Main advantage of air launch is that you can better match your target inclination or perhaps even orbit timing - just drop the rocket at the right time in the right direction over the ocean. With a fixed launch site you always need to adjust for some difference of your point of origin versus the orbit you want to achieve.
replyHow big a trebuchet would be needed to chuck a cubesat directly into LEO?
replycubesat + small rocket. Orbital mechanics require a burn at a later time in the orbit, to avoid coming back to say hello again to Mr. Trebuchet (Ignoring Earth's rotation)
reply100 or 200 km tall at point of release ought to do it.
replyIt helps a bit more than you imply, though: if you can launch from a higher altitude, you have less atmosphere to plow through. That lets you use more of your propellant to speed up instead of to push air out of the way.
replyThat isn’t very helpful considering rocket launches only spend a few seconds in atmosphere mostly going vertically to get above the majority as quickly as possible .
replyYou've just got the problem of building a fixed wing aircraft which can carry your rocket full of explosive propellant, successfully release it pointing in the right direction and then get the hell out of the way....
replyYou're extremely limited by the amount of mass you can even launch from a mothership aircraft.
replyThere's no future in this idea outside of small sat, and probably not even there.