NASA's X-59 "frankenjet" tests supersonic flight without the sonic boom - Ars Technica

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More than two decades since the Concorde supersonic airliner last took to the skies, NASA has been flying an experimental aircraft designed to replace loud sonic booms with a quieter thump equivalent to a car door slamming shut 20 feet away. A successful NASA flight test program could influence the design of future supersonic airliners capable of flying overland routes without rattling buildings—and people’s nerves.

The Lockheed Martin X-59 Quesst—an acronym for Quiet SuperSonic Technology—first took flight late last year and recently began supersonic test flights. But unlike with many experimental “X-plane” aircraft that may never leave restricted airspace near Edwards Air Force Base in California, NASA plans to eventually take the X-59 on a tour around the United States so residents of various cities and towns can provide feedback on the quieter sonic “thumps” it produces.

“Usually an X plane is kind of bare-bones—‘cobble it together from a bunch of parts from other airplanes and just demonstrate one thing,’” said Jim “Clue” Less, a NASA test pilot and aerospace engineer, in an interview with Ars. “We need to demonstrate that one thing, but then we need a plane that’s robust enough that we can fly it all over the place and gather that data.”

The move comes at a time when the US Congress has been advancing legislation that could legalize overland supersonic travel. That would reverse a 1973 ban implemented by the US Federal Aviation Administration, which was informed by the public backlash and noise complaints following US military tests of supersonic flights over Oklahoma City, Chicago, and St. Louis in the 1960s.

But even if the X-59 program shows that quieter supersonic travel is possible, any potential revival of commercial supersonic flights would still have to prove financially viable despite challenges such as massive fuel consumption costs.

Less and Peter Coen, the mission integration manager for NASA’s Quesst mission and former manager of NASA’s Commercial Supersonic Technology project, spoke at length with Ars about the quirks of piloting a supersonic aircraft with no front window, the X-plane’s “frankenjet” design, a harrowing early flight test, and what people around the United States can expect once the X-59 starts doing its national tour.

NASA’s X-59 quiet supersonic jet flies over the Mojave Desert during its third flight on Thursday, March 26, 2026, from NASA’s Armstrong Flight Research Center in Edwards, California.

Credit:<br>NASA | Carla Thomas

NASA’s X-59 quiet supersonic jet flies over the Mojave Desert during its third flight on Thursday, March 26, 2026, from NASA’s Armstrong Flight Research Center in Edwards, California.

Credit:

NASA | Carla Thomas

An airframe designed for sonic thumps

The X-59’s distinctive airframe, developed by Lockheed Martin Skunk Works in partnership with NASA, is most likely to stand out at first glance—especially the long, tapered nose that makes up almost a third of the aircraft’s nearly 100-feet length. The nose is designed to help break up the shockwaves that are typically created when an aircraft flies faster than the speed of sound.

“All the features of the X-59, from its long tapered nose to the engine mounted on top to the shape of the wing—each one of those features was done in one way or another to control the strength of a shockwave,” Coen told Ars.

A supersonic aircraft typically creates multiple shockwaves emanating outward from the nose, canopy, engine inlet, wings, and tail of the aircraft. Those individual shockwaves “start to pile up on each other” and eventually form two remaining shockwaves that travel down to the ground, Coen explained. People on the ground usually hear the double bang of the two shockwaves as a single sonic boom.

The “trick to solving the sonic boom problem” involved creating an airframe design that could make shockwaves of similar strength while spacing them out as equally as possible along the airplane, Coen said. That slows down the process of multiple shockwaves merging into larger ones and allows the atmosphere to weaken the smaller shockwaves to smear out the sharp pressure change into a more gradual increase.

The result is that human ears will hear a “thump or a whoosh” as opposed to a typical sonic boom, Coen said. Whereas the Concorde’s sonic boom noise was around 105 perceived level in decibels (PldB)—potentially enough to rattle window frames and household items if the...