[CALawyer]

"For an aircraft to achieve hypersonic speeds, ranging from 6,000 to 15,000 mph (Mach 9 to Mach 22), and reach altitudes between 100,000 to 150,000 feet, it needs an airframe structure designed to survive intense heat and pressure."

They should be close by now, given the development of the Aurora project. In LA, about 10-15 years ago, we used to hear sonic booms that the "experts" attributed to the Aurora. Caltech (I think) said the sonic booms were coming from a moving object traveling at a constant altitude (i.e., not plummeting to earth like a meteorite) and, IIRC, at 4,000 to 5,000 mph.

[NormsRevenge]

Artist’s drawing of the Falcon Hypersonic Technology Vehicle-1. Image Courtesy: Russ Partch