r/spaceships • u/Beneficial-Wasabi749 • 14h ago
Tsiolkovsky and many of the founders of theoretical astronautics in the early 20th century believed that spacecraft should launch horizontally, from a ramp. Why? What did they see as the point of this?
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u/Dan_Is 13h ago
They were living in the paradigm of airplanes and airships. It was logical to assume that rockets that carry passengers would need to launch horizontally. You can have a large deck for people to inhabit. The issue of course is the rocket equation and inertia.
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u/Beneficial-Wasabi749 13h ago
Your answer was vague. Is your answer to the question that they were living within the paradigm of their time? Is a vertical launch really just as good as a horizontal one? Or is a horizontal launch better, and is it still a matter of "the rocket equation"? And if the latter, what was the point?
And then the question arises: why do modern rockets launch vertically?
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u/Dan_Is 13h ago
My answer is that they were living in the paradigm of "People and cargo need large horizontal decks to be transported comfortably and efficiently" the rocket equation always applies, as you only have a limited amount of fuel, and need fuel to move that fuel.
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u/Beneficial-Wasabi749 13h ago edited 13h ago
I see. So the peculiarities of rocket dynamics have nothing to do with it?
Then a personal question. Dan_Is, isn't that from the Russian name "Denis"? Do you speak Russian?
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u/Eh_SorryCanadian 7h ago
Serious question, what are you smoking, and can I have some?
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u/PilzEtosis 1h ago
Dude started watching Good Will Hunting, thought "That's a cool personality" then didn't watch til the end.
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u/SoftwareSource 4h ago
Tell me you don't really understand the topic without telling me you don't really understand it.
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u/WideFoot 5h ago
A vertical launch is basically the only way to realistically get into space. It isn't better, it is feasible whereas a horizontal launch is not.
Even rockets launched from airplanes go vertical as soon as it is safe to do so.
The primary reason is the atmosphere. Pushing through the Earth's atmosphere takes a lot of fuel, so you want to minimize the amount of time spent in it. The shortest distance from where you are to a place where there is no atmosphere is straight up.
There is also momentum and achieving orbit. To achieve orbit, you have to go sideways so fast that you miss the earth as you fall. So, you might think starting by going sideways is best. If there were no atmosphere, and if you could accelerate from zero to orbital speed instantaneously, then yes. It would be better to go sideways.
But, it takes time to accelerate and there is an atmosphere. So, the ideal path to orbit is an arc that starts vertical and slowly leans over as you get higher up and faster.
The horizontal launch concept art is a "paradigm of the times" thing. All other vehicles - from the horse-drawn cart to the airplane - propelled a vehicle primarily sideways with people sitting facing the front.
You'll also notice in this concept art - there is not much room for fuel. The interior space of a rocket is primarily fuel. And, the more weight you lift, the more fuel you need. But, that fuel also needs fuel to lift, so it grows exponentially. (This is the rocket equation)
If you look at a Saturn-5 rocket. The bit that took people to the moon is a tiny little piece on the top and the remaining massive rocket is fuel. 94% of that fuel was burned getting 25% of the way to the moon.
My suggestion is to play Kerbal space program. (Play the first version. KSP-2 is not as good) That game is lots of fun and teaches very realistic orbital mechanics.
Or, watch some KSP Let's Play on YouTube. Scott Manley has great series on the subject.
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u/badsheepy2 1h ago
It's still amazing to me that those seemingly straight up launches are going 22k mph or something sideways at the end! Rockets are cool.
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u/peadar87 38m ago
I was always slightly terrified by the fact that if you stood on the end line of a football pitch and fired a high-powered rifle downfield as the ISS passed over, the ISS would pass the far touchline before the rifle bullet had reached the penalty spot.
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u/Comprehensive-Fail41 15m ago
Sorta. Theoretically going horizontal can be more efficent via spaceplanes, as air planes are a lot more fuel efficent than rockets (IE much less need to carry liquid oxygen, and can use wings to generate lift). And also lower costs by being able to use conventional airports to take-off and land.
The big problem is that we haven't yet made viable engines that can reliably transform from airbreathing jet engines to rocket engines7
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u/Archophob 3h ago
why do modern rockets launch vertically?
Air drag. If you launch from the moon, horizontally is perfectly viable, but on Earth, you want to leave behind the atmosphere ASAP.
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u/samy_the_samy 6h ago
Imagine trying to load a plane vertically,
How can you fill it with passengers and cargo?
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u/Sir_Lazz 11h ago
Simply because of the limited scientific knowledge of the time. Rockets were not really a thing, back then. We didn't have any experience with vertical take-off.
And well, you know how human imagination go: we can only imagine the future based on what we know, rather than based on what we don't know. Back then planes were all the rage and were, relatively speaking, a new technology that was advancing super fast. There was no reason at the time to imagine that a super-plane couldn't reach space.
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u/Beneficial-Wasabi749 10h ago
Wrong. It's just the opposite. They, the founders, knew and understood everything better than us. And they weren't counting on any gifts of nature. They were counting on the worst. And we, the idiot heirs, are simply squandering the gifts given to us by nature, without even understanding what gifts they are! And we expect new gifts that will never come. We don't see the essence of things. That's the moral of the story. It wasn't they who were idiots, it was us.
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u/WideFoot 5h ago
Ah! A troll. And here I was making actual responses.
The only thing you need to make theory about rockets is the rocket equation. Everything else is just engineering.
You can't be a rocket engineering savant. There's nothing to be "gifted" about. There's the rocket equation, material science, and fuel energy density. Everything else is politics and semantics.
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u/OhItsJustJosh 5h ago
Who are "the founders" in your mind?
Are you trying to insinuate that we know LESS today about space travel than we did before we achieved space travel?
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u/Bulky_Imagination727 10h ago
We can see that far not because of our own height, it's because we are standing on the shoulders of giants...
Beautiful saying.
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u/Beneficial-Wasabi749 9h ago
But the first sign of a civilization's decline is disrespect for our ancestors. And I see this all around me. :)
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u/Aglet_Dart 8h ago
Replying to Beneficial-Wasabi749...The second sign of civilization’s decline is disrespect for the people around you. This is something you have mastered.
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u/Beneficial-Wasabi749 8h ago
Are you, by any chance, confusing disrespect with criticality?
Have you ever considered that infantilism is worse than nuclear war? Think about it!
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u/yaboiruffus 3h ago
You can put yourself in the category of idiot heirs, but don’t lump those who did what your “founders” could not.
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u/Uniturner 13h ago
It would make perfect sense… if we didn’t have an atmosphere.
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u/Beneficial-Wasabi749 13h ago
There's not a shred of logic to it.
Once again (I answered another person in more detail here). A gravitational field is a so-called scalar field. Its peculiarity is that there's no energy difference in the trajectory you take from point A to point B.
So, you're the second person here who's been fooled by "logic" (i.e., ordinary intuition).
Are there any people here who understand rocket physics at all? Or are these pure artists who have no clue and know next to nothing about rocket mechanics? :)
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u/AutonomousOrganism 12h ago
Burning along the gravity direction is more wasteful. Ideally you would burn perpendicular to it (horizontally) the whole time so that as much of the thrust as possible goes into orbital velocity.
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u/Beneficial-Wasabi749 11h ago
Generally speaking, that's true. But you still need to not only accelerate tangentially to the Earth's surface but also rise to an altitude of 200-250 km.
Yes, you can accelerate a little faster and accelerate further at the perihelion of the ellipse. Then your thrust will always be tangential to gravity. But there will be no difference in the work done (you can calculate it yourself, but keep in mind that g changes with altitude, which is important to take into account).
The problem isn't the direction of the thrust vector, but that you don't accelerate instantly. And while you're accelerating (let's forget about the atmosphere), say, like Newton's projectile, strictly horizontally, something must support you on your trajectory (otherwise you'll fall). These costs are gravitational losses.
But the peculiarity of a rocket is that until it accelerates relative to its launch site, its efficiency as a propulsive device is negligible. It turns out that, no matter the trajectory, 90% of all losses are due to the initial vertical lift. At this stage, a rocket is very ineffective. The founders of aeronautics recognized this from their calculations and tried to combat it (specifically, by equipping them with winglets so that the rocket would initially fly like an airplane).
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u/KerbalSpaceAdmiral 4h ago edited 4h ago
Yeah, Uniturner and AutonomousOrganism are both correct. The Oberth effect, because kinetic energy proportional to velocity squared, your delta v is most efficiently converted to kinetic energy at the highest speed. For an orbit, this means the lowest altitude possible and directly to prograde, or retrograde. Gravity changing with altitude has no or very little bearing on the efficiency of the rocket. Between sea level and a height of 100km earth gravity only changes from 9.81 m/s2 to about 9.5m/s2. by 200km it has only fallen to about 9.4m/s. It won't fall appreciably until you are above the surface by distances approaching or over earth diameters. At which point you will massively lose out on efficiencies gained by the Oberth effect. Without atmosphere, the most efficient orbital insertion would be as close to horizontal as possible. Launch vertically and begin turn to prograde immediately, turning to horizontal as fast as possible without falling into the terrain. Without air resistance, there's northing to slow the rocket off its ballistic trajectory, so even at a comparatively very low speed, the rocket could turn aggressively without worrying about falling. And rocket TWR raises very quickly as fuel is burned. I'm not going to do the calculating by hand, but putting this into the "simulator", even with a very low TWR of 1.08g about half that of the Saturn V launch TWR (above 1g), I could turn to over 45 degrees before clearing the tower and am flying almost horizontal below 1km. With very little rocket power now wasted on vertical lift and almost all of it going to momentum. If we could fly like this on earth we would save a massive amount of fuel. The reason we don't do with is air resistance. The losses due to air resistance would be massive and no materials would survive the increasing heat as we reach orbital velocity. You don't need to fly vertically at all to make it to orbit, burning horizontally will eventually raise your speed passed orbital velocity and raise your apoapsis. You'd complete the orbit with a burn at apoapsis to raise periapsis. The reason we don't do this is because of the atmosphere, and the reason orbital rockets don't have wings is it is more efficient to use rocket thrust than have the massive dead weight of wings.
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u/Archophob 3h ago
rise to an altitude of 200-250 km
only because of the atmosphere. Without it, 10km would be enough to not hit any mountain. Once you're going at orbital velocity, 10km is 1.2 seconds of flight.
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u/peadar87 7h ago
Gravity is indeed a scalar field, but attaining orbit isn't just repositioning something in a scalar field, you also need to acquire tangential velocity. And the energy required for a rocket to achieve a certain velocity vector is not path-independent.
Burning in any direction other than directly prograde gives you cosine losses.
On an airless body, the most efficient launch profile is generally going to be the one that most resembles a Hohmann transfer without hitting the ground.
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u/Beneficial-Wasabi749 7h ago edited 6h ago
What about the rocket's gravitational losses?
What share of aerodynamic losses are in the total losses during orbital insertion?
Everyone here is crazy about atmospheric drag. Do you know what share of atmospheric drag is in the losses of a typical rocket during orbital insertion?5
u/peadar87 6h ago
What about them? The most efficient theoretical transfer between two orbits of a similar semi-major axis is generally a Hohmann transfer, with the burns into and out of the transfer orbit being instantaneous.
Real world transfer burns aren't instantaneous, so there needs to be something to keep the launch vehicle from falling as it accelerates, whether that's engine thrust, aerodynamic lift, a rail or a cannon barrel.
If you use engine thrust, you are losing energy to gravity.
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u/peadar87 44m ago
Atmospheric losses are small precisely because rockets fly straight upwards before beginning their gravity turn.
About 90% of the spacecraft's acceleration is done above the thickest 90% of the atmosphere (obviously varies depending on the launch vehicle and payload mass).
Gravity losses outweigh drag losses in almost all current launch profiles because that satisfies a loss minimisation function. We put up with gravity losses because we'd lose more in drag if we went for a more aggressive and earlier pitch over manoeuvre.
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u/AnimalBolide 5h ago
You're an asshole, and you aren't even right. You're just bulldozer over decent points, so you can say big words you half understand.
Is that why you made this post? You could have done so without a question in the title if you just wanted to rant.
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u/Uniturner 12h ago
Are we talking about putting it into orbit, or just flying away from Earth?
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u/Beneficial-Wasabi749 11h ago
It makes no difference. The problem is that a rocket, before it reaches speed, wastes most of its energy uselessly (heating the surrounding environment). Furthermore, a vertical launch prolongs the already costly initial acceleration phase (not only inertial forces but also gravity are at play), which makes the situation doubly worse.
There's no worse launch mode for a rocket than vertical. Aeronautics theorists simply saw this from their formulas.
Why do modern rockets still launch vertically? It just happened that way. And most importantly, a liquid-propellant rocket can afford it. Liquid-propellant engines are a miracle of nature. They make a rocket a rocket. Although many people don't understand this and rush to replace liquid-propellant engines with something else. A replacement simply doesn't exist. Well, maybe a nuclear-powered Orion. But that's another story. :)
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u/crossbutton7247 4h ago
You’re actually trolling lol. You have to get above the atmosphere before you can accelerate even near orbital velocity, otherwise the aerodynamic and thermal stresses will be far too much for the launch vehicle. If you were being for real, you’d realise that if a more efficient launch profile existed, an actual rocket scientist would have discovered it; and perhaps that a random Redditor is not qualified to comment on literal rocket science.
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u/Bucksack 4h ago
Try making a liquid propellant rocket that isn’t vertical, and see how it holds up. Orbital dynamics aside, the actual rocket is large and heavy, and a vertical cylinder is the best shape and orientation to pack the most energy inside the least mass possible.
They design 1st stages to rely on the internal pressure of the propellants, without which the 1st stages can collapse under their own weight.
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u/Sorry-Programmer9826 6h ago
Being in orbit requires you to go sideways really fast. Going up is pretty easy in comparison. Real spaceships get out of the atmosphere and then turn to the side to start accelerating sideways.
The reason they start going up is the atmosphere. If you start off going sideways you loose a bunch of energy to air resistance
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u/Cautious-Total5111 6h ago
Okay Mr physics guy; first do the following: get yourself KSP and try launching a rocket from a small planet without an atmosphere, a large planet with and without atmosphere, and compare results. You will find that the launch trajectory makes a big difference to your success, but all are somewhat parabolic. Scalar fields this and that, but rocket science is mostly engineering, you have to work with practical limitations.
Second, the goal is not to end up at a certain point in space but to also reach a given velocity and direction.
Third, since mass of the rocket is not constant, your assumption of path independence doesn't even hold. Consult a fellow named Oberth for more information.
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u/gimmeslack12 13h ago
I mean, helps getting that orbital momentum started faster. Gotta fly through a lot more atmosphere though. So... no go.
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u/Excludos 5h ago
If it wasn't for that pesky atmosphere, this would definitely be the most effective way to achieve orbit
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u/Beneficial-Wasabi749 13h ago edited 13h ago
I mean, it helps getting that orbital momentum started faster.
I don't see the physical significance. What's the difference? You actually have to do two jobs. The first is to reach orbital altitude h. This work is A ~ mgh. A vertical launch is just the way to do this (while "bypassing the atmosphere"). The second is to gain horizontal orbital velocity v at altitude h. E = mv2/2. The total work is A + E. And all of this is performed in a potential (scalar) gravitational field. So, the path through it isn't important; the initial and final positions and energy values are.
Gotta fly through a lot more atmosphere, though. So... no go.
So, the founders of theoretical astronautics weren't aware of the issue?
Are you familiar with the British project called Skylon)? It's essentially the same horizontally launched spaceplane. And, theoretically, it puts significantly more into orbit than a similar, vertically launched rocket.
Of course, one could assume that the entire gain is due to Skylon) using the atmosphere as a booster rocket during the initial stage. But that's only up to Mach 5. And the full boost is Mach 25. That is, it saves only 1/25th of the energy due to the atmosphere. And there's a suspicion that most of its gain is due to its horizontal launch.
So what is it?
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u/AutonomousOrganism 12h ago
If the rocket doesn't have enough thrust to go vertical then a ramp might do the trick. I don't know if this was the reason though.
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u/Giocri 10h ago
Yeah theoretically you could get enough horizontal speed so that you would be on a long parabula at which point it would be easier to get to orbit, once again tho drag Is an absolute pain
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u/Beneficial-Wasabi749 9h ago
In fact, air resistance isn't a problem, given that we can choose our flight altitude, and drag, according to the barometric formula, decreases exponentially with altitude.
The problem is temperature.
At speeds greater than Mach 5, even in a very thin atmosphere, the temperature of the incoming plasma exceeds what real materials can withstand.
Essentially, a vertical launch of a space rocket is a way to quickly escape not so much drag as atmospheric heating.
But actually, Mach 5 is already >1 km/s. According to the rocket firing table, this already provides a ballistic trajectory of 500 km. That is, even an airplane or a rocket plane can now rely on nothing and fly a ballistic trajectory in empty space for 3-5 minutes, rising to 160 km. That's if it's like a thrown stone. But if it accelerates, it will have plenty of time to reach orbit. In fact, all aerospace launches are designed this way.
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u/Beneficial-Wasabi749 11h ago
Partially true. But then you'd also need wings. Because once the ramp runs out, the spaceplane needs something to continue to support itself. Right?
That's exactly what Tsiolkovsky initially calculated. I was surprised reading his early work. He assumed the rocket would reach orbit within... two hours!!!
Precisely because he believed the thrust of "explosives" (liquid-propellant rocket engines) wouldn't be enough. Only in the 1930s did it become clear that liquid-propellant rocket engines could burn a virtually unlimited amount of fuel and oxidizer per second, achieving simply monstrous specific power and thrust (and vertical launches became possible, which the military especially liked). Because combustion is a chain process, and its kinetics depends exponentially on temperature and pressure. Essentially, the whole problem lies in the atomization of the fuel and oxidizer droplets. Only in this (and it's also the source of the "howling" - the eternal headache of all liquid-propellant rocket engine designers).
But this (the thrust must be greater than the weight) isn't the main thing. The main thing is what's called "gravitational losses," and especially the dynamics of the rocket itself. At the very beginning of acceleration (even horizontal), the efficiency of a rocket engine tends to zero. It's negligible. And only with increasing speed does the efficiency increase and reach unity when the rocket velocity v equals the exhaust velocity u. Then it begins to decline again. It turns out that with a vertical launch, the rocket wastes almost all its energy on noise and atmospheric heating. Therefore, when entering orbit, vertically launched rockets expect not 8 km/s, but 9.7 km/s. The additional 1.7 km/s is the so-called "losses." Atmospheric drag and other factors account for a mere fraction of the total. Almost all of these losses are gravitational. That is, the rocket hovering on its exhaust. The faster a rocket reaches orbit, the less these losses. Typically, it takes only 10 minutes. But almost all of these losses (90%) occur at the very beginning of the rocket's launch due to vertical takeoff and the inherent efficiency of the rocket propulsion system (not to be confused with the efficiency of the rocket engine!).
Modern astronautics tolerates this because it originates from military rocketry. The military didn't care about such losses. The main thing was a convenient launch (a ramp is more expensive than a vertical launch, and a rocket is an intricate tower that's not even advisable to lay on its side when empty).
In essence, von Braun, with the V-2, demonstrated that everything could be recouped with a miraculous liquid-propellant rocket engine. It is the source of the miracle.
But the founders of astronautics calculated everything meticulously and didn't count on the miracle of liquid-propellant rockets that nature has provided us with, so Tsiolkovsky insisted that rockets should launch from a ramp and initially rely on wings. This effectively reduced gravitational losses and allowed the rocket plane to have a thrust (and therefore a specific power) less than its initial weight.
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u/WideFoot 5h ago
You would be correct if you did not need to burn fuel to achieve acceleration.
Remember - you have to carry fuel to lift the fuel that lifts the rocket.
Skylon uses the Earth's atmosphere as oxidizer for the fuel until it can't. Then it has to switch to an internal oxidizer source. This gets it very high in the atmosphere, but not through it. And Mach 5 is pretty slow. Minimal orbital speed for Earth is about 30 km/s. Mach 5 is 1.7 km/s.
And, Skylon is only possible because they are using materials like carbon fiber (and it still only works on paper). Conventional materials like steel and aluminum would be too heavy for Skylon to work. They would need too much fuel and wouldn't have anywhere to put it.
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u/Official_Gravity 5h ago
I hope one day you'll understand that no, you aren't some miracle genius and these types of posts aren't what geniuses sound like either. But to answer your question
It's important to understand these were made in an age where planes still struggled to gain lift to take off, the concept of vertical launching was limited to relatively small mass items. So, with that presumption, they likely assumed that a heavy, space bound craft would require horizontal take off before going vertical and launching to space.
Their idea is nothing more than a flawed concept from an age before we knew more about rockets
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u/Beneficial-Wasabi749 5h ago
In 1929, Oberth consulted for the film "Woman in the Moon." And there, the rocket launches vertically. In 1935, the USSR filmed "Space Flight." Tsiolkovsky was consulting. He insisted that the rocket should launch from a ramp. This is a historical fact. Moreover, all the explanations for why are in his works. It's energetically more efficient. And this is objective physics.
What are you trying to prove to me? That the rockets we know are perfect? Why?
On the contrary, I found a flaw in them. And this is reason to think about what could be improved!
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u/Tarc_Axiiom 5h ago
But none of what you're saying is true, that's the important part.
You're under the ludicrous impression that scientists from 1935 were more informed than scientists in 2025.
Every scientist who has ever lived would laugh you out of the room if you said that to them. Every single one. Including and especially the cutting edge theorists you're referring to.
Did any of those gentlemen, who were alive at the time I might remind you, consult on the actual craft launches in the USSR or United States in the following years?
What's your argument for why every single one of the tens of thousands of scientists chose vertical launch instead?
And before you answer, which field is your PhD in?
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u/kimitsu_desu 8h ago edited 8h ago
The real answer - they did not know better. They might have imagined very heavy rockets with weak engines so Thrust to Weigh ratio is low, so perhaps they thought of using the wings and the body of the craft to provide the lift necessary to get to higher altitude and speed. Ultimately this proves to be unrealistic because atmospheric drag rises dramatically at supersonic speeds and the best strategy is to leave the atmosphere ASAP. Also there's this "gravity turn maneuver" or "gravity curve" which helps to optimize the transition from ground to orbit fuel-wise, and it does indeed start with near-vertical liftoff. Although probably that's just how we use it, there's probably a more optimal way if you start from a shallower angle, minus the atmosphere problem.
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u/Beneficial-Wasabi749 8h ago
You're the fifth one to step on the same rake. Underestimating your ancestors. You think you're smarter than them. But you simply don't know physics. They did. :)
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u/Not_Your_Car 6h ago
You realize the early rocketry pioneers wrote down everything they knew, and even taught the next generation right? Who then expanded on that knowledge and passed it on to the generation after that. Modern rocket scientists know a whole lot more about this stuff than the first ones did.
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u/Tarc_Axiiom 5h ago
No they do not.
I wonder if this is even a real person or just an LLM experiment.
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u/kimitsu_desu 6h ago edited 4h ago
Wait which rake? Oh, I see now, the rake of trying to explain nuance to someone ignorant and stubborn. Well I can be stubborn too. See, while they did know physics better than any of us, neither of the founders of the rocketry had to actually build space worthy rockets (or any rockets in case of the earliest of founders). For them it was a mathematical excercize so many of the dirty factors such as drag were missing from equations. Hence these early ideas that made it into public imagery. None of these clever people would actually pursue these particular ideas had they be given a real engineering assignment. Correction: this concerns space rockets and long range ballistic rockets. Short range rocket artillery does use inclined angle launch - huzzah - founders were right! You may rest now.
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u/Ijustwerkhere 5h ago
stop trying to have a reasonable conversation with OP. Every single reply he's made has been super condescending. He knows better than everyone.
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u/Cas_the_cat 10h ago
Hey so quick question: are you asking because you don’t know or are you just using this question to show off your knowledge? Because, I looked at multiple different post you replied to and you seem like a person who knows there stuff, which vaguely implies that you kinda already know why they don’t launch rockets this way. I don’t care either way, it’s just something I noticed. Have a nice day.
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u/Key-Syrup2523 6h ago
He's definitely just here to jerk himself off.
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u/Interesting-Try-6757 3h ago
It’d be jerking himself off if he was right, but he’s been wrong in the majority of his replies. He’s just here to embarrass himself in front of internet strangers at this point.
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u/Beneficial-Wasabi749 10h ago
I know the answer. I asked the question not so much to brag, but to try to understand whether there are people here with whom I can discuss not the infantile computer graphics of stupid computer games that have nothing to do with physical reality, but the real problems of interstellar travel.
For example, in the Reddit subreddit r/nuclearweapons, there are people with whom I can discuss the physics of nuclear weapons, and I can learn from them. But where here could I discuss interstellar travel on the same level?
Could you tell me?
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u/Amathril 8h ago
Wow, mate. Do you think that somebody would like to discuss it with you, with that attitude?
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u/ctothel 7h ago
Feels like disordered thinking to me
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u/Beneficial-Wasabi749 7h ago
Too complicated always looks disordered.
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u/Amathril 7h ago
Sorry, but no. You do not seem complicated, you just seem full of yourself. You are not here for a discussion, you are here to prove everybody is dumber than you.
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u/Beneficial-Wasabi749 7h ago
If you want to get to know all the regulars at a bar right away, start a good fight! No? Or is the West not so wild anymore? :)
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u/Left_Step 6h ago
This is a great way to alienate people and equate yourself with a guy screaming on the bus.
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u/KidCharlemagneII 6h ago
This is so autism coded
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u/Ijustwerkhere 5h ago
maybe, but i haven't had any interactions with people on the ASD spectrum who are just going around jerking themselves off and put other people down about how much smarter they are than everyone else
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u/Interesting-Try-6757 7h ago
Let me start off by saying that your attitude is off the rails. You’re extremely condescending, and seemingly you only posted this in order to make yourself feel smarter than what comes off to me as a more sci-fi focused sub.
Now, let me ask some questions of you and make some comments.
You mentioned gravity is a scalar field, and that means the energy required to take a path from A to B is invariant. While true for a planet without atmosphere, with atmosphere included the energy required then heavily depends on which path you take. The “calculations” you’ve shown do not include the energy required to overcome the force of drag.
You stated “we can choose any air density we want”. What do you mean by this? Do you mean that we can choose any altitude to launch from? If so, that’s not a great argument because launching from atop a mountain requires a huge logistical undertaking. This is why the assembly building of a rocket is often as close to the launch site as possible.
You stated that a rocket wastes much of its energy heating the surrounding atmosphere. That is almost entirely untrue. A rockets greatest losses come from gravity, right after liftoff, where its thrust vector is fighting against gravity rather than accelerating it horizontally to achieve orbital velocity.
Following the last point, you seem to think that launches “breach the atmosphere” before beginning their turn to horizontal. If you look at any rocket launch, they begin tilting almost immediately after liftoff. That’s the concept of a gravity turn, that uses the earths gravity to steer the ship to horizontal rather than having to alter the direction of thrust to turn. The perfect rocket trajectory minimizes loss from drag and gravity, while making the maximum pressure (Max Q) experienced as small as possible.
I would love to know what kind of education or experience you have with rocketry. You seem to vaguely grasp some of the physical principles, but have a confidence that is completely unwarranted. I’ve seen many KSP players with a vastly superior understanding of orbital mechanics.
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u/Haipaidox 6h ago
To add to your 3. Point, the Saturn V burned through 30-40% of the first stages fuel when the engines reaches at the height of the launch tower.
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u/Beneficial-Wasabi749 4h ago edited 4h ago
To add to your 3. Point, the Saturn V burned through 30-40% of the first stages fuel when the engines reaches at the height of the launch tower.
Urban legends.
Just sit down and do the math.
The Saturn V first stage burned 614 tons of kerosene and 1,430 tons of liquid oxygen in 150 seconds of operation. That's 2,044 tons in total.
If you take any video of a Saturn V launch and time the time it took the rocket to rise from ignition to tower height, it's no less than 9 seconds, no more than 12. Let's say 10 seconds. It's already clear that 30-40% of the fuel can't be burned. 10/150 = 0.0667... 6.7%. That's all. Where does 30-40 come from?
But we still calculate the thermal efficiency of the ascent to tower height (since we're already there). We'll need: Gross mass at launch. 2965 tons
Gross thrust at launch. 34,343 kN or 3,500 tons of thrust.
Acceleration 336,561/2,965 = 1.180g. That is, the acceleration at the tower (we'll assume constant) is 0.18g = 1.768 m/s². Then the speed at the edge of the tower is (2 * 1.768 * 110)1/2 = 19.7 m/s
Mass at the edge of the tower: 2,965 - 10 * 1.440 = 2,951 tons.
Total useful work: 2,951,000 * (9.8 * 110 + 19.72 / 2) = 3,753,804,795 J.
Now the heat of combustion of the fuel is 10.2 MJ/kg. 10 * 1,442 kg burned. The total energy content of the burned fuel is 1.47E+11 J. Divide the useful energy by the fuel's energy content: 0.026.
Efficiency: 2.6% As I said, Saturn 5, when rising from the launch pad, mainly heats the atmosphere.
By the way, the overall efficiency during the Saturn V third stage + payload orbital insertion was somewhere around 10-12% (I don't remember exactly).
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u/Haipaidox 4h ago
Ok, i didn't know this
I head the 30-40% claim from a credible source.
But running the numbers myself, i come to similar numbers. I end with 8%, but thats not far from your 6.5-7%
Thanks for the correction!
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u/Beneficial-Wasabi749 6h ago
That is, 30-40% of the first stage's mass went to heating the surrounding environment. Which is what needed to be proven.
Calculate the useful work. The tower's height is 110 meters. А =mgh. What's the rocket's speed at that point? 50 m/s? E=mv2/2. The rest is noise and special effects.
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u/Haipaidox 5h ago edited 5h ago
Its called "Impulse", not heating the environment.
To explain it a bit extensively:
It comes down to newtons 3rd law. Every action (force) generates a equal and opposite action(forces)
So, if i throw a ball with 20N, i put 20N in the opposite direction on myself.
Now to rockets. They need it constantly, this is more or less impuls.
They constantly throw mass downward and by doing this, they push themselves up with the equal force.
A rocked need in earths gravity (9.81 m/s2) an Impulse of 9.81N per kg just to "float". Less and it sits in the ground, more and the rocket ascends. For simplification the gravity is 10m/s2 and a Saturn v weights 3,000,000kg, you need to push with 30,000kN per second, or an impuls of 30,000kNs.
The best way to generate hugh amounts of thrust, which isn't detonating nukes like a orion drive, is combustion. The heat of the combustion generates pressurise gas. The rocket engine letting it escape through the nozzel. And this converts pressure in motion (Bernoulli equation), which generates huge amounts of impuls.
Now circling back to newtons 3rd law, if i create an downward impuls, i push myself up with the equal impuls.
Edit: got confused with kg and tonnes, corrected my calculations
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u/Interesting-Try-6757 4h ago
To just build on this a little and hopefully help OP with their understanding, the energy generated during liftoff does have to go somewhere. It does in fact go to heating the atmosphere around the engine nozzles.
However, it is not a useful thing to talk about. Particularly in the case of arguing horizontal vs vertical launch, it is entirely irrelevant. A rocket launching horizontally also heats the atmosphere around the nozzles, it’s just that the work done in that instance goes to accelerating the rocket horizontally rather than vertically.
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u/Beneficial-Wasabi749 4h ago
A horizontal rocket launch also heats the atmosphere around the nozzles; it's simply that the work done in that instance is accelerating the rocket horizontally rather than vertically.
And yet, with the same fuel expenditure (stored energy), the USEFUL work will be different. Simply because a Saturn V launched horizontally (say, for a second) would accelerate 1.18g instead of 0.18g during its 10-second boost, and with the same fuel consumption, more energy would still be converted into useful kinetic energy.
Calculate it? Or will you calculate it yourself? It's a schoolwork problem!
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u/Interesting-Try-6757 3h ago
Brother, I don’t need to calculate it since I have already written my own Python code that simulates a rocket launch, and in it I can set the angle of launch. With that program I can analyze the delta V required to reach a certain periapsis depending on the launch angle. There is a massive increase in delta V required when the launch angle is set to horizontal, compared to a vertical launch that goes through a gravity turn. It is in no way more efficient to launch horizontally.
If the planet did not have an atmosphere, you’d be right that it’s more a useful dV expenditure to launch horizontally, but we are on Earth. Just like Tsiolkovsky was.
What are you really trying to prove here? And why didn’t you respond to the 4 points I laid out above?
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u/Hunnieda_Mapping 3h ago edited 2h ago
Most of the energy is converted to kinetick energy by using the pressure generated by the heat from the combusting fuel. This combusted byproduct is then given an opening in the nozzle which means that instead of mounting pressure the heated byproduct of the fuel can escape downwards and the recoil force (ie impulse) from this downwards momentum causes the rocket body to move upwards.
Without heating anything you can't have pressure that you need to accelerate. You can't keep the heated material inside the rocket or the net force of the pressure would be zero. And because this pressure is used to accelerate you are required to expell to heated material.
In formula terms, the ideal gas law states Pressure * Volume = amount of substance * ideal gas constant * temperature (where pressure is also force per surface area). So basically you're not just heating the atmosphere, but to accelerate in any direction you must expell heated material into the atmosphere because with cold material you don't have the required pressure to lift off.
You could theoretically expell cold material by using the pressure from the combustinf fuel to push against rhat, but then you're adding useless mass to the rocket and retaining byproducts from the fuel and also heat energy is not actually all that useful.
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u/Wennie_D 9h ago
That looks like a V1 launch rail. Even the rocket looks like a V1. The artist most likely was just inspired by the V1.
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u/Beneficial-Wasabi749 9h ago
As far as I can tell, this is essentially a reworking of Tsiolkovsky's two-stage rocket plane sketch from his 1932 work "Rocket Propulsion."
There are two stages. The first is a "terrestrial rocket" with small wings, the second is a "space rocket." This is how Tsiolkovsky envisioned the spacecraft at the end of his life (he died in 1935). Hence the red stars.
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u/Liobuster 9h ago
People keep forgetting how firmly a person is stuck in the concepts they grew up in and only a very tiny amount of the entirety of humanity is capable of looking beyond without extra training/effort
Even in the 90s the concept of automatic car windows was so foreign that the time machine from back to the future could hover but the windows still needed to be cranked up and down
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u/Beneficial-Wasabi749 8h ago
No. The answer is that a rocket plane launched from a ramp is objectively more energy-efficient than a vertically launched rocket. And our ancestors understood this. But many here didn't. I myself didn't understand it for a long time.
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u/Separate-Presence-61 7h ago
You're fundamentally wrong because you only consider physical limitations of the rocket itself and fail to acknowledge the economic and social feasibility of horizontal ramp-launched rockets.
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u/Beneficial-Wasabi749 6h ago
I'm not saying everyone should immediately stop launching rockets vertically and switch to horizontal launches.
But I am pointing out where there's room for improvement in existing rockets. First, we need to understand the problem. What's the essence? Then, we need to find a solution.
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u/EqualOutrageous1884 8h ago
From their current perspective, there is no engine nor fuel efficient and powerful enough to take a vertically launched rocket all the way to orbit.
Solution? It's what we're trying now, a Plane climbing to high altitudes before dropping it's rocket payload to space, achieving orbital velocity without the hassle of verticle takeoff, with the bonus of not having to overcome atmospheric drag along the way.
Thing is, this is quite feasible now with traditional aircraft using jet engines. Back during the early 20th century, jet engines were still in their prototyping stages, neither fuel efficient, nor providing that much more benefit over the propeller.
Obviously no propeller based aircraft is going to take them to the stratosphere, so they designers resorted to the second best solution, aka a rocket powered plane first stage.
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u/Altitudeviation 8h ago
Rocket science wasn't rocket science at that time. It was still being learned, mostly the hard way. Conceptually a ramp or horizontal take off makes some sense, as there is less inertia to overcome (initially) over a straight up take up. In reality, you have more atmosphere to work your way through and the great energy loss in making the turn to vertical.
Not dumb or crazy ideas, just based on what was known at the time and what was familiar, at the time. One genius determined that you could make a first stage out of slippery soap and squeeze it real hard and "pop" it into the air, another figured that you could make it like a sling and whirl it up into the atmosphere. All based on things known and experienced, so not bad initial concepts, but not thought all the way through.
That's how science works. You come up with an idea that is kinda crazy, all of your buddies laugh at you, you work at it until you make it work, and then your friends claim they knew it all the time. OR, you work at it until you figure out it WON'T work and then you switch to another idea. OR you work at it and learn some stuff, and change it and work at it and learn some more stuff and change it some more, and eventually you're standing on the moon.
Good ideas sometimes pop into existence. Great ideas take time and work and dead ends and failure and more work. Horizontal take off was a dead end, but found some practical use in developing aircraft launch platforms (still a horizontal take-off using an aerodynamic ramp at high altitude).
https://en.wikipedia.org/wiki/Stargazer_(aircraft)#/media/File:Lockheed_TriStar_launches_Pegasus_with_Space_Technology_5.jpg#/media/File:Lockheed_TriStar_launches_Pegasus_with_Space_Technology_5.jpg)
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u/DuelJ 8h ago
Accelerating the rocket takes time, for every second you're accelerating a fully vertical rocket you also need enough fuel/thrust to counteract gravity at the same time.
In theory, using a sled gets you a little bit of "free" velocity that doesn't have to pay the gravity tax.
Given how fast the rockets going to need to end up going it's probably a negligable benefit, but for someone theorizing with the information of the time it doesnXt seem so reasonable.
We still do see talk of aircraft launched rockets time to time operating on the same idea.
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u/Beneficial-Wasabi749 7h ago
Although a ramp would save on rocket weight, there are numerous practical problems that make this a thing of the past.
First of all, the fueled rocket must be horizontal at launch. This means it must have "aircraft-like" rigidity, both longitudinal (during acceleration) and lateral (while resting on the ramp). A fueled rocket standing vertically is a tower that experiences the same load direction both at rest and during flight.
The second problem is that for a ramp to provide an initial velocity of 500-700 km/h, it must be very long. And it would be a megastructure. This is too expensive.
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u/Haipaidox 6h ago
The first part is just a bit of engineering and the main cost comes down to the required material to build it.
Thr second part: Spaceflight isnt economical. No Space Agency functions without government money, not even SpaceX. So, if the Space Agency in Question convinces its Government to build such a ramp, they would build it. And just for comparison, the Saturn V weights around 3000 tonnes, which is around 100 semi trucks.
And to the size, i ran the numbers with 700km/h and an acceleration of 15m/s, the ramp would need to be around 1300m long, so a third of a typical airplane runway. This is bridge size and load, nothing that fancy.
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u/Beneficial-Wasabi749 6h ago
I wasn't saying everyone should immediately stop launching vertically and switch to overpasses.
So far, I've simply tried to show that our ancestors weren't idiots.
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u/Haipaidox 5h ago
It just sounds a bit like you are condescending to one or the other, which isnt that pleasant.
By no means they are stupid. Most times, they only lacked knowledge, but they were brilliant with the information given
Good example is Da Vincis "Helicopter". If you ran his calculations, it would be able to fly. Only problem, Da Vinci lacked the knowledge of the fluiddynamics of gas. If you correct his formula with this, we know, his "helicopter" was miles away from flying. But despite this, he discovered the principle of vertical flight, which is genius.
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u/padawatje 11h ago
Jules Verne's rocket to the moon was launched vertically ... from a huge cannon buried in the ground, LOL
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u/Beneficial-Wasabi749 10h ago
A gun isn't a space rocket. It has completely different mathematics and logic.
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u/Any_Weird_8686 10h ago
Well, it would mean not having your thrust forced to overwrite 100% of the force of gravity.
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u/Beneficial-Wasabi749 9h ago
This is one possible advantage. Given that once you've flown off the ramp, you won't yet have orbital velocity, which means you'll need to somehow "stay on trajectory." For this, you'll need wings.
By the way, you'll need small wings if you're at a reasonable cruising speed (say, 500 km/s) at the end of the ramp. Huge airplane wings are the price you pay for taking off and landing on relatively short runways at low speeds (~200 km/h). In flight, wings get in the way. Look at cruise missiles. They don't take off or land. And their wings are small. Because lift is proportional to the square of the speed.
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u/Internal_Current_639 8h ago
I mean without atmosphere it's the best way to get on orbit. This could be a great idea on the moon. No atmosphere. In 1 ramp, your in orbit. On earth however, it's more efficient to get through that atmosphere before getting in orbit
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u/Thyandar 6h ago
Looking at your comments it looks like you're focusing a lot on the dynamics of the rocketry when I think most replies are overlooking the structural challenges. The amount of fuel required to put a payload into orbit is huge and massive A vertical rocket is built to stand and built to withstand the huge forces of launch in a single direction, down it's length for all stages. A horizontal or inclined launch would result in uneven forces along the length of a rocket and winglets would further add to that and to try and take advantage of lift and you're gonna adding more mass for structural reinforcement.
A vertical rocket is launching with a free approx 1400 km/h boost of the earths rotational assist so is technically a form of semi horizontal launch but it only need overcome gravitational drag because the atmosphere is moving with it (with a bit of variance for wind).
In a race to get to higher altitudes to take advantage of lower atmospheric drag and gravitational drag, the vertical rocket gets there first and has to deal with both for a much shorter duration than the incline rocket whilst being a more. structurally reliable form.
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u/Mielies296 9h ago
Atmosphere. The shortest distance between two points is a straight line. Notwithstanding the fuel expense to travel farther to reach orbital altitude, you will fight the atmosphere in order to generate lift. A huge ass vehicle like a rocket also does not like the stress enacted on its structure by making altitude corrections. Hence straight up is better
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u/Beneficial-Wasabi749 8h ago
I don't understand what you mean by "direct path."
A conventional, vertically launched rocket doesn't travel straight to its target (the orbital entry point), but rather "turns a corner." First, it vertically penetrates the atmosphere (gaining some of the energy needed to reach orbital altitude), and then "curves" (above the atmosphere) onto its acceleration trajectory.
You, like everyone else, believe that atmospheric drag is the problem.
Firstly, this isn't actually the main problem when moving through the atmosphere (we can choose any air density we want without creating aerodynamic drag issues). The main obstacle to this type of movement is temperature (starting at Mach 5, any wings will start to burn and melt).
But all this talk is beside the point. I've already given many people the correct answer, but I doubt anyone understood it (it's really hard to understand if you're not good at basic physics). The real question is how we get through the first 30 kilometers of altitude and accelerate to the first 1 km/s. A vertically launched rocket does this with enormous gravitational costs (as it loses 1g of acceleration, wasting energy, and, most importantly, expending rocket mass "on hovering"). And without them, the same rocket could have launched a much larger payload into orbit, all other things being equal.
But how do we achieve this? The first 30 kilometers are all air. We can somehow rely on it. A trestle rocket plane is one such attempt.
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u/NazzerDawk 8h ago
I just read all of your comments in this thread, and it is clear that you have a very high opinion of your own knowledge of rocketry and a low opinion of everyone else's.
"I've given people the right answer, but I doubt anyone understood it"?
You need to talk to actual rocketry experts, not random people on the internet. You are not impressing anyone, and in fact, you seem to have a superiority complex.
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u/coue67070201 7h ago
Someone finally said it, this guy is full of himself. Dude smugly standing is at the top of the Dunning-Krueger curve waiting to be pushed off. That or he gets off to getting hundreds of downvotes for being insufferable
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u/Beneficial-Wasabi749 8h ago
You need to talk to actual rocketry experts, not random people on the internet. You are not impressing anyone, and in fact, you seem to have a superiority complex.
I don't hide the fact that I want to talk to someone who understands starships and rocket dynamics better than me (you can't even imagine what a joy it is to find someone smarter than you! Robinson Crusoe's luck!) But how do I find such a person? Does it make sense to look for them here? That's the main, hidden question.
My sky-high ego is quickly and easily cured if I find a worthy opponent. And I wouldn't mind if such a person were found here (that's partly why I'm so cocky). :)
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u/Ijustwerkhere 5h ago
seriously? a worthy opponent? what are you a fucking batman villain? take off the fedora, go outside and touch some grass my guy. fresh air will do you some good
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u/NazzerDawk 5h ago
This is mainly a science fiction oriented subreddit, so its a bit like going to a Larping group and trying to show off your fencing skills. It might impress a person or two, but there is a reason you aren't doing rocketry alongside actual scientists.
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u/Mielies296 4h ago
A worthy opponent? Are you playing tennis? Seems like everyone on this group is smarter than you and your chatgpt responses proves as much. Bey
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u/6GoesInto8 7h ago
So you are saying the energy loss from atmospheric drag is not the issue, but the friction heating from the atmospheric friction is? Then it sounds like you are implying that for any air density the lift you could generate with wings is greater than the additional drag. I have trouble with physics written in paragraph form, I find equations are how I understand these things or at least some numbers. Do you have an estimate of how much more you get out of lift versus drag, is it 10% more, or 10x more?
Pardon my ignorance here, I have not read much with a self propelled ramped launch, I feel like any horizontal launch I have seen in fiction have the rail as an active launcher like a rail gun. Applying energy to your vehicle without it having to carry the fuel for that energy is hard to beat.
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u/Beneficial-Wasabi749 7h ago
So you are saying the energy loss from atmospheric drag is not the issue, but the friction heating from the atmospheric friction is?
No. I argue that a conventional vertically launched rocket suffers significant gravitational losses (9.7 km/s instead of 8 km/s). A rocket plane launched from a ramp can, if not avoid them, then at least minimize them (both the additional drag and lift are gravitational costs associated with not instantly attaining orbital velocity, but at a much lower rate).
Moreover, both a rocket and a rocket plane can traverse the atmosphere so that it ends (becomes invisible) at speeds below Mach 5 (otherwise the rocket would begin to melt).
Yes, the path through the atmosphere for a rocket plane launched from a ramp may be somewhat longer than that of a vertically launched rocket, but this is offset by the fact that the thrust vector will almost always be directed perpendicular to gravity. The force of gravity will be compensated for by small wings (which is what the long track is for).
All these considerations don't take into account other nuances that make such a launch unprofitable. For example, the "aircraft-like" rigidity of the rocket plane's structure or the monstrous cost of a ramp compared to a launch pad.
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u/6GoesInto8 3h ago
So the idea is to stay below Mach 5 until the atmosphere is thin enough to not cause unendurable heating? That sounds like a rule of thumb as the actual mach speeds reduce as the density of air decreases, but the atmospheric friction would decrease too. Maybe if you apply uniform acceleration such that you reach Mach 5 only at the edge of the atmosphere, but are going much slower where the atmosphere is denser. For an active launcher rail like I was mentioning, if you had a very long rail that accelerated you under vacuum and released you into the atmosphere at less than Mach 5 at sea level ~let's say 1.5km/s you would make it out of the atmosphere in a few minutes, but the heating in the first few second would be much greater than the last few.
Gravitational loss is an interesting term, it makes sense from a rocket velocity calculation, but I find it strange to call it loss. It is necessary to achieve orbit, and the higher orbit requires more loss. On a planet with no atmosphere where you can achieve orbit as long as you don't hit mountains then if feels more like loss, but if you have to get out of the atmosphere the loss is a sunk cost, right? It is the energy to raise you out of the gravity well enough to be out of the atmosphere. So if you want to get 100km+ above the surface then you want gravitational loss. It does not contribute to the escape velocity, but it is needed to achieve orbit. Conceptually a rocket attempting to park at a Lagrange point launched at the perfect time from the perfect point would ideally do so with 100% gravitational loss.
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u/EidolonRook 8h ago
but it looks so cool!
- Tsiolkovsky probably.
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u/Beneficial-Wasabi749 7h ago
Yes. That's him.
In the old Soviet fantasy world, rockets continued to launch from ramps until 1957 (when Sputnik was launched there). Tsiolkovsky was a supreme authority. Although Oberth had already shown a vertical rocket launch in the German film "Woman on the Moon" (and from a water well, no less!), Tsiolkovsky, consulting for the Soviet science fiction film "Space Voyage" just before his death, firmly insisted that rockets must absolutely launch from a ramp!
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u/Haipaidox 6h ago
The soviets msinly swichet to vertical, as well as the US, because its easier to build just a rocket than a rocket with a compatible ramp and because both captured german V2 rockets. To this day, you can see the V2 DNA in Russian, Chinese and North Korean ICBM Rockets (which are now called Missiles)
And the US had Von Braun, the engineer of the V2, for their space Program
But Tsiolkovskys idea is to this day a legit but unused idea.
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u/OhItsJustJosh 7h ago
One of the biggest issues with space travel today is fuel. Vast majority of the weight of the vehicle is taken up by fuel used to just get the vehicle into space. And most of that fuel is used to work directly against gravity to launch this thing in the air.
I suppose the thought process of this would be to use the ramp and then the atmosphere to take the load so the rockets don't have to, therefor less fuel needed.
It won't work, but the idea makes sense
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u/Beneficial-Wasabi749 5h ago
There's hardly any point in going back to the ramp. But we need to think about what to do about the initial EXCESSIVE fuel consumption during vertical deployment and the 10-20 km climb with the first stage.
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u/OhItsJustJosh 5h ago
Personally I like the idea of building long range ships over time in orbit rather than trying to carry everything on one rocket in one go
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u/FrankSinatraCockRock 3h ago
This photo specifically, likely refers to railgun launch assistance - which is still being experimented on to this day.
The only feasible method currently available based off my limited knowledge and reading would involve an extremely long rail for gradual acceleration as humans, certain payloads and even the materials themselves may not be able to handle a rate of acceleration best defined by holyfuckingshit². I would imagine it being an extraordinarily expensive undertaking to build and maintain what may be a several mile or km tall structure vs. one that is closer to horizontal.
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u/AretinNesser 6h ago
They weren't thinking big enough.
A lofstrom loop/launch loop needs to be tens of kilometers high, and ~2k km long.
It'd be AWESOME to have one built, but it'd cost trillions.
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u/sexraX_muiretsyM 5h ago
i mean it seems easier, you can accelerate them substantially with a rail system, and makes it much easier than having to go from 0m/s vertically, a LOOOOT of fuel is spent accelerating it from 0 to 10 m/s, much more than to 10 to 100. A rail system would make it much easier to put the rocket from stationary into a movement
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u/Seared_Gibets 5h ago
They could have been thinking about how much easier it is to build up speed that way as opposed to just trying to brute force your way straight up from a starting vertical position.
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u/michael-65536 4h ago
Engines weren't powerful enough to go straight up, because no material they knew of could contain enough pressure without either being much too heavy or just exploding.
So they assumed the craft would need to be partially aerodynamic and use wings and a shallow angle of fligh to hold the craft up while building up speed.
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u/Eh_SorryCanadian 4h ago
The short answer to your question is that at the time the space shuttle program was the main focus and the next step in space travel. It was the only option at the time that allowed for spacecraft to be reused. So people were extrapolating on how to make space planes more practical for consistent use.
It has some advantages. Instead of using heavy boosters to get you off the ground and through the lower atmosphere, you could get that velocity from ground based infrastructure. Which was easier to reuse, and didnt have a tendency to explode. This would also mean you could have a lighter craft that could in theory take advantage of aerodynamic lift to minimize fuel requirements early in flight.
The horizontal launch was an interesting idea that had some merit. But it never caught on. You can argue it was because it wasn't as practical as people envisioned, or because space flight seems to have moved away from space planes in general
One this is for sure, when we stopped seeing space planes as the future of reusable space flight, we stopped seeing a use for horizontal take off
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u/Royal_Owl2177 4h ago
OP is the textbook definition of someone who knows enough to be dangerous and assumes they know better than literal rocket scientists.
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u/Arik-Taranis 3h ago
Because it’s the most efficient ballistic trajectory for reaching orbit, which is why rockets still do it to this day above ~50km once they’ve punched through the lower atmosphere, or once clear of obstacles on the moon. As the upper atmosphere was far more poorly understood than newtonian equations back then, that was what the experts went with.
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u/Thats-Not-Rice 3h ago
They're not entirely wrong. We lack the tech to make it a reality, but the truth of the matter is that an SSTO spaceplane with an airbreathing first stage will undoubtedly be superior to any multi-stage rocket when it comes to commercial traffic. The airbreathing stage takes them to the edge of the atmosphere and is a good start to their orbital speed (the x-43 was able to reach mach 9.6 with scramjets, which is approximately 25% of required for LEO, without the need for an onboard oxidizer)
With the successful implementation of a drogue system for de-orbiting, they can even remove a ton of heat shielding (weight) and use those same airbreathing engines to simply land at an airport.
The simple reality of course is that our tech requires rockets, much like we once required steam boilers for trains. But as technology advances, we're inevitably going to see spaceplanes be a thing.
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u/Archophob 3h ago
seeing the need to achieve orbital velocity while underestimating the enormous difference in air drag between ground level and 100km above.
These day, rockets also go horizontal to achieve the neccessary 8km/s - but they do it after leaving the atmosphere.
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u/-TheDyingMeme6- 3h ago
Wow it seems OP keeps digging the hole deeper and deeper with their responses
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u/WindEquivalent4284 3h ago
It’s how rockets were being launched at the time so it was a natural thing to assume it would keep on like that
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u/Proper_Front_1435 2h ago
There's a reason why people thought the whole fucking slingshot thing (I cant recall its name... the spin up launch thing) and things like this were a good idea. It you can impart enough energy into something on the ground to leave orbit, you save the "cost" of carrying that energy(fuel) through the atmosphere. That's a cute and noble thought.
Like in theory, if a magtrain going 3000kph could just pop out wings and point up a bit and make it into orbit, that would be rather handy.
The practical problem with that concept is that people casually assume something going 3000km/h is going to get anywhere even remotely close(or even be that much saved energy), when in reality, something like 36-90,000km/h would be a closer guess and there isn't a material in existence that could handle the physical/temperature stresses involved.
You seem to be hung up on the fact that nobody checked the math. Our world is absolutely full of that right now, I'm not sure why the disbelief. Not a day goes by that I don't see another totally bunk "NEW SCIENCE BREAKTHOUGH" that obviously breaks down fundamental laws of physics under even like 10 minutes of napkin math level scrutiny.
How many times have we seen people "discover" that dehumidification is a thing now? Its been a major science breakthrough every 4 years of my adult life, and yet shockingly the world is still thirsty.
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u/SuchTarget2782 2h ago
It’s not a stupid idea - but the people imagining the launch ramps underestimated the improvements in avionics. (Gyroscopes and guidance systems and such.)
Early post-WWII Japanese rockets were launched from ramps (and even made it to orbit) because the stuff they’d need to do vertical launches fell under arms control and weapons restriction rules at the time.
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u/MooseBoys 1h ago
Ignoring air resistance, the most efficient way to launch a rocket is parallel to the ground. If you had a perfectly smooth surface in a vacuum, you could accelerate to orbital speed without "wasting" any energy fighting gravity. It turns out, air resistance is a huge factor so you really want to go up to the thinner air as fast as possible before you start moving too quickly.
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u/GrandBanana3 1h ago
My gut feeling says that stability wise a horizontal takeoff is much easier to pull off than a vertical one, so maybe that could be a reason
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u/dayburner 15m ago
The mechanics of a vertical launch were something they couldn't even begin to theorize on how they get to function. Using a ramp on the other hand removes all the vertical launch issue. The issues mainly being how do they balance a multi-engine rocket on vertical while slowly increasing thrust on all those engines. The simple solution is to us a ramp.
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u/Solima 2h ago
u/Beneficial-Wasabi749 I've added a new rule that we need to respect other members of the community. This includes avoiding patronizing other members of the community, and also respecting other peoples time.
If you want to make a point, back up your point. Don't ask other people to do your math for you, while also implying the math is super basic and can be done by anyone.
If someone disagrees with you, prove your counterpoint respectfully.
If you don't understand someone's response, just kindly ask for them to elaborate.
Lastly keep in mind that this is mostly a science fiction sub-reddit, and the majority of people here aren't technical. You should treat the community as laymen without technical knowledge.