Right. So, what is your problem? In a boundless, infinite absolute vacuum, you cannot have thrust because ignition can’t occur.
In a finite thrust vacuum chamber, you can get some ignition because the vacuum is not absolute ( and therefore it is not longer a vacuum, but just a container or chamber).
I was thinking about this overnight and there must be a mathmatical formula for this hypothetical phenonmena we are both trying to describe. I believe the problem is balancing out the pressure of a boundless infinte vacuum to whatever you are trying to have occur. Wondering if a nuke would even explode in a boundless, infinite absolute vacuum, or what would happen.
That’s a test I’d like to see.
Again, the rocket ignition never occurs in a vacuum; but the exhaust gas from the thrust chamber can be expelled into a vacuum.
Going back to my original post, the second link explains the de Laval nozzle. I will summarize:
In the thrust chamber after ignition, the pressure and temperature reach equilibrium. As the flow of gases moves toward the throat, it accelerates to the local speed of sound, which is roughly proportional to the square root of temperature. Then, after the throat, there is the nozzle, which keeps the flow captured from boundless space. As the flow moves down the nozzle, the pressure and temperature get lower, and the exhaust accerates until it reaches it maximum velocity, as described at the link.
The mathematics of this nozzle date back to 1880’s, and allows for zero exit pressure.