The Colorado-based company is aiming to build a Concorde-like supersonic aircraft—but has hurdles to clear before realizing that goal.

Boom Supersonic passed a major milestone Tuesday on its path to reintroduce supersonic commercial flights. After years of testing and refinement, a pilot flying the aerospace company’s XB-1 scale prototype finally broke the sound barrier during a livestream event—not once, not twice, but three times.

The return of supersonic travel has been remarkably slow for something faster than the speed of sound, but a landmark moment is set to happen on.