1000公里长的星际缆绳——天钩：英语精读讲义

Getting to space is hard.

进入太空并非易事。

Right now,

就目前而言，

it's like going up a mountain on a unicycle with a backpack full of explosives. 表達脈絡

就像骑着独轮车，背着满满一包炸药上山。

Incredibly slow,

速度慢得惊人，

you can't transport a lot of stuff,

带不了多少东西，

and you might die.

而且随时可能丧命。

A rocket needs to reach a velocity of about 40,000 km/h to escape from Earth. 短語搭配

火箭要逃离地球，速度得达到大约每小时四万公里。

To get to that speed,

为了达到这个速度，

rockets are mostly containers for fuel with a tiny tip of payload.

火箭内部几乎全用来装燃料，只有顶端一小块地方留给有效载荷。

This is bad if you want to go to other planets

这对前往其他星球来说可不是个好消息，

because you need a lot of heavy stuff

因为你需要带上大量重型设备，

if you want to survive and maybe even come back.

才能在上面生存，甚至有朝一日还能重返地球。

So,

那么，

is there a way to get to space

有没有一种方法可以进入太空，

with less fuel and more payload?

既能省燃料，又能多带些东西呢？

A nice thing that solved most of our transport problems on Earth

在地球上，有个好东西解决了我们大部分的运输难题，

is what you call infrastructure.

那就是基础设施。

Whether it's roads for cars, 語法

无论是汽车跑的公路、

ports for ships,

船舶停靠的港口，

or rails for trains,

还是火车行驶的铁轨，

we've made it easier to get to places. 語法

都让出行变得更轻松。

We can apply the same solution to space travel.

我们可以把这个方案应用到太空旅行上。

Space infrastructure will make getting into orbit

太空基础设施将让进入轨道，

and out to the Moon,

甚至前往月球、

Mars,

火星，

and beyond easier and cheaper.

乃至更远的地方变得更轻松、更便宜。

Great.

太棒了。

But what exactly is space infrastructure?

但太空基础设施到底是什么呢？

Unlike an Earth space elevator, 表達脈絡

与地球上的太空电梯不同，

which is currently science fiction,

它目前还只是科幻小说，

there is a simple yet promising technology

但有一种简单却前景广阔的技术

that does not require new science,

不需要全新的科学、

magic materials,

神奇的材料、

or huge investments,

或是巨额的投资，

and that has been tested successfully in orbit already. 語法

且已经在轨道上成功测试过。

A cable and a weight,

只需要一根缆绳和一个配重，

known as a tether. 短語搭配

被称为“系绳”（tether）。

The concept is so simple, 語法

这个概念简单到

it's surprising.

让人惊讶。

What if we put tethers, 語氣意圖

如果我们把系绳，

hundreds or thousands of kilometers long,

几百或几千公里长，

into space

放到太空中，

and had spacecraft use them as ladders to climb to higher altitudes and gain speed? 語法

让航天器把它当成梯子，爬到更高的地方并加速呢？

This concept is known as the skyhook.

这种概念被称为“天钩”（skyhook）。

It works even better if we make it spin.

如果让它旋转起来，效果甚至会更好。

A counterweight holds a long cable in place

用一个配重固定住长长的缆绳，

while it rotates around a circle.

让它绕着圆心旋转。

A rotating tether slows down its tip

旋转的系绳会减慢其底端的速度，

relative to the ground at the bottom 短語搭配

相对底部的地面而言，

and speeds it up at the top like a catapult.

并在顶端像投石机一样为其加速。

This means that you can transfer energy from the tether

这意味着你可以从系绳中获取能量，

and get a massive boost when released,

在松开时获得巨大的推力，

more or less for free, 短語搭配

而且这几乎是免费的，

equal to twice the tether's rotation velocity.

相当于系绳旋转速度的两倍。

Specialized fibers already exist

特殊纤维已经面世，

that can survive the extraordinary stresses a skyhook would be faced with. 短語搭配

它们可以承受天钩面临的极大拉力。

To protect against cuts and collisions from debris and meteorites,

为了防止被太空碎片和陨石割断或撞毁，

we can thread our tether into a web of redundant fibers.

我们可以将系绳编织成网状的冗余纤维结构。

Since our skyhook would pass over the same spot many times a day,

由于天钩每天都会多次经过同一个地点，

this would allow small reusable shuttles to catch up with it. 短語動詞

那些可重复使用的小型航天飞船就能顺利追上它。

Of course, 表達脈絡

当然，

it's not that easy.

事情没那么简单。

At its lowest point,

在最低点时，

the tether's tip is dashing through the atmosphere at around 12,000 km/h.

系绳末端正以大约一万两千公里的时速穿越大气层。

Because of Earth's atmosphere,

因为地球有大气层，

we can't lower the skyhook too much or it will get too hot from air friction.

我们不能把天钩放得太低，否则会因空气摩擦而过热。

So,

所以，

it will dip to a height of 80 to 150 km and no lower.

它的最低高度将被限制在80到150公里之间。

To match this,

为了配合它，

we'll need specialized spacecraft that can get to the tether.

我们需要能飞抵系绳处的特殊航天器。

While this isn't exactly easy, 語法

虽然这也不容易，

it's still much cheaper than getting a big tin can filled with rocket fuel to go 40,000 km/h. 習語

但总比给一个装满火箭燃料的大铁罐加速到每小时四万公里要便宜得多。

Catching the tip will be a challenge, too.

抓住末端也是一项挑战。

There's only a short time window of 60 to 90 seconds 短語搭配

只有60到90秒的短暂窗口期，

to find a tiny thing in the sky moving at Mach 12.

让你在天空中寻找一个以12马赫飞行的微小物体。

To make this easier,

为了降低难度，

the tip could have a sort of fishing line,

可以在末端系上类似钓鱼线的东西，

a kilometer long,

长度一公里，

with a navigation drone that helps the spacecraft connect.

搭配导航无人机，帮助航天器完成对接。

Another challenge is keeping our skyhook in orbit. 表達脈絡

另一个挑战是让天钩保持在轨道上。

As more and more ships latch onto it and pull themselves up, 短語動詞

随着越来越多的飞船勾住它并向上爬，

they use up the momentum that keeps it in place. 短語動詞

它们会消耗掉让天钩维持位置的动量。

If we don't do anything,

如果我们什么都不做，

it will slow down and crash into the atmosphere.

它的速度就会变慢并坠入大气层。

And here,

在这里，

we can cheat the universe a bit. 習語

我们可以稍微“欺骗”一下宇宙。

The skyhook is a battery of orbital energy. 習語

天钩就是轨道能量的“电池”。

It's possible to balance the payloads coming in and being sent off. 語法

我们有可能平衡往返的有效载荷。

Arriving ships bringing humans and materials home to Earth add energy to the tether,

那些将人类和物资带回地球的抵达飞船会为系绳增加能量，

which it can give to other ships departing into space.

它便能将这些能量传递给其他出发前往太空的飞船。

This way,

这样一来，

the tether doesn't lose any energy.

系绳就不会损失任何能量。

The more we use it, 語法

我们用得越多，

the cheaper it gets.

成本就越低。

If we're still losing energy with each boost,

如果在每次加速时仍然在损失能量，

we can recover it with small electric or chemical engines that regularly correct the tether's position.

我们可以用小型电动或化学发动机来恢复它，定期修正系绳的位置。

A set of tethers,

如果有一套系绳系统，

one around Earth and one around Mars,

一个绕地球，一个绕火星，

could make trips between the planets fast, straightforward,

就能让往返两颗行星之间的旅行变得快速、直接，

and low-cost compared to rockets.

并且比火箭便宜得多。

The Earth tether would sit in low Earth orbit 文化背景

地球的系绳将位于近地轨道，

to grab people and payloads and fling them off to Mars.

抓取人员和货物，将他们甩向火星。

The Mars tether catches them and slows them down for a landing on the surface.

火星的系绳则负责接住他们并减速，以便在表面着陆。

In the opposite direction,

反过来，

the tether could pick up a vehicle traveling through Mars's thin atmosphere at only about 1,000 km/h, 短語動詞

系绳也可以抓取在火星稀薄大气中仅以约1000公里时速飞行的载具（

not much faster than our airliners on Earth,

没比地球上的客机快多少），

and fling it back to Earth to be caught and lowered down.

再将它甩回地球，被抓取并降落。

The tethers could shorten trips between both planets from 9 months 短語搭配

这些系绳能将两颗行星之间的旅程从9个月缩短

down to 5 or even 3

到5个月甚至3个月，

and reduce the scale of the rockets required by between 84 and 96%.

并且把所需火箭的规模减少84%到96%。

Even better,

更好的是，

people may be able to travel in relative luxury

人们或许能在相对奢华的环境中旅行，

as we could afford to invest in passenger comfort.

因为我们有余力在乘客的舒适度上进行投资了。

Tether travel would be first class seats to Mars. 習語

系绳旅行将是前往火星的头等舱。

Together,

综上所述，

tethers around Earth and Mars

地球和火星周围的系绳

could provide the rapid and cost-efficient transportation backbone 習語

可以提供快速且具成本效益的运输骨干网络，

that would make space travel affordable.

让太空旅行变得负担得起。

But let's go further. 表達脈絡

但让我们想得更远些。

Starting from low Mars orbit,

从火星低轨道出发，

a tether could boost ships to the asteroid belt.

系绳还可以将飞船推向小行星带。

The first craft sent to a new asteroid would need rockets to slow down at its destination. 表達脈絡

第一艘前往新小行星的飞船需要在目的地使用火箭减速。

Subsequent arrivals might find a tether waiting to catch them

而后来的抵达者或许会发现一根系绳已经在那里等着接住他们，

and send them back for free.

并免费将他们送回。

Getting to asteroids cheaply

以低廉的成本前往小行星

is a major factor in opening up the resources of the solar system. 短語動詞

是开发太阳系资源的关键因素。

Precious metals and valuable minerals could be delivered to Mars

贵金属和有价值的矿物可以被运往火星，

just weeks after they were cut out of their asteroid.

就在它们从小行星上开采出来几周之后。

They would be the perfect building blocks for our interplanetary civilization. 習語

它们将是我们建立星际文明的完美基石。

But why stop here? 表達脈絡

可是为什么要止步于此呢？

Mars's moons are very convenient.

火星的卫星非常方便。

No other moons in the solar system orbit that close to their planet.

太阳系中没有其他卫星离它们的行星这么近。

Phobos is so heavy that we don't need to worry about slowing it down, 語法

火卫一非常重，我们完全不用担心它会减速，

making it the perfect attachment point 語法

这让它成为绝佳的附着点，

for super tethers just under 6,000 km long.

可以用来连接不到6000公里长的超级系绳。

The lower tip would fly just over the surface of Mars and be very easy to catch.

较低的末端将直接在火星表面上空飞行，非常容易抓取。

The upper tip can fling ships all the way to Jupiter and Saturn.

而较高的末端则能将飞船一路甩向木星和土星。

The same super tether can also bring the inner solar system closer.

同样，这根超级系绳也能拉近内太阳系的距离。

Venus and Mercury are a single swing away. 習語

只需一次甩动就能到达金星和水星。

Unlike Mars,

与火星不同，

they're bursting with solar energy 短語搭配

它们蕴藏着丰富的太阳能，

and are rich in minerals.

且矿物资源丰富。

In the long term,

从长远来看，

nothing is stopping humanity from constructing a zero propellant transport network 語法

没有什么能阻止人类构建一个零推进剂的交通网络，

for the terrestrial planets

覆盖类地行星，

centered on the Martian moons.

并且以火星的卫星为中心。

Tethers are a comparably cheap and sustainable solution to making space travel affordable 語法

系绳是一种相对便宜且可持续的解决方案，让太空旅行更加亲民，

and the rest of the solar system accessible

并让太阳系的其他地方触手可及，

for exploitation and exploration.

方便我们进行探索与开发。

Considering that we have the technology to build them today, 表達脈絡

考虑到我们今天已经拥有了建造它们的技术，

there's really no good excuse to wait any longer. 語氣意圖

真的没有好理由再等下去了。

Parts of the solar system are far away, 表達脈絡

太阳系的某些部分确实遥远，

but they could be very close.

但它们原本可以离我们非常近。