NASA’s X-59 quiet supersonic research aircraft has flown faster than the speed of sound for the first time, marking a key step in the agency’s effort to usher in an era of civil supersonic flight over land.
The aircraft reached about Mach 1.1, or 713 mph, during an 81-minute test flight on June 5, 2026, from Edwards Air Force Base in California, NASA said.
NASA test pilot Jim “Clue” Less flew the X-59 to 43,400 feet during the flight, which began at 11:08 local time. The test focused on the aircraft’s handling qualities at subsonic and supersonic speeds.
The flight testing is part of NASA’s Quesst mission, which is using the X-59 to determine whether an aircraft can fly supersonic while producing a quieter “thump” instead of a traditional sonic boom.
The X-59 was accompanied by a NASA F-15 chase aircraft during the flight. NASA said sonic booms from the F-15 obscured any sound made by the X-59 during the test.
NASA said the next major step is a “mission conditions” flight, expected in the coming days, in which the X-59 is planned to reach Mach 1.4, or about 925 mph, at roughly 55,000 feet.
That speed and altitude are the baseline conditions NASA plans to use when the X-59 eventually flies over several US communities. The agency will collect public response data on the aircraft’s sound and provide it to regulators.
The goal is to support new noise standards that could allow future supersonic civil aircraft to fly over land. Supersonic flight over land has long been restricted because of the impact of sonic booms on communities below.
NASA Administrator Jared Isaacman said the X-59 team has flown the aircraft 16 times in the last 90 days and as it prepares to push the aircraft to its fastest speeds yet.
The X-59 made its first flight on October 28, 2025. Since then, NASA and Lockheed Martin Skunk Works have been expanding the aircraft’s flight envelope through a series of tests at different speeds and altitudes.
The current phase of testing is focused on aircraft performance and flying qualities. After that, NASA plans to move into sound-profile testing to verify the X-59’s quiet supersonic design.
The long, needle-nose aircraft does not have a forward-facing cockpit window. Instead, the pilot uses NASA’s eXternal Vision System, a digital display that shows forward-looking imagery and flight data.
