NASA’s X-59 Reaches Supersonic Speed in First Mach 1 Flight; Sonic‑thump Tests Next

NASA’s X-59 experimental aircraft flew faster than the speed of sound for the first time Friday, a milestone for the agency’s effort to test whether supersonic flight can be made far less disruptive over land.

The achievement is an important technical step, but not yet the program’s central proof point. NASA’s Quesst mission is aimed at showing that the X-59 can produce a softer sonic “thump” instead of the sharp boom traditionally associated with breaking the sound barrier, with data eventually meant to help inform future noise rules for civil overland supersonic flight. On Friday’s flight, however, a nearby F-15 chase plane’s louder sonic booms obscured any sound made by the X-59, meaning the sortie did not produce the community acoustic data needed for that later phase of the mission.

NASA said the aircraft exceeded Mach 1 on June 5 during a flight from Edwards Air Force Base, home to NASA’s Armstrong Flight Research Center in California. NASA test pilot Jim “Clue” Less flew the sortie, which began at 11:08 a.m. PDT and lasted 81 minutes, with the aircraft taking off from and landing at Edwards.

The agency reported a top speed of about Mach 1.1, or roughly 713 mph, and said the aircraft reached about 43,400 feet. NASA also released an image from the X-59’s external vision system showing the aircraft at Mach 1.077. An F-15 chase plane monitored the X-59 during the supersonic run.

The X-59 is the centerpiece of NASA’s Quesst mission, a research program designed to test whether an aircraft can fly supersonically while producing a quieter sound signature than a conventional sonic boom. Lockheed Martin built the aircraft for NASA. The X-59 first flew on Oct. 28, 2025, and Friday’s mission marked its first supersonic flight.

Why that matters extends beyond the aircraft itself. Since the 1970s, U.S. rules have effectively prohibited routine civil flights over land above Mach 1 except under special authorization, largely because of the noise caused by sonic booms. NASA’s role in Quesst is not to launch a commercial airliner, but to gather technical and human-response data that regulators could use if they consider future standards for quieter overland supersonic travel.

Jared Isaacman, NASA administrator, said in a statement that the aircraft is “getting ready for its quiet supersonic debut” after a steady pace of recent testing. He said the team had flown 16 times in the last 90 days and was preparing for the next target speed.

That next step is to push the X-59 to Mach 1.4. NASA said its near-term objective is to reach that speed, with mission-condition flights planned at roughly Mach 1.4 and about 55,000 feet. Those later flights, rather than Friday’s milestone run, are expected to set up the quieter-sound demonstrations that will test the program’s core premise and generate the data NASA plans to share with regulators.