NASA’s Supersonic Jet Broke the Sound Barrier Twice on Test Flights
NASA’s X-59 is quietly reaching significant milestones.
The experimental supersonic aircraft, developed in partnership with Lockheed Martin, broke the sound barrier during two separate test flights in June. The tests mark a significant step in NASA’s quest for “quiet supersonic” flight, with the X-59 eventually expected to exceed the speed of sound with only a small thump, rather than the typical explosive boom.
The X-59 went supersonic for the first time on June 5, reaching a top speed of approximately Mach 1.1 (713 mph) and an altitude of 43,400 feet on an 81-minute mission from Edwards Air Force Base in California. That flight showed the aircraft performed as expected at high speeds, NASA said.
The next flight, carried out a week later on June 12, was even more critical, with the aircraft flying in the conditions it will also navigate in the future. The jet reached a top speed of Mach 1.4 (about 924 mph) and an altitude of 55,000 feet in just over an hour. It will fly at the same speed and altitude on upcoming flights over communities throughout the U.S. as NASA gathers public feedback on noise levels.
The X-59 taking flight for the first time in October 2025.
Garry Tice
U.S. regulators have banned supersonic overland flight for decades due to the noise produced when aircraft break the sound barrier, but the X-59 solves that problem. It is about half the length of the Concorde, which retired in 2003, and has a more streamlined design with a much longer nose. The aircraft’s sleek shape and wing configuration help minimize the boom when it goes supersonic, replacing an explosive bang of roughly 105 decibels with a thud of about 75 decibels. Think of it as going from a clap of thunder to the slam of a car door.
During the most recent test flights, the X-59 has been accompanied by a NASA F-15 research aircraft that does produce a supersonic boom. That means it was difficult to tell exactly how much noise the X-59 made. The aircraft is, however, heading into the “acoustic validation phase,” during which researchers will thoroughly measure its acoustic signature. On the upcoming flights, the F-15 will be equipped with a shock-sensing probe that will measure the X-59’s shock-wave signature to determine early supersonic performance.
The X-59 is, of course, not intended for commercial use, with space for one pilot rather than a cabin full of passengers, but it could help pave the way for quieter supersonic aircraft for the masses. A range of aviation companies are working on supersonic travel, from big names such as United Airlines and American Airlines to startups like Exosonic and Spike Aerospace.
