I&#x27;ll go beyond &quot;dense, propellant pure&quot; rockets - the whole concept of single-stage vehicles is a pipe dream.<p>Staging is immensely important because it lowers the &quot;order complexity&quot; of carrying additional payload.  In order to add payload you need to add fuel, and then you need to add more fuel to carry that fuel, and so on.  This is immensely easier if you don&#x27;t need to drag the dead weight of your initial stages along with you.<p>Single-stage is barely even feasible to orbit.  Anything past that is just flatly science-fiction.