NASA’s innovative X-59 aircraft has advanced towards achieving quieter supersonic flight after successfully traveling at supersonic speeds for the first time on June 5. During this flight, the plane reached a maximum velocity of 713 miles per hour at an altitude of 43,400 feet, equivalent to Mach 1.1.
“Achieving supersonic speeds marks a significant achievement for the X-59 team,” stated Cathy Bahm, the project manager for NASA’s program, in a late May announcement, prior to the flight. “The completion of the first flight under mission conditions is particularly significant as it marks the beginning of validating the aircraft in its intended environment.”
The flight, which lasted 81 minutes, was conducted from Edwards Air Force Base, with NASA pilot Jim Less executing the historic mission.
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The term “supersonic” can be misleading, as the speed of sound varies with the temperature and pressure of the surrounding atmosphere. Mach 1 signifies the local speed of sound, and any speed above this is deemed supersonic, while Mach 5 is the threshold for transitioning to “hypersonic” speeds. When objects exceed the speed of sound, the pressure waves they create are channeled to the rear, forming a cone. If this cone reaches the ground, it results in a loud sound known as a sonic boom.
Such booms, along with high costs, led to the discontinuation of the Concorde, the only supersonic passenger aircraft, in 2003. The Concorde, which began service in 1976, could cruise at 1,350 mph and fly from New York City to London in under three hours under ideal conditions.
For almost ten years, NASA has been striving to develop an aircraft capable of supersonic speeds without causing disruptive sonic booms. The X-59’s elongated nose is designed to diffuse shock waves, resulting in a “quiet supersonic thump,” as the agency described it in their late May statement, akin to distant thunder or a car door closing at a distance of 20 feet.
The X-59, which took its inaugural flight in October 2025, has conducted over a dozen flights to date. With its recent supersonic flight, the testing program will continue, aiming for speeds as high as Mach 1.6 (1,218 mph) and altitudes of up to 60,000 feet, while also undertaking less extreme flights to gather more data for engineers.
“These flights not only bolster our confidence in the X-59’s capabilities, but they also signify our progress towards future mission phases that will ultimately shape the future of supersonic travel,” Bahm remarked in the late May announcement.
Following this series of test flights, NASA plans to initiate a second phase focused on analyzing the aircraft’s noise production, determining if it generates the intended “quiet supersonic thump” or something more akin to the disruptive booms of other high-speed vehicles. The final phase will see these tests moved over populated areas, where NASA will gather feedback from residents regarding their perceptions of the aircraft’s noise.
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