2019 is kind of a big year for the space community,

because it marks the 50th anniversary of the Apollo 11 lunar landing.

50 years ago, the first astronauts successfully landed on another world

and came home to tell the story,

which is a pretty big deal.

It was such a big deal that we're doing something really special to celebrate!

On Wednesday, July 17th, SciShow is launching its first-ever documentary episode!

A few months ago, our team started asking the question,

“Was the Apollo program actually a good idea?”

And shortly afterward, SciShow writer Alexis Stempien and associate producer Hiroka Matsushima

traveled all over the country finding experts who could tell us more.

Alexis interviewed museum curators, former Apollo engineers, current NASA scientists,

and even some science YouTubers.

And now, we're super excited to share this episode with you.

But before you watch it, it might help to know a little bit about how all of the science and engineering

that went into the Apollo program.

We had to discover and invent a lot before we landed on the Moon,

but this episode should catch you up.

Many people think the American space program began in 1961,

when President John Kennedy made a famous speech announcing

that the U.S. would put a man on the Moon and bring him home

by the end of the decade.

But while this speech was important,

it actually happened after the first Americans had been to space.

People were dreaming of a Moon mission even before it had a deadline.

A lot of that work began with something called Project Mercury.

And here's Caitlin with more.

Project Mercury, America's first human spaceflight program, lasted from 1958 to 1963.

And in those few years, NASA went from a rocket that launched

half an hour before it was supposed to and blew up on the launch pad, by the way,

all the way to putting someone in orbit for almost a day and a half.

And at every step of the way, they were solving problems that influenced

the future of the American space program.

Project Mercury started out with three specific objectives:

One, NASA wanted to put a human in orbit around Earth;

two, they wanted to see how the human body responded to being in space

since no American had ever left Earth before; and three, they wanted to bring the astronaut

and their ship back to Earth safely.

And yes, it's a little alarming that putting someone in orbit and

bringing them alive back were separate goals.

The first launch of Project Mercury was on August 21, 1959, and it did not go well.

The goal of Little Joe 1, as the unmanned booster was called,

was to test the escape system

you know, that thing that astronauts would need in case something went terribly wrong.

About half an hour before the scheduled launch, there was an explosion.

When the smoke cleared, the crowd that had gathered

to watch the rocket lift off saw that Little Joe had unexpectedly launched.

At least, parts of it did.

Other parts were still sitting on the launch pad, waiting to be sent up into the sky.

The problem was that a pair of electrical circuits got crossed,

which sent mixed signals to the rest of the ship.

The next launch, Big Joe 1, successfully tested the heat shields

though there were still problems with the actual launching part of things.

Throughout the project, the unmanned missions would continue to be plagued with launch problems.

It's hard to send something into space, and NASA learned that over and over again.

But that's why they were unmanned missions: that's where the kinks were worked out.

Some of the twenty unmanned missions tested individual components,

like the escape system or the heat shields.

Others, especially later on in the project, were tests of whole missions

a kind of dry run before sending humans along for the ride.

There were also six manned missions in Project Mercury.

First came Mercury-Redstone 3, in May 1961, which made Alan Shepard the first American

to ever reach space.

He was also the first person to ever go to space and then land back on Earth inside the

capsule, since the two Soviet cosmonauts who had gone up earlier in 1961

both ejected from their ships and parachuted down to the ground.

The third mission was Mercury-Atlas 6, in February 1962.

It brought John Glenn into orbit, making him the first American,

and the third person in human history, to ever orbit the Earth.

You might have noticed that I skipped the second manned mission the one between Shepard's

and Glenn's flights.

That's because the second and fourth missions of Project Mercury had a very particular purpose:

they were duplicates of the previous missions.

So Mercury-Redstone 4, with Virgil Grissom on board,

was pretty much a carbon copy of Shepard's flight two months earlier.

And Mercury-Atlas 7, with Scott Carpenter on board,

was pretty much a carbon copy of Glenn's orbit.

Project Mercury had a lot of scientists working on it who knew that there's no use doing

something once if you can't prove that you can do it again.

And that turned out to be a good idea.

After Grissom became the second American in space,

his capsule landed in the Atlantic Ocean and pretty much sunk like a rock because the hatch

blew open.

He got out safely, but the capsule itself wasn't recovered from

the bottom of the ocean until almost forty years later, in 1999.

Now, Project Mercury could have stopped after Carpenter's orbits,

but it had two more manned missions to go: Mercury-Atlas 8 and Mercury-Atlas 9.

Each orbited for longer than the previous mission had,

with Mercury-Atlas 9 orbiting Earth for almost thirty-four hours.

This let NASA really nail down that second objective of Project Mercury, which was to

see what happened when humans were in low gravity for a long time.

They were especially interested in seeing if anything happened to the astronauts'

bodies or brains that would've made it hard to put together longer missions like the week-long

flight to the Moon that was already in the early planning stages.

And what they found was encouraging: being in space for a few days didn't seem

to affect an astronaut's health or brain very much.

Gordon Cooper, the astronaut on board, was just as good a pilot after a day and a half in space.

Project Mercury also taught NASA how to effectively put together a series of missions

that built on one another, and they learned how to train astronauts

so that they could succeed in their missions.

So not only did America's first manned space program get us to space

it set the stage for all our future space programs, too.

Now, even though we knew astronauts did pretty well in space,

we didn't actually have a way to get them to the Moon by the time Project Mercury finished.

The rockets for that program were awesome,

but they weren't powerful enough for missions beyond low-Earth orbit.

To get people to the Moon, we needed something bigger.

And that “something” was the Saturn V rocket,

which was built by a team in one of my favorite towns ever, Huntsville, Alabama.

That team was led by German scientist Wernher von Braun, and while his story is important,

it's also a bit messy.

Let's just start with the uncomfortable fact that the American space program would not be what it is today

if it weren't for the contributions of a scientist

who was a former Nazi.

Wernher von Braun was an SS officer during World War II

and led a team of German scientists in developing the world's first long-range ballistic missile.

A military program aided in large part by slave labor at concentration camps.

And yet less than two decades later von Braun was leading a team of NASA scientists

in the design and development of the Saturn V rocket,

the vehicle that ultimately propelled more than a dozen Apollo astronauts to the moon.

Historians still debate whether he was

an apolitical scientist who had no choice but to work for Hitler

or a cunning opportunist who knowingly made a deal with the devil to pursue his research.

But what we do know is that he was a rocket science prodigy.

Upon earning his PhD in physics in 1934 at the age of 22,

he joined the German army as a civilian employee.

Younger than most of his colleagues von Braun led the team that began developing a long-range

ballistic missile.

Borrowing heavily from the work of an American rocket scientist, Robert Goddard, von Braun's

team built a rocket called the A4 later renamed the V2 or vengeance weapon.

The V2 was essentially a larger version of the liquid-fueled rockets built by Goddard,

though von Braun made changes to the engines that dramatically increased their power.

First he used alcohol instead of gasoline as the main propellant along with liquid oxygen.

The real power of his design came from two turbo pumps turbines that moved huge volumes

of fuel into the combustion chamber at high speeds

His turbo pumps could force 58 kilograms of alcohol and 72 kilograms of liquid oxygen

into the combustion chamber every second,

giving him the thrust of more than 25,000 kilograms, far more than Goddard had achieved.

Using this technology on October 3rd 1942,

von Braun's creation became the first man-made object to reach the threshold of space,

flying to an altitude of 80 kilometers,

The missile could travel more than 5,600 kilometers per hour and carry a 1000 kilogram warhead.

As military weapons go the V2 was terrifying but not always accurate.

While the Germans launched 5,000 of the missiles toward Western Europe,

only about 1,100 actually reached their targets.

Still the V2 was believed to have killed nearly 3000 people.

Now there's at least some evidence to suggest that von Braun's sympathy for the Nazi

cause only went so deep.

For one thing he was jailed briefly in 1944 after some Nazi spies infiltrated his program

and began to suspect that he wasn't loyal enough.

But more importantly for science, when the end of the war was in sight,

von Braun was ordered to destroy all work related to the V2,

but instead he hid his documents in an abandoned mine

and recovered them shortly before he and his team surrendered to the US Army.

As part of a carefully orchestrated mission known as Operation Paperclip.

Von Braun and his team were sent to the US where he demonstrated his weapon to the US

Army in New Mexico.

Later he was transferred to Huntsville Alabama and eventually became director of NASA's Marshall

Space Flight Center.

He was here that von Braun led the team that developed the Saturn V rocket,

the most famous of all the rockets.

While his V2 rocket was a pretty nifty piece of machinery the Saturn V was truly revolutionary.

102 metres tall and it liftoff weighed more than a dozen 747s.

And as the world witnessed during the Apollo missions the Saturn 5 was not only incredibly

powerful it, divided the work of spaceflight into an elegant three-stage system.

The first of its three expendable stages produced 3.4 million kilograms of thrust making it

130 times more powerful than the V2.

It had five separate F1 engines designed by von Braun's team so that the outer four engines

could move in order to control the direction of the rocket, while the center engine just

provided more thrust.

After lifting the whole thing to about 68 kilometers the first stage would separate

and the second stage would fire, carrying the spacecraft to the edge of orbit.

Once there the second stage would detach and a third stage pushed the craft into orbit

and then toward the moon.

Nearly half a century after they were first used, the five first stage engines that were

designed by von Braun's team are still the most powerful single chamber liquid-fueled

rockets ever made.

As for von Braun, he went on to rise through the ranks of NASA and worked for aerospace companies,

eventually being awarded the National Medal of Science not long before his death in 1977.

But he never truly escaped his past.

Whether you consider him a villain or a visionary or both, there still no disputing his legacy.

Von Braun turned the dreams of early 20th century rocket scientists into reality and

he did it in less than three decades.

Regardless of how it came to exist, the Saturn V was an amazing rocket.

But it wasn't the only piece of technology that had to be invented to send astronauts to the Moon.

Another big one was the navigation system.

Like you might guess, computers weren't all that advanced in the 1960s,

but astronauts needed them to navigate safely around the Moon.

Because I don't know about you, but I can't do orbital mechanics calculations off the top of my head

while also piloting a spacecraft.

The story of how NASA got those computers is impressive and kind of hilarious,

and it makes me thankful for how much engineering has grown in the last 50 years.

Here's another one from Hank.

Back in the 1960s and 70s, the Apollo missions blasted their way from Earth to the Moon.

And they carried two of the smallest most sophisticated guidance computers ever invented,

which were running on software knitted by little old ladies.

No, really.

The software running Apollo's guidance computers was literally woven, by hand, out of wires