NASA’s newest X-plane, the X-59, is on track to match or exceed the speed of sound with a test in early 2023, the space agency says. The plane is designed to do what the X-1 supersonic test pilots did, but quietly.

Instead of a thunderous sonic boom that would disturb people on the ground, it should create a softer, less-intrusive “thump.” If successful, its technology could prove fast and safe enough for future commercial passenger transport.

Designed by Lockheed Martin, the QueSST (Quiet Supersonic Transport) X-59 will take to the skies over the Mojave Desert in California. Residents in several neighborhoods it flies over will be able to provide survey comments about any noise they notice. Based on their feedback, new regulations could lift the ban on supersonic flight over land.

“And when that happens it will mark another historic milestone in flight, potentially opening a new era in air travel, where airline passengers might hop on a supersonic jet at breakfast time in Los Angeles to make a lunchtime reservation in New York City,” according to an October 14 NASA news release.

The first time pilots attained speeds faster than Mach 1, surpassing the speed of sound, was on October 14, 1947, with the joint X-1 team of NACA, the newly formed Air Force, and Bell engineers and pilots. Test pilot Chuck Yeager is now an icon for being the first to break the sound barrier.

“That first supersonic flight was such a tremendous achievement, and now you look at how far we’ve come since then. What we’re doing now is the culmination of so much of their work,” Catherine Bahm, an aeronautical engineer at NASA’s Armstrong Flight Research Center in California, says in the release.

Because of the crack as an airplane pushes past the sound barrier, supersonic flight over land was banned in 1973.

Supersonic flight of any commercial craft ended with the final Concorde Supersonic Jet flight in 2003. In the 1960s, the Concorde became the first aircraft ferrying passengers on commercial flights. It traversed the Atlantic Ocean, from JFK International Airport to London Heathrow Airport. Facing a host of practical challenges, including cost, only 14 Concorde aircraft ever went into service.

Yet, X-plane research in both the military and scientific spheres hasn’t stopped. Engineers have a deeper understanding of how to shape an aircraft to temper the intensity of a sonic boom, particularly with NASA’s Shaped Sonic Boom Demonstration program in 2003 and 2004. At the time, the Northrop F-5E jet’s fuselage was reshaped to change the pattern of shock waves it would generate, resulting in less-intrusive sonic booms.

If successful, QueSST will demonstrate that the X-59 can regain the dream of supersonic flight for all.

In 2018, Popular Mechanics spoke to NASA’s Deputy Chief Pilot for the X-59 program, Jim Less, to learn what he expects from the X-59, an aircraft design like nothing that has ever flown before.

(The following interview has been lightly edited.)

Popular Mechanics: How does it feel to be a test pilot for NASA’s first supersonic X-plane in years?

Jim Less: Well I grew up in junior high and high school reading Popular Mechanics and Popular Science and reading about X-planes and various things that the Air Force and NASA was doing out here at Edwards—hard to believe I’m now out here doing it myself.

 

NASA/Lockheed Martin

PM: It’s pretty special to be involved in a brand new aircraft program. How did you get started in flight test?

Less: In the Air Force. I went to college and went through Air Force ROTC, went off to Air Force pilot training, and along the way went through the Air Force test pilot school. I worked the rest of my Air Force career as a test pilot, and then retired after almost 21 years in the Air Force, and started up here with NASA coming up on eight years ago.

PM: What aircraft were you testing for the Air Force?

Less: Primarily the F-16. That was about 1999 for three years until 2002, specifically doing flight test. Then I taught at our test pilot school as an instructor for two years, and I went off and did my obligatory staff job in Washington D.C., and then got back to a little bit of flying.

PM: Are you looking forward to flying this plane more than others you’ve flown and tested?

Less: I’d say probably more. It’s a manned supersonic X-plane, those don’t come along every day. We’re doing something that hasn’t been done before, that’s the kind of thing that test pilots like to do. So I can’t wait. It’s going to be two or three years before this flies, and that’s going to be a long wait, but I know there’s a lot of work to do and it’s going to go by quickly.

Less: The fact that it’s a unique, one-of-a-kind aircraft, and not a whole lot of people are ever going to get to fly it—that’s the kind of thing that test pilots find… professionally rewarding, let’s say. It’s also rare that you can get in on the design of an aircraft and stay with the program all the way through building it, flying it—I hope to be flying it until we’re done with the program.

We’re all very curious to see if it really works—maybe I shouldn’t say that out loud (laughs). They’ve done all the studies, they’ve done all the computer models, and everything projects that it’s going to be quiet. Part of me would want to be on the ground listening to the first quiet sonic boom, though I’d rather be up flying the airplane. But if we fly it over and you can barely hear it, then it’s going to be a huge success and everyone is going to be very excited.