NASA’s X-59 achieves supersonic flight and prepares for higher tests

NASA’s X-59 completed its first supersonic flight on June 5, 2026, reaching Mach 1.1 and an altitude of 43,400 feet at Edwards Air Force Base in California.

The flight used an F‑15 chase aircraft, whose louder sonic booms obscured any sound made by the X‑59 itself. The X‑59’s first flight occurred on October 28, 2025, from Lockheed Martin’s Skunk Works facility in Palmdale, California, operating subsonic at 230 mph and 12,000 feet. NASA’s Quesst mission is divided into two phases: Phase 1 focuses on proving the X‑59’s performance and airworthiness, while Phase 2 involves measuring its supersonic flight signature and gathering public feedback on its acoustic impact.

The mission aims to collect data on quiet supersonic flight to help regulators establish new noise standards, potentially enabling commercial supersonic flight over land. The X‑59’s design is intended to produce a sonic ‘thump’ of less than 75 perceived‑level decibels at ground level, roughly a third quieter than the Concorde’s 100–110 dB. The X‑59 features a long tapered nose measuring 38 feet and a top‑mounted General Electric F414‑GE‑100 engine delivering 22,000 pounds of thrust.

The top‑mounted engine helps separate shockwaves, preventing them from merging into a loud sonic boom and instead producing a quiet thump, and also avoids ingesting debris kicked up during takeoffs and landings. Instead of a conventional windshield, the aircraft uses an eXternal Vision System (XVS) of cameras feeding a 4K monitor in the cockpit. The pilot relies on a life support system delivering oxygen and powering a g‑suit, along with an ejection seat adapted from a U.S. Air Force T‑38 trainer.

By late May 2026 the X‑59 had completed 15 flights, including its first gear swing on April 3, 2026, and a May 12 flight reaching 43,000 feet at Mach 0.95 (627 mph). After 38 flights, duct dives have found nothing but a damage‑free engine, according to Deputy Propulsion Lead Paul Dees. The inspection by Lockheed Martin mechanic Jonathan Reynaga occurred during a pause between the 11th and 12th test flights in the California desert at NASA’s Armstrong Flight Research Center.

Reynaga, a general flight mechanic with Lockheed Martin Skunk Works, climbed a ladder to the wing, walked to the air inlet and dove headfirst inside to inspect fan blades and sensors. Paul Dees said the procedure is a normal part of aircraft maintenance, checking for damage, foreign objects or debris that could affect engine performance. He noted the job is not temperature‑cool, with desert temperatures regularly rising over 100 °F and the aircraft still cooling after flight, and that technicians are kept in the shade to avoid overheating.

Technicians perform duct dives on NASA research jets across centers; at Armstrong this includes the accompanying F‑15 and F/A‑18 aircraft. Juan Salazar, crew chief for the Low Boom Flight Demonstrator project, said the X‑59’s inlet is similar in diameter to the F/A‑18’s but shallower, making the dive easier, and that a human mechanic remains the best way to perform the inspection. The moment of Reynaga’s dive was captured on video in the spring of 2026.

NASA plans to push the X‑59 to Mach 1.4 (925 mph) at 55,000 feet in upcoming flights, matching the conditions for future community overflights to gather public feedback on its quiet sonic ‘thump’. The X‑59 is expected to reach its performance ceiling of Mach 1.6 (1,218 mph) at 60,000 feet during upcoming test flights.

On March 24, 2026, the U.S. House of Representatives passed the Supersonic Aviation Modernization Act, calling for the FAA to update the 1973 ban on civil supersonic flight over land within a year if no sonic boom reaches the ground. The executive order issued on June 6, 2025, instructed the FAA to lift the 1973 ban on supersonic flight over land within 180 days and publish a notice of proposed rulemaking within 18 months.

The 1973 FAA ban on supersonic flight over land was enacted after incidents, including a 1968 Air Force Academy flyby that shattered 200 windows and injured 12 people, demonstrating public intolerance for sonic booms.