After Artemis II brought out the moon joy in people, I found that a lot of newbies to space travel had some questions about what they were seeing. This video is meant to help explain some of the basics of space travel that most people don’t know. Things like how orbital mechanics work, how gravity works in space and why the astronauts are weightless up there, how rocket engines don’t melt, and why everything just works differently in a vacuum.
TRANSCRIPT:
It’s been a couple of months since Artemis II left the launch pad and we all watched four of the most wholesome astronauts of all time fly around the moon. It was kind-of a rare moment these days that allowed us to set aside our differences and just be awed by human achievement.
Are you still feeling the moon joy?
I don’t know about you but it was really nice to see my social media filled with people freaking out with excitement about space stuff for once and not just people screaming at each other.
I don’t know about you but it was really nice to see my social media filled with people freaking out with excitement about space stuff for once and not just people screaming at each other.
But perhaps my favorite thing was seeing posts like this one on Threads:
“People keep shitting on other posting “basic” facts or asking “stupid” questions about Artemis II but thank god they are because I’m learning so much that I had no idea to even ask”
I absolutely loved that people were watching this event who had never really paid any attention to space stuff and wound up learning little bits of knowledge along the way. And those little bits of knowledge inspired them to look more deeply into space stuff, and it kinda reshaped their view of the world.
This! EXACTLY THIS! This is how it works! This is why there was famously a massive uptick in engineering and physics degrees in the 70s and 80s because people were inspired by the Apollo missions.
This is one of the countless intangible benefits to space travel that pays so many dividends that you can’t calculate on a spreadsheet. It was so cool watching that happen in real time with Artemis II.
It was also a reminder to people like me, and, I’m sure most of you in my audience, that we kinda live in a nerd bubble. And we assume that most people know at least the basic stuff about space travel. But yeah, no… They don’t.
Most people out there are just living their lives, focused on their own jobs and hobbies and really don’t know what we might consider basic space facts.
And unfortunately a lot of times that lack of information manifests as conspiracy theories and skepticism. But there’s also the flipside, when there are big events like Artemis II, it can also manifest as genuine curiosity, which was really great to see on display a couple months back.
So I decided to make a video for those people, the normies, who saw Artemis go up and… had questions.
Many people in my regular audience will already know everything in this video, but for those who don’t, I picked five misconceptions about space that most people get wrong, and I guarantee you by the time you’re done with this video, you will know more about space travel than 90% of people in the world.
Commence nerding out in 3….2….1….
Before I dive in, I want to make it clear, this isn’t meant to mock or make fun of anybody who doesn’t know this stuff. Once upon a time, I didn’t know this stuff. Some of this I didn’t get for a very long time. Some of this I still have questions about.
If anything I’m kind-of excited for anybody who learns something in this video because I remember learning it and thinking it was really cool, some of this even blew my mind, and sent me down rabbit holes that changed the way I thought about the world.
Will this video do that for you? Will this video CHANGE YOUR LIFE?
Yes, I’m gonna go with yes.
This is kind-of a big one, and it trips a lot of people up.
We’re all brought up seeing footage of astronauts floating around in space weightless. Zero gravity, as they say. And it leads a lot of people to believe that when you go into space, there’s no gravity.
And it makes logical sense. If gravity is what holds you to the ground, then the further away you get from the ground, the less you would feel the gravity, right?
And here’s the thing… That is true, technically.
Gravity does fall off over long distances. It works kinda the same as light in that way. They call it the inverse square law, I’ll spare you all that for now, but the point is, gravity is still working in space.
I mean think about it, gravity is still strong enough to keep the moon from flying away, and that’s WAY further away than the astronauts are at the ISS. And way bigger.
To be more specific, the moon is 384,000 km from Earth. The ISS is 400 km. It’s almost 1000 times further away.
And yet, astronauts on the ISS are floating… Why?
The simple answer, they’re not floating, they’re falling.
Forget about space for just a second, imagine you’re in an elevator. I’m sure at some point you’ve been in an elevator in a tall building and had that intrusive thought, that… “what if this thing fell?” thought? You know?
Chances are you imagined this in your head, and what you imagined was probably just… the floor dropping out from under you. You wouldn’t slam into the ceiling, you’d just kinda float there. Maybe you’d find yourself turning in the air because you can’t stabilize yourself. And then eventually you’d slam into the ground and splatter everywhere.
But imagine there wasn’t a ground. Imagine the elevator shaft goes on for miles and miles, maybe to infinity, whatever.
Eventually your speed would equalize and your inner ear would adjust and it would just feel like floating. Inside the elevator, with no reference to the outside, it wouldn’t even feel like you were going anywhere at all.
Well replace the elevator with a capsule or the space station and that’s exactly what the astronauts are feeling. Because technically they’re falling.
What are they falling toward, you may be asking. Well… they’re falling toward the center of the Earth, just like you and I are. The reason they don’t hit the ground is because they’re traveling horizontally, very very fast.
Most people have no idea just how fast astronauts and satellites are traveling out there. The speed is different depending on the height of your orbit, but most things in low Earth orbit are traveling around 17,000 miles per hour.
When you see a rocket launch, it only travels upward for like 10 seconds before it dips down and starts traveling sideways. That’s why in shots of rockets launching they eventually seem to even point down. Because it’s traveling away from the camera and following the curvature of the Earth.
They only travel upward so they can get above the thickest part of the atmosphere, after that, it’s mostly horizontal. They are accelerating sideways.
Just to give you a sense for how fast this is, the ISS is about the size of a football field. 100 yards. 300 feet.
If the fastest F1 racecar on Earth drove through here right now, it would take a little over half a second to clear this field.
That’s 300 miles per hour.
The ISS is traveling at 17,000 miles per hour.
At that speed, it would cross the length of this football field in point zero one two seconds. Or twelve point three milliseconds.
Keeping in mind that the ISS is almost the exact length of this football field, if the ISS were to fly past me at orbital velocity, it would look like… Did you miss it?
It’s actually impossible for me to show you in real time on video because this video is 30 frames per second, making each frame about 33 milliseconds, which is twice as long as it would take for the ISS to pass by me.
Think about that. Something the size of a football field is moving so fast that it could fly right over your head and you would never even know it. And if you were in space with no air, you wouldn’t feel it, either.
Of course if it passed you at ground level here in the atmosphere, it would feel like this:
This is why satellites burn up in the atmosphere and humans need heat shields. Because orbital speed is so fast that the friction of the air basically just turns it into plasma… More about re-entry later.
The analogy that always gets used to explain orbit is imagine throwing a ball. It goes horizontally, in the direction you threw it, but of course because of gravity, it curves toward the ground. And you know from experience, if you throw it harder, it will still fall toward the ground, but it will travel farther away because of the extra energy you put into the ball.
Throw it harder, it will go farther. Throw harder than that, and it’ll go farther still. Now imagine firing a bullet. It’ll go waaay further, but it’ll still fall to the ground. Bullets with more explosive power behind them will travel further, and if you want you can go up to cannons and gunships, and they’ll keep going further and further away.
Eventually you could fire something so far away, it follows the curve of the Earth. And if you keep scaling up in this way, assuming there’s no pesky air to slow you down, you could fire an object so fast that it goes all the way around the planet.
That’s basically what orbit is. The astronauts are constantly being pulled toward the Earth by gravity – in other words, falling – but they’re traveling so fast, they keep missing the Earth. And assuming there’s nothing to slow you down in space, you can just do this, basically forever. That’s what the moon is doing around Earth. That’s what the Earth is doing around the Sun, that’s what the sun is doing around the Milky Way.
All of that is just gravity and speed. That’s what kinda controls the universe.
But the astronauts are not weightless because there’s no gravity. If there was no gravity, they’d fly off into space. But because there is gravity, their speed makes them like that elevator falling down an infinitely long shaft. And they’re just floating in the middle of it.
“But wait,” you might be saying, “I’ve seen those New Sheppard flights, and they’re sub-orbital, but people are floating around. Explain that, mister handsome science man!”
To which I would say, “Oh my god, thank you! You think I’m handsome? Really? Wow, I… I really needed that today. I really needed that.”
The explanation is that no, they are not going orbital speed but they are going straight up, very fast. Fast enough that once they cut off the engines, and they stop accelerating, the capsule keeps climbing for a while, working against the pull of gravity, until it eventually slows and stops and starts falling back toward Earth.
Or, just jumping on a trampoline, that’s part of the fun, you get to feel weightless for just a fraction of a second with every jump.
This is basically just a very tall jump. And since the passengers are moving at the same speed as the capsule, it feels like they’re just floating there.
By the way, they use this same technique on the zero-G planes that NASA uses to train their astronauts, affectionately called the Vomit Comet. I’ll let you figure out why.
They fly in a bell curve, kind-of a parabola, and at the top of the curve, everyone in the plane experiences weightlessness, usually for about 30 seconds at a time.
But anyway, that’s why astronauts float in space, it’s not the gravity, it’s the speed. So when you see this…
What you need to imagine is this…
Oh, the ISS just flew by. You probably missed it.
You can be forgiven for thinking that if you were exposed to the vacuum of space, you would immediately freeze, after all, that’s pretty much how it’s been portrayed in movies for decades.
But that is, in a word, horseshit.
Here’s something that blew my mind.
You can’t feel “cold.” What your brain interprets as cold is actually heat leaving your body.
Like I’ve got my hand on the ice here, and my hand is getting colder, so you might think that the cold is transferring into my hand. But that’s not how energy works. Energy always moves from a higher energy state to a lower energy state. That’s what temperature basically is, a measure of thermal energy.
So my hand is getting colder because the heat from my hand is transferring into the ice. That’s the second law of thermodynamics.
Specifically what’s happening with my hand right now is called conduction. That’s when heat transfers from one solid material to another. My hand is solid. The ice is solid. Conduction.
There are actually three ways that heat energy transfers, one of them is conduction, again, heat moving between two solids. Then there’s convection, which is movement through air or fluids. Third is radiation, which is electromagnetic, mostly infrared waves that don’t need any medium to pass through.
Which, you are radiating heat right now. Hence the nice glow in an infrared lens.
But you’re also experiencing convection with the air around you. If you’re under an AC vent or standing in front of the fridge, you feel cooler because your body heat is moving to the colder air through convection.
So, what happens when you’re in the vacuum of space, and there’s no air for convection? The only way for the heat to leave your body is through radiation, which is a far, far slower process.
So if anything, the danger is in overheating when you’re in space. That’s why astronauts have cooling tubes underneath their spacesuits, to keep from overheating.
In fact, thermal regulation is a huge, huge issue on space stations and spacecraft. Like if you look at the ISS, you see all these solar panels all over it, but actually, only these are the solar panels. These guys, they actually aren’t solar panels at all, they’re radiators. It’s called the Heat Rejection System. They radiate heat out to space by creating a large surface area for the excess heat of the station to leech out.
By the way this is also a major hurdle for the whole idea of data centers in space. Data centers, which famously use insane amounts of water to cool themselves off because they get so hot. All of that heat would need to be radiated away in space.
Now, you might be asking, “How is this possible? When you climb up a tall mountain, it gets colder the higher up you get. When you’re in an airplane, that little information screen says it’s like minus 40 degrees outside. Surely if you go up even higher it will get even colder, right?”
Well actually no, that’s not right.
Let’s look at this graph that used to confuse the hell out of me. So on the vertical axis is the altitude, the higher up you go, well athe higher up you go, simple. On the horizontal axis is the temperature. You can see zero degrees Celsius just right of center here, goes all the way down to -100 and then up to 60C.
And if you follow the line, you see that yeah, the temperature drops going up to 10-15 km in altitude, which just happens to be the cruising altitude of most airliners. And you can see, yeah, -40 degrees
This is because the air pressure is dropping, and when air expands, it cools.
But above that look what happens, it warms up. As you go up through the stratosphere, the temperature warms up to around zero degrees, which still not tropical but warmer. The reason, is because this is where you find the ozone layer. And if you know anything about the ozone layer, you know that it absorbs UV light from the sun. This warming you see here is the ozone layer absorbing that energy.
Above that, in the mesosphere, it plunges back down, again, because of the lowering air pressure.
But then above the atmosphere, it goes up again. Because there’s all that pure solar radiation to absorb, and no air to transfer the heat into.
Like a lot of space stuff, this is very counter-intuitive. And that’s how it became a myth.
Take a look at this video. This is a SpaceX Falcon 9 launch at sunset. And it looks weird. Like a giant tadpole in the sky. And almost inevitably when these videos spread around the internet, someone tries to make it about aliens or something sinister, which is kinda understandable if you don’t know what you’re looking at.
But what you’re looking at is a perfect visualization of the difference in air pressure that I was talking about earlier. You see down at the bottom of the smoke trail, closer to the ground, that column of exhaust is tighter. The smoke stays together. That’s because the air pressure close to the ground is stronger – it squeezes the smoke together.
But way up here at the top, the air pressure gets weaker and weaker, and there’s less pressure pushing in on the exhaust, which lets the flame flare out in all directions. And in this case, if it’s the right time of day, the sun shines through it and makes it glow, giving this crazy effect.
Here you can see it from a different angle. Again, at the beginning of the launch, closer to the ground, the exhaust flame remains tight. But the higher it climbs… The more it flares out.
In fact, rocket companies have to compensate for this by making sea level engines and what they call “vacuum-optimized” engines that go on the second stage of the rocket. These have larger, longer engine bells that can direct the exhaust and keep it from flaring out, because the more you can point it in one direction, the more efficient it will be.
I point this out as an example of how things work differently in a vacuum.
I have a phrase I’ve repeated a million times on this channel, which is, “pressure changes everything.” And I keep coming back to that idea because we live in this very particular air pressure, it’s 14.69 pounds per square inch, or 1,013 millibars in non-freedom units.
So, almost 15 pounds per square inch. This is a 15 lb weight. Right now roughly this much weight is being applied to every inch of your body, from every direction. Isn’t that wild?
It doesn’t feel like it. It doesn’t feel like anything, because we’re evolved for this air pressure, we’re a part of it, our skin is made to push back against this pressure, so it’s nothing to us. They say the fish is the last to know it’s in the water, that kind of thing.
But this is not normal in the universe, it is a very specific feature of this planet, and to our knowledge, only this planet.
Venus has 90 times the air pressure of Earth, which is partially why it’s so hot on the surface it can melt lead. Mars only has 1% of the pressure here, so it’s generally much colder there.
The closest air pressure to here on Earth is actually Saturn’s moon Titan. It has an atmosphere about 1.5 times our air pressure. So technically you wouldn’t need a pressure suit if you landed there, just like scuba gear because there’s not much oxygen. There is also the fact that’s -179° C there, so you’d need a warm coat. A very warm coat.
Anyway, I digress.
The main point I’m trying to make is that we live in and understand this specific air pressure. We know, intrinsically, how things move here, the physics of this air pressure. You know that if you drop a feather, it’ll float more slowly down to the ground. You know that a piece of paper will flop and flap around on its way to the trash can. You know that if you throw something out the window of a moving car, it’ll fly backwards.
This is all completely normal to us. But it’s only normal here.
In space, even though they’re traveling at 17,000 miles per hour, if something detaches from the space craft, or a person takes a space walk, they don’t fly away from the ship, they just float there beside it.
By the way, they actually tested the feather and rock thing on the moon on Apollo 12.
Commander David Scott did an experiment where he dropped a hammer and a feather to see which would land first in a vacuum, and sure enough, the feather fell at the exact same speed as the hammer.
While we’re on the moon… Let’s talk about this thing. Why is this flag standing straight out and flapping around when there’s no wind? That is the “gotcha” that a lot of people point to when they say the moon landings were faked.
This isn’t a debunking video but let’s go there for just one second.
First of all, there’s a metal rod going across the top of it to hold it out horizontal. They knew that with no wind, the flag would just hang to the ground like a wet rag. So they put that in there to make it look good for the cameras.
Because let’s be honest, that photo of the American flag on the moon was like… the point.
To be fair, most people know about the bar holding it up, what trips people up is how it moves.
As you can see in the footage, the flag is flopping around a lot, for a place with no wind. What’s that about?
So first of all, it’s moving because… well because they moved it. Just like here, if you move the flag, that momentum would travel through the fabric and cause it to whip around a little bit. That’s normal. Nothing weird about that.
There is something weird about how it’s moving though. Like it’s just flopping around a little too much, you know, there’s something uncanny valley about it.
Once again… things move differently in a vacuum.
Here on Earth, there’s 15 pounds per square inch of air pressure pushing against the flag. Every single whip and flop is slowed down by the thick, soupy air around it. That slows it down and the flag stops waving pretty quickly.
But without that air pressure, on the moon, there’s nothing to slow down that motion. Nothing except the fibers in the flag rubbing together. So it waves for a lot longer than it would in our air pressure. Which looks weird.
Here’s footage of a test that they did in a vacuum chamber, here you see the flag waving with one atmosphere of pressure… And here in a vacuum. You can see it moves much differently.
Pile on top of that the fact that there’s only 1/6th the gravity on the moon, so there’s less pulling down on it. There’s just an entirely different set of forces at work on that flag than what you’re used to. It’s moving exactly as weirdly as it should.
Which is true of most things regarding moon landing conspiracies, the footage and images from the moon are super weird and counterintuitive, but it’s exactly what you’d expect from a place that is so much different than Earth. It’s literally another world. And that’s all I’m going to say about that.
Imagine you’re in low Earth orbit, and it’s time to re-enter the atmosphere. How do you do that?
Well intuitively, you might think you just fire your thrusters in the direction you want to go, down. But that’s not how it works.
Because, you’re still traveling at orbital speed, you’re going too fast for gravity to pull you back down. All you would manage to do is make your orbit a bit more egg-shaped.
The way it actually works, is you have to slow down your speed, so gravity can pull you down. To do this, you have to do what they call a retrofire – you turn the vehicle backwards and fire your thrusters into the direction you’re traveling, which slows down your speed and allows you to drift down into the atmosphere.
And this is a delicate act because there’s a re-entry window you have to hit. Hit at too shallow an angle and you can actually skip off the atmosphere just like a rock skipping on a pond. Hit it at too steep of an angle, and you’ll burn up in the thick atmosphere.
The trick is to come in at just the right angle so you can use the super-thin upper atmosphere to slow down enough to survive the thicker, lower atmosphere below. So that by the time you get to the cloud layer, you’re just in freefall, and can deploy your chutes without them ripping apart.
The point of re-entry is to slow a craft from 17,000mph to 0 as softly as possible.
There’s actually something they call the 7 Minutes of Terror, it refers to a 7-minute gap during re-entry when the crew loses contact with the ground because of the plasma coma surrounding the ship from all the energy its putting off.
So yeah if you’ve ever wondered why asteroids burn up in the atmosphere but astronauts don’t, that’s why. It’s a very specific trajectory that obviously most asteroids don’t hit.
It’s a delicate maneuver, but it’s one that we’ve gotten down to a science, it’s all handled by computers now but once upon a time, the “computers” were a room full of people with slide rules. Most of whom were women.
One other thing on re-entry is that they actually can kind-of steer capsules through the atmosphere.
The surface of the heat shield is actually slightly uneven. So it’s kind-of like surfing across the sky. And just like a surfer, they can turn in one direction or another by rotating the craft with their reaction control thrusters. Rotate clockwise, turn right. Rotate counterclockwise, turn left. All of which is controlled with computers in modern capsules, and they can steer them pretty accurately, to within half a mile of the landing site.
So in this video, all those clanks and pops, those are the reaction control thrusters going off, making tiny micro-adjustments to keep them on track.
Also I’ll get crucified in the comments if I don’t say this, the big fireball you see when space ships are re-entering, that’s actually not from friction – there is a lot of friction, but most of the heat comes from the compression of the air in front of the heat shield, it basically turns the air into a plasma.
Anyway, going back to my guy in orbit here, like I said, if you want to go down, you have to slow down. But what if you want to go up in altitude, to a higher orbit?
Again, intuitively you think you just point your rocket in that direction and fire – but space is not intuitive.
In the same way that you have to fire against the direction you’re traveling if you want to go down, you have to fire IN the direction you’re traveling to go up.
Remember, orbiting is all about speed. The higher your speed, or your velocity, the higher your orbit.
So you fire your thrusters and increase your speed, and what happens is you wind up with this kinda egg-shaped orbit, creating an apogee and perigee. The apogee is the furthest point from the Earth and the perigee is the closest point.
If you want to make your orbit a circle – and generally you do want that – you have to fire again on the apogee in order to raise the perigee on the other side and boom goes the dynamite, you’ve got a circle.
So yeah that means to raise your orbit, you actually have to do two burns. This is known as a Hohmann Transfer Maneuver.
The whole thing about launching something into the sun taking more energy than leaving the solar system
Also why most launches go east, because the Earth is already rotating at just over 1670km/h, and they can use that as a boost
Apollo astronaut Charlie Duke had a great response to a question about people who think the moon landing was faked when he said this:
I am constantly amazed by the number of people who think we just flew to the moon, landed, planted a flag, took some pictures and flew home. No. We landed Six times. Was supposed to be seven but Apollo 13 got borked. Actually, there was an Apollo 18, 19, and 20 planned, but those missions were scrapped. You can see the Saturn V rockets they built for them at places like the Johnson Space Center in Houston and the Kennedy Space Center in Florida.
This was an entire program, and each landing got better and longer and more complex, in fact Hank Green has a great video about how Apollo 11 was by far the worst landing of the entire program. Like it barely worked.
But here’s the thing, I don’t blame anybody for not knowing about this. There are some very smart people I know that didn’t know this.
So last year, my wife and I hosted a foreign exchange student. One of the places that she wanted to visit while she was here was Johnson Space Center, which was surprising to me because she wasn’t particularly into space stuff.
She clearly was not alone because when we were there, I was blown away at the number of foreign languages I heard. People around the world have many opinions about the United States and the things we’ve done over the years, but one thing that is lauded almost universally is that we went to the moon.
Anyway, that’s not the point I’m trying to make.
I spent the day at Johnson Space Center with my wife and host daughter, both of whom are very smart people, and we saw all the exhibits, we did all the things – short of getting a personal VIP tour – we even paid extra to see the mission control exhibit where they’ve maintained the mission control room from Apollo to exactly how it was during the landings.
So we saw it all. And a week or two later, I found myself having to explain to my wife, who again, is smarter than me… that we actually landed on the moon 6 times.
She went through that entire exhibit and came out still unaware that we landed more than once. Because ALL THEY TALK ABOUT is Apollo 11.
And I get it, Apollo 11 was a major milestone in human history, those things get carved in stone. Everyone remembers Columbus. Who were the next 5 explorers to reach the new world? Exactly.
But Apollo 11 has just become marketing for NASA and especially Johnson Space Center. And it really is a shame because there’s so much more to the story, and there’s so much information that doesn’t make its way to the general public.
Anyway, I get feisty about this.
This is something that I only found out about relatively recently. Like while running this channel, I first learned this. Kind-of embarrassing really.
Rockets are not full of rocket fuel. They are only half full of rocket fuel. The other half of the rocket is filled with oxygen.
When you see rockets on the pad and they’re loading it up with fuel, you see these hoses pumping fuel into the rocket there, that’s not just fuel, that’s actually filling up two different tanks inside the booster, one with rocket fuel, and the other with oxygen.
Fuel needs oxygen to combust. Cars pull it from the air to make gasoline explode and push pistons, airplanes scoop air into their turbines and compress it. So you only have to put fuel in them. But rockets are going to a place with no air. And no oxygen. So they have to bring their own.
This oxygen is then compressed and liquified, meaning it’s being pumped at -183C or colder. And this is all about being able to store as much of it as possible. The colder it is, the denser it is, thus the more you can carry.
They do the same thing with the fuel for the same reason, to get as much as possible into the vehicle. And that fuel varies depending on the rocket, there’s RP-1, which is a like a refined kerosene, and newer rockets like the Starship and New Glenn use liquid methane, mostly because it burns cleaner and makes them more reusable.
You also might have noticed whenever you see a launch that the rocket is covered with ice and steam, that’s because the oxygen and fuel is made as cold as possible. It’s liquid oxygen in there. We’re talking minus 220 degrees celsius.
In fact you can see how full the rocket is as they load it because the frost level on the outside.
But that’s basically how the rocket engine works, it mixes the fuel and the oxygen from the two different tanks, ignites them in the combustion chamber, and directs the explosion out the end to create force.
I’m obviously leaving a lot out – rocket engines are extremely complex – but there is one mind-blowing thing about rocket engines that’s worth sharing. Have you ever wondered why the engine bells don’t melt?
The the bell of the SpaceX Merlin engine that powers the Falcon 9 gets up to 1800 degrees celsius (3250F). But that engine bell is made of a steel and copper alloy. And steel melts at around 1500 degrees celsius (2800F). So why don’t they melt?
They don’t melt because the bells are actually cooled by that cryogenic fuel.
Yeah, the skin of the engine bell itself is actually made up of a series of channels that they pump the fuel through before they burn it. This keeps the engine bell just cool enough to not melt. Crazy.
Just to be thorough, not every type of rocket engine uses oxygen. There’s hypergolic engines that combine two different chemicals that combust when they touch each other. These are super reliable and mostly used in the reaction control thrusters. Very toxic, though.
And there’s also solid rocket boosters like you saw on the SLS in the Artemis launch. These are basically gigantic versions of the model rockets you might have played with as a kid. They’re super powerful but you can’t control them once they’re lit. They’re basically just good to get up into the upper atmosphere.
They’re basically a way to get around the tyranny of the rocket equation. If you’re not familiar with that term, the big problem with rockets is that you need fuel to get into space, but fuel is heavy. The heavier the rocket, the more fuel you need. The more fuel you add, the heavier the rocket, which means more fuel, which means more weight, which means more fuel…
Like 90% of the weight of a Falcon 9 rocket is just fuel. Remember, we’ve got to get up to 17,000 mph with this thing, that takes a lot of fuel.
When people talk about “rocket science” as being so hard, that’s what they’re talking about, stuff like this. It is a constant negotiation between speed, weight, payload, orbital mechanics, and about a thousand other factors we don’t need to get into here.
It’s hard, but it’s doable. And we’ve been doing it for nearly 70 years, thanks to the tireless efforts of space nerds who, once upon a time, dear normie viewer, were just like you.
Every rocket engineer started with a wow moment, when they realized something they thought they understood about space or rockets was flat-out wrong and they couldn’t help but go down the rabbit hole and learn more.
It’s my sincere hope that someone watching this video has a moment like that, and if you did, I encourage you to follow channels like my buddy Tim Dodd, and Felix over at What About It and Marcus House and the NASA Spaceflight team.
Another great place to start is to dig into the history of NASA and see how we learned all these lessons, each one is a fascinating story on its own. Amy Shira Tietal is a friend of mine and a great place to learn more about space history, also check out the channel Homemade Documentaries, they’ve got spectacular videos on the early US space programs, I promise you’ll get sucked in.
Or, another great place to get started, is right below this video in the comments because I guarantee there’s thousands of people who love talking about this stuff so if there is anything in this video that was confusing to you, ask away down below and you should have an answer by someone on Team Space pretty quickly.
Also, like I said, this is a very high-level overview of these basic space facts, I left a lot out so if any of you nerds want to clarify or expand on anything I said – or if I happened to get a detail or two wrong – chime in down below.
Also share your favorite space creators if I didn’t list them. I’ll put more links to creators in the description.
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