Boom Supersonic XB-1 Breaks Sound Barrier During Historic Test Flight

The XB-1, a civilian supersonic jet developed by Boom Supersonic, successfully broke the sound barrier during a test flight over the Mojave Desert. It reached an altitude of 35,290 feet before accelerating to Mach 1.22, the company said in a press release. CBS News reports: It marks the first time an independently developed jet has broken the sound barrier, Boom Supersonic said, and the plane is the "first supersonic jet made in America." The sound barrier was broken for the first time in 1947,