a short time during reentry. 在重返大气层期间有一段很短的时间
(radio static popping) （无线电静电声）
But on this occasion, 但是这次，
contact was never reestablished with Columbia. 与哥伦比亚的联系无法恢复
Damage during launch,which no one had noticed, 发射过程中的损伤，没人注意到，
caused Columbia to burn up during reentry over America, 导致哥伦比亚号在美国上空返航时烧毁，
killing all onboard. 所有人死亡
TC, Flight. TC，航班
Flight, TC. 航班，TC
Lock the doors. 关闭
Copy. 收到
♪ ♪
The risks of flying such a complex spacecraft 如此复杂的航天器的风险
were brought into sharp focus. 引起了强烈的关注
It was time for NASA to rethink 现在是美国宇航局重新考虑的时候了
how they launched their astronauts into space. 他们该如何将宇航员送入太空
There was a decision after the Columbia accident in 2003, 2003年哥伦比亚号事故后有个决定，
to retire the shuttle as soon as the International Space Station 航天飞机会退役，一旦国际空间站
was fully assembled. 完成了组装
Rather than build a new spacecraft themselves 不是自己建造一艘新的宇宙飞船
to reach the Space Station, 去空间站
NASA decided they would buy future astronaut seats 美国宇航局决定购买宇航员船票
and cargo delivery missions from private companies. 从私人公司购买船票和货物运送服务
The man charged with finding and developing those suppliers 负责寻找和发展那些供应商的人
was Alan Lindenmoyer. 是艾伦·林登莫耶
SpaceX was a new start-up company; SpaceX是一家新创公司；
they had only been in business for a few years, 他们入行才几年，
and when we visited them, 当我们拜访时，
they had maybe a couple hundred people. 他们大概只有几百人
They were very busy, 他们很忙，
and we could sense,and we could see 我们可以感觉到，我们可以看到
that this was extremely talented team 这是一支非常有才华的队伍
that we believed had the ability 我们相信他们有能力
to, to complete it, the job. 完成这项工作
Closing a deal with NASA 与美国宇航局达成协议
to send cargo and crew to the Space Station 把货物和乘员送到空间站
was a huge boost to SpaceX, 是对SpaceX的巨大推动，
but also a risk for the space agency. 但对宇航局来说也是个风险
So they appointed their long-time aerospace partner Boeing 所以他们指定了长期航天合作伙伴波音公司
to build another new crew vehicle, 建造另一艘新的载人飞船，
to fly on their existing single-use rockets 用在现有的一次性火箭上
like the Atlas V. 就像宇宙神5号
SpaceX was in the spotlight,as they set about SpaceX成了焦点，他们试图
trying to develop a brand-new, reusable rocket. 开发全新的，可复用火箭
It's classic Elon Musk. 这是典型的伊隆·马斯克
He's set himself up to do something 他想做点什么
that no one else says he can do,or is really asking for, 没有人说他能做到，或者说真的要求他做到，
but if he delivers,it might change the world. 但如果他做到了，就会改变世界
♪ ♪
Attempting to fly a reusable rocket to space and back 试图将可重复使用的火箭送入太空并返回
is about as hard as aerospace engineering gets. 代表了航天工程中最难的程度
♪ ♪
It's hard enough building a rocket that can get to orbit. 建造一枚能进入轨道的火箭已经够难了
Now, if you have to build the additional capability 现在，如果您必须构建附加功能
to bring it back, 让它返回来，
the margins get even tighter. 余地变得更小了
Returning a rocket safely back to the launch site 让火箭安全返回发射场
involves a series of complex steps, 需要一系列复杂的步骤，
which begin on the edge of space, 从太空边缘开始，
when still traveling at over 3,500 miles per hour. 当仍然以每小时3500英里的速度飞行时
First the rocket does what's called a boost-back burn, 首先火箭进行反推点火，
it fires its engines,slows itself down, 发动机点火，减慢速度，
and starts returning in the opposite direction. 开始向相反的方向返回
Now on a trajectory 现在在返回轨道上
that's taking it back towards the launch site, 让它回到发射场，
this giant, 14-story tower must turn itself around once more 这座14层楼高的巨塔必须再次翻个身
to point the engines forward 使发动机向前
as it starts to reenter the top of the atmosphere. 就在它重入大气层顶部时
And that's when things begin to get tricky. 就在那时问题开始变得棘手
A rocket is an unstable vehicle. 火箭是一种不稳定的运载工具
You have to deal with the control elements, 你必须处理好控制的部分，
so how do you keep it stable on the way down? 在下降的时候你怎么保持它的稳定呢？
It has maneuvering jets at the top 上面有机动的喷气
that shoot out bursts of compressed air 喷出压缩空气
to keep it aligned, 为了保持对准，
but its main way to keep going in the right direction 但它的朝着正确方向前进的主要方法是
are something called grid fins. 是一种叫做格栅翼的东西
These fins--the size of dining tables-- 这些翅膀--餐桌的大小--
act as paddles to steer and slow the falling booster rocket 充当桨叶来操纵和减缓坠落的火箭
as it enters the denser lower atmosphere. 当它进入较稠密的低层大气时
As the rocket gets closer and closer to land, 随着火箭离地面越来越近，
it does more controlled burns with its engine 它的发动机更多地控制燃烧
to slow down and align itself with the landing pad. 减速并与着陆场对齐
As the engine ignites into a hypersonic headwind, 当发动机点火形成超音速逆风，
the 33-ton rocket suddenly becomes even more unstable. 33吨重的火箭突然变得更加不稳定
It's like balancing a pencil on the end of your finger 就像在你的手指末端平衡一支铅笔
and think of how much effort and work you need 想想你需要付出多少努力
to do that yourself. 自己试试看
An array of sensors 一系列传感器
is now constantly relaying the rocket's orientation 正在不断地传递火箭的方位信息
to the engines at the base, 到底部的发动机，
that swings left and right 左右摇摆
to keep the vehicle upright as it slows down. 在火箭减速时保持垂直
Landing on a, a pillar of fire, 喷着火焰降落，
that last five feet can be critical 最后5英尺很关键
if you don't know where the ground is. 如果你不知道地面在哪里
Approaching the landing pad, 接近着陆场，
the onboard autopilot now deploys legs 火箭的自动驾驶展开腿
and throttles back the engine, 然后发动机减速，
so that velocity and altitude both equal zero together. 最后速度和高度都等于零
All of these different variables just show 所有这些不同的变量说明了
how much has to go right 有多少事情要做得恰到好处
every time the rocket comes back to earth 每次火箭返回地球
for it to land. 然后着陆
Easy to pull off in a slick animation, 很容易在流畅的动画中展示，
but a long shot in real life. 但是现实中需要长期奋斗
Then another internet entrepreneur with similar dreams 另一个有着相似梦想的互联网企业家
stepped forward-- 站出来了--
Amazon founder Jeff Bezos, 亚马逊创始人杰夫•贝佐斯，
who'd quietly founded a company in the year 2000 他在2000年悄悄地创办了一家公司
called Blue Origin. 叫做蓝色起源
One example 举个例子
of the secrecy behind Blue Origin 保守秘密的蓝色起源公司
is the first time we really learned what they were doing 我们第一次了解到他们在做什么
is when a journalist went through the trash cans 是一个记者在他们的垃圾桶里翻东西
outside of their office in Washington 在华盛顿的办公室外面
and discovered the plans, 才发现了计划，
or at least memos discussing their goals of space tourism. 或者至少是讨论太空旅游目标的公司备忘录
♪ ♪
Working quietly,without fanfare, 安静地工作，不张扬，
it takes Bezos and Musk more than a decade to pull off 贝佐斯和马斯克花了十多年才做出
their first successful vertical-landing rockets. 他们第一款成功的垂直着陆火箭
Bezos' rocket--named New Shepard 贝佐斯的火箭--命名为新谢泼德
after the first American astronaut Alan Shepard-- 以第一位美国宇航员艾伦·谢泼德命名--
reached the edge of space 到达了太空的边缘
on the 23rd of November 2015, 2015年11月23日，
and returned to the launch pad a few minutes later. 几分钟后回到发射台
♪ ♪
Within a month, 一个月内，
Musk's first reusable SpaceX rocket booster, 马斯克的第一个可重复使用的太空助推火箭，
called the Falcon 9,touched down vertically too, 叫做猎鹰9号，也垂直降落，
after delivering a payload all the way to orbit. 在将有效载荷送入轨道之后
These two triumphs marked a major step 这两次胜利标志着一大步
in the pursuit of a more reusable rocket, 对可复用火箭的追求，
and perhaps the beginning of a new era 也许是新时代的开始
for lower-cost trips to Earth orbit 低成本到达地球轨道
and the long-awaited promise of more affordable space tourism. 以及人们期待已久的可承受的太空旅游
♪ ♪
While Space X has continued its successful track record, 虽然SpaceX继续保持着它的成功记录，
with over 20 commercial launches in 2018 alone, 仅2018年就有20多次商业发射，
another, quieter rocket revolution is underway-- 另一场更安静的火箭革命正在进行--
one that's being driven by miniaturization. 由小型化所驱动
Today, everybody knows that microchips, batteries, 今天，大家都知道微芯片，电池，
solar panels are smaller and more powerful 太阳能电池板更小更强大
than they ever have been, 比起以往任何时候，
but what that allows engineers to do 但是工程师可以做的
is build small satellites that are cheaper and weigh much less, 建造更便宜更轻的小卫星，
but can do everything old satellites do. 但可以做以往卫星所做的一切
Such small,low-cost satellites-- 这些小的低成本卫星--
some known as cube sats-- 有些叫立方星--
can be deployed very quickly 可以很快部署
and may transform 并且可以改变
the way we communicate,navigate, and observe Earth 我们沟通、导航和观察地球的方式
from space. 立足于太空
One of the advantages 优点之一
of having multiple spacecrafts 拥有多个航天器
working in synergy with one another 协同一致工作
is that you can monitor things like wildfires 你可以监测像野火这样的
that are spreading rapidly. 迅速蔓延的事情
You can do this in real time. 你可以实时完成
We can track earthquakes, 我们可以追踪地震，
whether or not it's going to shoot off a tsunami. 不管它是否会引发海啸
We have much more data 我们有更多的数据
to be able to pinpoint the location 可以精确定位
of catastrophic events 灾难性事件的位置
and then take action to remedy that. 然后采取行动补救
This new generation of tiny satellites 新一代微型卫星
is spawning a new array of rocket-launch companies. 正在催生一批新的火箭发射公司
Because, thanks to Tsiolkovsky's rocket equation, 因为，多亏了齐奥尔科夫斯基的火箭方程，
once the payloads are smaller, 一旦有效载荷变小，
the mass of fuel can be smaller too. 燃料的质量也可以更小
And that makes it cheaper to get to orbit. 这使得进入轨道的成本更低
♪ ♪
One company aiming at this new market is Rocket Lab. 一家瞄准这个新市场的公司是“火箭实验室”
♪ ♪
Its founder is New Zealand engineer Peter Beck. 它的创始人是新西兰工程师彼得·贝克
The whole purpose of Rocket Lab is, is to enable frequent, 火箭实验室的全部目的是，实现频繁的，
affordable access to space,and if we can do that, 可承受的太空任务，如果能做到，
then some really incredible things will start to happen. 那么一些真正不可思议的事情就会开始发生
♪ ♪
Until Rocket Lab came along, 直到火箭实验室出现，
the most affordable rocket ride to orbit 最实惠的轨道任务发射
would set you back around $60 million. 需要你花费6000万美元左右
But they can do it for less than a tenth of this price. 但他们能以不到十分之一的价格做到这一点
Our prices start at $5.7 million. 我们的起价是570万美元
♪ ♪
So that's a, a dramatic order of magnitude change. 所以这是一个巨大的变化
Five, four, three, two... 5,4,3,2...
Ignition. 点火
(engine ignites) （发动机点火）
Getting to orbit for this sort of price 以这样的价格进入轨道
requires a new approach to rocket building. 需要一种新的火箭制造方法
It's the world's first 这是世界上第一款
all-carbon composite launch vehicle 全碳复合材料运载火箭
to ever reach orbit. 能够进入轨道
The carbon-fiber gives us a strong advantage 碳纤维给了我们强大的优势
with mass and structural performance. 优良的质量和结构性能
Using carbon fiber instead of heavier metal alloys 用碳纤维代替更重的金属合金
reduces the rocket's weight,allowing for more payload. 减少火箭的重量，允许更多的有效载荷
The rockets are incredibly light. 火箭非常轻
You can wheel it around with no issues at all. 你可以用轮子这样移动，一点问题也没有
The actual structures and the tanks of the rocket 火箭的实际结构和燃料箱
weigh almost nothing. 几乎没有什么重量
Rocket Lab has already put 24 cube sats into orbit 火箭实验室已经将24颗立方星送入轨道
on three flights. 通过3次发射
They hope their radically cheaper carbon-fiber rocket 他们希望他们廉价的碳纤维火箭
will create even greater demand for launch services. 将创造更大的发射服务需求
♪ ♪
Hacking the rocket equation can bring costs down-- 破解火箭方程式可以降低成本--
but only so far. 但是也有局限
So innovators are looking at other ways to economize. 因此，创新者正在寻找其他节约的方法
For example, 比如说，
what if a rocket doesn't need to take off from a launch pad, 如果火箭不需要从发射台起飞，
eliminating the expensive infrastructure 消除昂贵的基础设施
which accompanies all liftoffs? 点火起飞必须的那些？
What if you could launch to orbit 如果你能够发射到轨道
from almost anywhere? 从随便什么地方？
Even from back of a truck? 甚至从卡车后面？
That's exactly what Delta Clipper veteran John Garvey 这也是三角快帆的老将约翰·加维
is trying to do. 正在尝试要做的
We've designed the rocket certain ways 我们通过特定方式设计火箭
to make it simpler. 使它更简单
We use a trailer, drive it a mile or two to the pad, 我们用拖车，开一两英里到发射场，
go vertical, and launch. 垂直起竖，然后发射
We basically need a paved road, 我们只需要一条铺好的路，
a concrete pad,and, and some utilities, 一块混凝土场地，还有一些公用设施，
power and the internet's nice. 电源和网络都很好用
♪ ♪
By focusing on really small satellites-- 通过着眼于非常小的卫星--
under 130 pounds in weight-- 重量在130磅以下--
Garvey can reduce the size of his rocket, 加维可以缩小火箭的体积，
allowing him to experiment with much cheaper solutions. 让他尝试更便宜的解决方案
We use liquid oxygen as the oxidizer, 我们用液氧作为氧化剂，
and we're using propylene as the fuel. 我们用丙烯作为燃料
It gives us just enough extra performance, 它给了我们足够的额外表现，
a thrust on the order of 20,000 pounds at liftoff. 升空时达20000磅的推力
♪ ♪
Garvey's rocket engines might be puny 加维的火箭发动机可能很小
compared to NASA's main SLS engine, 比起美国宇航局的SLS发动机，
but they have the potential 但它们有潜力
to change the way we launch very small satellites 让我们发射小型卫星的方式
in a very big way. 发生巨大改变
Our job is to get to the point 我们的工作就是要达到
where when we launch,people don't even look up. 我们发射火箭，人们甚至不会抬头看
It's just like,"Oh, yeah, okay, fine." 就是像，“哦，是，好的，可以”
And we'll be truly successful-- 我们要真正成功--
we, collectively as an industry-- 我们，作为一个行业--
when we're doing that, 当我们这么做的时候，
and people barely look over and say, 人们几乎不会关心，说，
"Oh, yeah,that's another Vector launch. “哦，是，那是又一次‘矢量’发射
They do that all the time." 他们一直在那样发射”
That's going to be the metric that we are really establishing 这将是我们真正想建立的标准
we're hitting the numbers. 我们在创造数量
♪ ♪
Garvey imagines a low-cost mass market 加维设想了一个低成本的大众市场
where rides to orbit are as mundane as jet travel. 进入轨道和乘坐喷气式飞机一样平淡无奇
(engine roaring) （发动机轰鸣）
♪ ♪
Another way to reduce costs to orbit 另一种降低轨道运行成本的方法
is to start your rocket closer to space 就是离太空更近的地方发射你的火箭
by eliminating the need to launch from the ground at all. 完全不需要从地面发射
One company, Virgin Orbit, 一家公司，维珍轨道，
thinks it can cut launch-to-orbit costs down 认为它可以降低发射到轨道的成本
by allowing the rocket to hitch a ride partway to space. 让火箭在半路上搭便车飞向太空
Their CEO is Dan Hart. 他们的CEO是丹·哈特
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Well, Virgin has been working on air-launch systems 维珍公司一直在研究空中发射系统
for quite a while. 很长一段时间了
And so there's a whole Virgin Galactic company 所以有一家维珍银河公司
that is working on space tourism, 致力于太空旅游，
where a spaceship comes off of an aircraft 宇宙飞船从飞机上脱落起飞
and takes tourists into space. 把游客送上太空
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And from that,the discussion of, 从那儿，讨论就开始了，
"Well, what else can we get into space, “还有什么能发射到太空，
and "How can we use similar technologies?" 以及“我们如何使用类似的技术？”
really rose. 真的起来了
Virgin Galactic's rockets are designed to carry 维珍银河的火箭设计用来运载
a relatively heavy cargo of humans 相对较重的人类货物
high enough to reach space, 高到足以到达太空，
but not fast enough to get into orbit. 但没有足够的速度进入轨道
But by reducing the mass of the payload, 但是通过减少有效载荷的质量，
a small rocket carried to altitude under the wing 用飞机运载到高空的小火箭
of a plane could reach the speeds needed 能达到所需的速度
to get to orbit. 去往轨道
So, it was an easy,logical progression 所以，这是一个简单的，合理的过程
to use those technologies 使用这些技术
for the purpose of taking satellites into space. 为了把卫星送入太空
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Spinoff Virgin Orbit 分拆的维珍轨道
has a fully reusable,first-stage launch vehicle 具有完全可重复使用的第一级运载工具
in the shape of a repurposed jumbo jet airliner, 是一架改装的大型喷气式客机，
christened Cosmic Girl. 被命名为宇宙女孩
Cosmic Girl is the carrier aircraft. 宇宙女孩是天空母舰
She'll carry our rocket,Launcher One, 她会带着我们的火箭，一号发射器，
to about 35,000 feet 到35000英尺高
and get close to Mach One,the speed of sound. 接近马赫1，音速
Having altitude and velocity 有高度和速度
is a good thing for a rocket to start off with, 对火箭来说是一件好事，
and it gives us an initial boost. 它给了我们最初的助力
That helps us, 帮助我们，
because it allows us to make the rocket smaller 因为它能让我们把火箭造小一点
and less expensive. 便宜一点
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Just like Vector and Rocket Lab, 就像“矢量”和火箭实验室一样，
Virgin Orbit's also chasing 维珍轨道也在追逐
the burgeoning small-satellite market. 新兴的小卫星市场
So, are there enough new small satellite companies 那么，有没有足够的小型卫星公司
to keep all these new rocket companies in business? 让这些创新的火箭公司继续营业？
The eternal bane of all rocket companies 火箭公司的永恒的烦恼
is making sure there's enough cargo 就是确保将来有足够的货物
for you to launch in the future. 在未来让你发射
And with so many rocket companies forming right now, 现在有这么多火箭公司成立，
it's not clear that they'll all survive. 不清楚他们是否都能活下来
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While these small-rocket companies fight it out 当这些小火箭公司奋力拼搏
to see who'll become king of the micro-satellite market, 谁将成为微型卫星市场之王者，
the bigger players--like NASA, SpaceX, Boeing, 更大的玩家——比如美国宇航局，SpaceX，波音，
and Blue Origin-- grapple with the challenges 蓝色起源——正在应对挑战
of carrying immense payloads into deep space. 将巨大的有效载荷送入深空
Elon Musk and Jeff Bezos are talking 伊隆·马斯克和杰夫·贝佐斯在谈论
about millions of people living in space habitats 让数百万人生活在太空栖息地
or colonizing Mars. 或者火星殖民
And even though it sounds crazy, 尽管听起来很疯狂，
it is a difference in their approach, 他们的方法不同，
and it shows in how they try and do things-- 这展示了他们是如何尝试和行事的--
to be cheap, to be long-lasting, 要便宜，要持久，
to be infrastructure that can be built on by the broader economy, 建立由通常的经济可以维持扩张的基础设施，
not just a one-time military mission. 不仅仅是一次性的军事性质的任务
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Behind these ventures is a common impulse, 在这些冒险背后是一种普遍的冲动，
one that drives some of us to build rockets. 驱使我们中的一些人制造火箭
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We're all explorers. 我们都是探险家
We're departing from low Earth orbit, 我们要离开近地轨道，
and we're going to go further than we've ever gone before. 我们会比以前走得更远
And I think that we're really going to do this someday. 我想总有一天我们会这么做的
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SpaceX has announced it is building prototypes SpaceX宣布正在建造原型
of its giant Starship rocket, 巨型的星舰火箭，
intended to ferry hundreds of people to Mars. 打算把数百人送上火星
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So could today's "Rise of the Rocket" 今天的“火箭的复兴”
really carry us all to the stars? 真的能把我们带到星际空间？
I really believe that, just like 我真的相信，就像
we are now taking humans to low Earth orbit commercially, 我们现在通过商业航天把人类带到近地轨道，
that pretty soon there will be a commercial space station 不久将有一个商业空间站
in orbit as well, 在轨道运行，
which will be the next destination. 这是下一个目标
So what I tell people is 所以我告诉人们的是
"If you don't think you can go to space today, just wait." “如果你认为你不能去太空，就等着瞧吧”
A hundred years ago,when all there were 一百年前，当所有的
were biplanes that didn't fly very fast, 双翼飞机都飞得不快的时候，
the, the average person would say, 一般人会说，
"I will never fly an airplane." “我决不会开飞机”
So you have to think about, 所以你得想想，
"What's it going to be like tomorrow?" “明天会是什么样？”
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A hundred years after the first powered flight, 在第一次动力飞行一百年后，
airplanes and air travel are commonplace, 飞机和航空旅行司空见惯，
something we take for granted. 我们认为理所当然
Will the same be true of rockets 火箭也一样吗
a hundred years after Goddard's first flight? 戈达德的首次飞行一百年后？
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Will this be the dawn of an age 这将是一个时代的开端吗
that ultimately propels society even further? 推动社会进一步的发展？
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(door opening) （门打开）
翻译：@火星学会
To order this "NOVA" program on DVD, 订购“NOVA”DVD，
visit ShopPBS or call 1-800-PLAY-PBS. 访问ShopPBS或拨打1-800-PLAY-PBS
This program is also available on Amazon Prime Video. 亚马逊Prime视频也可以看
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