X-59 crosses Mach 1 milestone, quiet supersonic next

X-59 goes – NASA’s experimental X-59 flew supersonic for the first time on June 5, reaching a peak speed of 713 miles per hour at 43,400 feet. The 81-minute test out of Edwards Air Force Base is the beginning of a larger validation effort aimed at replacing disruptive son

On June 5, NASA’s experimental X-59 left the comfort of subsonic flight and pushed through the speed boundary it was built to cross. The aircraft flew supersonic for the first time, reaching a peak speed of 713 miles per hour at an altitude of 43,400 feet—equivalent to Mach 1.1.

The milestone was not a publicity stunt; it was a defined step in a sequence meant to prove the plane can perform in the conditions it was designed for. “Flying at supersonic speeds is a major milestone for the X-59 team. ” Cathy Bahm. project manager for the program at NASA. said in a statement in late May. before the flight. “Completing the first mission-conditions flight is especially meaningful—it’s the moment where we begin validating the aircraft in the environment it was designed for.”.

The flight lasted 81 minutes and was based at Edwards Air Force Base. NASA pilot Jim Less flew the milestone sortie.

Getting past Mach 1 matters for a reason that’s both physical and personal. “Supersonic” is a slippery term. given that the speed of sound depends on the temperature and pressure of the local atmosphere. Mach 1 represents the local speed of sound; above it, movement is considered supersonic. Mach 5 marks the transition to even faster “hypersonic” speeds. When objects travel faster than the speed of sound. the pressure waves they produce are funneled to their rear and form a cone; if the object is flying low enough for this cone to hit Earth. the result is a loud noise called a sonic boom.

That noise—and its consequences—helped bring the 2003 retirement of the only supersonic passenger plane: the Concorde. It began carrying passengers in 1976 and reached cruise speeds of 1. 350 mph. making it possible to fly from New York City to London in less than three hours under good conditions. But the sonic booms that came with supersonic travel made everyday access hard to imagine.

For nearly a decade. NASA has been working to design a plane that can fly faster than the speed of sound without producing disruptive sonic booms. The X-59’s long nose is designed to disperse the shock waves so that flight produces merely a “quiet supersonic thump. ” as NASA described it in the late May statement—somewhere between distant thunder and a car door shutting 20 feet away.

That aircraft is the X-59, which first flew in October 2025. It has made more than a dozen flights to date. The supersonic test now keeps the overall program moving, with planned speeds reaching Mach 1.6 (1,218 mph) and altitudes reaching 60,000 feet. Even as the team aims higher. the plane is also expected to make less superlative flights. giving engineers more data to sort through.

“These flights not only deepen our confidence in the X-59’s performance—they mark our progression toward the future phases of the mission that will ultimately help shape the future of supersonic travel,” Bahm said in the late May statement.

Once this round of test flights is complete. NASA plans a second phase of tests focused on the noise the plane makes—specifically whether it produces the planned “quiet supersonic thump” or something more like the unacceptable sonic booms of other high-speed vehicles. The final phase will relocate those tests over communities. with NASA surveying residents on their impressions of the airplane’s noise.

In other words, June 5 didn’t just mark a speed record. It set the runway for what will be much harder to prove: that a plane can cross Mach without bringing back the boom that ended the public era of passenger supersonic travel.

NASA X-59 supersonic Mach 1.1 sonic boom quiet supersonic thump Edwards Air Force Base Jim Less Cathy Bahm