The Lockheed Martin X-59 Quesst ("Quiet SuperSonic Technology"), sometimes styled QueSST, is an American experimental supersonic aircraft under development by Skunk Works for NASA's Low-Boom Flight Demonstrator project. Preliminary design started in February 2016, with the X-59 originally planned to begin flight testing in 2021. After delays, it began flight testing near the end of 2025. It is expected to cruise at Mach 1.42 (1,510 km/h; 937 mph) at an altitude of 55,000 ft (16,800 m), creating a low 75 effective perceived noise level (EPNdB) thump to evaluate supersonic transport acceptability.
https://globe.airplanes.live/?icao=abc9f4
https://en.wikipedia.org/wiki/Lockheed_Martin_X-59_Quesst
The Lockheed Martin X-59 Quesst ("Quiet SuperSonic Technology"), sometimes styled QueSST, is an American experimental supersonic aircraft under development by Skunk Works for NASA's Low-Boom Flight Demonstrator project. Preliminary design started in February 2016, with the X-59 originally planned to begin flight testing in 2021. After delays, it began flight testing near the end of 2025. It is expected to cruise at Mach 1.42 (1,510 km/h; 937 mph) at an altitude of 55,000 ft (16,800 m), creating a low 75 effective perceived noise level (EPNdB) thump to evaluate supersonic transport acceptability.
(first flight is today, October 28th, 2025)
NASA X-59 Makes Historic First Flight Over California - https://avweb.com/aviation-news/nasa-x-59-makes-its-historic... - October 28th, 2025