Name: How the Apollo Spacecraft works: Part 2
Uploaded: 2021-04-26T06:50:35.000Z
Duration: 5 min 18 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Here we are in a parking orbit of 118 miles high.

Adverbs of degree

And just how high is that? Let's take a look...

Basic passive voice

The Karman Line is generally considered to be the start of outer space.

The International Space Station orbits here.

it's not high enough to stay in orbit for a long time.

But don't worry, we'll only be here for about 2 hours.

After orbiting the Earth 2 or 3 times and confirming all systems are good

it's time to ignite the 3rd stage one more time for about 6 minutes.

This is what sends us away from the Earth and towards the Moon.

Remember that's the 3rd stage at the top of the Saturn V.

The Spacecraft Lunar Module Adapter panels detach

The Command and Service Module do a complete 180 degree turn around.

The Command Module must dock with the Lunar Module and pull it out.

In space, temperatures are a lot more extreme.

There was a real danger of parts of the spacecraft freezing

To prevent this, the spacecraft was now put into a slow roll

so that there was an even heat distribution.

If we ignore the moon, this is what our flight path will look like

we're still orbiting the Earth but we're in the shape of an elipse

heading all the way out into the middle of nowhere.

With the Moon however, everything starts to make a little more sense.

At the time of launch, the Moon is about here.

During the next 3 days, their paths converge.

Just to be clear, this is the Earth and Moon drawn to scale.

I animate it out of scale so it's easier to see the flight paths.

So, the Moon's gravity changes where the spacecraft flys.

This is called a "Free Return Trajectory"

If something were to go wrong with the engines

the astronauts would still be able to get home.

This is called the Lunar Orbit Insertion.

the Service Module engine was fired up for about 6 minutes to slow the spacecraft down.

At times like this they would loose contact with mission control

because they are on the far side of the Moon.

Unfortunately, this is where a lot of important events happened.

The guys at mission control just had to sit tight until the astronauts came around the other side.

One of them stays behind and continues to oribit the Moon.

Side note: the Lunar Module was usually just called the LM.

And when the Command Module and Service Module were together

they were usually referred to as the CSM.

After making sure everything still checks out

The LM must get to a safe distance of about 2 miles away

The engines fire up for about 30 seconds.

This is called the Descent Orbit Insertion.

This puts the LM down to about 50 thousand feet above the surface.

Now the engine fires up again for Powered Descent Initiation.

to give the astronauts a good view of the surface they'll be landing on.

The landing site needs to be on level terrain

There's a limited amount of fuel so the astronauts can't take too long to land.

Now it's time to step down the ladder, say some historic words,

plant the American Flag, get some rock samples

After the Lunar stay was over, it's time to take off from the surface.

Thanks for watching and I'll see you in the next video.

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How the Apollo Spacecraft works: Part 2

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extreme

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initially