I'm not sure the concussive force inside the closed chamber would help because the wall pushes back with the same force via Newton's 3rd law.hoi.polloi wrote:However, if the explosion happens within a non-vacuum chamber, the concussive force is utilized, then the very next instant the explosion is exposed to vacuum, causing the entire chamber to be emptied with no work; and then the chamber is re-pressurized and more gas is added to create the next explosion — and all this is done at such a tremendous pace and with such precision that the vacuum never enters the equation except to eject the used explosion, could this different kind of engine function to propel the contraption surrounded by vacuum?
So the energy generated by combustion inside the closed chamber would partially be absorbed by the ship and the rest would be (quickly) later let into the vacuum of space where it does no work.
If the ship were floating in water or sitting on ice it would move because the energy absorbed would be transferred to the water or the ice via the hull and the ship would vibrate, rock, etc.... Vibrating a ship in the vacuum of space is not going to get you moving.