Does Rocketry Work beyond Earth's atmosphere?

If NASA faked the moon landings, does the agency have any credibility at all? Was the Space Shuttle program also a hoax? Is the International Space Station another one? Do not dismiss these hypotheses offhand. Check out our wider NASA research and make up your own mind about it all.
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Flabbergasted
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Re: Does Rocketry Work in the Vacuum?

Unread post by Flabbergasted » Wed Aug 05, 2015 7:23 pm

I, Gestalta wrote:It would be an attempt at creating a combustion reaction with lesser and lesser degrees of oxygen.
I was going to answer, but rusty beat me to it :)

Rocket fuel requires no oxygen (or atmosphere) for "combustion". It does however require a combustion chamber sealed off from the environment (in this case, space vacuum), or else the fuel/gas will instantly expand into "infinity". I am an ignoramus in rocket science (whatever that is), but the question seems to hinge on how the nozzle/valve can keep the combustion chamber tightly sealed while hurling out the exhaust at many times supersonic speed AND producing an insane recoil effect in a specific direction.

I, Gestalta
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Re: Does Rocketry Work in the Vacuum?

Unread post by I, Gestalta » Thu Aug 06, 2015 3:32 am

Well, yeah, we've been over the absurd "nozzle" nonsense again and again, I feel. I hate even thinking about it, because it sounds like such a Deus-Ex-Machina copout, the likes of which would be employed by Tolkien, or old episodes of Star Trek: Voyager---"Oh, we cannot understand their language? Hmmm. Well, 'just remodulate the universal translators', Janeway said". I guess I digress.

The ultimate goal of what I am proposing is that, first, we establish the elementary/fundamental point that gas cannot perform work in a vacuum.

While I already believe that it makes absolutely no sense for an object to be able to propel itself by pushing against itself, the experiment(s) might greatly benefit from creating an engine (and environment) as close to what we are given by NASA as possible.

Perhaps I am mistaken, but it might seem that one way to deal with the problem of the thrust reacting with the internal shell of the sphere would be to make our makeshift rocket very small by comparison to the volume of the sphere, thus allowing us a wider berth to account for things like d=rt, etc.

Question is, how much actual sense does this "nozzle" malarkey actually make from an engineering perspective?

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Re: Does Rocketry Work in the Vacuum?

Unread post by omaxsteve » Thu Aug 06, 2015 2:44 pm

I am just curious as to how, and why, we are certain that there even is a "vacuum" in (outer) space.

Is it simply taken for granted, or has there been any concrete evidence put forth of the lack of "earth like" atmosphere above the Karman line (100 km above sea level)?

regards,

Steve O.

"when everyone is thinking the same thing, chances are no one is thinking at all"

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Re: Does Rocketry Work in the Vacuum?

Unread post by brianv » Thu Aug 06, 2015 3:02 pm

omaxsteve wrote:I am just curious as to how, and why, we are certain that there even is a "vacuum" in (outer) space.

Is it simply taken for granted, or has there been any concrete evidence put forth of the lack of "earth like" atmosphere above the Karman line (100 km above sea level)?

regards,

Steve O.

"when everyone is thinking the same thing, chances are no one is thinking at all"
Indeed Steve. It has even crossed my mind that "space" could be an abstraction - the product of our brains and some sort of collective consciousness that keeps us all on the same page. The clowns would have us looking trillions of miles away when all the answers lie within us, wouldn't they? Like has any one of their "missions" brought back a jar of "space"? They claim it has a "fabric" so it must be collectable.

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Re: Does Rocketry Work in the Vacuum?

Unread post by I, Gestalta » Fri Aug 07, 2015 12:04 am

I am of the same opinion, actually, and I do not accept at face-value that space is simply a vacuum. If it is, or something similar, fine. That's great. It really means nothing to me either way. Nevertheless, yes, it's kinda easier to take "vacuum" for granted, even though we all employ a certain level of skepticism toward what I would call the scientific establishment ::coughs:: dictatorship.

However, being that it is supposably (not supposedly) observable that oxygen levels and air pressure are significantly decreased to extreme levels even at an altitude as low as the peak of Mount Everest, I don't think it's wholly irrational to, for instance, infer that an exponential jump from that altitude will most likely result in a still more significant reduction. While I have not taken these readings, myself, they're reasonable to me.

If at any point it seems as though I am writing from a place of what appears to be foregone conclusions, I assure you that this is not the case (for most subjects, that is). If I've learned anything from the past 3 years of reading and interacting at Clues, it is that there is always room for doubt and self-debunking, so to speak.

So, all of that said (and perhaps quite unnecessarily so), I'm just trying to think of ways to replicate NASA-ish conditions to run NASA-ish simulations, instead of resigning myself to the idea that these people are super-intelligent geniuses whose scientific throne will be usurped by no peasant/goyim.

The curiosity is so...irksome that it almost burns, in a way.

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Re: Does Rocketry Work in the Vacuum?

Unread post by ICfreely » Mon Aug 10, 2015 6:05 am

Interesting musings all-around from I, Gestalta, omaxsteve, Flabbergasted, rusty, pov603, hoi.polloi, Kham, Farcevalue and simonshack. I found the following statement from brianv very intriguing.

brianv wrote:It has even crossed my mind that "space" could be an abstraction - the product of our brains and some sort of collective consciousness that keeps us all on the same page. The clowns would have us looking trillions of miles away when all the answers lie within us, wouldn't they?

I have to hand it to you brianv, I admire your no-nonsense straight-to-the-point communication style. In two short sentences you managed to convey the sentiments I’ve struggled to convey in 70 posts. I, Gestalta’s inquiry (and your response) also piqued my interest.

I, Gestalta wrote:Finally, what would be the harm in seeing if a flame could be created in an environment which has been entirely relieved of oxygen?
brianv wrote:One of the first "Science" experiments we did as school-children was to put a candle inside a Bell Jar and extract the air. The candle went out.

One of the most memorable science experiments I was introduced to in the 4th grade was the ‘Match and water in a glass’ experiment.

Methods/materials:

1) Fill a small plate with water.
2) Affix a matchstick to a small piece of Styrofoam or wood cork.
3) Place it on the water-filled plate.
4) Light the match.
5) As soon as the match is lit, place a small glass cup (inverted) onto the plate to enclose the floating match.

Observations/results:

The match continues to stay lit briefly. Eventually the flame extinguishes and the water on the plate gets vacuumed into (and remains in) the inverted cup.

Conclusion/explanation:

The gist of how it was explained to me,

“Fire consumes (is fueled by) oxygen. If a flame is deprived of oxygen it will extinguish (i.e. placing a damp rag onto a stovetop fire). Upon being enclosed, the flame initially consumes the oxygen in the air within the cup. After depleting its limited air oxygen supply; the flame ‘sucks up’ the oxygen within the water – thereby causing the rise of the water level within the glass.”

Anne Helmenstine, Ph.D. offers the following explanation,

“The heat of the flame raises the temperature of the gases trapped in the glass, causing them to push outward against the liquid. When the flame is extinguished, the temperature of the gas falls, lowering the pressure and allowing the water to flow into the glass.”

Here’s her YouTube demonstration and chemistry.com explanation,

Fire and Water Magic Trick

full link: http://www.youtube.com/watch?v=hd7vbYzodoo
https://www.youtube.com/watch?v=hd7vbYzodoo

Match and Water in a Glass Science Magic Trick
http://chemistry.about.com/od/chemistry ... strick.htm



If the gasses (air) within the enclosed glass pushed ‘outward against the liquid’ (water) as she claims, then one would expect the water level within the glass to drop. I’m perplexed by her explanation because, IMO, it contradicts the observation. In the dozens of times I've conducted this experiment I've seen no evidence of water being pushed outward. To the contrary, I've only seen water being pulled inward.

Science (as I see it) is about what works! There will always be competing/diverging theories regarding the ‘cause & effect’ aspect of ‘why it works.’ Scientists have a propensity towards blurring the lines between correlation and causation. They have a tendency to, ‘muddy their water to make it appear deep’ (bending reality to fit their theories) in order to distinguish themselves. It’s important to differentiate the ‘what works’ observations from the plethora of ‘why it works’ theories. Espousing particular ‘establishment approved’ theories as eternal truths and proscribing alternative theories leads to circus clown shows – NASA!

Anyhow, I’m also perplexed by how a flame could be created (and maintained) in an environment which has been entirely relieved of oxygen.

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Re: Does Rocketry Work in the Vacuum?

Unread post by brianv » Mon Aug 10, 2015 1:23 pm

ICfreely wrote:Interesting musings all-around from I, Gestalta, omaxsteve, Flabbergasted, rusty, pov603, hoi.polloi, Kham, Farcevalue and simonshack. I found the following statement from brianv very intriguing.

brianv wrote:It has even crossed my mind that "space" could be an abstraction - the product of our brains and some sort of collective consciousness that keeps us all on the same page. The clowns would have us looking trillions of miles away when all the answers lie within us, wouldn't they?
I have to hand it to you brianv, I admire your no-nonsense straight-to-the-point communication style. In two short sentences you managed to convey the sentiments I’ve struggled to convey in 70 posts. I, Gestalta’s inquiry (and your response) also piqued my interest.


Having stood on the shoulders of giants...I have pissed in their ears :lol:

I know all our good readers can use google, but a link might have helped https://en.wikipedia.org/wiki/Abstraction

Xious
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Re: Does Rocketry Work in the Vacuum?

Unread post by Xious » Thu Aug 13, 2015 11:38 pm

It crossed my mind after watching this, that instead of building a big enough vacuum chamber, you just build a big enough rocket with camera and/or measuring equipment.

https://www.youtube.com/watch?v=qY7W3EM ... be&t=2m15s

This one was said to have reached 100,000 feet.

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Re: Does Rocketry Work in the Vacuum?

Unread post by hoi.polloi » Fri Aug 14, 2015 7:47 am

Haha! But Xious — will any of these ever get far above the Karman line before losing their ability to combat gravity's effects? 100,000 feet is about 30 and a half kilometers. This demonstrates that when atmosphere runs out, so does the ability of the rocket to do any work. At best, one could — like a dolphin jumping out of water — shoot it into a near-vacuum for a short time before gravity reclaims it. A big, strong whale could jump a little higher but only technically. It seems to me a more successful projectile height would be reached by something strong but small and lightweight. And even if it could enclose a bit of near-vacuum in a capsule using an automatic process, that container of near-vacuum would have to resist being crushed by atmosphere upon return to Earth. So we can pretty much only presume atmosphere "runs out" as one goes higher, using math.

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Re: Does Rocketry Work in the Vacuum?

Unread post by pov603 » Fri Aug 14, 2015 11:00 am

Interesting how the Earth's realm containing air, wind, rain, clouds etc. became known as the 'atmosphere' [the Greek for vapour+globe = Latin for atmosphaera] only since the 17th century according to google: https://www.google.co.uk/?gws_rd=ssl#q= ... atmosphere thus further 'cementing' the Earth as a globe/ball/sphere, not that it might not be...

Xious
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Re: Does Rocketry Work in the Vacuum?

Unread post by Xious » Fri Aug 14, 2015 6:48 pm

hoi.polloi wrote:Haha! But Xious — will any of these ever get far above the Karman line before losing their ability to combat gravity's effects?
Of course my theory is that it will slow down and/or lose control and cease to work at some point before the Karman line but I would like to see exactly what happens when and where. No more room for doubt from the zealots, if you get me. Then again, you can't put anything past them.
100,000 feet is about 30 and a half kilometers. This demonstrates that when atmosphere runs out, so does the ability of the rocket to do any work.
Do you mean the video in question? If so, I would also like to believe that is what happened when the rocket started whistling and such but I suspect that the rocket possibly just ran out of fuel. I would like to verify that with the launch team.
At best, one could — like a dolphin jumping out of water — shoot it into a near-vacuum for a short time before gravity reclaims it.


I agree but has this test actually been done to verify it? I mean, in public? lol

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Free Expansion of Gas in a Vacuum

Unread post by hoi.polloi » Wed Aug 19, 2015 10:04 am

A test like it could be done. But it hasn't been, or hasn't been released to the public.

Well? Go ahead and get started, if you are convinced it would (ahem) work.

I'd like to review some answers to Boethius' explanation, which are appearing at the Stock Stack Exchange site, which — to me, at least — is indicative of the inadequate explanations for why it supposedly should. The posted question references our own CluesForum thread: http://physics.stackexchange.com/questi ... ion-of-gas
Chris White (my bolds) wrote:If someone ever says "free expansion does no work" all they mean is that it does no work on the vacuum, which is pretty obvious in retrospect. This is because 19th century experimenters and 21st century high schools find it easiest to talk about gas properties in terms of pistons pushing on containers of gas. If the piston is replaced by nothingness, well clearly no work will be extracted from the system.
Credible beginning? The onus of work is on the vacuum instead of the rocket? I am not so sure ...
This doesn't mean the gas doesn't do anything. Think of it this way: First, you have a closed container, sitting in vacuum and containing a gas with some nonzero pressure P inside. The force on the walls is the same in all directions, no matter the shape of the container, but for simplicity you can picture it as a cube with side length s. Each wall will have a force Ps2 pushing on it.
The following is a priceless explanation, worthy of a NASA charlatan.
Now remove one wall.
With what? Oh, well. Now it's easy. Dispense with Ps2. We have physics working one way the first moment, and another way the next, due to the conditions being changed with imagination.
There will no longer be any force acting on it (your "free expansion" principle), but until the gas is fully evacuated there will be a force on the opposite wall. So your container has a net force in the opposite direction from the gas expulsion lasting for some time. Momentum is conserved; rockets work.
— Sincerely (ostensibly), Mister 'Chris White'

Aaaaah. Brilliant.

Step 1. Act as if all six walls are there up until the moment you need the rocket to move.
Step 2. Add fuel from somewhere.
Step 3. Remove one wall from the design but keep all the old physics of the previous design for "some time"!

You've got rocket power! Holy shit.
B)

Unfortunately, for all the prefacing 'Chris White' does, the questions remain: how a wall appears and disappears; or what the reinforced, super strong, but extremely agile, vacuum-proof membrane is made of; whether it takes sufficient time at all for the "combusting" gas to evacuate once the membrane is open larger than a single molecule's width; what those time periods look like; etc. As you can read yourself, he concluded curtly, "momentum is conserved," and, "rockets work." before making this quotable NASA apology:
"One always needs to understand context: What has no work done? Whose perspective says time is dilating? Physics is not about magic combinations of words that one can invoke like some sort of incantation."
One could modify his/her/its/their statement to read something like this:

"Statements are not about combinations of words that one can say."

~or, roughly~

"Shut up, don't think, and let me tell you how it is without needing to actually explain my perspective."

However, a slightly more illustrated (if still inadequate) explanation follows, thanks to 'John Rennie':
'John Rennie' (my bolds) wrote:When you're considering the properties of gases there are often two ways to look at the problem. The first is to use the continuum approximation leading to the usual laws like Boyle's law, Charles' law etc.
... which is probably closer to what we are seeking, but which nobody has produced the formula for yet!
The second is to treat the gas as many tiny particles (i.e. the gas atoms/molecules) and use Newtonian mechanics. In this case I think the second way is to understand what's going on.
In other words, treat us like children who cannot possibly understand the high concepts (that they fail to provide, anyway). Hmm.
The rocket motor burns a mixture of fuel and oxygen to produce a very hot gas. By very hot we mean that the gas molecules have very high random velocities [LOL! Orly? -hp]
aO8hX.gif
This diagram is supposed to show a representative sample of the atom/molecules in the flame. They are all moving in random directions, so the total momentum of all the atoms is going to be close to zero.
... so we're being told to imagine the closed box system given to us by 'Chris White'. But surely, we aren't going to be given the old "switcheroo" explanation again, are we?
This means burning the fuel has not changed its momentum - this may seem a funny thing to say, but bear with me.

If the fuel were burning in a vaccum [sic] the random directions of the atom velocities would mean the ball of atoms expands in a roughly spherical way and the total momentum stays zero. But the fuel is not burning in a vacuum, it's burning inside a combustion chamber:
HdcTg.gif
AAAAAHH!!! They did it again!

Imagine a cup full of water sitting on a table. How does the water get in your mouth without your touching it? It's actually not sitting on the table; it's being suspended in the air, at an angle, and the water is pouring into your mouth right now!

:unsure:

I ... see.

So, again, with illustrations, we're meant to imagine a totally fictional boxed bit of non-vacuum, built strong enough to resist an infinite vacuum, in which the expansion occurs. Then, with no regard as to the construction of this mechanism, we are meant to — once more, like 'Chris White' — picture the structure morphing into something else while preserving the imagined activities of the original!
The reason this matters is that the atoms can't escape to the right or up or down because the walls of the combution [sic] chamber are in the way. So they will bounce around until some random collision (with the walls or other atoms) gives them a velocity pointing to the left:
fgP09.gif
Now, this is novel. The nozzle (formerly imagined as a closed system) won't direct atoms due to its design as a nozzle; it will simply be caused by random collisions between the chamber and by less than half of the explosive force going "right" — which is made evident by all the atoms going to the "left". No mention of collimating parabolas or further dissection of a continuum approximation. Just a box.

:huh:

Presumably, what he/she/it/they means to say is that when the chamber is exposed to vacuum (still waiting for a single explanation as to how that is done) then restores pressurization (an even more physically remarkable feat, if one is to presume the chamber must be constantly in a state of depressurization and repressurization — all from some extremely strong, extremely compressed pressure slowly being doled out from inside the main body of the rocket) the molecules all rush to the vacuum due to free expansion.
So very quickly all the atoms are going to end up with their velocities pointing in roughly the same direction, because at that point they can escape from the combustion chamber and go flying off into space.
Right. So ... this debunks Boethius' explanation ... how, again?
Now let's calculate the momentum of all those atoms. If there are N atoms and the mass of each atom is m and their average velocity is v then the total momentum is now Nmv (we'll take velocity to the left to be positive). The momentum of the fuel before burning was zero, and after burning it's Nmv, so the momentum has changed by Nmv. Conservation of momentum means the rocket must have changed its momentum by −Nmv so that the total momentum change adds up to zero.
Ha ha ha! Right. Because the atoms unattached to the rocket are escaping into the vacuum, that means the rocket must have changed its momentum. Interesting move — swapping the words "spent fuel" for the word "rocket". Still doesn't work, but ...
So burning the fuel and allowing it to escape to the left means the rocket must have accelerated to the right.
Oh sure, it must have! That's what we see in a childhood drawing of flames rushing out the back end of something. So, right. It totally flew in a vacuum. Makes sense.
In other words the rocket engine has produced a force on the rocket, and we've calculated this without needing to think of pressures or other macroscopic quantities.
Ooo. Ouch. The word "calculated" is so stretched here, it's going to need a deep tissue massage after their post.
In fact we can be more precise about the force. If the rocket produces Ns particles of exhaust gas per second then the momentum change of the rocket per second is −Nsmv. Momentum change is force times time, so the force on the rocket is simply:

F=Nsmv

This force is produced simply because atoms moving to the right bounce off the end of the combustion chamber, and hence push the rocket to the right, but atoms moving to the left don't.
- 'John [hobby programmer and photochemist] Rennie'
NFoAF.png
Real professionals! :D

But even on that site of willing believers, you have people asking questions of the so-called explanations given.
Interestingly, the flow will be choked at some point along your hypothetical shaft. I've always struggled with exactly what choked flow means in the molecular model of gases. Nonetheless, you could use your model to justify several aspects of a De Laval nozzle. For instance, the outward facing cone is at least a little parabolic-ish, so we can tell ourselves that rocket engine designs collimate the particles. But that's not the exact same justification as the continuum model. Exactly how you jump between those models is a funny question. – Alan Rominger Jan 7 '14 at 19:38
@AlanSE: the discussion above is highly simplified, but at the end of the day, and regardless of how the rocket engine is designed, the thrust generated is the rate of change of momentum of the exhaust gases. – John Rennie Jan 8 '14 at 7:12
An amateur physicist and his student walk into a bar.
The students says to his teacher, "Uh, excuse me, sir, but on the last test, we were working on rockets and we learned that the momentum was not adequate to propel the rocket at necessary velocities due to the lack of atmosphere. Yet you gave me a bad mark for catching the trick question. How, exactly, did you switch models in the problem from an atmosphere to a vacuum?"
The other replies, "Regardless of how I did it, it is done! It is up to you to figure out how the switch occurred, not to change it back just because you don't like it."
The student replies,"Well, sir, would you get me a beer then?"
The other says, "But didn't you say you were treating? I thought I taught you well."
The amateur physicist student concludes, "You did, sir. If you can't make a rocket fly where you want it to go, you can at least give it a little motivation."

Alternative ending: "... with just a bit of hot air." :P
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Xious
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Re: Free Expansion of Gas in a Vacuum

Unread post by Xious » Wed Aug 19, 2015 2:59 pm

hoi.polloi wrote:A test like it could be done. But it hasn't been, or hasn't been released to the public.

Well? Go ahead and get started, if you are convinced it would (ahem) work.
Great response to White and Rennie, Hoi. I understand your use of sarcasm there but it seems to me that the Truth is your weapon. Anything else is redundant. Sarcasm can only serve to undermine your argument by appealing to the opponents emotions and thereby clouding their judgement, at the least. In this way, you are actually working against yourself. I for one, can not help but respect someone who simply delivers the facts only so I can form my own conclusion.

I myself do not have the resources to carry out the rocket experiment in question but actually, I do believe that it would "work". However, not work in the sense that you are probably thinking that I mean it. I believe that it would "work" in so far as it would settle the argument that rockets do not operate in a vacuum.

If this is Chris White (the debunker), I have to say that I'm not impressed with his response... to say the least. Why use hypothetical situations at all? Since he is convinced that rockets work so well, why not just use the actual working rocket and simply explain what happens as it transitions from atmospheric pressure to near zero pressure?

The fact that NASA has not produced any record of such an experiment should be enough for anyone, especially "Chris White" to be suspicious. Hmmmm.... interesting.

To me, the "Nerd" video says a lot. The balloon car is obviously operating on differential air pressure, moving from high to low pressure. Once the high pressure is negated by the vacuum cleaner hose, it ceases to move. So, in the same way, my "test rocket" would start out moving fine in the atmosphere with its differential pressure propelling it along but as it moved closer and closer toward the vacuum, the differential pressure would decrease and approach zero causing the rocket to slow down, then lose control, tumble uncontrollably, and then simply fall back to earth. At least, this is what I believe would happen. I'm just saying that it would be nice to be able to document it.

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Re: Does Rocketry Work in the Vacuum?

Unread post by hoi.polloi » Wed Aug 19, 2015 4:30 pm

I am skeptical of what you describe as universally effective. Isn't it enough to simply say that sarcasm doesn't appeal to you, personally?

Speaking of saying things we don't mean in order to make a point — Yes, it would be nice to have the thing documented as you claim you want. Will you do it or just talk about it? My guess is, for the time being, just the latter.

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Re: Does Rocketry Work in the Vacuum?

Unread post by Xious » Mon Aug 31, 2015 10:25 pm

The following site has a lot of interesting data regarding the fake lunar missions.

Here is a detailed analysis of a film showing a Saturn V rocket from it's initial launch to 175 seconds into it's flight:
http://www.aulis.com/apollo11saturn_v.htm
Therefore, based on the results of this study, it is experimentally established that:

1) at the 105th second into the flight the rocket was three times behind the stated ascent rate;
2) at the same time (or more accurately, in the interval of 107-109 sec) the rocket travelled nine times slower than it should have done, according to the NASA record.

Did this Saturn V rocket get to the Moon? Based on these experimental results, it must be concluded that such a slow rocket most likely ended up in the waters of the Atlantic. Moreover, it carried no space craft, and had no astronauts aboard.
Update:

I did a bit more searching for info regarding rockets operating in a vacuum but didn't turn up much except this somewhat amusing article which discusses the lack of a blast crater left by the fake lunar lander.
http://www.aulis.com/gashasmass.htm

It touches on rockets in a vacuum but only lightly. Here are some quotes... can you spot the humor?
A portion of the challenge was that the effect of thrust might actually be different in a vacuum than in the Earth’s atmosphere.
Some believe that the gasses expelled forcefully from a rocket engine in a vacuum dissipate or disintegrate into nothingness instantly as they reach the edge of the rocket engine nozzle. If the negative effects of a vacuum were that powerful Earth’s atmosphere would have been sucked into the void millions of years ago. It seems however, that Earth’s gravitational field is sufficient to keep our atmosphere intact.
The shape of the rocket exhaust nozzle is designed to maximize that effect and has the result of forcing the residual gasses in a common direction. Thrust has nothing to do with the effects of rocket exhaust gasses emitted from a rocket engine until those gasses make contact with another mass and impart some amount of kinetic energy on that mass. In this case soft lunar dust.

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