Aug 19, 2026 · 16 min · 9 segments
NASA’s experimental X-59 airplane went supersonic for the first time on June 5, 2026. What's next for the mission that aims to reopen the skies to quiet commercial supersonic flight?
Jim LessGuest
Andres AlmeidaHost
We've not really begun to test or measure the, the sonic thump, the shock waves that come off it.
At this point, we're in envelope expansion, making sure that we can get to the conditions that we need, that the airplane is safe to fly and operate under those conditions.
The flight after that, I got to 1.20, and then the last flight we flew, Nils, my colleague, took it up to 1.40, and that i- that's the design condition.
The, uh, scientists that thought of this whole program at the very beginning felt that if we could show it was-- it produced a quiet thump at 1.40, that would show that the, the technology worked.
Future airplanes could probably push it as much as about 1.7 and still have a quiet enough sonic thump.
Um, but we, we felt we had to show at least 1.4 in order to prove that the concept works.
So with a, a new airplane, one of the big unknowns is just the air speed and the, uh, the air speed indicator and the altimeter, the, the indicator that shows what our altitude is.
They measure the, the air pressure of the wind coming in as well as just the static pressure of the air around the aircraft.
And because the airplane disturbs the air around it, these pitot-static measurements are not always exactly what you expect them to be, and so there needs to be calibration of those.
I think they later figured out that that was maybe about 1.07 in reality, so it was clearly supersonic.
We had already found out that when we indicated 1.0, we were still slightly subsonic.
So calibrating all those indications is one of the things you do early on in a flight test program.
It's a software update to just calibrate the readings and make sure that, uh, what we're seeing on our gauges is actually correct.
We've not really begun to test or measure the, the sonic thump, the shock waves that come off it.
At this point, we're in envelope expansion, making sure that we can get to the conditions that we need, that the airplane is safe to fly and operate under those conditions.
The flight after that, I got to 1.20, and then the last flight we flew, Nils, my colleague, took it up to 1.40, and that i- that's the design condition.
The, uh, scientists that thought of this whole program at the very beginning felt that if we could show it was-- it produced a quiet thump at 1.40, that would show that the, the technology worked.
Future airplanes could probably push it as much as about 1.7 and still have a quiet enough sonic thump.
Um, but we, we felt we had to show at least 1.4 in order to prove that the concept works.
So with a, a new airplane, one of the big unknowns is just the air speed and the, uh, the air speed indicator and the altimeter, the, the indicator that shows what our altitude is.
They measure the, the air pressure of the wind coming in as well as just the static pressure of the air around the aircraft.
And because the airplane disturbs the air around it, these pitot-static measurements are not always exactly what you expect them to be, and so there needs to be calibration of those.
I think they later figured out that that was maybe about 1.07 in reality, so it was clearly supersonic.
We had already found out that when we indicated 1.0, we were still slightly subsonic.
So calibrating all those indications is one of the things you do early on in a flight test program.
It's a software update to just calibrate the readings and make sure that, uh, what we're seeing on our gauges is actually correct.
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