土星五号的方向问题：英语精读讲义

This is the Saturn V rocket moments away from lifting off and taking the Apollo 11 astronauts to the moon. 短語搭配

这是土星5号火箭即将升空，将阿波罗11号宇航员送往月球的几秒钟前。

With 15 seconds to go,

距离发射还有15秒，

NASA commentator Jack King says this.

NASA评论员Jack King这样说道。

T minus 15 seconds, 文化背景

T减15秒，

guidance is internal. 用詞

制导转为内部控制。

It may not seem very significant,

这听起来似乎不怎么起眼，

but it meant that the Saturn V

但这意味土星5号

was now relying on its own guidance system,

现在要完全依赖自身的制导系统，

the one that would steer it towards the moon.

也就是那个将引导它飞向月球的系统。

This incredible system

这个不可思议的系统

was completely independent from the outside world

与外界完全独立，

and worked by measuring how the rocket's velocity and orientation

其工作原理是测量火箭的速度和姿态

had changed relative to its starting position. 短語搭配

相对于初始位置发生了多少改变。

Because of this,

正因如此，

the rocket needed to be absolutely sure of its starting position

火箭需要极其精确地确认其初始位置，

or else it would end up on a completely different trajectory. 講解

否则它最终会进入一条完全不同的轨道。

In this video,

在本期视频中，

we're going to look at the Saturn V's incredible guidance system

我们将探究土星5号令人惊叹的制导系统，

and how a hidden bunker below the launch pad

以及发射台下方的一个隐藏地堡

helped to keep it pointing in the right direction.

是如何帮助它保持正确指向的。

We'll also be giving away this awesome Falcon 9 framed print.

我们还将送出这幅超酷的猎鹰9号装裱画。

So stick around to the end of the video 短語動詞

所以请一直看到视频最后，

to see how you could win.

看看你如何才能赢取。

The Saturn V had a predetermined starting position

土星5号有一个预设的初始位置，

with its Y-axis facing north and south,

它的Y轴朝向南北，

the Z-axis facing east and west,

Z轴朝向东西，

and its X-axis pointing directly up.

而X轴则径直朝上。

But as the Earth rotated,

但是随着地球的自转，

these axes would no longer reflect the rocket's true orientation.

这些坐标轴将不再反映火箭的真实姿态。

So how did NASA correct this in time for launch?

那么NASA是如何在发射前及时纠正这一点的呢？

The entire Saturn V rocket was controlled by the instrument unit 文化背景

整枚土星5号火箭都由仪器单元控制，

located at the top of the third stage.

该单元位于第三级火箭的顶部。

It contained the inertial guidance platform, 文化背景

它内部包含惯性制导平台，

an advanced mechanical gyroscope

这是一个先进的机械陀螺仪，

that could measure the rocket's orientation with incredible accuracy.

能够以惊人的精度测量火箭的姿态。

The basic principles of a gyroscope involves

陀螺仪的基本原理涉及

a disc mounted on a three-axis gimbal.

一个安装在三轴万向节上的圆盘。

The disc is free to rotate in every direction,

这个圆盘可以自由地向各个方向旋转，

but once the disc starts to spin,

但一旦圆盘开始转动，

its angular momentum keeps it perfectly stable 文化背景

它的角动量就能让它保持绝对稳定，

even if the gimbals are rotated.

即使万向节发生旋转也是如此。

The Saturn V's gyroscope worked on the same principle 短語搭配

土星5号的陀螺仪工作原理与此相同，

but was much more advanced.

但要先进得多。

Instead of a single spinning disc,

它的制导单元并没有使用单个旋转圆盘，

the guidance unit had a central platform

而是有一个中央平台，

containing three spinning gyros

其中包含三个旋转的陀螺仪，

placed 90 degrees apart from each other.

它们彼此之间呈90度角放置。

If the rocket's orientation changed,

如果火箭的姿态发生改变，

these gyros would sense a slight change in torque, 用詞

这些陀螺仪就能感应到扭矩的微小变化，

which was turned into an electrical signal.

并将其转化为电信号。

That signal was then sent to motors on each gimbal,

随后这个信号被发送到每个万向节上的电机，

which would reproduce the change in torque

电机会重现这一扭矩变化，

but in the opposite direction,

但方向相反，

canceling out the rotation 短語動詞

从而抵消了旋转，

and keeping the platform completely stable.

让平台保持完全稳定。

On the opposite side of the gimbal,

在万向节的另一侧，

a device would measure how much the gimbals had rotated

有一个设备会测量万向节相对于平台的

relative to the platform,

旋转幅度，

telling the rocket exactly what direction it was pointing in.

从而确切地告诉火箭它所指向的方向。

This, along with the acceleration data,

这一点，再加上加速度数据，

would allow the flight computers to plot the rocket's trajectory. 短語搭配

就能让飞行计算机绘制出火箭的轨迹。

But if the gyroscope wasn't perfectly aligned to the rocket's axes,

但如果陀螺仪没有与火箭的坐标轴完美对齐，

during launch,

在发射过程中，

it would completely throw off the rocket's trajectory. 短語動詞

火箭的轨迹就会完全偏离。

Say you have a car that's programmed to follow this trajectory 表達脈絡

假设你有一辆车，程序设定它要按照这条轨迹

through a crossroads.

穿过一个十字路口。

Its guidance system only knows that it accelerated

它的制导系统只知道它加速了，

and took a right turn.

并右转了。

If we change the starting position of the car,

如果我们改变这辆车的起始位置，

the guidance system will see the exact same thing,

制导系统所看到的将完全一样，

but the car will end up in the wrong place.

但车最终却会到达错误的地方。

In the 5 hours leading up to the launch, 短語搭配

在发射前的5个小时里，

the Saturn V's gyroscope would be powered on

土星5号的陀螺仪会通电启动，

and trying to keep itself stable.

并试图保持自身的稳定。

However, the Earth was constantly rotating,

然而，地球一直在不断自转，

which meant the rocket's orientation was also slowly changing.

这意味着火箭的姿态也在缓慢发生改变。

Without any external input,

如果没有任何外部输入，

the gyroscope would become so misaligned

陀螺仪的偏差会变得非常大，

that the rocket would think it was pointing sideways.

以至于火箭会认为它是横向指着的。

And so in order to fix this,

因此，为了解决这个问题，

the gyroscope had to be constantly reset

陀螺仪必须不断地被重置，

by a special piece of machinery on the ground.

而这是由地面上的一台特殊设备完成的。

That's where this tank came in. 表達脈絡

这就是这辆坦克出场的时候了。

Just kidding, this has nothing to do with the Saturn V, 語法

开个玩笑，这和土星5号毫无关系，

but it does have something to do with the sponsor of this video.

但它确实与本期视频的赞助商有关。

World of Tanks is a fun free-to-play PC game

World of Tanks 是一款好玩的免费PC游戏，

which allows users to compete

它让玩家可以与

against more than 100 million players worldwide.

全球超过1亿名玩家同场竞技。

With more than 600 tanks in their collection,

他们收集了超过600辆坦克，

there are always new ways to play.

让你总能找到新的玩法。

You can drive your tanks across open fields, deserts,

你可以驾驶你的坦克穿越开阔的原野、沙漠，

climb steep hills, and sneak through forests.

攀爬陡峭的山丘，或是潜行于森林之中。

Choose from destroyers, artillery vehicles,

在坦克歼击车、自行火炮、

light, medium, and heavy tanks,

轻型、中型和重型坦克中做出选择，

and play matches in more than 40 arenas.

在40多个竞技场中进行对决。

All of the tanks are historically accurate

所有的坦克在历史上都是真实准确的，

and each model has a huge amount of attention to detail. 短語搭配

每一个模型都拥有对细节的极大关注。

With World of Tanks, you can earn experience,

在 World of Tanks 中，你可以赚取经验，

modify, and upgrade your tank,

改装并升级你的坦克，

creating a steel beast ready for any challenge.

打造一台准备好迎接任何挑战的钢铁巨兽。

Download World of Tanks today using the link in the description

立即使用简介中的链接下载 World of Tanks，

and use code Tankmania when you sign up

并在注册时使用代码 Tankmania，

to get a free 7-day premium account

即可获得免费的7天高级账号，

along with 250,000 credits,

以及250,000银币、

the premium tank Excelsior,

高级坦克 Excelsior，

and three rental tanks for 10 battles each.

以及3辆各可租用10场战斗的租赁坦克。

In order to reset the Saturn V's gyroscopes to the desired axes,

为了将土星5号的陀螺仪重置到预期的坐标轴，

it used highly accurate reference points.

它使用了极其精确的参考点。

The Y and Z axes were reset by two pendulums

Y轴和Z轴通过两个钟摆来重置，

located inside the guidance unit.

它们位于制导单元内部。

These were weighted iron rods that floated on a pocket of air.

这些是漂浮在气囊上的配重铁杆。

As the Earth rotated,

随着地球自转，

gravity would pull the mass downwards,

重力会将质量向下拉，

keeping the rod perfectly level.

让铁杆保持完美的水平。

The gimbals would then rotate the stable platform to match this.

随后万向节会旋转稳定平台以匹配这个水平面。

But in order to reset the X-axis,

但是为了重置X轴，

NASA came up with a much more impressive solution. 短語動詞

NASA想出了一个令人惊叹得多的解决方案。

200 m away from the base of the Saturn V was a bunker

在距离土星5号底部200米远的地方有一个地堡，

built into the ramp of the launch pad. 短語搭配

它是建在发射台斜坡内的。

Inside, there was a device called a Theodolite, 文化背景

在里面，有一台名为经纬仪的设备，

which would emit a beam of light

它可以发射出一束光，

and control its direction with incredible accuracy.

并以极高的精度控制光束的方向。

During the launch countdown,

在发射倒计时期间，

infrared light was emitted from the Theodolite

经纬仪会发出红外光，

and up to the rocket at precisely 25 degrees,

并精确地以25度角向上射向火箭，

where it would enter via a small window

光束会通过一个小窗口

on the Saturn V's instrument unit.

进入土星5号的仪器单元。

From there,

从那里，

the light would reach one of two porro prisms. 文化背景

光线会照射到两个普罗棱镜中的一个。

When light enters a porro prism,

当光线进入普罗棱镜时，

it's reflected twice,

它会被反射两次，

causing it to leave the prism at the same angle it entered. 語法

导致它离开棱镜的角度与进入时的角度相同。

One prism was fixed to the stable platform

一个棱镜固定在稳定平台上，

and the other was motorized.

另一个则装有电机。

The Theodolite in the bunker would communicate with the rocket

地堡中的经纬仪会与火箭通信，

and slowly rotate the motorized prism.

并缓慢旋转那个电动棱镜。

Once the prism was in the correct orientation,

一旦棱镜处于正确的方向，

it would reflect the beam of light back to the Theodolite,

它就会把光束反射回经纬仪，

where a set of mirrors would direct it onto a detector.

那里有一组镜子会将其引导到探测器上。

Each prism was coated with a special material

每个棱镜都涂有一种特殊材料，

that would only reflect a specific wavelength of infrared light.

这种材料只会反射特定波长的红外光。

This allowed the detector to plot exactly where each prism was

这使得探测器能够精确描绘出每个棱镜的实际位置

relative to where it should be.

与其应有位置的相对关系。

Since the light left the prism at the same angle it entered,

由于光线离开棱镜的角度与其进入的角度相同，

the orientation could be determined by how offset

所以可以通过探测器上发出的光束和返回的光束之间的偏移量

the outgoing and returning beams were on the detector.

来确定方向。

The Theodolite system was so accurate 語法

这个经纬仪系统非常精确，

that it could align the gimbal to within 1/1000 of a degree. 短語搭配

它可以将万向节对准到1/1000度以内。

Once the motorized prism was correctly positioned,

一旦电动棱镜定位正确，

a device would measure how much it had rotated

就会有一个设备测量出它相对于稳定平台

relative to the stable platform.

旋转了多少度。

The motor on the inner gimbal

内部万向节上的电机

would then rotate the stable platform by this exact amount.

然后会将稳定平台旋转完全相同的幅度。

If everything was correct,

如果一切无误，

the second prism would then line up perfectly 短語動詞

第二个棱镜就会完美对齐，

and reflect the light back to the Theodolite.

并将光线反射回经纬仪。

This system worked perfectly,

这个系统运行得十分完美，

but it relied on the Saturn V being completely still. 語法

但它依赖于土星5号必须完全静止。

That wasn't always the case. 表達脈絡

但情况并非总是如此。

When a rocket sits on the launch pad,

当火箭停在发射台上时，

strong winds can cause it to sway back and forth. 短語搭配

强风会导致它来回摇晃。

This kind of movement would completely throw off

这种运动会完全破坏

the accuracy of the Theodolite.

经纬仪的精准度。

And so in order to get a reference

因此，为了获得一个

for how much the rocket was swaying,

关于火箭摇晃幅度的参考，

the Theodolite would focus on a third prism

经纬仪会聚焦在第三个棱镜上，

mounted to the outside of the rocket.

该棱镜安装在火箭的外部。

This would shine the light back to the Theodolite's detector,

这会将光线反射回经纬仪的探测器上，

which would see it moving back and forth as the rocket swayed.

探测器就能看到它随着火箭的摇晃而来回移动。

The target points for the other two prisms

另外两个棱镜的目标点

could use this as a reference point.

就可以将其用作参考点。

This system could account for the top of the rocket 短語動詞

这套系统可以处理火箭顶部

swaying more than 30 cm in either direction.

在任何方向上超过30厘米的摇摆。

All of these ingenious systems worked autonomously

所有这些巧妙的系统都在自主运作，

to reset the gyroscope until 15 seconds before launch.

直到发射前15秒，都在不断重置陀螺仪。

From there,

从那一刻起，

the rocket was on its own 習語

火箭只能依靠自己，

with the task of guiding it and three astronauts

肩负起引导它自己以及三名宇航员

all the way from the launch pad 短語搭配

一路从发射台

to the translunar trajectory.

飞向地月转移轨道的重任。

And now it's time for something really special.

现在，是非常激动人心的时刻了。

The winner of this awesome space shuttle canvas

这幅超酷航天飞机帆布画的获奖者

is Evan Larson.

是Evan Larson。

Sorry if you didn't win this time,

如果你这次没中奖很遗憾，

but don't worry.

但别担心。

We give away an awesome space prize in every video.

我们在每一期视频里都会送出一份超棒的太空奖品。

Next time,

下次，

we'll be giving away this Falcon 9 framed print.

我们将送出这幅猎鹰9号装裱画。

All you have to do is sign up at the link below 語法

你所要做的就是通过下方链接注册，

and leave a comment about your most controversial space opinion.

并留言说说你最受争议的太空观点。

Thank you very much for watching

非常感谢您的观看，

and I'll see you in the next video.

我们下期视频再见。