Elon Musk once discussed why air launch from planes was not a good idea, and his criticisms apply to Rockoons as well.<p>“seems like...you're high up there and so surely that's good and you're going at...0.7 or 0.8 Mach and you've got some speed and altitude, you can use a higher expansion ratio on the nozzle, doesn't all that add up to a meaningful improvement in payload to orbit?<p>"The answer is no, it does not, unfortunately. It's quite a small improvement. It's maybe a 5% improvement in payload to orbit...and then you've got this humungous plane to deal with. Which is just like having a stage. From SpaceX's standpoint, would it make more sense to have a gigantic plane or to increase the size of the first stage by five percent? Uhh, I'll take option two.<p>"And then, once you get beyond a certain scale, you just can't make the plane big enough. When you drop...the rocket, you have the slight problem that you're not going the right direction. If you look at what Orbital Sciences did with Pegasus, they have a delta wing to do the turn maneuver but then you've got this big wing that's added a bunch of mass and you've able to mostly, but not entirely, convert your horizontal velocity into vertical velocity, or mostly vertical velocity, and the net is really not great.”<p>For SpaceRyde the extra height is a trivial benefit given that the velocity of reaching orbiting is the key part, altitude is a free byproduct of that velocity. The real benefit is being able to use a more efficient nozzle.<p>By not having to throttle for MaxQ, with a vacuum optimized nozzle, at most balloon launch adds 10%, at the cost of substantial size and payload limits.<p>One benefit of SpaceRyde over plane launch is the rocket can launch at a better orientation, not requiring the added weight/complexity of wings like Pegasus.<p>But the problem is that SpaceRyde lacks the single major benefits of airplane launch, the ability to launch almost regardless of weather by flying around it, and in a mission specific latitude that can be reached in flight from a home launch base. SoaceRyde is not launching in inclement weather, though it can be launched in different latitudes.<p>It’s sole advantage is going to be cost over other air launch systems (should be way less complex) and other ground launched small sat providers but is unlikely to be able to serve more than the tiniest payload sizes.