&quot;DuPont’s configuration devised under COPPER CANYON had included no landing gear, orbital manoeuvring system or fuel reserves.&quot;<p>I&#x27;ve long held the opinion that the real lesson to take from NASP is that the higher the level of decision making, the more detached it is from physics or business.<p>Air breathing works for cruise (limited speed and altitude range, long duration, low thrust requirements).<p>Rockets work for acceleration (wide speed and altitude range, short duration, high thrust requirements).<p>Orbital missions are only about acceleration. Bringing very heavy air breathing engines to orbit doesn&#x27;t make sense at all.<p>The lowest dry mass (=lowest cost) single stage to orbit vehicle designs tend to be dense propellant pure rockets.<p>In Finnish there&#x27;s a saying &quot;ajaa käärmettä pyssyyn&quot;: make the snake go into a gun barrel. An organization trying to achieve a needlessly hard thing because of political reasons. Closely related to Not Invented Here.