Trust me, the last entity on Earth I would ever defend is NASA. However, I have to take issue with this statement.P from the UK wrote:Hello again Simon.
But if you want an even simpler (& more practical) demonstration of how NASA's model of rocket propulsion is flawed, then take an ordinary firework rocket & attach a shield to it, just below the nozzle, thus blocking the exhaust from interacting with the atmosphere.
According to NASA it should still take off, as the work is being done within the rocket itself, but of course it will not; it will merely sit & sputter & go absolutely nowhere..
The author does not cite a reference where NASA said such a contraption would "still take off" and of course they would never say such an obviously idiotic thing as they still have to keep up some semblance of believability for all those physics students who would see through such idiocy immediately. Of course such a rocket would just "sit & sputter and go absolutely nowhere" and NASA would never claim otherwise.
The key word in the description of this experiment is "attach."
Obviously if such a shield were attached to the rocket then the exhaust would apply as much force to the shield as to the rest of the rocket and, since this shield is attached to the rocket, no motion would result. A shield that was not attached to the rocket, however, would not prevent it from taking off.... take an ordinary firework rocket & attach a shield to it, just below the nozzle, thus blocking the exhaust from interacting with the atmosphere.
I certainly don't mind criticisms of NASA but when criticisms are made in such a fallacious and unsupported manner it tends to feed the flames of criticism of this forum and makes us all appear like idiots for not calling foul on statements like this. Perhaps that is the purpose of this “contributor” who refuses to even register on the forum?
The above is far from the only unsupported claim made on his thread and I can't help but wonder where the usual standards of research such as citing sources, etc have gone?
There are ways of proving, or at least demonstrating, the concepts of "rocket propulsion doesn't work in a vacuum" or of "rockets push against the air" as has been claimed. Small vacuum chambers, such as those used in class room demonstrations, do exist and are not expensive. Experiments involving propulsion from rearward expelling of masses can be done with models or even skateboards and weights, and so on.
How about the proponents of these concepts showing us some real world demos? Throwing theories and equations around is easy and can be done comfortably from one's easy chair. How about providing some -- dare I say it? -- real world PROOF?
And, by proof, I don't mean just saying "if you do this ..." or " if you do that ..." or drawing pictures and diagrams. I mean actually getting out of your chair and DOING it and SHOWING us. Or, at least pointing toward someone who has done it ... for real.