[Eala]

it is perhaps time to revisit the intentions behind the now-cancelled National Aerospace Plane (the X-30) program.

I worked on the Shuttle program when its only flights were still in wind-tunnels ('73-'75). The Shuttles are long past their time -- but NASA has become so encumbered by bureaucracy I wouldn't expect to see anythng new without a HUGE infusion of cash. (It was while I was there, 30 years ago, that one of the scientists observed a bleak milestone attained: NASA's staffing had reached the level one bureaucrat for each researcher.)

[LS]

Yep. I discovered, when I wrote my history of NASP, that NASA never believed in the scramjet, but went along to get the money. It was an abuse. The AF, however, believed in the scram, and wanted to make it work. Had NASA put its heart into the program, I think today we'd have an airbreathing engine that could go at least Mach 8, and maybe 10.