The X-15 was a rocket-powered research aircraft that pushed human flight to the edge of space and deep into the hypersonic ...

Dropped in mid-air from beneath the wings of a B-52 mothership, the X-15 A-2 ignited its powerful rocket engine and streaked into the upper-atmosphere. Previous burns only lasted 90-seconds, but on ...

An aircraft capable of hitting 4,520 mph (nearly seven times the speed of sound) is ludicrous to even think about, but the North American X-15 achieved this, defying comparison to any other aircraft ...

"The X-15, which flew from 1959-1970, is still the most advanced research aircraft ever developed and flown, and hangs in a place of honor in the Smithsonian's Air and Space Museum. Its test pilots ...