No, I'm not bringing up some ancient sci-fi tale from the Golden Age of Radio. X-15 was a space craft from the early 1960s that launched from under the wing of a lumbering B-52 and propelled itself above 50 miles altitude. Neil Armstrong (of Apollo fame) was an X-15 pilot/astronaut. That was the Air Force approach to space flight. Fly up and everything is re-usable. The OTHER approach, the NASA approach that got humans to the Moon (including Armstrong) is the disposable rocket engine and ground launch. What got me to thinking about all this (from my childhood) was that I noticed that Branson's Virgin Galactic program uses essentially the X-15 technique while Jeff Bezos' Blue Origin follows NASA orthodoxy. There was considerable debate between the two methods back in my youth. Apparently that debate isn't settled even yet?
Reusable rockets. Its what has turned into a staggering competitive advantage for them. Also was the concept that caused an early divide between the two billionaires. There’s write ups online of their early partnership talks years ago and how they broke down over this and ultimately their end-game goals.
Interesting. At some point, the USAF was considering an X-15 orbiter that would use rockets for launce. The lines are a bit blurred.
The X-15 program had roots that pre-dated Sputnik. But when the Russians got to space first, the race to the moon was on and that's where the emphasis was placed. The X-15 was great for learning about really fast atmospheric flight, and likely contributed to our ability to employ the SR-71. But it was gone before we got to the moon.
