Does Rocketry Work beyond Earth's atmosphere?

[dblitz]

brianv, with all due respect, how can you challenge anyone to describe the behavior of something, and how it interacts with something else if you cannot prove it is there in the first place? Or, in this case, not there. How can you claim to know what characterizes the space between planets and why assume that it is something less existent than what a planet is? What we are discussing is outer space, not 'nothingness,' which has never existed. There has never been nothing.

I don't like the name of this thread, it's a dogmatic statement about a reality with which we have no experience, and I don't think it's worthy of clues forum. Reality is, every assumption in the standard model of astronomy rests on the force of gravity acting on bodies in a vacuum, a set of dynamics that has never been shown to exist outside of a computer simulation.

Much of the micro, atomic and sub-atomic worlds, and the macro, galactic and super-galactic worlds can only be known by analogy. They are understood via mathematics and models that have never been 'proven' by direct observation because you simply cant get that big or that small, you can only describe observations digitally, through measurement, but since very few people can understand the mathematics completely enough, an analogy is used describing a 'force' or a 'law' but it is only a convenience, no such things exist, regardless of how many scientists demand that they become 'truth.'

Regardless of how 'self-evident' the nature of space might seem, it's just another piece of 'common knowledge,' which is what NASA primarily exists to perpetuate.

Who says space is not more dense than our atmosphere? How do we know rockets dont push against some substance that exists between the atoms of atmosphere? The thinner the atmosphere got, the more thrust you would get! Is that what space is, something even more immovable than matter? I'm not saying I believe that, I'm just trying to make you think.

Who says matter is not a vacuum of space?

So my challenge to you brianv, and whoever is responsible for naming and re-naming threads, is this:


Prove a vacuum exists in nature.

Prove Space is a vacuum.


I've been homeless for a while, with only intermittent internet access but I have a new place now so I can post more and make the graphics I need to illustrate my ideas. I want to put a bit of life back into this thread and I'm starting by asking the doubters to question some assumptions about space and energy. I really think space travel is possible (unmanned at least) and a reality, though perhaps not for the reasons you might expect. My new house is number 11, by the way

[Flabbergasted]

There has never been nothing.

I have often argued against the possibility of propulsion in near-zero gravity and near-absolute vacuum, but in reality the entire discussion is based on a false assumption: the existence of "space" as an infinite-while-relative three-dimensional nothingness in which bodies are "suspended" and move, whether it be planets or protons. Due to the appearance of separation between objects in our daily, microcosmic existence, we are predisposed to accept this model, though it cannot correspond to actual reality.

( I did mention this in an earlier post: cluesforum.info/viewtopic.php?f=23&t=1424&start=150#p2380347 )

Space and matter are coextensive. Space does not "contain matter". The "inseparableness" of space and matter, however, does not imply rockets could work under conditions other than those of the atmosphere.

The notion of an infinite and empty manifested nothingness ("space") is an attempt to absolutize the relative, with all its spiritual implications. Something and nothingness do not pertain to the same level of manifestation.

I don't like the name of this thread, it's a dogmatic statement about a reality with which we have no experience, and I don't think it's worthy of clues forum.

On a forum committed to the study of media fakery, you have to take the media´s stories and claims as a point of departure.

[simonshack]

Yes, if the speed of the spring releasing it's energy is the same as the exhaust velocity of Ariane's fuel, 2,400 m/s, the medicine ball will begin to move up, (...)

The key words here are exhaust velocity.

Dear Citronbleu,

I agree that "exhaust velocity" are the key words here and in fact, in a previous post, you asked this key question:

"Now is the fuel exhaust velocity of the Ariane 5 correct?"

To be sure, we have no means of verifying if ESA's exhaust velocity data is correct / truthful. Yet, we may ask ourselves a few legitimate questions - on the basis of what we should expect of such tremendous velocities in the physical world, in terms of acoustics and ballistics.

So let's see: 2400m/s is about 7 times (yes, seven times) the speed of sound. So:

Question 1: Should we not expect some massive sonic boom / shockwave - as the ARIANE 5 rockets get ignited (and any similar, large ESA / NASA rocket, for that matter)?


Oh well - maybe she wears earplugs!

Secondly, I have looked up for comparison (so as to get a sense / perspective of what that 2,400m/s figure entails) the most modern type of armour-piercing projectile, the "APFSDS" (aka "KE penetrator") . These devastating "state-of-the-art" military projectiles (infamously known for containing depleted uranium) do not carry explosives - they only use their kinetic energy to penetrate their (armoured) targets. Here's how fast they can go:

"Typical velocities of APFSDS rounds vary between manufacturers and muzzle length/types. As a typical example, the American General Dynamics KEW-A1 has a muzzle velocity of 1,740 m/s".

Now, this 1,740m/s figure relates to the very top / max velocity of the "KE" armour-piercing projectile as it gets ejected. Once it reaches its target, its speed will be reduced by aerodynamic drag - but it still pierces heavy armour very nicely, it seems. To be sure, intense military research has gone into making these kinetic armour-piercing bullets travel as fast as possible. Yet, the destructive kinetic speed of a "KE penetrator" is - roughly speaking - about 25% slower than the alleged exhaust velocity of the ARIANE 5 rockets.

Question 2: Why can't the military produce projectiles with speeds similar / or higher than ARIANE's claimed "2,400m/s" exhaust velocity?

Question 3: What material are ESA / NASA launch pads made of? Unobtainium, perhaps?

[CitronBleu]

Hello simonshack,

We all know on the forum the value of these purported launches. Nevertheless their authenticity form a different problem to the question of whether the physics upon which they are based are correct, which is the issue we were discussing in the previous posts.

[simonshack]

Hello simonshack,

We all know on the forum the value of these purported launches. Nevertheless their authenticity form a different problem to the question of whether the physics upon which they are based are correct, which is the issue we were discussing in the previous posts.

Interestingly, some physics questions raised on this thread are being discussed at this Physics Forum:

"Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics."

We know, the rockets in space use Newton's 3rd law to increase their velocity and hence move. What I don't understand is how it is possible in space aka vacuum-state without air? From what I know, Joule's "Free Expansion of Gas" says that free-expansion compresses the gas and is therefore "affected" by vacuum so it can't make the rocket move as the gas will have zero press/force. Could someone please explain me how rockets do really work and the above-mentioned statement?

Actually, please have a look at this site: http://cluesforum.info/viewtopic.php?f=23&t=1632

Not: The site appears to include some conspiracy theory thingummies, but made me wonder anyway.

http://physics.stackexchange.com/questi ... ion-of-gas

[dblitz]

Rockets work in a vacuum because rocketry does not operate by pushing against air, or anything else for that matter. A rocket rides the blast wave of an energetic event initiated by the explosive force of the heat generated by the engine. People don't get blown to bits by the air being pushed out of a bomb, they are caught in a wave of space that cannot co-exist with things. Space is not a thing, it's a place. When it's randomized, or heated (same thing, as heat is a measurement of random motion) that which is ordered gets out of the way, or the thing heated is expelled from that locality.

Same as a flame can't coexist with your flesh, a rocket cannot co-exist with the energy expelled from its exhaust, so it escapes as fast as it can. A machine that creates a succession of such waves is called an engine.

Rockets do not push against air, they ride the blast wave of their own energetic event point, limited in scope to determine direction.

They tried to get rid of the aether, but that did away with the very logic of their own physical principles, leading to confusion among researchers.

Edit: punctuation and a bit of grammar.

[simonshack]

Rockets work in a vacuum because rocketry does not operate by pushing against air, or anything else for that matter.

"ROCKETS DO NOT PUSH AGAINST AIR (2)"
NASA keeps denying the existence of air & aerodynamics

Here we go again. It seems that NASA's wackiest claim just won't go away: "rockets do not push against air, whatsoever."

Here's a real, amateur rocket taking off. According to NASA, it does not push against air - at all (???) :
"it is (exclusively) propelled by the recoil effect caused by its fuel being ejected out of its tank":

"Steve Eves and his Saturn5-model amateur rocket launch": http://www.youtube.com/watch?v=uxgMhHOaUSY

Come, come, let's get real - and stop kidding ourselves.

Before we proceed, dear reader, let me ask you to open these two earlier posts of mine in separate windows - for reference:
"The Power of Air" http://cluesforum.info/viewtopic.php?p=2385809#p2385809
"40 MILLION HP - The Wondrous Power of Air" http://cluesforum.info/viewtopic.php?p=2385835#p2385835

Here's a brief summary of the main points illustrated / expounded in those two earlier posts :

A- Air drag increases exponentially with speed. Overcoming air drag is the main opposing force encountered by an accelerating vehicle.
B- To propel a Porsche at 200km/h, its engine will need to use 4X as much horsepower as it needs to travel at 100km/h.
C- To travel at a hypothetical 16.000km/h (max exhaust velocity of the Space Shuttle engines), a Porsche would need 40 million hp.
D- Hence, if we can imagine a rocket's exhaust plume (roughly the same size/ frontal area / Cx of a Porsche) as a steady flow of Porsches pushing against the air below the rocket, it should be perfectly evident that this massive, 40 million hp air-displacing vortex IS THE MAIN FORCE WHICH PROPELS THE ROCKET THROUGH THE ATMOSPHERE :



HOW DO SPACE-GOING ROCKETS REACH "ESCAPE VELOCITY"?
NASA tells us that the maximum exhaust velocity attainable with chemical propellants is 4,4km/s (or 16.000km/h). We are told that the far higher speed of 27.000km/h (the required, so-called "escape velocity") is easily reached because their rockets keep accelerating as they meet ever thinner air resistance (at 100km, air is 2,2 million times thinner than at sea level). Very well, so "less air-drag = faster rocket". But wait: wouldn't also the rocket's thrust force (as illustrated above), in all logic, decrease accordingly?

WHAT ABOUT GRAVITY? DOES IT CEASE TO EXIST AT 100km altitude (aka "the Kàrmàn Line") ?
No - apparently not. A rocket weighing, say, 100.000kg at sea-level - will still weigh 97.000kg at 100km altitude.

MISCONCEPTIONS
"Zero gravity" or even nearly zero gravity is a misnomer, and does not really exist anywhere in the universe. (...) For example, the force of gravity at 100 km altitude in Earth's orbit is actually 97 percent of what it is for people standing on the ground.
http://www.ehow.com/about_4798210_zero- ... facts.html

In spite of this - and amazingly enough - NASA claims that, once their spaceships (Space Shuttle and all) reach "escape velocity" (at around 100km of altitude), they can just switch off their engines - and thereafter keep orbiting indefinitely around Earth "for free", with no more fuel needed ! It is said that, once they exit the atmosphere (above 100km or so) at sufficient speed, they will start 'free-falling' around our planet (at a brisk 27.000km/h). Moreover, once inserted in the vacuum of space, their wondrous spaceships can nimbly maneuver / climb / descend / accelerate / & slow down at will - with utmost precision (for instance, when catching up & docking with the ISS, or when shooting the LEM back up from the moon surface to rejoin the Apollo Command Module, or when deciding to re-enter the atmosphere and return back to Mother Earth...).

I submit that all of these NASA claims are nothing but sheer science-fiction fantasy - and that rockets / spaceships (while working perfectly well within our atmosphere) may not be physically able to surpass the 100km altitude mark - let alone keep orbiting (with engines off) at hypersonic speeds - or much less propel themselves and maneuver in the vacuum of space. In doing so, (please note that I am respectfully observing our ol' friend Isaac's laws) :




I should probably also re-post here this old diagram of mine (based on NASA's own graphics) :

Source of graphics used for above diagram:
http://en.wikipedia.org/wiki/Rocket_engine

[CitronBleu]

I submit that all of these NASA claims are nothing but sheer science-fiction fantasy - and that rockets / spaceships may not even be physically able to reach / surpass the 100km altitude mark

Not even with a Moog valve?

[RaoulMarz]

I have just lost a post that I spend more than an hour one. I guess that is not the first time that this have happened ever.

This will be a more summarised version of my understanding about rocketry in a vacuum, and I will also try to explain a theory on how rockets possibly could work in a vacuum. One of the biggest stumbling blocks in Physics is Newton's laws of motion and in my mind particularly the third law. When googling "Newton's third law incomplete".

http://central.collegeboard.com/apc/mem ... 40921.html I came across a page that states that many students state the third law as "Every action causes an equal and opposite reaction" and because of this then don't apply this law to forces correctly. The author then gives a more comprehensive statement of the third law "If object A exerts a force on object B, then object B exerts a force on object A that has the same magnitude as the first force, but whose direction vector is rotated 180°. These two forces are called an action-reaction pair and are never applied on the same object." To me with this definition we get closer to understanding this law. But I am still not satisfied as what precisely so we consider an object, and also I can envisage more than two objects interacting simultaneously. The reason why I am repeating this, is because the third law is stated by NASA and many science professionals as the reason why a rocket works. Here is the NASA education link confirming this belief. http://exploration.grc.nasa.gov/educati ... ton3r.html. On this page they use Newton's second law to explain how the thrust - a force - is produced and show the well known equation F = m * a. Because of this force we go in reverse using the third law, that infers because object A (hot exhaust gas) exerts a force on object B, then object B exerts a force with same magnitude. Can we really assume the hot exhaust gas is one singular object and can we also assume the interaction is always with the rocket?

Also another term often appearing in rocketry is "thrust". And NASA education once again gives a nice example. http://www.grc.nasa.gov/WWW/k-12/airplane/thrust1.html Within the first paragraph the educators at NASA already confirm that thrust is used to overcome drag or the weight of a rocket. "Thrust is the force which moves an aircraft through the air. Thrust is used to overcome the drag of an airplane, and to overcome the weight of a rocket. Thrust is generated by the engines of the aircraft through some kind of propulsion system." Now a very simple question is that if thrust was impossible to generate, what force would then be needed to overcome the weight of rocket? So it is a matter of the atmosphere is really a hindrance, but yet nice to have because it allows the rocket to create thrust, that allows the rocket to overcome gravity. Okay I know what comes next. Of course what I am saying is correct in layman's terms, but a rocket would still have an easier time in a vacuum, because there would be no drag i.e aerodynamic drag. I would agree, if I can be convinced that object A (the hot exhaust gas collective) interacts completely with object B - the rocket. Or that a fractional part of hot exhaust gas collective interacts with object B - the rocket. But I don't believe this is the case, I can use principle of free expansion why it can't be, but others have already done so in a comprehensive fashion. I don't claim Newton's third law does not apply, I actually insists that it does. My contention is of course that the objects in question are not object A interacting with object B - the rocket. The 2 objects in question really are one gas molecule interacting with another gas molecule. To avoid an attack from some smarmy scientist I will that these separate molecules can no longer be considered a gas. So I will simplify it even to infinitesimal matter instead of gas molecule. So a vast proportion of the "infinitesimal matter" previously knowns as exhaust gas interact with each other on a one to one basis, trying to stick to the expanded statement of Newton's third law as given at the start.

I also have a very much speculative theory on how a rocket could be modified to work in a vacuum. Given my explanation before, I believe a rocket does function in a "fluid-like" medium like the atmosphere. So one needs to carry an "atmosphere" with the rocket. One could entertain the notion that if the exhaust gas no longer "disappears" in the vacuum but is contained somehow, then the rocket would be able to function pretty much the same way as in Earth's atmosphere. I speculate this containment can be through a field, like a gravity field. This exhaust gas, if contained, would be able to form the medium of interaction, or put differently become object B (earth-like atmosphere with different chemical compositon). What is object A then? Object A is the exhaust gas. Crazy!! Yes of course object A (exhaust gas) is not the same as object B (exhaust gas). Object A is pretty much the exhaust gas being accelerated in the vicinity of the rocket nozzle. Object B is the prior exhaust gas released at N instants before, lets guesstimate this as 20 - 50 microseconds before the current moment. Of course if all the exhaust gas is contained then this globular gas medium would just become more dense and heavier. So the containment must be such that the gas molecules must be able to leave the containment field. This would be possible to do by regulating the strength of the field. Coming back to the rocket - the propulsion is due to the pressure differential in this glob in which the rocket resides. So that it implies the high density gas would be in the area surrounding the rocket nozzle, and the lower density gas more or less above rocket nozzle in the direction of the nose cone.

Thanks for bearing with me, I hope my explanations are not too convoluted. I am starting to realise how difficult it is to explain ideas and thoughts, and well done to many of the posters that makes it seem so effortless!

[hoi.polloi]

No offense to your efforts, but please familiarize yourself with the topic and the posts; this point has already been raised and contended in the thread.

[simonshack]

Coming back to the rocket - the propulsion is due to the pressure differential in this glob in which the rocket resides. So that it implies the high density gas would be in the area surrounding the rocket nozzle, and the lower density gas more or less above rocket nozzle in the direction of the nose cone.

Hi Raoul - and welcome to the forum. I will take your questions as an exercise towards perfecting / clarifying my argumentation against the possibility of rockets being propelled in the vacuum of space.

I think that what you're saying is similar to what this self-professed 'rocket scientist' is saying :

KAREN (self-professed rocket scientist of the Straightdope website) - says:

"The truth is that the rocket does have something to push against: namely, its own fuel."
http://www.straightdope.com/columns/rea ... m-of-space

The thing is, what Karen refers to is the recoil effect / or recoil force that occurs in nature when, for instance, you fire a gun: the bullet ( object A ) will exit at high speed from the gun's nozzle - and might even pierce an armor plate - while you ( object B ) will just feel a slight backward jolt in your wrist. The force of that jolt is given by the amount of air displaced by the gunpowder's explosion inside the gun's muzzle - while its energy is obviously proportionate to the bullet's weight / size / mass - AND SO ARE THE RELATIVE SPEEDS of the objects ( A & B ) involved: the bullet (object A ) will travel at maybe 1000km/h - while your wrist ( object B ) will be nudged backwards at, well... perhaps 10 km/h at the most?

Just for once - I'm going to trust Wickedpedia on this matter...

Misconceptions about recoil
Although energy must be conserved, this does not mean that the kinetic energy of the bullet must be equal to the recoil energy of the gun: in fact, it is many times greater. For example, a bullet fired from an M16 rifle has approximately 1763 Joules of kinetic energy as it leaves the muzzle, but the recoil energy of the gun is less than 7 Joules.
http://en.wikipedia.org/wiki/Recoil

Similarly, if you sit in a wheelchair holding a basketball - and throw it with all your strength in front of you (at a speed of, say, 40km/h), this will not propel your wheelchair backwards at 40km/h. Yes, It will make you and your wheelchair slowly roll a bit backwards - but not much.

This is to say that I do not deny the existence of the recoil effect / or recoil force. However, I do not think that - as NASA claims - this effect is sufficient to propel, say, a 100.000kg rocket (still bound by Earth's gravity) at hypersonic speeds - just by ejecting a certain amount of fuel-per-second out of its nozzle. You may argue: "but NASA says the fuel is ejected at the hypersonic speed of 4,4 km/s!". Well, here we have another big problem with NASA's claims - because they also tell us that their rockets need to attain almost twice that speed (the famous "8km/s escape velocity") in order to exit our planet's atmosphere & gravitational pull. So, even if a given, constant mass of fuel is being ejected at 4,4km/s - it couldn't possibly propel the 100.000kg rocket mass at 8km/s !

Here is a diagram to illustrate my points, once again. Hopefully, it isn't too cluttered / unreadable (sorry for the vertical text!) :


(In the right-hand diagram, the puff seen below "A" symbolizes the free expansion of the rocket exhausts in the vacuum of space.
Any gases expelled in vacuum - as of the laws of thermodynamics - will not do any work whatsoever. Even Newton would agree!).

I dearly hope Karen-the-rocket-scientist (of the Straightdope website) will come by and defend her theories - and their website's slogan : "Fighting ignorance since 1973". http://www.straightdope.com/columns/rea ... m-of-space

We (the human species - or any of our gravity-bound objects) have no means to propel our weights beyond the boundaries of the fluids of air, much as dolphins have no means to propel their weights beyond the boundaries of the fluids of water. Squibs (calamari) propel themselves very fast indeed by ejecting water out of their bodies (much like rockets eject hot air from their nozzles), and sometimes, squibs will even jump out of the sea and crash-land upon ship decks. But so far, we don't know of any high-flying, cosmic space-squibs.

[RaoulMarz]

I am derailing myself it seems. Everytime I trust the form editor to make a lengthy post I get logged out when I click "submit" and lose my entire post. Is there a timeout setting somewhere?

I realise I may have repeated a lot of what others have already said. Just to be clear: I don't believe your typical off the shelf rocket works in a vacuum as suggested by NASA. I certainly DO NOT say what this KAREN person is saying. What I was conjecturing about was a theoretical rocket that doesn't exist except in my mind, that is able to create a containment field in the vacuum, that could conceivably function in the vacuum. I am sorry that I was not clear on that, as I believe just as you and the others that the NASA rocket, is an "atmosphere" rocket. My understanding is that it works because of air pressure that "pushes" it upwards, and wouldn't work in a vacuum because there would be no such pressure in a vacuum, because of free expansion. I can't see that what I am writing here is in agreement with NASA's theories on rocketry. To me an area of interest is to refine all the forces at play as a rockets ascends through the atmosphere.

I certainly could have a detail wrong or could not be clear enough in my explanations but I truly do not believe in NASA's or KAREN's theory. To me, a NASA rocket in the vacuum, is like a car that is in neutral and with the parking brakes on and being revved to 5000 rpm but goes nowhere.

[HonestlyNow]

Everytime I trust the form editor to make a lengthy post I get logged out when I click "submit" and lose my entire post.

One way to get around worrying about timing out is to construct your post in Notepad (text editor). (Then copy/paste into Reply box. Make sure to use Preview to help in cleaning up any errors.) This way you can take as much time as you need. Learn the basic HTML tags, too.

[simonshack]

I am derailing myself it seems. Everytime I trust the form editor to make a lengthy post I get logged out when I click "submit" and lose my entire post. Is there a timeout setting somewhere?

Raoul, this may be because of my recent settings limiting to 3 hours the editing of posts. I have now extended it to 10 times as much. Sorry about that.

[hoi.polloi]

Okay, thanks for your clarification Raoul. That is helpful.

As for the problem of messages disappearing: yes, we highly suggest you compose your messages in a separate text area which does not add extra carriage returns. A good program to use is WordPad which comes with Windows. Then you paste this into the content window, and carefully re-read it and edit it to fit the forum. I.e.; use tags, proper carriage returns, a good clean edited appearance and so on. We have suggested NotePad before, but this is stupid because people forget to remove the extra random and obnoxious line breaks and it makes their post indistinguishable from a post we would suspect of being made by a robot.

Also, browsers like Opera and Firefox tend to automatically cache your content such that hitting the 'go back' button in your browser (upon encountering an error) should restore what you were typing.

Finally, you can "select all" and "copy" the content once in a while. This will preserve your last edited content unless your computer freezes or crashes before you post. But the best option is using a separate composing document such as WordPad or a quick "notes" expansion/widget.