Comments by "Sebastian Nolte" (@sebastiannolte1201) on "Real Engineering" channel.

"We always look at NASA rockets, they do not go straight" Of course they don't go straight up. Why should a rocket that goes into orbit or beyond should go straight up? A rocket that goes straight up will just fall down at the end. Of course, what else should happen? " but deviate for a certain distance and then fall into the sea." What is your evidence? And what is even so unbelievable that the rocket has enough fuel so that it can run for a few minutes more until it reaches orbital speed and so doesn't fall down? ". No one can get out of the ground." What? Rockets obviously get of the ground. And airplanes. And helicopters. So what do you want to say? "All the videos are taken from 3D NASA" Normal private companies build satellites and offer services to normal customers. They book rocket flights from normal private rocket companies to bring their satellites into orbit. It is a regular business, there are many startups meanwhile. Nobody prevents you from working there or found a rocket or satellite company. So what does NASA has to do with it? " there is a big sea of water, " Where is it, so at what altitude? What is your evidence that it exists? There is hint for that.
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So you want to tell me that people could book a regular flight with an airliner that goes 2,200 km/h in 1977, with the the computer technology of back then, and now in 2024 we cannot fly with more than 1000 km/h? LOL, we "lost the technology" in 2003! Makes no sense, the Concorde was fake! (yes, I am making fun of "Moonlandings were fake" people, who use such an argument...).
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The space shuttle is not so so fast by accident - it was accelerated to 28000 km/h on purpose, because at that speed you stay in orbit. Look at the launch at 3:23. The Orange thing is just a huge tank, so full of propellant. And additionally you have these two big boosters. And at the end that is all needed to accelerate up to 28000 km/h. The reason why rockets are so big and need so much fuel is not because they just have to reach altitude, but because they have to reach a certain speed. And you need the same amount of energy to decelerate a certain object from 28000 km/h to 300 km/h as you need to accelerate it from 300 km/h to 28000 km/h. In practice a rocket would not need the same amount of fuel to decelerate after it accelerated (because it carries less fuel at that point, so it is lighter), but still much. And that extra fuel has to be accelerated before. So you would not only need the extra fuel for the deceleration, but also more fuel for the acceleration- because the deceleration fuel makes it heavier, and so on...
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It doesn't. Gravity becomes weaker with the distance continuously, but never zero. But that is irrelevant here, we can just assume that it is the same (at 250 miles you have 87% of sea level gravity). Never wondered why the orbiter flies around the earth with 7 km/s at the beginning of this video? The purpose of a rocket is to accelerate horizontally (so sideways, parallel to the ground) to such a high speed. At that orbital speed objects "fall around the earth forever", so without getting closer to the ground. That is what we call "orbit". Watch this short video to understand the concept: https://www.youtube.com/watch?v=ALRdYPMpqQs
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@JackH2478 " is that where grabbity stops working and you magically float?! Lol." No, 62 miles is the altitude where the necessary speed to get aerodynamic uplift becomes as high as orbital speed.. Some people once decided to use that as the thresold between aeronautics and astronautics. US air force uses 50 miles. All definitinions are arbitrary, the atmosphere becomes thinner fluently, so you cannot say where it ends. And it doesn't matter. The ISS at 250 miles loses some altitude all the time because there is still some atmospheric drag at that altitude. Why should gravity stops working suddenly? Have you ever even looked into the formula for gravity? It becomes weaker with the distance but never zero. And it has nothing to do with the atmosphere. At 250 miles (the altitude of the ISS) it is only 13% weaker than down here. In a launching rocket the astronauts don't begin to float when they reach a certain altitude. Instead they begin to float when the rocket stops the engine and the spacecrafts begins to coast/fall/move only by its momentum. ZeroG airplanes don't "simulate" the weightlessness that you have in the space station. Instead it is the same effect. You are weightless when no other force than gravity effects you, so in free fall. "Or where you have a vacuum next to a pressurised system without a barrier?! " How do you come to such a weird idea? The air pressure gets lower when you go higher. You can feel and measure that (you feel the pressure change in your ears in a high elevator; and altimeters usually work by measuring the air pressure). - sea level: 1013 hPa - top of Mount Everest: 325 hPa - cruise altitude of airliners: 191 hPa - 12 miles: 78 hPa - 22 miles: 10 hPa - 31 miles: 165 Pa - 62 miles: 0.3 Pa - somewhere between earth and moon: 0.00000001 Pa - somewhere in open space: 0.00000000000001 Pa I don't know what pressure threshold you use to talk of a "vacuum". There are common used definition to distinguish between a "low (or rough) vacuum", a "medium (or fine) vacuum", a "high vacuum", a "ultra-high vacuum" and "extreme-high vacuum". "Space is dogshit. Anyone who believes in it is a mong" The problem of you guys is that you have totally misconceptions about "space". And the biggest is, that you think that space is something special. But it isn't. As I explained, there is not even a real definition where it begins. Let's say we all live in space. I meanwhile prefer to even avoid the term, becuase it means nothing and just leads to misconceptions. Let's just talk about altitude/distance to earth. And if you want to know the conditions for that certain altitude/distance to earth (gravity, temperature, air pressure, radiation,...) then calculate it or look it up. Why are some people so obsessed with the question if something is in space or not? I don't get it.
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NASA retired the the Space Shuttle in 2011 because they wanted to contract private companies instead, and Boeing and SpaceX won. And SpaceX delivered successfully so we have now a SpaceX spacecraft that brings astronauts to the ISS. So what even is your point, we already have what you asked for. And BTW we have to wait how starship can fullfill the visions. Musk is obsessed with 100% reusabilty an we have to see if that makes sense for all cases and if it really will be like aircrafts ("you only have to pay for the fuel"). They still talk about 100 tons into LEO, fully reusable. The current prototypes cannot deliver that, they don't have much payload. That is why the version that just launched (and exploded...) a few days ago was already bigger than the versions before.
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Airliners do that all the time, they go from an air pressure of 1013 hPa to only 191 hPa at an altitude of 13 km. You can see rockets that go much higher with your own eyes. So up to what altitude do you believe can we go and why shouldn't we go higher?
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The most efficient way to do it. Why do you think rockets are so huge? Because they need all that fuel to accelrate up to 28000 km/h. You need the same amount of energy to decelerate an object from 28000 km/h to 0 km/h that you need to accelerate it from 0 km/h to 28000 km/h. So the day when we will decelerate down to a speed where you don't need heat shields will be the day where we have some unknown propulsion system better than rockets. BTW you mixed up Challenger and Columbia 🙂
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You see this huge tank that the Shuttle is sitting on when launching? You need all that fuel to accelerate from 0 to 28000 km/h. You need the same amount of fuel to decelerate from 28000 km/h to 0 (well, not really when you already have less fuel after the launch so you are lighter... but you get the point). Using the atmosphere to slow down is just efficient, comparing to using rockets to slow down.
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@James-zp5po " space starts at 62 miles high" At 62 miles the necessary speed to get aerodynamic lift becomes as high as orbital speed. And some people thought to use that to define where "aviation" ends. And so use it as the "beginning of space". But that is of course an arbitrary definition. There is no beginning of space, the atmosphere becomes thinner fluently - you really never noticed that? You have never felt the pressure change in your ears when using a fast and high elevator? You have never heard that people need oxygen supply when climbing the Mount Everest? You have never wondered why oxygen masks fall down from the ceiling of an airplane in emergency? Already at 22 miles you only have 1 % of sea level air pressure, so not much air anymore. On the other hand there is still some atmosphere at 250 miles, so that the ISS loses more than 200 feet of altitude every day because the drag slows it down. " because rockets can not produce thrust in a vacuum" Bullshit. Why should that be the case? It seems you have no idea how rocket engine works. But OK, let's assume for a while that you are right, while all the thousands of engineers (including the ones who design the engines) don't know how rockets work. Then please give some details about the relation between air pressure /air density and thrust. Is it that there is a threshold? So the engine produces 100% of thrust all the time, also when you have less and less air, but when the air pressure or air density goes below a certain threshold, it suddenly doesn't produce any thrust at all? If yes, what is the threshold? Or is there a relation like "half the air density = half the thrust"? Or a combination? So what is the formula? And BTW even if it would be correct that the rocket would suddenly don't produces any thrust anymore at 62 miles - why should it immediatly fall down? Have you ever throw something straight up, or shoot it straight? You know that there is inertia, so that the object keeps on going? The New Shepard tourist rocket goes straight up and stops the engine at about 40 miles. But at the end reaches 66 miles before falling down. If it would run all the time until 62 miles (so also reach higher speed then) it would go even much higher than only 66 miles.
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Don't want to take away anything from the in deed mind blowing engineering - but we always see into the past. You can see Andromeda galaxy with your naked eyes, which is 2.5 million lightyears away. So you see how it looked like 2.5 million years ago. A strong telescope just helps us to see even further into the past.
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"Why can't a spacecraft/aircraft enter the outer atmosphere at a much lower speed, " Well, you see how huge rockets are? They are basicly just giant fuel tanks. Because you need that much fuel to accelerate from 0 to 28000 km/h. Or even nearly 40000 km/h when you want to go to the moon or further, and not only into low earth orbit. And the deceleration of an object from 28000 km/h to 0 needs the same amount of energy as the acceleration of that object from 0 to 28000 km/h (in a case of the rocket you would not need the same, because with less fuel onboard it would be lighter on the way back, but still). Using the atmosphere to slow down is the cheapest option. " maybe by deploying a couple of large parachutes, like the mercury, gemini and apollo reentries? " Parachutes don't work outside of the atmosphere. If they would the spacecraft would already slow down by itself enough because of the drag.
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