The air force says, this rack is named as "breaker," test flight from B - 52 bomber from California Edwards air force base carrier to the Pacific Ocean on new test. "Breaker," will be in the ancient near Angle for about 15240 meters high with B - 52 separation, a rocket booster will be immediately ignite, "breaker," speed up to 4.5 Mach (Mach is speed quantifier, a Mach is a times the speed of sound. Sound velocity is 340 meters per second, 1.2 times the speed of sound to 5 times the speed of sound is defined as "supersonic", more than 5 times for ultra-high speed of sound).

But in the booster rocket smooth ignition after 16 seconds after flight, the aircraft is on a balance tail appear problem, in and booster rocket separation, aircraft soon out of control and fell into the Pacific Ocean, failed to recovery. The air force research laboratory X - 51 a project manager Charlie brinks said, it is for vehicle balance system appear problem, it before the fire is out of control.

This test is X - 51 a third test, after two test also only once have had limited success.