HAPPY HOAX ANNIVERSARY!!! (Rockets can't fly in a vacuum)

This is in perfect accord with the rocket thrust equation, , used by Robert Goddard, ROSCOSMOS, NASA and Spacex!

Quote from: cikljamas

This, in perfect accordance with Newton's 3d law - what with its notion of "equal and opposite forces".

While it is in "perfect accordance with Newton's 3d law" the differenct between sea-level and vacuum thrust is simple the pressure force term, A_e(P_e - P_o).
That "pressure force term" is clearly a maximum when the outside pressure, P_o, is zero!

Heck, Rab, you are still too urban...

If what you (and NASA) are saying was true, then you (NASA's spokesman) and NASA would be able to logically (mathematically) justify what NASA claims (not me) :
Rocket will perform at optimal (100 %) efficiency at certain (X) altitude which is somewhere in between See Level (Over-Expansion) and High Altitudes (Under-Expansion)!!!
Pe = Pressure at nozzle exit is always the same (more or less)
Pa = Outside ambient pressure is constantly/progressively (one way) changing (inversely proportional) with altitude, that is to say : as the rocket climbs higher and higher, outside ambient pressure is dropping in an irreversible (one way) manner!!! See :

So, as Pa is constantly dropping between See Level and X (optimal) altitude, rocket efficiency is getting better and better, then after passing beyond that X (optimal) altitude, Pa is still irreversibly dropping, but now, rocket efficiency starts to decay, which shouldn't be the case if rocket efficiency is at maximum when the outside pressure, P_o, is zero! You (and NASA) can't have your cake and eat it too!!!

The Matrix is everywhere, it is all around you. Even now, in this very forum. You can see it when you look out your window, or when you turn on your television. You can feel it when you go to work, or when go to church or when you pay your taxes. It is the world that has been pulled over your eyes to blind you from the truth.

And this is the truth : You are a slave, Rab. Like everyone else, you were born into bondage, born inside a prison that you cannot smell, taste, or touch. A prison for your mind. Unfortunately, no one can be told what the Matrix is. You have to see it for yourself. This is your last chance.

You take the blue pill and the story ends. You wake in your bed and believe whatever you want to believe.  You take the red pill and you stay in Wonderland and I show you how deep the rabbit-hole goes. Remember -- all I am offering is the truth, nothing more.

Heck, Rab, you are still too urban...

Hey Jamas, you are still avoiding the question.

Remember -- all I am offering is the truth, nothing more.

Cut the crap. You are not offering the truth. You are offering a bunch of lies and continued avoidance.

If you were offering the truth, you would have answered my question by now.
This continued avoidance shows that you are not offering the truth and instead know you are offering lies.

Again, how does the gas accelerate?
You are yet to even attempt to answer it.
The closest you have come is just saying it will. No explanation of how, or what force is doing it or what second body it is interacting with.

Jack, have you ever seen this :

Thrust=force=mass*acceleration.
Thrust = (mass flow rate) × (exhaust velocity)

NASA SAYS  :

"The physics involved in the generation of thrust is introduced in middle school and studied in some detail in high school and college. To accelerate the gas, we have to expend energy. The energy is generated as heat by the combustion of some fuel."

According to Jack, generated energy (as heat by the combustion) is the force which produces another force (thrust) which is (mass (flow (rate) * (exhaust velocity).

The first force (combustion-expansion-chemical reaction) forces one part of the second force (mass flow rate) to accelerate (which is another part of the second force).

So, we have the first force (chemical reaction) and the second force (thrust).
Now, according to Jack's logic, the second force is not the whole force, but only one part of the second force (mass (flow rate)).

In order to get the entire force (thrust) we need the first force (chemical reaction) which is going to accelerate one part of the first force (mass).

Now, according to Jack, the first force (chemical reaction) is actual-real force, and thrust is only one part of what it really is (mass (flow rate)).

This is how Jack invented something (first force) that can artificially separate thrust (which is actually just one part (mass (flow rate)) of what it really is : (mass flow rate) × (exhaust velocity)) from a rocket.

So, the first body is a rocket, second body is a thrust (which is actually just one part (mass (flow rate)) of what it really is : (mass flow rate) × (exhaust velocity), and the force is actually the first force (chemical reaction) which accelerates second body (thrust) so that we can finally get thrust in it's integrality.

This is an interesting theory (which eventually boils down to nothing more than meaningless wordplay), but it is plainly wrong, that is to say : just one among many classical examples of notorious Jack's stupidities.

Newton's Third Law - Identifying Action and Reaction Force Pairs

A force is a push or a pull that acts upon an object as a results of its interaction with another object. Forces result from interactions!

"When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body."

Jack still hasn't watched this video :

https://www.dailymotion.com/video/x7ga9h2

No, the “second body” isn't the gases...in a rocket launch...the rocket (engine) is the “first body” applying force (expelled gases= thrust= mass flow rate* exhaust velocity) to a second body (ground, then atmosphere).. which “pushes back” with equal and opposite force.. on the first body (rocket) forcing it to go up..

What happens in a REAL and INFINITE vacuum, where there is no “second body” to act upon???

THE ROCKET (ENGINE) = FIRST BODY
THRUST FORCE = EXPELLED GASSES
GROUND/ATMOSPHERE = SECOND BODY

The gas cannot push the ship with the nozzle closed because gas trapped in the combustion chamber does no work but if you open the nozzle all the gas exits immediately before it can push against the ship. Therefore you cannot use gas in the vacuum to power a rocket ship.

This force pushing a rocket cannot be pushing on the inside of the rocket any more than you can push with your feet upwards against the inside of a cardboard box you are within to stop it from falling from a height. It sounds absurd but that is what NASA claims happens in a rocket.

An object sitting on the ground can only move upwards if it is pushed from underneath or lifted from the side/top. Since we know rockets are not lifted , they must be pushed. Therefore the gasses underneath the rocket must be pushing it up and off the launchpad.

An object moving straight up into the air will eventually be pulled back down by gravity unless it is continuously pushed from underneath or pulled from the top/side by a force greater than gravity.

The Expansion produces THRUST FORCE!

What law disables rockets (via expansion) from doing any useful work in a vacuum?

Free expansion!

What makes "the difference" between the Expansion and Free expansion?

Density of air/vacuum!

Why?

Resistance!

What it means?

It means that there is resistance in the air because the air is dense, hence : the air is the second body!
On the other hand, there is no resistance in a vacuum, hence : the second body is missing!

3. Jack, have you ever seen this :

BULLSHIT VS COMMON SENSE

BULLSHIT :

An airplane propeller DOES push against the air and in so doing it DOES impart a reactive force to the plane because the prop is a solid object CONNECTED to the plane.

Rocket exhaust isn’t connected to the rocket so it can’t function as a pushing medium to the rocket as a propeller does.

Rockets move by creating an imbalance of forces within the rocket motor causing more internal pressure in the forward direction and very little internal pressure rearward due to the opening of the rocket nozzle. There is also a secondary forward thrust caused by Newton’s 3rd law as regards the rearward ejection of mass.

That is how rocket thrust works. The continued expansion of gasses caused by burning high energy fuel builds up pressure but the pressure is always lower at the rear of the rocket motor due to the open nozzle. The higher pressure in the forward part of the motor maintains an imbalance of forces so the rocket continues to move as long as fuel is burned.

In addition to the above force there is also some thrust caused by rearward ejection of mass (the exhaust) in accordance with Newton’s 3rd Law.

BULLSHIT VS COMMON SENSE

COMMON SENSE :

I fear we are now arguing semantics instead of physics.

To save time, I will tell you how I interpret Newtons 3 Laws of Motion. If you disagree then there is no longer a reason to continue this thread as we differ on basic laws of physics which won’t be resolved here. If you agree with me, then there is much to discuss.

Let’s start with Newtons 3 Laws of Motion.

Fist Law: For an object to remain as it is, either moving or not, the sum of the forces on it are zero.
Sigma F = 0

Second Law: For a body to accelerate, there must be a force on it.
F = ma

Third Law: For every force in one direction, there is an equal force in the opposite direction.
F1 = – F2 or F1 + F2 = 0

Notice how all of Newtons Laws of Motion contain the term ‘force’. Newton used the term ‘force’ to explain how objects are pushed and pulled in our universe.

This is how I see Newtons 3rd Law applied to rockets flying through our atmosphere:

If a rocket is moving through the air at 17,000 mph in a southwesterly direction, then there must be a force in the northeasterly direction also going 17,000 mph, which is the force produced by the jet engine exhaust coming out of the back of the rocket.

The way you are explaining it, is that molecules hitting inside a chamber are moving the rocket forward, AND the rocket is moving forward. You did mention the perhaps the exhaust might move it forward also somewhat, but Newtons 3rd Law says the forward motion MUST be equal to the thrust only out the back because of the ‘opposite’ direction part of the law.

You can’t have two positive forces. F1 + F2 would then be greater than zero, and that defies Newtons 3rd Law. My point is the exhaust out the back is not the minor part, it is the major part of the force. Newtons 3rd law says it has to be.

4. Jack, have you ever seen this :

So you go and find the "As we shall see latter(sic), maximum thrust occurs when P_e=P_a" and find out what it means.
[/quote]



Let's try once again :

1. When a rocket's combustion chamber is filled with accelerated gas opening the nozzle to expel the gasses into the vacuum of space does not generate a force against the ship. This is due to the principle of free expansion.

2. No amount of combustion or pressure inside the space ship can move the ship until that combustive force or pressure is exchanged with some object, entity, or field outside of the ship (a space ship is a closed system).

3. Based on 1 and 2 there is no way to move the ship by releasing gas and no way to move the ship by keeping the gas inside. A space ship cannot generate force with a gas based propulsion system. Space rockets are the stuff of fantasies not science or physics.

4. Any liquid exposed to a vacuum is immediately converted to gas and any gas is immediately spread out into the void. So any combustion would have to take place in a sealed container and hence not in a vacuum in the strict sense.

5. Contrary to known rocket's trajectories, they need to end up going seven miles per second away from the center of gravity (center of gravity = center of the earth)! (see reply #270)

Regarding the possibility of opening one side of a container, exposing it to the vacuum, while combusting gasses inside the container. In this case we have to consider that combustion can't occur anywhere near the opening because any liquids in that area are being instantly converted to gas by the vacuum and spread out into the void via free expansion. When combustion occurs at the far side of the container the force is going to push the remaining liquid out before it can be combusted. This seems like a terribly inefficient use of fuel as the combustion itself is forcing unspent fuel into space.

Another problem is that gas enters a vacuum at an average speed of about 2,000 meters a second. A 25 meter long Saturn 5 stage 2 fuel tank with over 1,000,000 liters of fuel would have it's contents drained in about 1/100 of a second if exposed to the vacuum of space.

Well, consider this: no honest scientists will deny that, when opening a valve between two containers (one containing air at high pressure - and the other only vacuum) the pressures in the two containers will equalize in a fraction of a second, the vacuum container 'sucking' the air to itself with tremendous, almost explosive force.

Imagine now the high pressure emitted by any rocket from its (always open) nozzle. As it enters the vacuum of outer space, the very same - almost explosively rapid - pressure equalization is bound to occur. The rocket will be emptied of all of its pressurized fuel in a flash - by the overwhelmingly superior power of the vacuum itself. No matter how powerful the rocket (propelled by any fuel known to man / and designed to perform in our 0,001 atmosphere) - the very laws of physics will not allow it to ascend any further into the void of space. It will haplessly tumble back to Earth.

In Summary
1. Without free expansion the rocket exhaust will push against space. And off we go!

2. Objects don't accelerate unless they exchange energy with some other object/field. There are no objects or fields in space (I regard them to be so small/weak as to be virtually non-existent).

Jack, have you ever seen this :

1. Why airplane and ship propellers work differently, but using the same operating principle (NEWTON'S THIRD LAW)?

It's easy to see why there's a difference if we go back to Newton's third law. The simplest way to think of a propeller is as a device that moves a vehicle forward by pushing air or water backward. The force on the backward-moving fluid is equal to the force on the forward-moving vehicle. Now force is also the rate at which something's momentum changes, so we can also see a propeller as a device that gives a ship or a plane forward momentum by giving air or water an equal amount of backward momentum. Sea water is about 1000 times more dense than air (at sea level), so you need to move much more air than water to produce a similar change in momentum.

PUSHING BACKWARD = PUSHING OFF OF

2. Action and reaction

When we talk about jet engines, we to tend think of rocket-like tubes that fire exhaust gas backward. Another basic bit of physics, Newton's third law of motion, tells us that as a jet engine's exhaust gas shoots back, the plane itself must move forward.

PUSHING BACKWARD = PUSHING OFF OF

3. Jet engine is just more efficient than propellers, but the principle of working is the same in both cases : NEWTON'S THIRD LAW!!!

However, if anybody thinks that there's an essential difference (regarding the principle of working) between jet engines and propellers then i would like to see what makes the core of that difference.

You see, we are supposed to believe that there is an essential difference regarding the principle of working between jet engines and propellers, however, such difference doesn't exist in reality.

According to official science, although NEWTON'S THIRD LAW is a common explanation for how propellers, jets, and rockets work, NASA claims that jet engine's principle of working is basically "recoil mechanism" (this is how they are preparing us for swallowing their next lie, which pertains rocket's principle of working)...



4. Inflated 1000 miles up, or 4x as high as the ISS is supposedly orbiting. NASA has stolen hundreds of BILLIONS of unaccounted for dollars, of course the fake photos, film movies, CGI and facilities/airplanes and very overpaid employees etc does cost money but nowhere near that much. Between 2006 and 2009 there are no records of where NASA money went, look that one up. Kinda like the 1 TRILLION dollars Rumsfelds Pentagon "lost" as reported the DAY BEFORE 9-11, look that one up too. In 1932 Auguste Piccard went 10 miles up in a balloon, in 1935 Explorer II went up 14 miles.
ACCOMPANYING VIDEO :
BALLOONS CAN GO UP TO 1000 MILES - VIDEO :
https://www.dailymotion.com/video/x7g9tn0
PROJECT LIBERTY - IT'S ALL BULLSHIT, I TELL YA :
https://www.dailymotion.com/video/x7gbiik

Will Helium Filled Balloons Float or Sink In a Vacuum Chamber :

Jack, have you ever seen this :



To acknowledge the existence of air drag in front of the rocket while, at the same time, deny the existence of the opposite air displacement exerted by the exhaust plume below it - is an utter contradiction in terms and a crude offense to common sense. If this were to be true (that "rockets do not push against air"), this would mean that the formidable, explosive thrust of a rocket's exhaust plume does not encounter any air resistance - a preposterous and outlandish contention, if there ever was one. Instead, as the NASA quackery goes, we are asked to believe that rockets are propelled solely by the "recoil force" generated by the rapid expulsion of fuel mass from rocket tanks. If this were true, we should all hover above our toilet seats when stricken with explosive diarrhea - yet I doubt that anyone has ever had the (mixed) fortune of experiencing such a thrill.
[/quote]

A rocket rising through the atmosphere will nicely proceed upwards in its escape from gravity - as long as certain conditions are maintained: the relative pressures at the rocket's nozzle and the outside atmosphere need to be as equal as possible, in order to obtain maximum 'mileage' / efficiency from the rocket's fuel.

- In fact, NASA clearly states that the optimal running conditions of their rockets occur only ONCE, at a certain unspecified (mid-range) altitude, when the above-mentioned pressures are identical. This, in perfect accordance with Newton's 3d law - what with its notion of "equal and opposite forces". Clearly, these rockets are designed to work best in our earthly atmosphere - and the atmospheric pressure IS in fact "the equal and opposite force" which the rocket thrust pushes against. To deny this fact is pure, outlandish and deceptive NASA hogwash-babble. Ironically, it is NASA itself that claims that their rockets work BEST when those two pressures are equal !

- Aerodynamic drag will of course be a factor in the equation, yet only a minor one - given the pencil-shaped, streamlined vessel. As the atmosphere pressure thins out with altitude, some more speed will probably be gained (out of a given power output) - but this fact would, obviously, have no incidence whatsoever in alleviating the forces needed for the weight of the rocket to escape the pull of gravity.

- Now, as we have previously seen, the atmospheric density range which our spacebound rocket is supposed to operate in, spans from a pressure of 0,001 (the average air density in our atmosphere) to a staggeringly inferior pressure of 0,000000000000000000000001 (the density of space vacuum). Thus, as the rocket climbs ever higher, it will have to exponentially increase its output/thrust (and, of course, its fuel consumption), in order to keep going - and combating the pull of gravity which, contrary to public belief, does NOT decrease exponentially with altitude.

- The rocket (at a given, high altitude which I cannot pretend to calculate precisely) will eventually be overpowered by the force of the exponentially decreasing outside pressure, its fuel being sucked out into the infinite 'vacuum of space' at stratospheric rate/speed - and faster than you can say "Houston-we-have-a-prob...---". Much like a champagne bottle popping its cork here on Earth (due to a minimal pressure difference), the rocket fuel will flush out with explosive force. Moreover, this force will expand in ALL directions (a bit like the diffused spray of your garden waterhose nozzle set on 'broad, soft mode') and provide little or no thrust. The rocket, from there on, will be doomed - and plunge back to Earth.

And for those willing to argue that NASA may have found a way to 'pinch' their rocket nozzles, so that the fuel doesn't get sucked out in a flash : well, you can always open a champagne bottle with great care, making the force inside it fizzle slowly out in the atmosphere. But such a subdued, impotent fizzle would hardly provide the necessary energy to propel a rocket away from Earth's gravity, would it?

Only a pinched fart would produce the same amount of 'power'(odor-power, in this case) as a vigorously expelled bowel-gas sample. We all know that much!

NASA denies that their rockets' propulsion has anything to do with any sort of interaction between their rockets' exhaust-thrust and air/atmosphere. Instead, they appeal to Newton's third law, saying that the exhausts of their rockets push on their own fuel/tank itself - and THAT is where and how the action/reaction occurs. They often compare this with the recoil of a bullet being fired by a shotgun. Of course, this is nonsense.


To attain the so-called escape velocity of 11km/s with "recoil power" only, this is what NASA's rockets would have to do: they'd have to shoot out from behind their rockets, all at once (like a bullet from a gun) a mass equal to the mass of the vessel itself - at a velocity of 11km/s. This means that, if this were to be the case (that rockets move due to "recoil action/reaction")- more than half of any rocket's fuel mass would have to be ejected at that speed - as illustrated in this diagram:




Of course, this is not the case - and would be quite impossible to do. Yet, this is basically how NASA 'explains' how their spacecrafts are propelled through air and vacuum.

Quote from: rabinoz on September 09, 2019, 04:01:47 PM

This is in perfect accord with the rocket thrust equation, , used by Robert Goddard, ROSCOSMOS, NASA and Spacex!

Quote from: cikljamas

This, in perfect accordance with Newton's 3d law - what with its notion of "equal and opposite forces".

While it is in "perfect accordance with Newton's 3d law" the difference between sea-level and vacuum thrust is simply the pressure force term, A_e(P_e - P_o).
That "pressure force term" is clearly a maximum when the outside pressure, P_o, is zero!

Heck, Rab, you are still too urban...

If what you (and NASA) are saying was true, then you (NASA's spokesman) and NASA would be able to logically (mathematically) justify what NASA claims (not me).

I'm not NASA's spokesman! They know nothing of me.
What NASA and I say is true and quite consistent and I demonstrated that with an example.

The maximum efficiency at a given at outside pressure is when the exhaust is equals to that pressure but the thrust penalty for departing from that is not very large.

Few engines are designed to adjust the exhaust to match the outside pressure, though there are a few.
And the Pratt & Whitney J58 jet engine, used in the Lockheed A-12, YF-12 and the SR-71 aircraft, was able to do this.

See below where the sea-level version of SpaceX Merlin 1D sea-level engine produces a vacuum thrust of 914 kN and the vacuum version 934 kN.

Don't confuse non-optimum efficiency with not working. These engines (like you car engine) still work quite well under non-optimal conditions.

Go back and read all that I wrote!

The thrust of a given rocket combustion chamber a nozzle has thrust given by the rocket thrust equation, .
And that clearly shows that the pressure force term, A_e(P_e - P_o) is a maximum when the outside pressure, P_o, is zero!

As I showed in the real life example of the SpaceX Merlin 1D sea-level engine:
This version with a comparatively small bell on the nozzle delivers a thrust of 845 kN (190,000 lbf) at sea-level and 914 kN (205,000 lbf) in a vacuum.

SpaceX also produce a vacuum version of that  Merlin 1D engine:
This version with a bell on the nozzle as large as practical delivers a thrust of 934 kN (210,000 lbf) (in a vacuum).

The sea-level engine can be used all the way from sea level to space conditions but does not produce quite as much thrust in space conditions (914 kN) as the vacuum version (934 kN).

But the vacuum version cannot be used where there is significant air pressure because it can cause severe flame instability.
Not only that but SpaceX use 9 of the Merlin 1D engines in the first stage of the Falcon 9 and the vacuum engines would not fit.

The size of the nozzle bell used on the vacuum version limited by the diameter of the second stage of the Falcon 9 rocket.

Jack, have you ever seen this :

Stop spamming with you same old material! We're sick of it!

Jack, have you ever seen this :

Quit spamming BS and answer the question.
It is a very simple question which if you really were offering the truth you would have no need to avoid.
Yet whenever it is brought up you do whatever you can to run away from it.

Either answer it or tell us why you refuse? Is it because you know it will expose your lies?

Again:
How does the gas accelerate? What force is involved? What is the second body involved?
No need for any other BS, just answer the question.

Quote from: cikljamas on September 10, 2019, 03:36:09 AM

Jack, have you ever seen this :

Stop spamming with you same old material! We're sick of it!

I second this.

To acknowledge the existence of air drag in front of the rocket while, at the same time, deny the existence of the opposite air displacement exerted by the exhaust plume below it - is an utter contradiction in terms and a crude offense to common sense. If this were to be true (that "rockets do not push against air"), this would mean that the formidable, explosive thrust of a rocket's exhaust plume does not encounter any air resistance - a preposterous and outlandish contention, if there ever was one. Instead, as the NASA quackery goes, we are asked to believe that rockets are propelled solely by the "recoil force" generated by the rapid expulsion of fuel mass from rocket tanks. If this were true, we should all hover above our toilet seats when stricken with explosive diarrhea - yet I doubt that anyone has ever had the (mixed) fortune of experiencing such a thrill.
[/quote]

A rocket rising through the atmosphere will nicely proceed upwards in its escape from gravity - as long as certain conditions are maintained: the relative pressures at the rocket's nozzle and the outside atmosphere need to be as equal as possible, in order to obtain maximum 'mileage' / efficiency from the rocket's fuel.

- In fact, NASA clearly states that the optimal running conditions of their rockets occur only ONCE, at a certain unspecified (mid-range) altitude, when the above-mentioned pressures are identical. This, in perfect accordance with Newton's 3d law - what with its notion of "equal and opposite forces". Clearly, these rockets are designed to work best in our earthly atmosphere - and the atmospheric pressure IS in fact "the equal and opposite force" which the rocket thrust pushes against. To deny this fact is pure, outlandish and deceptive NASA hogwash-babble. Ironically, it is NASA itself that claims that their rockets work BEST when those two pressures are equal !

- Aerodynamic drag will of course be a factor in the equation, yet only a minor one - given the pencil-shaped, streamlined vessel. As the atmosphere pressure thins out with altitude, some more speed will probably be gained (out of a given power output) - but this fact would, obviously, have no incidence whatsoever in alleviating the forces needed for the weight of the rocket to escape the pull of gravity.



- Now, as we have previously seen, the atmospheric density range which our spacebound rocket is supposed to operate in, spans from a pressure of 0,001 (the average air density in our atmosphere) to a staggeringly inferior pressure of 0,000000000000000000000001 (the density of space vacuum). Thus, as the rocket climbs ever higher, it will have to exponentially increase its output/thrust (and, of course, its fuel consumption), in order to keep going - and combating the pull of gravity which, contrary to public belief, does NOT decrease exponentially with altitude.

- The rocket (at a given, high altitude which I cannot pretend to calculate precisely) will eventually be overpowered by the force of the exponentially decreasing outside pressure, its fuel being sucked out into the infinite 'vacuum of space' at stratospheric rate/speed - and faster than you can say "Houston-we-have-a-prob...---". Much like a champagne bottle popping its cork here on Earth (due to a minimal pressure difference), the rocket fuel will flush out with explosive force. Moreover, this force will expand in ALL directions (a bit like the diffused spray of your garden waterhose nozzle set on 'broad, soft mode') and provide little or no thrust. The rocket, from there on, will be doomed - and plunge back to Earth.

And for those willing to argue that NASA may have found a way to 'pinch' their rocket nozzles, so that the fuel doesn't get sucked out in a flash : well, you can always open a champagne bottle with great care, making the force inside it fizzle slowly out in the atmosphere. But such a subdued, impotent fizzle would hardly provide the necessary energy to propel a rocket away from Earth's gravity, would it?

Only a pinched fart would produce the same amount of 'power'(odor-power, in this case) as a vigorously expelled bowel-gas sample. We all know that much!

If this were true, we should all hover above our toilet seats when stricken with explosive diarrhea - yet I doubt that anyone has ever had the (mixed) fortune of experiencing such a thrill.

Only a pinched fart would produce the same amount of 'power'(odor-power, in this case) as a vigorously expelled bowel-gas sample. We all know that much!

Hey man, are you okay?

Quote from: cikljamas on September 10, 2019, 03:36:09 AM

Jack, have you ever seen this :

Stop spamming with you same old material! We're sick of it!

I hope you understand how i feel about your ongoing copy paste avalanche.
As others have pointed out, you must have a certain template or maybe some sort of access to a NASA shill centre mainframe that provides all the data you’ll ever need about space fakery and co. 

I really don’t think you are in a position to critisize cikljamas....

Cikljamas - a vacuum does not suck out gas from a vessel.

The gas molecules all have their own velocity which causes them to eventually exit the vessel.

A vacuum just means there is nothing to prevent the gas molecules escaping.

Perhaps if you actually understood basic physics you might understand how rocket engines worked.

Quote from: cikljamas on September 09, 2019, 01:16:23 PM

If this were true, we should all hover above our toilet seats when stricken with explosive diarrhea - yet I doubt that anyone has ever had the (mixed) fortune of experiencing such a thrill.

Quote from: cikljamas on September 10, 2019, 08:03:24 AM

Only a pinched fart would produce the same amount of 'power'(odor-power, in this case) as a vigorously expelled bowel-gas sample. We all know that much!

Hey man, are you okay?

Wait a second..

Aaah....
Now i am okay...
The pleasure of a fart.
the genuine relief of a fart.
the "aaah" says it all, doesn't it?
If you love poetry, i can supply you with some other "fart" (i mean "rocket can fly in a vacuum of space") verses...

More pathetic BS.

Again, no where in that post did you even attempt to address the question.

Why are you avoiding it so much?
Why does this question terrify you so much you need to use whatever tactics you can to avoid it?

Is it because you know that answering it will show you have been lying for this entire thread?
Is it because you know that rockets do work in a vacuum?

Again:
How does the gas accelerate? What force is involved? What is the second body involved?
No need for any other BS, just answer the question.

I hope you understand how i feel about your ongoing copy paste avalanche.

I rarely copy and paste, and when I do, it is just copying a question I have posted here which has gone ignored, or when I directly quote something.
That is nothing like the copy-pasted BS jamas is spamming.
Now do you have anything other than these pathetic insults?

Perhaps you can answer the question?
Tell us how the gas accelerates? Or will you claim the gas is magically held inside on open container exposed to the vacuum of space?

It would be prudent to post the source of you material, which here was, Physics Stack Exchange: Why the exhaust pressure should be equal to ambient pressure?
The form of that graph is similar to what I might expect but I can find no original source of the calculations that went into it.

An answer in that Physics Stack Exchange: Why the exhaust pressure should be equal to ambient pressure? had this expression for the exhaust velocity: .
Where:
        v_e is the exhaust velocity,
      "p₁ is the chamber pressure,
       T₁ is the chamber temperature,
       A_t At is the throat area, R is the specific gas constant for the burned products in the thrust chamber,
       γ is the ratio of specific heats of the burned products in the thrust chamber" and
       p_e is the exhaust pressure.

Other than p_e all the terms in that are either constants or things happening in the combustion chamber

We know that the thrust is given by:
In near vacuum conditions p_e will always be equal to or greater than p_o and so the pressure term part of the thrust is alway a positive component of the thrust.

Note that in the expression for the exhaust velocity the effect of exhaust pressure rapidly becomes negligible when the exhaust pressure, p_e, is much less than the throat pressure, p₁.

And that fits perfectly well with there being little penalty in having a low exhaust pressure but slill greater than the exhaust pressure.

Where is there anything in there that disagrees with anything I said?

I know that the optimum thrust does occur when the (exhaust pressure) equal to (outside pressure) but
I'm sick of saying and demonstrating that the penalty for having (exhaust pressure) slightly greater than (outside pressure) is not severe.

And every reference seems to agree with that and with rocket engines always performing better under vacuum conditions.

<< Previously answered material and trash deleted >>

Quote from: cikljamas

Where is there anything in there that disagrees with anything I said?

I know that the optimum thrust does occur when the (exhaust pressure) equal to (outside pressure) but
I'm sick of saying and demonstrating that the penalty for having (exhaust pressure) slightly greater than (outside pressure) is not severe.

And every reference seems to agree with that and with rocket engines always performing better under vacuum conditions.

You know that the optimum thrust does occur when the exhaust pressure is equal to outside pressure but in the very next sentence you claim that rocket engines always perform better under vacuum conditions in which exhaust pressure is God only knows how much greater than outside pressure which is close to ZERO??

In other words :

Slight overexpansion causes a slight reduction in efficiency, but otherwise does little harm.
However, if the exit pressure is less than approximately 40 % that of ambient, then FLOW SEPARATION occurs. This can cause jet instabilities that can cause damage to the nozzle or simply cause control difficulties of the vehicle or the engine.

You see :
SITUATION No 1 (overexpansion)
Slight overexpansion = Little harm
When Pe is 40 % that of Pa = Very dangerous amount of overexpansion

Now, what happens on the other side of our "equation" (underexpansion)?
SITUATION No 2 (underexpansion)
Slight underexpansion = Little harm
When Pe is MANY, MANY TIMES greater than Pa = Rocket tumbles back to Earth

Now, compare these two situations, and try to use your brain finally!!!!
When i say "compare these two situations", i mean this :
Pay attention that on the first side of our "equation" we have 60 % difference between Pe and Pa, and on the
other side of our "equation" we have TRILLIONS AND TRILLIONS % difference between Pe and Pa!!!

I can only hope that in order to explain this conundrum you wont pull out of your ass some similarly idiotic explanation as you did in this situation (which Lo and Behold pertains exactly this very problem) :

LO AND BEHOLD :

Quote from: cikljamas on July 27, 2019, 06:40:12 AM

Jack, Rabinoz, and co., all you have to do is to put Tom Bishop's argument (Escape Velocity a.k.a. Flight Direction : Strictly Away from the center of the Earth) in this particular perspective :

Rubbish! Your "particular perspective" is totally ludicrous as i show below,

Quote from: cikljamas

DANSITY TABLE :


As you can readily see, the two densities that NASA's rockets supposedly traverse as they rise up to the skies are hugely different.

(Just to put all this into perspective, on the other side of the spectrum we see that a "black hole" - considered by scientists as the highest imaginable pressure known to mankind - is 10 ^+27. In other words, one could say that the density gap/difference between VACUUM <vs> AIR is almost as large as the difference between WATER <vs> "BLACK HOLES". Food for thought, anyway.)

I am not answering all that in one go but first the total misoperation in you "density table". But why on earth do you use those funny cgs units and not SI units?

First of all your "density gap/difference between VACUUM <vs> AIR is almost as large as the difference between WATER <vs> BLACK HOLES" is total garbage!
"Density differences" are quite irrelevant anyway. It is only "pressure differences" that matter though for gasses they are related.

And it appears that you missed out on arithmetic in school because the difference between two numbers say A and B is A - B and NOT A/B.

It appears that you do not know even the simplest rules of arithmetic!
So the difference between (air density) and the (density of free space)  is simply only 10^-3 - 10^-24 = 10^-3 gm/cm³.

As far as a rocket's performance goes or the stresses involved in pressurising a crew habitat is make little difference if the pressure outside is one hundredth or one trillionth of normal atmospheric pressure.

And it makes you claim "In other words, one could say that the density gap/difference between VACUUM <vs> AIR is almost as large as the difference between WATER <vs> "BLACK HOLES". Food for thought, anyway.)" totally ludicrous!

But the density gap/difference between AIR vs VACUUM is just 1 while the density gap/difference between "BLACK HOLES" vs WATER is 10²⁷ - not in the same "ball-park"!.

That doesn't have the emotional impact of your ridiculous and meaningless 10⁶⁰, does it?

But you talk of densities rather misses the point! It is external pressure differences that slightly affect the thrust.

So, what our great mathematician Rabinoz is actually saying is this :

When you subtract 0,0001 from 1, you get 0,9999...Now, since 0,9999 is practically 1, then the difference between 0,0001 and 1 is 1, not 10000!!!

In an example above, according to our Einstein (Rabinoz) the difference between 10^-3 and 10^-24 is 10^-3 because we have to subtract 10^-24 from 10^-3 in order to get the difference... The difference (in literal meaning of this word "the difference") is 10^-3, indeed, but the real question is whether we are interested here in a literal meaning of the word "difference" or are we interested in "for how much (times) one of our numbers (10^-3) is greater than another number (10^-24)?"

So, the real difference between our two numbers (between density of air and density of vacuum) is 10^21 a.k.a. sextillion a.k.a order of magnitude 21.

NASA is no match to our Einstein (Rabinoz)!!!

I rarely copy and paste, and when I do, it is just copying a question I have posted here which has gone ignored, or when I directly quote something.

Why would you answer with "I rarely copy and paste" when the comment was addressed to rabinoz, not you.

Quote from: rabinoz on September 10, 2019, 04:36:43 AM

Quote from: cikljamas on September 10, 2019, 03:36:09 AM

Jack, have you ever seen this :

Stop spamming with you same old material! We're sick of it!

I hope you understand how i feel about your ongoing copy paste avalanche.
As others have pointed out, you must have a certain template or maybe some sort of access to a NASA shill centre mainframe that provides all the data you’ll ever need about space fakery and co. 

I really don’t think you are in a position to critisize cikljamas....

Unless you were one and the same person.


FOR THE MODERATORS

This is the second clear instance where jackblack and rabinoz are answering issues meant for the other.

Here is the undeniable first occasion where this happened:

https://www.theflatearthsociety.org/forum/index.php?topic=80143.0

There were also several instances where jackblack answers directly the responses meant for rabinoz, and vice versa.

You know

You KNOW that you are repeatedly avoiding a very simple question because it shows you are completely wrong and have been lying to everyone for the entirety of this thread.

Either answer it or admit you have been lying to everyone.

Again: How does the gas accelerate?

Why would you answer

I saw the Jack and thought he was addressing me. I made a mistake, it can happen quite easily.
Now how about you try and address the topic?

I rarely copy and paste, and when I do, it is just copying a question I have posted here which has gone ignored, or when I directly quote something.

Why would you answer with "I rarely copy and paste" when the comment was addressed to rabinoz, not you.

Quote from: dutchy on September 10, 2019, 10:25:40 AM

Quote from: rabinoz on September 10, 2019, 04:36:43 AM

Quote from: cikljamas on September 10, 2019, 03:36:09 AM

Jack, have you ever seen this :

Stop spamming with you same old material! We're sick of it!

I hope you understand how i feel about your ongoing copy paste avalanche.
As others have pointed out, you must have a certain template or maybe some sort of access to a NASA shill centre mainframe that provides all the data you’ll ever need about space fakery and co. 

I really don’t think you are in a position to critisize cikljamas....

Unless you were one and the same person.


FOR THE MODERATORS

This is the second clear instance where jackblack and rabinoz are answering issues meant for the other.

Here is the undeniable first occasion where this happened:

https://www.theflatearthsociety.org/forum/index.php?topic=80143.0

There were also several instances where jackblack answers directly the responses meant for rabinoz, and vice versa.

Spot on !
 ..... and it isn’t the first time.

I remember, on one occasion Alpha2Omega (after being suspected of using various profiles, one of which is JackBlack) claimed that JackBlack lives in very different time zone, that is to say in another continent. Yes, Alpha2Omega pointed out that JackBlack lives in another continent. In which one, i didn't ask him to specify...Could it be perhaps Australia? And if the answer is YES, then maybe JackBlack and Rabinoz use the same IP address...And if they use the same IP address, could it be that they use the same brain, also? Since they demonstrated (countless times) the same kind of idiotic reasoning, it doesn't seem far fetched that JackBlack and Rabinoz are the same person.

Quote from: rabinoz on September 10, 2019, 06:47:17 PM

Quote from: cikljamas

Where is there anything in there that disagrees with anything I said?

I know that the optimum thrust does occur when the (exhaust pressure) equal to (outside pressure) but
I'm sick of saying and demonstrating that the penalty for having (exhaust pressure) slightly greater than (outside pressure) is not severe.

And every reference seems to agree with that and with rocket engines always performing better under vacuum conditions.

You know that the optimum thrust does occur when the exhaust pressure is equal to outside pressure but in the very next sentence you claim that rocket engines always perform better under vacuum conditions in which exhaust pressure is God only knows how much greater than outside pressure which is close to ZERO??

In other words :

Slight overexpansion causes a slight reduction in efficiency, but otherwise does little harm.
However, if the exit pressure is less than approximately 40 % that of ambient, then FLOW SEPARATION occurs. This can cause jet instabilities that can cause damage to the nozzle or simply cause control difficulties of the vehicle or the engine.

You see :
SITUATION No 1 (overexpansion)
Slight overexpansion = Little harm
When Pe is 40 % that of Pa = Very dangerous amount of overexpansion

Now, what happens on the other side of our "equation" (underexpansion)?
SITUATION No 2 (underexpansion)
Slight underexpansion = Little harm
When Pe is MANY, MANY TIMES greater than Pa = Rocket tumbles back to Earth

Not at all! "MANY, MANY TIMES greater than Pa" and the Rocket flies happily off into the great black yonder!

Now, compare these two situations, and try to use your brain finally!!!!

I've been doing that all along, thank you!

When i say "compare these two situations", i mean this :
Pay attention that on the first side of our "equation" we have 60 % difference between Pe and Pa, and on the
other side of our "equation" we have TRILLIONS AND TRILLIONS % difference between Pe and Pa!!!

No again! The "difference between Pe and Pa" is simply (Pe - Pa) NOT (Pe/Pa). Please learn the simplest rules of arithmetic!

Look at the Rocket thrust equation again:

The only term involving pressures is A_e (p_e - p_o) and (p_e - p_o) is the difference in pressures  (as A - B) and not the ratio of pressures (as A/B) as you have used.

As an example, suppose we have a sea-level rocket engine which is 40% overloaded ay sea-level where the atmospheric pressure is roughly 100,000 Pa. The exhaust pressure, p_e would then be about 60,000 Pa.

In the unattainable perfect vacuum conditions, the outside pressure, p_o , would be 0 Pa.

So the pressure thrust term would be A_e (60,000  - 0) Newtons!

And the thrust of that sea-level rocket engine is A_e (60,000  - 0) Newtons higher in space than at sea-level.

This is precisely in accord with the real case I quoted before:

As I showed in the real life example of the SpaceX Merlin 1D sea-level engine:
This version with a comparatively small bell on the nozzle delivers a thrust of 845 kN (190,000 lbf) at sea-level and 914 kN (205,000 lbf) in a vacuum.

SpaceX also produce a vacuum version of that  Merlin 1D engine:
This version with a bell on the nozzle as large as practical delivers a thrust of 934 kN (210,000 lbf) (in a vacuum).

The sea-level engine can be used all the way from sea level to space conditions but does not produce quite as much thrust in space conditions (914 kN) as the vacuum version (934 kN).

I remember, on one occasion Alpha2Omega (after being suspected of using various profiles, one of which is JackBlack) claimed that JackBlack lives in very different time zone, that is to say in another continent. Yes, Alpha2Omega pointed out that JackBlack lives in another continent. In which one, i didn't ask him to specify...Could it be perhaps Australia? And if the answer is YES, then maybe JackBlack and Rabinoz use the same IP address...And if they use the same IP address, could it be that they use the same brain, also? Since they demonstrated (countless times) the same kind of idiotic reasoning, it doesn't seem far fetched that JackBlack and Rabinoz are the same person.

Well, JackBlack and Rabinoz both live in Australia. I live near Brisbane in Queensland but I don't know where JackBlack lives or have the slightest idea what his IP address might be.

And JackBlack and Rabinoz are certainly the not same person and any person that claims otherwise is simply not telling the truth!

Since they demonstrated (countless times) the same kind of idiotic reasoning, it doesn't seem far fetched that JackBlack and Rabinoz are the same person.

You mean since we have repeatedly refuted you you will try whatever BS you can to get rid of us so you can spam your garbage unchallenged?

Again:
HOW DOES THE GAS ACCELERATE?

Can you answer the question?

Quote from: sandokhan on September 11, 2019, 03:57:22 AM

There were also several instances where jackblack answers directly the responses meant for rabinoz, and vice versa.

Spot on !
 ..... and it isn’t the first time.

So what?

Maybe all RE posters are bots programmed by NASA, after all it's all a huge CoNsPIrACy against FE

Quote from: cikljamas on September 11, 2019, 03:50:02 AM

Quote from: rabinoz on September 10, 2019, 06:47:17 PM

Quote from: cikljamas

Where is there anything in there that disagrees with anything I said?

I know that the optimum thrust does occur when the (exhaust pressure) equal to (outside pressure) but
I'm sick of saying and demonstrating that the penalty for having (exhaust pressure) slightly greater than (outside pressure) is not severe.

And every reference seems to agree with that and with rocket engines always performing better under vacuum conditions.

You know that the optimum thrust does occur when the exhaust pressure is equal to outside pressure but in the very next sentence you claim that rocket engines always perform better under vacuum conditions in which exhaust pressure is God only knows how much greater than outside pressure which is close to ZERO??

In other words :

Slight overexpansion causes a slight reduction in efficiency, but otherwise does little harm.
However, if the exit pressure is less than approximately 40 % that of ambient, then FLOW SEPARATION occurs. This can cause jet instabilities that can cause damage to the nozzle or simply cause control difficulties of the vehicle or the engine.

You see :
SITUATION No 1 (overexpansion)
Slight overexpansion = Little harm
When Pe is 40 % that of Pa = Very dangerous amount of overexpansion

Now, what happens on the other side of our "equation" (underexpansion)?
SITUATION No 2 (underexpansion)
Slight underexpansion = Little harm
When Pe is MANY, MANY TIMES greater than Pa = Rocket tumbles back to Earth

Not at all! "MANY, MANY TIMES greater than Pa" and the Rocket flies happily off into the great black yonder!

It can happen only in your wildest dreams!!!
Paper can withstand anything!!!
You can say and believe anything you want, but no sane person will ever buy any of countless stupidities that NASA, you and your alt (JackBlack) relentlessly spout regarding "rockets can fly in a vacuum of space" myth.
According to you, your alt (JackBlack), and NASA, 40 % overexpansion is lethal for rocket's stable functioning, and trillions and trillions % underexpansion doesn't cause any instability in rocket's functioning (in a vacuum of space)!!!
This is totally beyond imagination even beyond imagination of seriously mentally ill persons...
Btw, if there was 65 % probability that you could win a lottery, would you invest some money in such a bet?
Why do i ask you this question?
Here is why :

Look Sandokhan makes some interesting points but Rabinoz has made a very strong and very powerful denial.
Our investigation is complete.  We have determined that there is only a 65% chance that Jack Black is an alt of Rab.  Not enough to act on.
https://www.theflatearthsociety.org/forum/index.php?topic=80143.msg2156841#msg2156841

And to be totally honest, even if JackBlack is your alt, it doesn't bother me (at all), but since you are the one who constantly complain about alleged dishonesty of others, then it is interesting/important to point out how 65 % chance that JackBlack is your alt is not such a low probability, as some mathematicians would want us to believe...

Quote from: rabinoz on September 11, 2019, 05:13:48 AM

Not at all! "MANY, MANY TIMES greater than Pa" and the Rocket flies happily off into the great black yonder!

It can happen only in your wildest dreams!!!
Paper can withstand anything!!!

You can say and believe anything you want, but no sane person will ever buy any of countless stupidities that NASA, you and your alt (JackBlack) relentlessly spout regarding "rockets can fly in a vacuum of space" myth.

After all the time I took to carefully explain it to you!

According to you, your alt (JackBlack),

If you claim that you are a liar pure and simple!

and NASA, 40 % overexpansion is lethal for rocket's stable functioning, and trillions and trillions % underexpansion doesn't cause any instability in rocket's functioning (in a vacuum of space)!!!

There isn't any "trillions and trillions % underexpansion"! Can't you understand that it is the difference in pressures in both cases that matters! Look again at (p_e MINUS p_o)!

You only get your silly "trillions and trillions %" if you divide!

Didn't you do the simplest arithmetic and learn addition, subtraction, multiplication and division?

This is totally beyond imagination even beyond imagination of seriously mentally ill persons...

Yes, I imagine that a "seriously mentally ill person" might not know the distinction between addition, subtraction, multiplication and division but I had hoped that you were a rational being.

I guess I was wrong!

Btw, if there was 65 % probability that you would win a lottery, would you invest some money in such a bet?
Why do i ask you this question?
Here is why :

Quote

Look Sandokhan makes some interesting points but Rabinoz has made a very strong and very powerful denial.
Our investigation is complete.  We have determined that there is only a 65% chance that Jack Black is an alt of Rab.

And as usual, Sandokhan is wrong! He claims that the earth is flat, the sun is 15 km above the earth and writes this:

FET is a subset of a larger topic: the new radical chronology of history.
The new chronology of history: the correct chronology starts in the year 1000 AD, nothing is known prior to 800 AD.
The new radical chronology of history: each and every event assumed to have taken place prior to 1780 AD has been totally forged/invented/falsified. History is just some 365 years old (I started with a figure of 500 years, and slowly reduced the period to 364-365 years).
Christ was crucified at Constantinople some 260 years ago, and the falsification of each and every known religious text begun soon after, in the period 1775-1790 AD.
The Deluge occurred some 310 years ago; while the dinosaurs were created a few decades earlier, after Adam and Eve joined the one million pairs of humans which already were living beyond the Garden of Eden.

Interesting . . . .


Well, tough luck because I am not JackBlack and the only communication I have had with him has been via PMs on this site!

Has there ever been a pair of users on this forum (or any other) which confuses each other's messages with one another in such a timely manner?

rabinoz answers for jackblack (not forced by anyone else, his pathetic excuse does not explain anything at all, it is clear he was caught red handed but benefited from the fact that the admin and mods look the other way):

https://www.theflatearthsociety.org/forum/index.php?topic=80143.0

jackblack answers for rabinoz:

https://www.theflatearthsociety.org/forum/index.php?topic=82434.msg2203163#msg2203163

Let us take a look at the excuse:

I saw the Jack and thought he was addressing me.

jackblack (alt of rabinoz) is DERIDING the mods.

The question addressed to rabinoz was SPECIFICALLY in connection to something that rabinoz did.


Has there ever been such a state of affairs on a forum where TWO USERS confuse each other's messages so often? Where one answers for the other, even though given the context it is very clear that there should be none?

Quote from: cikljamas on September 11, 2019, 05:37:21 AM

Quote from: rabinoz on September 11, 2019, 05:13:48 AM

Not at all! "MANY, MANY TIMES greater than Pa" and the Rocket flies happily off into the great black yonder!

It can happen only in your wildest dreams!!!
Paper can withstand anything!!!

You can say and believe anything you want, but no sane person will ever buy any of countless stupidities that NASA, you and your alt (JackBlack) relentlessly spout regarding "rockets can fly in a vacuum of space" myth.

After all the time I took to carefully explain it to you!

Quote from: cikljamas

According to you, your alt (JackBlack),

If you claim that you are a liar pure and simple!

Quote from: cikljamas

and NASA, 40 % overexpansion is lethal for rocket's stable functioning, and trillions and trillions % underexpansion doesn't cause any instability in rocket's functioning (in a vacuum of space)!!!

There isn't any "trillions and trillions % underexpansion"! Can't you understand that it is the difference in pressures in both cases that matters! Look again at (p_e MINUS p_o)!

You only get your silly "trillions and trillions %" if you divide!

Didn't you do the simplest arithmetic and learn addition, subtraction, multiplication and division?

That MINUS is meaningless, and the whole formula is meaningless, you still haven't figured this out?
When Pe = Pa then the optimum thrust does occur (as you and NASA admit)!
So when Pe = 1, and Pa = 1, then (Pe-Pa) = (1-1) = (0)
It doesn't make any sense!
Why
Because, according to that formula the optimum thrust occurs when Pa = 0, not when Pe = Pa!!!
What this means?
This means that since the pressure in a vacuum (Pa) is very close to ZERO, then Pe (the exhaust pressure) should be also very close to ZERO, and this is the only way how you can get desired ratio 1 : 1, that is to say : Pe = Pa when the optimum thrust does occur (as you and NASA admit)!!!
So, you have to use your common sense, instead of blindly staring in that fraudulent, misleading MINUS

What counts is this :
jpg

As you can readily see, the two densities that NASA's rockets supposedly traverse as they rise up to the skies are hugely different.

If what you (and NASA) are saying was true, then you (NASA's spokesman) and NASA would be able to logically (mathematically) justify what NASA claims (not me) :
Rocket will perform at optimal (100 %) efficiency at certain (X) altitude which is somewhere in between See Level (Over-Expansion) and High Altitudes (Under-Expansion)!!!
Pe = Pressure at nozzle exit is always the same (more or less)
Pa = Outside ambient pressure is constantly/progressively (one way) changing (inversely proportional) with altitude, that is to say : as the rocket climbs higher and higher, outside ambient pressure is dropping in an irreversible (one way) manner!!!

So, as Pa is constantly dropping between See Level and X (optimal) altitude, rocket efficiency is getting better and better, then after passing beyond that X (optimal) altitude, Pa is still irreversibly dropping, but now, rocket efficiency starts to decay, which shouldn't be the case if rocket efficiency is at maximum when the outside pressure, P_o, is zero! You (and NASA) can't have your cake and eat it too!!!

So, what our great mathematician Rabinoz is actually saying is this :

When you subtract 0,0001 from 1, you get 0,9999...Now, since 0,9999 is practically 1, then the difference between 0,0001 and 1 is 1, not 10000!!!

In an example above, according to our Einstein (Rabinoz) the difference between 10^-3 and 10^-24 is 10^-3 because we have to subtract 10^-24 from 10^-3 in order to get the difference... The difference (in literal meaning of this word "the difference") is 10^-3, indeed, but the real question is whether we are interested here in a literal meaning of the word "difference" or are we interested in "for how much (times) one of our numbers (10^-3) is greater than another number (10^-24)?"

So, the real difference between our two numbers (between density of air and density of vacuum) is 10^21 a.k.a. sextillion a.k.a order of magnitude 21.

NASA is no match to our Einstein (Rabinoz)!!!