Comments by "Scott Franco" (@scottfranco1962) on "Dawn of the Space Plane" video.

  1. The issue with rockets to space vs. flying to space is that it takes more net power to fly to space than to rocket to it. Flying to space leaves the craft taking more time in the atmosphere and inducing drag, which takes power to overcome. A ballistic rocket spends less time fighting the atmosphere. The factor that could change that is using air breathing engines to the highest point possible. Since part of an air breathing engines power comes from the oxygen in the atmosphere, that can replace carried fuel, ie., oxygen. Additionally, the air can be quite thin. A craft flying very fast scan scoop a lot of oxygen from a very thin atmosphere. Hence, the interest in ramjets. However, without advanced jets, and perhaps even with them, it still does not make that much sense to fly to orbit. It takes more time, exposes the aircraft to heating effects longer, etc. So the question is, as it was, why bother with it when we know so much about getting to space directly, with rockets. Most of the "flying space vehicles", such as the shuttle, don't use the wings to go to space, but rather to be maneuverable once it returns to atmosphere. Ballistic entry vehicles have no guidance at all (Apollo). Elon has proposed an intermediate solution, a rocket that uses fins designed to direct its path on return, sort of a cross between the two.
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