Known for its unconventional appearance and active supersonic testing over the United States, the Nasa X-59 experimental jet is at the forefront of efforts to address the persistent challenge of disruptive sonic booms in aviation.
Nasa’s vision for the X-59 centers on enabling quiet supersonic commercial travel. To achieve this, the jet features a remarkably long nose, components sourced from other aircraft, and a pilot who navigates using external cameras instead of a traditional forward view.
Advancing Toward Quieter Supersonic Flight
Developed for Nasa by Lockheed Martin, the X-59 is engineered to show that supersonic flight doesn’t have to produce loud sonic booms. This issue previously confined the legendary Concorde to overwater routes, preventing its commercial viability on U.S. cross-country flights. The X-59’s stretched nose is specially designed to manipulate and soften the shockwaves formed at Mach 1 (roughly 660 mph at cruising altitude). As Peter Coen, the Nasa programme manager, describes, years of study have led researchers to theorize that these shockwaves can be transformed into a muted noise—more like a distant car door shutting than an explosive bang.
Through a combination of X-59 flight tests and surveys in communities along its route, Nasa will pinpoint just how subdued the “sonic thump” must be for routine acceptance. Coen notes, “We want to figure out what level of boom is acceptable to people on a regular basis.”
Building on a Tradition of Experimental Flight
Nasa’s tradition of “X-planes” began with the Bell X-1, in which Chuck Yeager shattered the sound barrier back in 1947, and progressed with the X-15 rocket plane, which soared to 6.7 times the speed of sound (4,520 mph) and approached the edge of space two decades later. The guiding principle has always been to concentrate on singular goals and create specialized airframes. “Minimise goals, the more goals you have the more expensive it gets,” Coen says, reflecting on the X-plane strategy.
Echoing that legacy, the X-59 focuses exclusively on the challenge of reducing sonic booms. Its design relies on the integration of various aircraft systems: the cockpit and ejection seat come from a T-38 training jet, the landing gear originates from an F-16 fighter, and its engine is taken from an F-18. Because the cockpit is positioned further back than usual, a real-time camera system and digital display ensure the pilot has full external visibility.
The aircraft completed its first flight in 2025, but the debate continues regarding whether the test planes of the future will require human pilots. Coen observes that while a shift to uncrewed X-planes is probable, certain scenarios still demand onboard pilots—especially for piloted research activities or when drone certification poses excessive cost and complexity.
Crewed Aircraft’s Enduring Value in Testing
A number of aviation authorities argue that human presence remains vital for specific test flights. Despite increasing reliance on drones in conflict situations such as Ukraine, Guy Gratton, a professor at Cranfield University, warns against eliminating pilots from all testing. He emphasizes, “You lose a huge amount without pilots—you miss lessons a pilot would identify, plus it can take four times as many people on the ground to test a drone.”
The United Kingdom also has a history of building technology demonstrators. According to Chris Yeo, who flew the 1986 Experimental Aircraft Programme (EAP) prototype, the approach aligns with the X-plane philosophy: “They all research some facet of flight, and demonstrate the design is working correctly.” With eyes on the next generation, BAE Systems is taking the lead on a new demonstrator—supported by 100 UK suppliers including Rolls-Royce—to test technologies for the Global Combat Air Programme (GCAP). This fighter concept, powered by current Typhoon engines, aims for its own first flight in 2028, and BAE’s Tony Godbold reports that virtually every UK fast jet test pilot has already tried simulated flights in it, indicating widespread excitement in the field.
Godbold also stresses the strategic aspect of these ongoing projects, considering them evidence of the UK’s dedication to international defense collaboration with Italy and Japan. “This proves we are serious in this space,” he states.
The Persistent Importance of Human Involvement
Even as technology evolves rapidly with simulations and drones, most in the field agree that human expertise is essential when it comes to testing and certification. “You can model a lot on computers and simulators, but the experience of test pilots is when stuff gets real—we only really learn things when we get their feedback,” Godbold says.
Whether piloted or autonomous, advancements from initiatives like the X-59 are poised to change the course of both civilian and military aviation on a global scale.