An experimental aircraft just achieved a “major milestone” that NASA officials say brings the future of quiet supersonic flight closer to being a reality.
The test flights involved the American space agency’s secretive X-59 aircraft, which reportedly reached speeds of 1.4 Mach—roughly 924 miles per hour—during a flight last Friday.
Reaching an altitude of 55,000 feet, the experimental aircraft’s speed and height during last week’s test flight met the conditions the agency says are required for future flights aiming to achieve supersonic flight without the noisy booms it usually generates.
In a statement, NASA said the aircraft’s tests are far from complete, although Friday’s test marks a significant milestone toward reaching its current mission goals.
“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,” NASA’s statement on Friday read. “Those community overflights will include flights at Mach 1.4 and 55,000 feet.”
Another Milestone for NASA’s X-59
Last week’s test occurred within days of an earlier takeoff that sent the X-59 on its first successful supersonic flight, where the plane reached a top speed of Mach 1.1.
The earlier test also marked a leap forward for the Quesst mission, which is in the process of completing several crucial steps that are expanding the X-59’s capabilities.
Deployed for test flights at various speeds and at different altitudes, flight engineers are currently gauging the aircraft’s flight envelope by having it perform in a range of different flight conditions.

During its current test flights, NASA said the supersonic aircraft was accompanied by a NASA F-15 research aircraft, which still produces a sonic boom when it flies, unlike the X-59. NASA engineers plan to mount a shock-sensing probe on the accompanying aircraft during future flights, which the agency says will collect vital information about the shock waves the experimental aircraft produces.
The resulting experiments will help engineers measure the exact capabilities of the new aircraft and its supersonic performance.
Additional Prep for NASA’s Quesst Mission
Although designed to function as a “quiet” supersonic aircraft, the X-59 still produces audible signatures, which NASA likens more to being a soft “thump” than a sonic boom.
During its final testing phases, the X-59’s supersonic acoustic signature will also be measured.
If all goes according to plan, the supersonic aircraft will complete its full round of testing in the months ahead, marking a successful series of demonstrations that it meets all the requirements for quiet flight under a range of different altitudes and other flight conditions.
Ultimately, the technologies being innovated by this experimental plane will help to enable the first supersonic flight over land in decades, paving the way toward a new future of commercial flight faster than the speed of sound.
Additional details about NASA’s Quesst program can be found on its official site.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.
