Does Rocketry Work beyond Earth's atmosphere?

[MagicFlame007]

Thank you SacredCowSlayer.

Imagine you had to get produce to the market.
You live down in the valley and the market is on top of a hill. Do you hoist it up the sheer cliff face on the one side, or load it on a cart (thus adding the weight of the cart to your burden) and pull it up the winding road on the other side?
Why?
Hint: wheels.

Vertical launches have the following going for them:

1. Fantastic Spectacle.
Who would doubt what NASA says once they saw the awesome power of a Saturn V launch? Even NASA employees woulde be all like: holy hell! Looks like we really are going to the moon then! Looks fantastic on TV too, as you said!

2.To pre-empt difficult questions.
You don't want to have to explain how its possible to launch vertcally from the moon, when you are using a runway, atmosphere and wings to launch from earth.

p.s. love the little tumbling shack!

[MagicFlame007]

To all reading this thread i just want to mention for clarity that I am not necessarily "married" to this idea of a horizontal vs. a vertical launch. Also I did not want to hijack this thread that after all seeks to discuss rocketry in a vacuum. For that reason, I will not be arguing this point too vehemently. Perhaps if it had a thread of its own someone more knowledgeable than me could explain why it makes sense.

However, the reason I even brought it up at all is that it was the one thing that initially set off my "B.S.-o-meter" long before I ever even heard of the whole Apollo-hoax theory. I've turned many a gathering "weird" by even uttering a word about it!

[SacredCowSlayer]

To all reading this thread i just want to mention for clarity that I am not necessarily "married" to this idea of a horizontal vs. a vertical launch. Also I did not want to hijack this thread that after all seeks to discuss rocketry in a vacuum. For that reason, I will not be arguing this point too vehemently. Perhaps if it had a thread of its own someone more knowledgeable than me could explain why it makes sense.

However, the reason I even brought it up at all is that it was the one thing that initially set off my "B.S.-o-meter" long before I ever even heard of the whole Apollo-hoax theory. I've turned many a gathering "weird" by even uttering a word about it!

Well I'm of course no moderator around here, but I don't sense that this particular point derails or "hijacks" the topic in any way. After all, one cannot thoroughly discuss maneuvering through the vacuum without considering how one gets there to begin with. And since NASA brought the topic to us, it's clearly fair and on point to discuss the logic (or lack thereof) of a vertical launch.

I can't think of a legitimate reason to create such intense force and danger that a vertical launch would involve. Unless of course trying to look cool, and like something . . . well, out of this world counts as legitimate.

P.S. Yes the little shack is quite the funny spectacle to be sure. Simon has it posted somewhere which led me to looking for any clip shown by NASA of their oddly named Mercury launches. After a couple of hours I had those three. Time permitting, I just may hunt down any others that could be out there. But I think 3 distinctly different ones make a good enough point.

[MagicFlame007]

To all reading this thread i just want to mention for clarity that I am not necessarily "married" to this idea of a horizontal vs. a vertical launch. Also I did not want to hijack this thread that after all seeks to discuss rocketry in a vacuum. For that reason, I will not be arguing this point too vehemently. Perhaps if it had a thread of its own someone more knowledgeable than me could explain why it makes sense.

However, the reason I even brought it up at all is that it was the one thing that initially set off my "B.S.-o-meter" long before I ever even heard of the whole Apollo-hoax theory. I've turned many a gathering "weird" by even uttering a word about it!

Well I'm of course no moderator around here, but I don't feel at all like this is a derail or "hijack" in any way. After all, one cannot thoroughly discuss maneuvering through the vacuum without considering how one gets there to begin with. And since NASA brought the topic to us, it's clearly fair and on point to discuss the logic (or lack thereof) of a vertical launch.

You're probably correct there.

I'll just add that in my opinion it makes little sense to launch a very massive load (note that to my knowledge - correct me if I'm wrong, the majority of the total mass is made up by the first stage and it's fuel), from it's point of maximum inertia (when its at rest) against the angle at which gravity has the best "leverage" (tangential to earth).

[MagicFlame007]

As I understand it NASA states that rockets work in space because of Newton's third law of motion. It is the action of ejecting particles of fuel from the nozzle of the thrusters that makes the craft want to move in the opposite direction. The fuel is always moving with the craft and is thus always "at rest" in relation to the craft. Whenever a particle is ejected, it imparts an opposing force to the craft. This at least is my understanding of the forces at work.
It must be understood that the ignition of the fuel and the resulting rapid expansion of gasses has nothing to do with how it creates "thrust", other than rapidly accelerating the individual particles in the nozzle. The way a rocket works in an atmosphere is quite different from how it is purported to work in a vacuum! In fact there is no reason it has to be a rocket at all. It might be a pump ejecting water particles (or maybe some heavier liquid like perhaps mercury or something - less volume for the same force).
If that's the case I want to propose a possible design for a space rocket engine: Steam Power!
Huh?
Using steam power in space means you could use a less volatile mix of rocket fuel (or a small reactor) to create steam and then eject the high pressure water particles to create thrust. Since you are bombarded by an un-shielded by atmosphere sun all the way anyway, you might even use a radiator of some description to make more steam and travel for free!

[MagicFlame007]

Actually in retrospect I would appreciate a little input on what I suspect might be a bit of flawed logic in my little story.

In the story I mused that if a rocket did work in space, the "speed limit" would be equal to the velocity at which I could "throw" particles away from my desired direction of travel. Surely if all particles of fuel traveling with me are at rest in relation to the craft (until they are forcibly ejected), I should continue to accelerate as long as I run my engine, regardless of my velocity? In other words, there should theoretically be no limit to my maximum speed (except for amount of fuel left in tank). I am always pushing against the inertia of the fuel particles while the engine is running. The only remaining "speed limits" then must be other laws of physics such as what happens as you approach light speed, which for obvious reasons are hard to fathom.

The rate of acceleration in a vacuum is affected by:
1.the mass of each particle of fuel.
2.the number of particles ejected.
3.the rate of acceleration of each particle as its being ejected.

The nanosecond that particle leaves the engine, it ceases to have any effect on the craft altogether and then, depending on the velocity of the craft and the power of the engine either follows along at an ever increasing distance forever, stays put, or speed off in the opposite direction forever.

To conclude then; if NASA's rockets are so effective in a vacuum (according to them even better than in the atmosphere!) even Juno's 25 miles per second seems a tad slow and don't even get me started on the whole "slingshot" malarkey.

[MagicFlame007]

I've read all the 39 pages of this thread, and, someone please correct me if I'm wrong, I didn't find the escape velocity as an argument.

We all learnt that a rocket has to gain the First Escape Velocity in order to leave the Earth's gravitation. But we don't speak of a truck having to have an "escape" velocity required to climb a hill, or an elevator's "escape" velocity to climb to the 68. floor. The truck and the elevator simply pull/push their way up to the destination. If there was a road, one could rich the Moon by a bike, right?

What is the point of talking about the escape velocity, if not because the pioneers of the rocket science, were aware that the rocket cannot push/pull in the vacuum, so they then concentrated into the rocket gaining the necessary velocity while in the atmosphere, in order to, just by the inertia alone, escape the Earth

Sorry Feblogger, I was meaning to respond to your post sooner as I have also not seen the issue of "escape velocity" mentioned in this thread until you did.
For me this is a glaring red herring too. There can be no such thing, since the earth's gravity does not suddenly cease at a certain distance or velocity, it gradually diminishes as you get further away. I must therefore wholeheartedly agree with you that "escape velocity" can be nothing but the minimum speed (momentum) you must attain while your thrusters still have some "oomph" (inside the atmosphere) to let you coast until you reach your destination, or until you run out of steam and start falling back to earth.
This decisively bolsters my feeling that rocket thrusters must be rather feeble in a vacuum.

[Maarten Rossaart]

MagicFlame007 used the analogy of a rocket launch being like bringing goods to a hilltop market from out of a valley. This image helped clarify a question I have been tossing around in my head.

Any other market you might want to visit (i.e., any other body in this solar system) is up an even higher and steeper hill: namely, the gravity well of the Sun.

According to the Wikipedia article on Escape Velocity, the required speed for breaking free from Earth's gravity is 11.2 km/s. But once one has come free of the gravity of the Earth and the Moon, one is at a place in the solar system (93 million miles from the Sun) where solar escape velocity is still 42.1 km/s. In fact, according to the chart in the Wikipedia article, solar escape velocity does not drop lower than Earth's escape velocity until one is past the orbit of Saturn. If your rocket cannot get you up to escape velocity, you have a long, hot ride to meet old Sol.

https://en.m.wikipedia.org/wiki/Escape_ ... velocities

Perhaps I am wrong, but these numbers tell me that the most powerful stage of a rocket cannot be the first stage. It must be a stage after that, one with the power to accelerate the spaceship to solar escape velocity, which is to say, up a hill with a grade four times steeper than your first hill. Meanwhile, stage one still has the task of getting the whole hot mess out of Earth's gravity well.

Am I wrong, or does this smell like a paradox? My apologies if someone has made this point previously.
MR

[MagicFlame007]

Morning Maarten,
Thanks for letting the proverbial cat among the pigeons! I must be honest; I had not even considered the sun's gravity at all! I slept little trying to wrap my head around the implications.
Do you think then one would be travelling "gravitationally" downhill if you planned your trip so that the moon for example was inetween earth and the moon on the way there and the opposite for your return journey?
Is your mass on earth reduced in sunlight as opposed to nighttime?

[Maarten Rossaart]

Good morning to you, MagicFlame007,

I am no expert in astrophysics. I only know what I read from the experts.

Your first question is not clear to me. You seem to ask if there could be a gravity-assist from the Moon in plotting a course toward an outer planet. I couldn't say. If I understand what I read, it is ultimately not the Moon or the Earth per se whose gravity the rocket must escape, but rather the barycenter of the Earth-Moon system. If so, the Moon is more hindrance than help in the long run.

Your second question is very interesting. I have read physicists online who say that, yes, the Sun does affect one's weight, depending on position in the sky (i.e. is it night or day?). The effect is very small, almost negligible, and other factors (the Moon, air pressure) have a greater (but still slight) effect on one's weight. They also speak of solar tides: the Sun's gravity has a pulling effect on the oceans just like the Moon's, but it is a lesser force.

I cannot reconcile all of this, though, with the claim that the Earth is in orbit around the Sun: that is, we are in constant free fall. As such, with respect to the Sun, we should not experience any weight effect. The only weight we (and anything else on Earth or linked to Earth's gravity and orbit) should experience is due to the gravity of the Earth and the Moon. Think of that airplane, the Vomit Comet, on which Zero-G scenes for movies are filmed. When in free fall on the Vomit Comet, the passengers experience weightlessness with respect to Earth's gravity. In regard to the Sun, the planet Earth should act as our Vomit Comet, and the Sun's gravity should not have a bearing on our weight. How can the oceans (which are likewise with the rest of the planet in free fall around the Sun) experience any tidal effect from the Sun?

I wonder, too, about those Hollywood movies depicting interplanetary travel. The ship spins slowly on its long axis to generate centrifugal force that mimics gravity. But if one is traveling away from the Sun, there is already plenty of gravity pulling you toward the sun-facing side of the ship. You would not need to generate gravity, would you? If anything, you would need some way to counteract the crushing gravitational force of the Sun at the range of Earth orbit. Even at an alleged distance of 93 million miles, the Sun's gravity is strong enough to keep in its firm grasp a massive object moving at the velocity of 110,000 km/hour (namely, the Earth). Once a spaceship has managed to free itself from Earth's gravity well and the blessings of Earth's free fall in orbit, that tiny little ship is on its own to struggle against the Sun's gravity. It would be like swimming out to sea against the tide, only to reach open water and face a tsunami.

Or so it seems to me. No physicist am I.
MR

[hoi.polloi]

Do you think then one would be travelling "gravitationally" downhill if you planned your trip so that the moon for example was inetween earth and the moon on the way there and the opposite for your return journey?

Do you mind please re-reading your posts before posting? This doesn't make sense.

Is your mass on earth reduced in sunlight as opposed to nighttime?

Where is your justification for this question? When was this suggestion ever mentioned?

[hoi.polloi]

As I understand it NASA states that rockets work in space because of Newton's third law of motion. It is the action of ejecting particles of fuel from the nozzle of the thrusters that makes the craft want to move in the opposite direction. The fuel is always moving with the craft and is thus always "at rest" in relation to the craft. Whenever a particle is ejected, it imparts an opposing force to the craft. This at least is my understanding of the forces at work.
It must be understood that the ignition of the fuel and the resulting rapid expansion of gasses has nothing to do with how it creates "thrust", other than rapidly accelerating the individual particles in the nozzle.

I think that idea is flawed. If a particle must eject into a vacuum in some way, can we see and test the precise mechanisms modelled by NASA's diagrams? We keep failing to explain (as mentioned earlier in this thread, multiple times, actually) how the transition from "pressurized chamber" to "pure vacuum" occurs. I don't think NASA/ESA does an adequate job with this explanation either.

[hoi.polloi]

Also, just to continue the comments on official gravity, I would like to request that further discussions on this start using citation. It's getting a bit foggy and cluttered in this thread.

For example, it can be easily discovered where the official stance is on gravity. Even if you are 1,000 km from Earth, which you aren't — and which nobody is, since we apparently cannot leave Earth by the means demonstrated with fake videos and slightly more expensive illusions — the official story says you'd still be feeling a great deal of Earth's gravity.

Of course, it is slightly confusing to think about if you are lazy in your thinking, but to act as if they haven't attempted mathematical/physical simulation/modeling is to act the fool. Please, let's not dumb down the topic unnecessarily. Sorry if I haven't put that in a British enough way.

Now, I agree with your questions. But if you haven't sought your answers from official sources, you're not really directly challenging their information in an effective way. They've been fighting our intelligence for some time. I apologize if this seems hypocritical, but if we post lengthy metaphors I would really want them to come to some sort of sharp critique of official data. Maybe we can start to compare official information that contradicts?

Otherwise, if you're ready for real science against their mountain of bogus data, let's get out our middle-class telescopes, our scratch pads, and thinking caps and start doing that.

[MagicFlame007]

Do you think then one would be travelling "gravitationally" downhill if you planned your trip so that the moon for example was inetween earth and the moon on the way there and the opposite for your return journey?

Do you mind please re-reading your posts before posting? This doesn't make sense.

To my mind it does make sense. If it's so that the sun's gravity vastly "outweighs" that of earth, even out here at 150 000 km form the sun, surely any trip in a direction away from the sun would require a great deal more thrust than one where you travel essentially towards the sun, not so?

Is your mass on earth reduced in sunlight as opposed to nighttime?

Where is your justification for this question? When was this suggestion ever mentioned?

Don't see why I cannot raise a "new" question that had not been raised before. I'm merely trying to get my head around the idea of the gravitational forces existing around nearby heavenly bodies. It clearly greatly affects any possibility of space travel. I do understand that the effect of the sun's gravity on earth is countered by centrifugal force as we hurtle around it at enormous velocity. Although the centrifugal force almost perfectly counters the effect of the sun's enormous gravitational pull, the side of the earth closest to the sun must logically experience more gravity (from the sun) and less centrifugal force (albeit a minuscule difference). I will leave it at that, as the question clearly has little bearing on rocket based travel in the vacuum of space.

[MagicFlame007]

As I understand it NASA states that rockets work in space because of Newton's third law of motion. It is the action of ejecting particles of fuel from the nozzle of the thrusters that makes the craft want to move in the opposite direction. The fuel is always moving with the craft and is thus always "at rest" in relation to the craft. Whenever a particle is ejected, it imparts an opposing force to the craft. This at least is my understanding of the forces at work.
It must be understood that the ignition of the fuel and the resulting rapid expansion of gasses has nothing to do with how it creates "thrust", other than rapidly accelerating the individual particles in the nozzle.

I think that idea is flawed. If a particle must eject into a vacuum in some way, can we see and test the precise mechanisms modelled by NASA's diagrams? We keep failing to explain (as mentioned earlier in this thread, multiple times, actually) how the transition from "pressurized chamber" to "pure vacuum" occurs. I don't think NASA/ESA does an adequate job with this explanation either.

In my opinion it would be unwise to "blanket reject" every claim made by NASA on principle. Claiming that a rocket makes no thrust whatsoever in a vacuum is one such example, as that is simply unscientific and is way too easy for NASA to refute. Making a claim like that only makes one look uneducated which is exactly what NASA and their de-bunkers enjoy.

What happens to the fuel particle being ejected after it leaves the "throat" of the rocket engine has no bearing at all initially (apart from resisting acceleration due to it's inertia), whether it is ejected into a vacuum or not. As a matter of fact it is actually easier to accelerate the particle into a vacuum at 0 atmosphere as opposed to 1 atmosphere at sea level and somewhat less at altitude.

I just happen to believe that a rocket in an atmosphere must make a lot more horsepower as there is a secondary thrust developed when that large volume of gas erupts from the thrusters, pushing air molecules out of the way, particularly when the velocity of the craft is still quite low (similar to how a sports car's acceleration might be rather brutal at first, but then tapers off as it nears top speed).

Just for clarity it seriously pains me to sound like I'm defending NASA, but believe me I have no doubt that they are lying through their teeth when they claim that man will ever walk on the moon, mush less that he did so in 1969!