NASA X-59 flies faster than sound for the first time

NASA X-59 reaches supersonic speed

NASA achieved a major milestone on Friday 5 June when its experimental X-59 aircraft travelled faster than the speed of sound for the first time, paving the way to demonstrate its quiet supersonic capabilities later this year.

NASA test pilot Jim “Clue” Less took off from and returned to Edwards Air Force Base in California, reaching a top speed of around Mach 1.1 (713 mph, or 1,147 km/h) at an altitude of 43,400 feet (13,228 metres).

The X-59 flight began at 11:08 PDT (Pacific Daylight Time) and lasted 81 minutes. The team initially concentrated on the aircraft’s handling characteristics at subsonic speeds before moving into the supersonic regime.

“The X-59 is preparing for its quiet supersonic debut. Since the aircraft’s first flight on 28 October 2025, the team has made tremendous progress, flying 16 times over the past 90 days and settling into a steady testing rhythm. In the coming days, we expect to take the next step and advance to Mach 1.4,” said NASA Administrator Jared Isaacman. “I am grateful to the NASA team and Lockheed Martin Skunk Works for helping bring us to this point, and I hope this will be the first of many collaborations as we rebuild NASA’s X-plane portfolio.”

The X-59 has been designed to operate at supersonic speeds while producing only a quiet thump rather than a loud sonic boom. During this flight, a NASA F-15 chase aircraft flew nearby to observe the X-59. The F-15’s loud sonic booms masked any sound generated by the X-59.

“The X-59’s first supersonic flight is a testament to America’s enduring leadership in aerospace science, engineering and innovation,” said Michael Kratsios, Assistant to the President for Science and Technology and Director of the Office of Science and Technology Policy. “This achievement comes as the Trump Administration continues its work to unlock supersonic flight and enable American ingenuity.”

Mission-condition flight for the X-59

Although this first supersonic flight represents an important milestone, an even more critical event for the mission is imminent. Within just a few days, the aircraft is expected to undertake its first flight in “mission conditions”, reaching a cruising speed of Mach 1.4 (925 mph, or 1,488 km/h) at an altitude of approximately 55,000 feet (16,764 metres). A chase aircraft will also accompany the X-59 on this flight.

This speed and altitude form the baseline operating conditions for the X-59 when it ultimately flies over several communities across the United States, allowing NASA to gather data on how people may perceive its quiet thump. NASA will provide those findings to United States and international regulators to support the creation of new data-led noise standards, enabling a viable future market for commercial supersonic flight over land.

Quesst mission and quiet supersonic flight

Over recent months, the X-59 has taken part in an ongoing series of flights covering a broad range of speeds and altitudes, a process known as envelope expansion. These trials make up the first stage of the X-59 flight-test programme. They focus on performance and include monitoring by a chase aircraft. Once the aircraft completes this stage, it will move into another phase centred on its sound profile, verifying its quiet-thump capability.

The X-59 is the centrepiece of NASA’s Quesst mission, short for Quiet SuperSonic Technology, which seeks to demonstrate quiet supersonic flight and help make commercial supersonic travel over land possible worldwide. These developments will help travellers reach their preferred destinations faster while spending less time in the air.

Through the Quesst development of the X-59, NASA will also provide design tools and technology for quiet commercial supersonic aircraft. These aircraft will achieve the high speeds sought by commercial operators without disturbing people on the ground.

NASA will validate the design tools through ground and flight testing, giving United States aircraft manufacturers the ability to explore new quiet supersonic concepts and the confidence that their resulting designs will meet quiet-flight requirements.

Information from NASA