Though the X-59 was designed to negate the “sonic boom” typically found on supersonic aircraft, it has stayed well short of supersonic speeds—at least for now.

NASA’s X-59 experimental aircraft, part of the “Quesst” (Quiet Supersonic Technology) mission, conducted its second flight on the morning of Friday, March 20. The flight was scheduled to spend roughly one hour in the air, but was abruptly canceled after a cockpit warning. It returned to the ground at 11:03 a.m. PST, roughly 10 minutes after takeoff.

In spite of the flight’s short duration, NASA engineers praised it, claiming that they had been able to collect valuable data that would help in subsequent flights.

“Despite the early landing, this is a good day for the team,” said Cathy Bahm, the NASA Low-Boom Flight Demonstrator’s project manager, according to a NASA news release. “We collected more data, and the pilot landed safely. We’re looking forward to getting back to flight as soon as possible.”

The X-59 aircraft, designed to test supersonic flight without a sonic boom, is intended to pioneer an aviation breakthrough that would lift sound-related restrictions on supersonic travel.

The abortive flight took place near Edwards Air Force Base in California, with NASA test pilot Jim “Clue” Less at the controls. While the program’s first flight simply verified that the aircraft could take off and land, without actually testing the “quiet” sonic boom, future flights are intended to begin the transition into structured performance testing. 

The X-59’s Specifications

• Year Introduced: 2025 (experimental aircraft only)
• Number Built: 1
• Length: 99 ft 7 in (30.35 m)
• Wingspan: 29 ft 6 in (9 m)
• Weight: 25,000 lb (11,340 kg)
• Engines: One General Electric F414-GE-100 afterburning turbofan (22,000 lbf); engine more commonly used in F/A-18 Super Hornet
• Top Speed: ~Mach 1.4 (925 mph, 1,490 km/h) at altitude
• Range: Unknown
• Service Ceiling: ~60,000 ft (18,200 m)
• Loadout: None; ~600 lb (270 kg) payload
• Aircrew: 1

About the X-59’s Design

The X-59 aims to demonstrate that aircraft can fly faster than sound while producing only a soft “thump” rather than an explosive boom. To achieve this end, the X-59 features an unusually long nose cone, specifically engineered to break up the shockwave. While the aircraft measures 99.7 feet long, the narrow nose makes up a full third of the aircraft’s length, an elongated shape that spreads out shockwaves rather than allowing them to merge.

The X-59’s engine, a General Electric F414, has been mounted on the top of the fuselage, as positioning the engine this way helps direct shockwaves upward rather than towards the ground.

Because the plane’s nose is so long, the cockpit has no traditional forward window. Instead, the pilot relies on NASA’s External Vision System (XVS), which uses cameras and sensors to project a real-time image onto a high-resolution cockpit display. In other words, when “Clue” piloted the X-59, he wasn’t able to see out of the cockpit in the traditional sense.

The X-59’s Second Flight Didn’t Get Very Far

Though the second flight was cut off far before it reached its performance limits, the flight plan had not called for it to test those limits in any case. Instead of breaking the sound barrier at once, NASA planned a series of test flights to ensure the plane could fly safely at low speeds before increasing to higher ones.

Accordingly, the expected parameters ahead of Friday’s flight included speeds of 230 miles per hour at 12,000 feet and 260 miles per hour at 20,000 feet. The plane did not reach these speeds, and even if it had, they would have remained well below the aircraft’s ultimate supersonic performance targets. Engineers will deliberately increase flight conditions in small, controlled increments to ensure that the aircraft behaves exactly as expected. 

Eventually, the X-59 is expected to reach speeds of up to Mach 1.4, or 925 miles per hour (1,490 km/h). At that speed, the aircraft would operate at around 55,000 feet of altitude—or roughly 20,000 feet higher than commercial airlines. Achieving sustained supersonic flight is only part of the objective, of course; the real purpose of the aircraft is to prove that supersonic flight can be made quiet enough for overland travel. If achieved, that capability could fundamentally change the future of commercial aviation, allowing for supersonic flights along land routes—pulling the corners of far-flung locations closer together through supersonic speed. 

Why Supersonic Passenger Planes Are So Rare

Traditional supersonic aircraft generate powerful shockwaves that merge into a loud sonic boom when they reach the ground. These loud booms are more than an annoyance to people on the ground; they can break windows and cause hearing damage, two of the major reasons the United States banned commercial supersonic flight over land in 1973.

After the ban took effect, supersonic aircraft such as the Concorde had their supersonic flight routes restricted to areas over the ocean—chiefly between the East Coast of the United States and Western Europe—sharply limiting their commercial application.

While military aircraft are almost all supersonic, they rarely travel at supersonic speeds outside of combat; demonstration teams such as the US Navy’s Blue Angels and the Air Force’s Thunderbirds almost never do, with consequences if those limits are breached by mistake.

About the Author: Harrison Kass

Harrison Kass is a senior defense and national security writer at The National Interest. Kass is an attorney and former political candidate who joined the US Air Force as a pilot trainee before being medically discharged. He focuses on military strategy, aerospace, and global security affairs. He holds a JD from the University of Oregon and a master’s in Global Journalism and International Relations from NYU.

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