NASA’s X-59 enters a new testing phase after the second flight and moves closer to quiet supersonic traffic

NASA’s X-59 entered a new testing phase: second flight opened the way toward quiet supersonic traffic

NASA’s experimental X-59 aircraft, a project developed to demonstrate that supersonic flight over land does not have to mean a destructive sonic boom, has entered a new stage of testing. After the first flight carried out on October 28, 2025, the American space agency also conducted the aircraft’s second flight on March 20, 2026, in the California airspace around Edwards Air Force Base and NASA’s Armstrong Flight Research Center. Although the flight ended earlier than planned because of a technical warning in the cockpit, NASA says the mission still provided valuable data and that the program is moving forward. That very detail best shows what the real development of aviation technology looks like: progress is not measured only by ideal scenarios, but also by how safely and methodically one responds when a problem appears.

X-59 is not an ordinary research aircraft, nor merely a demonstration of futuristic design. It is the central element of NASA’s Quesst mission, a program that aims to make room for the return of commercial supersonic flights over land, but without the classic powerful “sonic boom” that for decades was the main reason for regulatory restrictions. Instead of a loud shock wave heard for kilometers, the X-59 is expected to produce a much quieter sound, which NASA describes as a softened bang or a dull “thump.” If that is confirmed in tests and in the field, the results could help American and international regulators when considering future rules for faster civil aviation.

From preparations to an actual flight in just a few days

In mid-March, NASA announced that the X-59 was preparing for its second flight, which was supposed to mark the beginning of the so-called envelope expansion phase. This is a standard, but extremely important process in the development of experimental aircraft, during which the confirmed range of the aircraft’s speeds, altitudes, and operating modes is gradually expanded. Put more simply, engineers and pilots do not head immediately toward ultimate performance, but instead move the aircraft forward step by step, with constant checks of safety, system behavior, and the consistency of real data with what simulators, calculations, and ground tests have shown.

Before the second flight, NASA and Lockheed Martin, the main industrial partner on the program, carried out extensive inspections after the first takeoff. According to NASA’s data, after the first flight the team removed the engine, part of the tail structure known as the lower empennage, the pilot’s seat, and more than 70 access panels in order to perform detailed inspections and maintenance. After that, the systems were reassembled and returned to operational condition. An additional important step was an engine run test on March 12, 2026, at the Armstrong center in Edwards, when the modified F414-GE-100 engine was activated, a version of the engine also used in the F/A-18 Super Hornet fighter aircraft.

At that stage, NASA was announcing that the second flight would in many ways resemble the first one, but also that at the same time it would open the door to more demanding testing. The plan was for the X-59 first to fly at about 230 miles per hour at an altitude of 12,000 feet, with functional checks, and then to climb to 20,000 feet and accelerate to about 260 miles per hour. These are still far more modest figures than the final design goals, but that is precisely why they serve as a transition between the initial confirmation that the aircraft can take off and land and the later approach to full supersonic operation.

The second flight was short, but not unsuccessful

According to NASA’s official announcement of March 20, 2026, the X-59 took off that day at 10:54 local time from Edwards base. At the controls was NASA test pilot Jim “Clue” Less, while Nils Larson, the first pilot of the X-59 program, again had an important role in escorting and observing the flight from a separate aircraft. But a few minutes after takeoff, Less noticed a warning in the cockpit related to one of the aircraft’s systems. In accordance with prescribed procedures, the decision was made to return to base, and the aircraft landed safely at 11:03.

At first glance, such an outcome may sound like a setback, but in test aviation the opposite is often a sign that the system and the team are functioning as they should. When flying a prototype unlike anything else in the world, the most important thing is that warnings are recognized in time, that the pilot has clear procedures, and that the ground team can quickly assess the risk. NASA therefore emphasized that, despite the shortened mission duration, an additional amount of data was collected that will help in planning the next tests. Project manager Cathy Bahm said it was a good day for the team because the pilot landed safely and useful data were obtained for the continuation of the campaign.

This practically confirmed that the second flight, although not carried out in its full planned profile, still marks the real entry into 2026 as a year of more intensive flight testing. Instead of big, marketing-friendly promises, NASA in this case as well is characteristically cautious: each next step follows only after telemetry, cockpit warnings, system responses, and the aircraft’s behavior in all operating modes reached so far are examined in detail.

Why the X-59 is so special

At first glance, the X-59 already differs from classic civil and military aircraft. Its elongated, extremely pointed nose, narrow fuselage, and specific surface arrangement are not the result of an aesthetic experiment, but of an aerodynamic goal: reshaping the shock waves that arise during flight faster than sound. In conventional supersonic aircraft, these waves combine into a powerful shock wave that people on the ground experience as an explosive bang. NASA’s concept tries to distribute those waves differently, so that a much milder acoustic signature reaches the ground.

The program is not aimed only at proving that the aircraft can briefly break the sound barrier. The X-59’s design goal is about 925 miles per hour, or approximately Mach 1.4, at an altitude of about 55,000 feet. Those figures, however, are not reached quickly. NASA clearly points out that the first major leap was already made simply by the fact that the aircraft flew for the first time in 2025, while further increases in speed and altitude will proceed in small, strictly controlled steps. There is no spectacle in such an approach, but it is precisely what is crucial if the aim is to obtain an aircraft whose data can be used as a basis for future regulatory decisions.

An additional special feature of the program is the way safety is monitored in the air. Alongside the X-59 flies an escort aircraft, the so-called chase aircraft, with another experienced pilot serving as an additional pair of eyes and monitoring the condition of the experimental aircraft in real time. NASA states that this escort helps with visual checks, supplements communication with flight control, monitors weather conditions, and, if necessary, enables more detailed close observation of the aircraft. For slower test segments, an F/A-18 is often used, while in the faster, supersonic phases NASA’s F-15s will also play a major role, as they can follow the X-59 in modes closer to its ultimate performance and carry additional instruments for measuring shock waves.

What follows after envelope expansion

Envelope expansion is only the first phase of the broader Quesst mission. After NASA confirms that the X-59 operates reliably across an ever wider range of speeds and altitudes, a phase focused on acoustic validation follows. Then it will no longer be decisive only whether the aircraft can fly safely, but whether it truly produces the quiet acoustic signature for which it was developed in the first place. This means that the way the structure disperses shock waves will be studied and how closely the theoretical model matches actual in-flight measurements.

After that, NASA plans flights over selected communities in the United States in order to collect data on how people on the ground perceive the sound of the X-59. That part of the program is especially important because future rules will not depend only on the physics of flight and laboratory measurements, but also on how the population perceives the sound in real conditions. NASA has previously emphasized that it intends to share the results of those tests with American and international regulators. In translation, the success of the X-59 would not be only a technological trophy for NASA, but a possible foundation for changing rules that have for decades restricted supersonic traffic over land.

It should also be kept in mind that there is a broader historical context. Classic commercial supersonic traffic remained limited precisely because powerful sonic booms over populated areas caused unacceptable noise and complaints. Because of that, flights such as Concorde’s were mainly focused on routes over the ocean. NASA’s approach does not try to bring back the old model of supersonic travel, but to offer a new technical basis on which future civil aircraft could be both faster and more acceptable for life on the ground.

Why even a shortened test matters for the industry

In the aviation industry, especially in the segment of experimental aircraft, the public often sees only two extremes: great success or great trouble. But the reality of developing complex systems is almost always somewhere between those two points. An early return because of a cockpit warning does not automatically mean that the project is in difficulty, just as one neatly completed flight does not mean that all challenges have been solved. What truly matters to experts is the quality of the data, the consistency of the procedures, and the team’s ability to make more precise decisions for the next step on the basis of each test.

In the case of the X-59, NASA communicates in precisely that way. The agency does not hide that the second flight was shorter than planned, but at the same time clearly points out that this is the beginning of a longer campaign that includes dozens of flights during 2026. Such a tone is important both for the industry and for the public, because it shows that this is a serious research program, not a demonstration designed only for headlines. For manufacturers of future civil supersonic aircraft, for regulators, and for communities that might one day live under new fast air corridors, these methodical tests will be more important than any promotional image of an aircraft in the sky.

If NASA succeeds in proving that supersonic flight can be made quiet enough, the possibility opens for one of the greatest changes in civil aviation since the end of the Concorde era. Travel within the United States, but also in other major land markets, could be significantly shortened. But the road to that is still long, and the second flight of the X-59 showed why: every new speed, every new altitude, and every warning in the cockpit are part of the process by which technology is transformed from a concept into something that could one day become an industry standard. That is exactly why this flight, although short, was not a passing episode but an important step in verifying whether the future of supersonic travel can be both fast and quieter.

Sources:

• NASA – official announcement on the second X-59 flight and the shortening of the mission due to a technical warning (link)
• NASA Armstrong – preparations for the second flight, the planned flight profile, and the start of the envelope expansion phase (link)
• NASA – media announcement of tests with data on planned altitudes, speeds, and the role of the Quesst mission (link)
• NASA Aeronautics – explanation of the role of F/A-18 and F-15 chase aircraft in safety and future acoustic measurements (link)
• NASA Quesst – overview of the program’s goals and the planned steps after aircraft testing (link)