NASA’s X-59 is preparing for its first supersonic flight. Redundant systems, real-time data, and digital control ensure the safety of the tests.
Summary
NASA’s X-59 program, developed with Lockheed Martin, aims to demonstrate that an aircraft can fly at supersonic speeds without producing the classic sonic boom. The challenge is to reduce this noise to a simple “thump,” thereby making fast commercial flights over populated areas a possibility. Safety remains a priority at the heart of the project. The Flight Test Instrumentation System records more than 20,000 parameters in real time, allowing the integrity of the aircraft to be analyzed at each stage. More than 200 days of ground testing have already validated these functions. The X-59 also features fiber optic digital flight controls, redundant electrical and hydraulic systems, emergency thermal batteries, and even a hydrazine engine restart system. With a first flight limited to 386 km/h (240 mph) to verify integration, the aircraft is expected to gradually exceed Mach 1, while demonstrating the technology on which future supersonic air transport ambitions are based.
A program focused on supersonic noise control
The X-59, designated Quiet Supersonic Technology (QueSST), is a NASA technology demonstrator entrusted to Lockheed Martin Skunk Works. Its mission is simple in principle but complex in execution: to break the sound barrier while reducing the supersonic boom to a noise comparable to a car door slamming. Traditionally, an aircraft flying at Mach 1 generates a shock wave that results in a detonation that can be heard several kilometers away. This phenomenon had condemned Concorde commercial flights to flying over land, limiting its operation to ocean routes. To overcome this constraint, the X-59 adopts a 30-meter-long fuselage with a wingspan of only 9 meters, optimized to channel and attenuate shock waves. The goal is to collect scientific data to convince the Federal Aviation Administration (FAA) and the International Civil Aviation Organization (ICAO) to adapt regulations. If the results are conclusive, the prospect of supersonic commercial aircraft flying over continents could be revived, with intercontinental flights taking half the time.
A first flight designed for safety
The X-59’s first flight will be deliberately limited in speed and altitude: a loop at 386 km/h at low altitude. This phase will be used to verify system integration, control responsiveness, and aerodynamic balance. Engineers have programmed a gradual increase in power, with speed and altitude increments, before breaking Mach 1. This caution is justified by the experimental nature of the aircraft. Unlike a military prototype, the X-59 is not designed for combat but to collect reliable data in a civilian environment. Each flight is therefore calibrated to provide actionable information to regulators and manufacturers. This strategy illustrates NASA’s desire not only to demonstrate a technical feat, but to build a solid scientific and regulatory framework for the future of supersonic aviation.
The key role of the Flight Test Instrumentation System
At the heart of the program is the Flight Test Instrumentation System (FTIS). A true real-time black box, it collects approximately 60 data streams and more than 20,000 parameters. This data includes audio, video, sensors, avionics, and structural telemetry. It allows the health of the aircraft to be monitored continuously. More than 200 days of ground testing have already validated the FTIS’s ability to identify anomalies instantly. In practical terms, this means that a hydraulic fault, overheating, or loss of pressure is immediately detected and transmitted to engineers. The benefits extend beyond the safety of the X-59: these monitoring technologies can be transferred to future supersonic civil aircraft and even to conventional subsonic commercial aircraft. Modern aviation is thus evolving towards predictive maintenance, where sensors and AI anticipate failures before they occur, reducing costs and increasing reliability.
Advanced digital flight control
The X-59 is based on a fully electric digital flight control system, based on the fly-by-wire principle. Here, the control stick and throttle no longer act directly on the surfaces, but send electronic signals via fiber optics to computers. These computers translate the pilot’s intentions into precise control surface movements. The use of fiber optics reduces latency and protects against electromagnetic interference. Three independent computers provide redundancy, ensuring that control is maintained even if one of them fails. This is a strategic choice: the aircraft, designed with a very elongated fuselage and a cockpit without a direct windshield (replaced by a digital external vision system), requires artificial stability. Without computer assistance, the X-59 would be difficult to fly. This flight system therefore fulfills a dual imperative: ensuring safety and demonstrating technology that can be transferred to future transport aircraft.
Redundant systems to guard against any failure
NASA has increased the number of backup protections. The X-59 has duplicate electrical and hydraulic circuits, supplemented by backup batteries. These include thermal batteries capable of powering the hydraulic system’s electric pump in the event of a total power failure. Another innovation is an engine restart device based on hydrazine, a highly reactive chemical fuel, which provides independent ignition capability in the event of a main turbine failure. These solutions are reminiscent of military aviation practices, where system resilience is a vital imperative. For NASA, it is a matter of ensuring that each test flight takes place in a controlled environment, with a backup chain ready to intervene. These redundant devices represent an additional cost but significantly reduce the risk of accidents. They also reflect a philosophy: every safety innovation tested on the X-59 could benefit civil aviation in the future.
The strategic challenges of the X-59 for aviation
The X-59 is not just a scientific project: it will determine the return of civil supersonic flight. The Concorde demonstrated the technical feasibility but failed on economic and environmental acceptability, with high hourly costs and a ban on overland flights due to the sonic boom. By proving that it is possible to reduce this sonic boom to a level that is tolerable for the population, NASA hopes to reopen the way for commercial aircraft capable of flying from New York to Los Angeles in two and a half hours, or from Paris to Dubai in less than five hours. On the industrial front, several players such as Boom Supersonic and Spike Aerospace are closely monitoring the results of the X-59. If the demonstration is conclusive, the prospect of a market estimated at tens of billions of euros could materialize by 2035-2040. The program therefore determines both the technology and the economic future of rapid air transport.
War Wings Daily is an independant magazine.