[ ♪ Intro ] 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 and magnetic rings that looked like tiny donuts. It was called Core Rope Memory. The Apollo missions were a huge hurdle for
both navigation and portable computing. The orbital mechanics were complicated, and
they needed guidance, especially while they were on the far side of the Moon, unable to
communicate with Earth. Navigating there and back was a serious problem
… and NASA needed computers to solve it. A team at MIT invented the navigation software
to run on these computers. Programmers wrote it from scratch and tested
it on huge mainframe computers, using paper punch cards to input the programs. Running any given program could take an entire
night. And, of course, the software had to be bug
free, because once the programs were loaded onto the hardware of Apollo computers, they
couldn’t be changed. So they had to be perfect. Why couldn’t they be changed? Because the program was hardware, essentially. There were a few different forms of storage
that existed in the 1960s that could hold a computer program. One involved paper punch cards with holes
in them, read in a giant reader. There were also disk drives that were so big
they had to be pushed on wheeled steel carts, and magnetic tape on reels. But these options were all way too heavy to
fly into space. Or, in engineer-speak: they weren’t flight-weight. Even if they were light enough to fly, they’d
still need to be able to withstand the shock, vibration and G-forces of launch, temperature
changes, and cosmic radiation. And if they couldn’t withstand all that,
the astronauts could die. So, the memory storage had to be small, lightweight,
safe, strong and robust enough that even if you lost power, you didn’t lose the program. The only technology at the time that met these
specs was core rope memory, which coded ones and zeros, the fundamental language of programming,
into wires and magnets. It was woven on a type of loom, by threading
individual wires through various holes with large needles, kinda like knitting needles. Engineers at the time called it LOL memory,
a not-very-nice acronym for “little old lady” memory, because it took highly skilled
garment workers, often older women, to weave it. To represent a one, a seamstress wove a wire
through a little magnetic donut called a core. The donut acted like a transformer, a device
that changes the voltage of an electrical current running through it. If the computer saw a voltage change at the
other end of the wire, it assigned it the number one. To get a zero, they weaved the wire outside
of the core. Electrical current through it wouldn’t change. The computer would interpret that lack of
voltage change as a zero. They'd weave the entire program out of wires
going through or around cores. There were lots of wires and donuts, which
meant that Core Rope Memory was incredibly hard to manufacture. It came out looking a lot like a rope, but
it was really a program made out of woven electrical pathways. It also provided the most storage per cubic
centimeter at the time, the Apollo Guidance Computer came with a whopping 36 kilobytes
of memory. This tiny microSD card has almost a million
times that. But core rope memory is Read Only Memory. You can’t write to it, which is really good
if you don’t want to accidentally record the 1960s equivalent of a podcast over what
would be steering you to the Moon. But it also meant the programs had to be perfect
the first time around. When each core rope was finished, the program
was run and compared with the program stored on magnetic tape from MIT, they actually had
a defense contractor build a machine to do this automatically. If they found a mistake, the program could
be rewired before it left the factory, though fixing it was an enormous pain. So there’s a lot more to knitting than scarf
patterns: it can also take you to the moon and back. The way NASA handled its computing challenge
was really impressive. But the reality is, at the end of the day,
it’s impossible to make space travel 100% foolproof. No matter how much you invent, or how many
precautions you take, there’s still a chance that something will go wrong. And the U.S. got a firsthand look at that
risk early on in the Apollo program, with Apollo 1. Here is what happened. If there’s anything we’ve learned about
space travel over the last 56 years, it’s that it’s dangerous. So space agencies like NASA do all they can
to minimize the risks, most importantly, the risks to astronauts’ lives. But learning how to deal with those risks
has been an ongoing process. And in some cases, NASA has had to learn from
profound tragedy. One of those tragedies was the Apollo 1 fire
on January 27, 1967, which claimed the lives of the three astronauts involved: Gus Grissom, Ed White, and Roger Chaffee. Both Congress and NASA immediately launched
investigations, and what they learned changed a lot about how we’ve approached spaceflight
ever since. The plan for the Apollo 1 mission was to test
the command module, the capsule on a rocket where the astronauts sit, in low Earth orbit. Since eventually, NASA wanted to send that
command module to the Moon. The fire happened during a sort of rehearsal
for the launch. It was what’s known as a “plugs-out”
test, meaning that the rocket was unfueled, and it didn’t have the explosive bolts that would separate the different stages of the rocket in-flight. Since there weren’t as many explosives or
any fuel around, NASA mission control thought that the test would be safe. Obviously, they were wrong. After the astronauts got inside the capsule,
it was filled with 100% oxygen gas at 115 kilopascals, which is about 15% higher than
standard air pressure at sea level. There was an electrical failure during the
test, and the resulting spark caused the fire. The pure oxygen atmosphere was completely
consumed within thirty seconds, and the astronauts couldn’t open the hatch to escape. Meanwhile, the smoke billowing out of the
command module kept the launchpad personnel from being able to rescue the astronauts,
because there were no smoke masks at the launchpad. The investigations into the fire found that
several factors, both on an engineering level and on an organizational level, contributed
to the tragedy. NASA implemented every suggestion made by
the investigation committees, leading to major changes that have made spaceflight much safer,
even though it is still dangerous. One of the biggest engineering-related changes
they made was to the gases they used to fill the capsule. The first problem was the fact that they used
pure oxygen, which was meant to make the capsule lighter, so it would take less fuel to launch. Plus, breathing pure oxygen would get rid
of the nitrogen in the astronauts’ bloodstreams, which meant that they wouldn’t have to worry
about nitrogen bubbles forming in their blood during the launch and causing the bends. But oxygen is really flammable, it’s basically
what fire runs on. You don’t want pure oxygen near any kind
of spark, and you definitely don’t want it anywhere that a fire could be fatal. The other issue was that the pressure inside
the capsule was higher than the pressure outside, and the fire just made that worse. The hatch opened inward, and the extra pressure
inside meant that the astronauts couldn’t open it. That’s why, ever since, instead of using
a high-pressure, entirely oxygen atmosphere, NASA has used a mix of gases at standard atmospheric
pressure. For the rest of the Apollo missions, the atmosphere inside the capsule during the launch was made up of 60% oxygen and 40% nitrogen, while the astronauts breathed pure oxygen inside their spacesuits. It was still a higher oxygen concentration
than Earth’s atmosphere, but it was low enough that a fire wouldn’t spread too rapidly for astronauts to escape. NASA made another major engineering change, too: they started constructing the command module, and astronauts’ suits, entirely out of non-flammable materials. This way, any electrical spark would have
nothing to catch on. And to make sure the materials they used were
up to scratch, the command module was tested to make sure that it would be safe in a fire. But NASA changed more than just the gases
and materials they used. They also overhauled their safety procedures
and attitude toward spaceflight as a whole. The tragedy was a huge wakeup call for NASA. They realized that, as an organization, they
were so focused on beating the Soviet Union in the space race that they’d become somewhat
… cavalier … about safety. Before the fire, for example, there were no
fire safety procedures in place, and they only had minimal firefighting equipment at
the launchpad. The command module hadn’t been tested in
simulations to see if it met any safety standards, and when the test was underway, there were
no emergency staff present, like EMTs or firefighters. So NASA implemented a whole series of changes
to fix every one of those problems, and resolved to be a lot more cautious in general. In the words of Gene Kranz, who led Mission
Control for the Apollo program: “We will never again compromise our responsibilities. Mission Control will be perfect.” Apollo 1 marked a huge turning point for NASA, which we’ll talk more about in our special episode celebrating the 50th anniversary of Apollo 11. Obviously, we wish it had never happened,
and it was a huge tragedy. But we did learn from it, and those lessons
helped us finally succeed. From rockets to computers to astronaut tests,
it took a lot to land the first humans on the Moon. And when we did, it was a huge moment of celebration. Here’s Hank with one more episode, which,
coincidentally, we made for the forty-fifth anniversary of Apollo 11. Discovery number 1: there is no life on the
moon. Remember this is 1969 we're talking about. We'd never been anywhere else but earth, so
we truly had no idea of what awaited us. And we didn't even know for sometime after
the Apollo crew returned home. When Armstrong, Aldrin, and their pilot Michael
Collins splashed back down in the Pacific Ocean, NASA made sure they didn't bring back
any tiny hitchhikers with them. They were bathed in a solution of sodium hypochlorite
and then quarantined for 21 days. Their command module was sanitized and the
raft with all the cleanup supplies was intentionally sunk to the bottom of the ocean. But after extensive testing of the soil and
rock samples the astronauts brought back, it turned out that there was no sign of life. Materials were totally inorganic and at the
time it seemed like there was not even any water. Actually though there was water. Scientists assumed that the traces of water
they detected in the samples were the result of contamination because there was so little
of it and because they didn't find any minerals that form in the presence of water. Well we now know that there is a trace amount
of water. We remain fairly sure that there's no life
on the moon. Number 2: the moon is more like Earth than
we thought. Before Apollo 11 we had no idea what the moon
even was. Was it a chunk of space rock that had been
captured by Earth's gravity like Mars's moons are or was it a piece of the earth that had
broken off? We're still not totally sure, but we've learned
how to read the clues thanks to Buzz and Neil. Among the equipment they planted on the moon
was a seismometer which measured and transmitted data back to earth about moon quakes. By studying the seismic waves from these quakes
at various depths we found out that the moon has layers Much like earth, there was a crust, a mantle, and a core composed of materials much like Earth's, only depleted in iron. And the rocks and dirt that Apollo crew brought
back also told us about the moon's geologic history. Namely the samples showed that moon rocks
share the same distinct ratios of oxygen isotopes as Earth rocks, suggesting they have a common
origin. So thanks to Apollo 11, we now have the giant
impact theory. A model that suggests 4.5 billion years ago
a giant body collided with earth and broke off the chunk that became the moon. And it's hard not to love number 3: Einstein,
as he so often is, was right. Early in the twentieth century Albert Einstein
proposed the Strong Equivalence principle. This posited in very basic terms that all
forms of matter accelerated at the same rate in response to gravity. So by extension, even though they're very
different sizes and compositions, both earth and the moon would be drawn toward the Sun
at the same rate. To prove this Einstein calculated the exact
orbit of the moon. But from Earth we weren't able to measure
it precisely enough. Then Apollo 11 installed the lunar laser ranging
array, a panel of 100 small mirrors. By aiming a laser from Earth at this array
and recording the time it took to reflect back, astronomers were able to measure for
the first time the exact distance between the Earth and the moon. It turned out the moon's orbit was the same
shape and size predicted by Einstein to within one millimeter. And to this day we still use that array to
study the moon's orbit. And finally, maybe the most inspiring thing
that Apollo 11 taught us was just we can do it. In a technological sense, we were never sure
that we could send humans to another planetary body, until we just did it. To do it we have to invent things like the
first computer to use large scale integrated circuits or chips. We had to develop a renewable efficient fuel
source known as the fuel cell. And I'm not even talking about heat shields
and dehydrated foods and cordless tools and any of the other countless patentable inventions
that went into that historic mission. Thanks for joining us for this Apollo-themed
compilation! If you want to keep celebrating with us, you
can watch our extra special episode tomorrow when it debuts on the main SciShow channel. You can check it out over at youtube.com/scishow. And for more space content year-round, you can subscribe to this channel at youtube.com/scishowspace, or by clicking the button below. [ ♪ Outro ]
