Simon has a way of making things clear to me, and this post is no different. Love the diagram.
PROPULSION REALITY CHECK
Perhaps the most common question inquiring minds have about space travel is: “how can rockets function in the vacuum of space – or in very thin air pressure”? To this question, NASA (and its believers) unfailingly respond roughly like this: “that’s because rocket thrust is not achieved by pushing against air. Air has little or no influence on rocket propulsion. What makes a rocket move is the rocket fuel pushing onto itself. Have you ever heard of Newton’s 2nd & 3d laws of motion?” Well, the claim that “air density has NO influence on rocket propulsion” has to be the silliest of all NASA lies.