12 Jun 2026

NASA’s X-59 experimental aircraft reached a major milestone Friday, June 12, flying Mach 1.4 (about 924 mph) and an altitude of 55,000 feet, the conditions required for the aircraft to make future flights critical to its mission.  

The X-59 still has months of performance testing ahead, but after those are complete, NASA’s Quesst mission will fly the aircraft over several U.S. communities to collect data on public perception of the quiet sonic thump it will make at supersonic speeds. Those community overflights will include flights at Mach 1.4 and 55,000 feet. 

The milestone comes just days after the X-59’s first supersonic flight. That flight showed the aircraft performed as expected at Mach 1.1, but Friday’s mission conditions flight was an even more critical step for NASA. 

The aircraft’s team has steadily expanded the aircraft’s flight envelope by evaluating its performance at a variety of speeds and altitudes, and having its pilots take on a battery of maneuvers.  

The X-59 was designed to fly supersonic without causing a loud sonic boom. However, for these early supersonic flights it has been accompanied by a NASA F-15 research aircraft, a traditional supersonic jet that causes booms obscuring any noise the X-59 makes. During upcoming flights, a shock-sensing probe mounted to the F-15 will gather measurements of the X-59’s shock wave signature, an early measure of its supersonic performance. 

After the team conducts more tests at a variety of altitudes and conditions to complete envelope expansion, the X-59 will enter the acoustic validation phase of Quesst. During this phase, researchers will thoroughly measure the aircraft’s supersonic acoustic signature — the quiet thump it’s designed to make — to confirm it is performing as intended. 

Each flight brings NASA one step closer to flying the X-59 over communities and gathering feedback that could help shape the future of commercial supersonic flight over land. 

[Image]

(A) NASA’s X-59 quiet supersonic research aircraft reached its target speed and altitude for future community overflights for the first time during a flight on Friday, June 12, 2026. The milestone marked the first time the aircraft flew at Mach 1.4 and 55,000 feet — conditions it will fly when gathering community response data to its quiet sonic thump.

(B) NASA’s X‑59 eXternal Vision System (XVS) shows Mach 1.4 at 55,030 feet on Friday, June 12, 2026 during the aircraft’s first mission conditions flight, the approximate conditions it will fly when gathering community response data to its quiet “sonic thump.” The milestone marks the first time the aircraft flew at its designed speed and altitude.