Believing that a rocket engine and propellant are the same object is untrue.
^Brainwashing.
^lol.
Perhaps you're confusing 'system' and 'object' with each other. They are not synonyms.
^Playing with words like crooked lawyer.
^Better Call Markjo!
A rocket is quite obviously ONE object; look at one & count it for proof of what I say.
Rocket without fuel = ONE object.
Rocket with fuel = ONE object.
When rocket does not have fuel it CANNOT create Force via F=pa.
When rocket does have fuel it CAN create Force via F=pa.
No matter what, it is ONE object.
Therefore, when it IS creating Force via F=pa, it needs a SECOND object, EXTRINSIC to itself, in order to produce motion.
This second extrinsic object can ONLY be the atmosphere through which it moves.
Therefore, remove the atmosphere & no motion can be produced.
Therefore, rockets cannot wok in a vacuum.
Simple.
But don't let facts, science & experimental evidence distract from your lying...
Toodle-pip, Losers!