NASA's X-59 Experimental Jet Aims to Quiet Supersonic Flight
The X-plane program, with its history of focused, experimental aircraft, continues with the X-59 designed to significantly reduce sonic booms.
NASA's X-59 aircraft, an experimental jet with a distinctively long, pointed nose, is designed to tackle the challenge of sonic booms, potentially paving the way for quieter supersonic air travel over land. This unique design, featuring a cockpit positioned far back and reliant on external cameras for forward vision, aims to transform the sharp shockwave of a sonic boom into a softer sound, akin to a car door closing.
The X-59 embodies a long-standing philosophy within NASA's X-plane program, which dates back to the Bell X-1's breaking of the sound barrier in 1947. This approach, as explained by program manager Peter Coen, involves setting specific, limited goals for each experimental airframe. The X-1, for instance, was shaped like a bullet to efficiently achieve supersonic speeds. Later, the X-15 rocket plane, a cylinder with small wings, pushed the boundaries of speed and altitude, contributing vital data on heat-resistant materials for projects like the Space Shuttle.
The current X-59's primary objective is sonic boom suppression. Its elongated nose is engineered to manage the airflow and shockwaves, aiming to reduce the traditional loud boom to a more acceptable level. NASA is conducting community surveys during the X-59's test flights over selected towns to gauge public reaction to these quieter sonic events. Coen anticipates the sound will be comparable to a nearby car door closing when the aircraft exceeds Mach 1 at cruising altitudes.
This experimental jet is a composite of parts from existing aircraft: its cockpit and ejector seat are from a T-38 trainer, its landing gear from an F-16 fighter, and its engine from an F-18. Lockheed Martin assembled the aircraft for NASA, with a camera system feeding a screen in front of the pilot to compensate for the lack of direct forward visibility. The X-59 first flew in 2025 and is now actively testing its supersonic capabilities.
The development of the X-59 also raises questions about the relevance of piloted X-plane projects in an era of rapidly advancing drone technology. While NASA has explored uncrewed X-planes, such as the blended-wing-body X-48, the decision to crew the X-59 was partly driven by the cost and complexity of certifying a robotic jet for supersonic flight over populated areas. The need for a larger airframe, necessitated by the requirements for a cockpit, also played a role.
Future X-plane projects are likely to be uncrewed, according to Coen, unless the research specifically involves piloting technologies or if crewing proves more cost-effective. This aligns with broader trends in aerospace, although the value of human test pilots in validating complex systems remains significant. As seen with the UK's Experimental Aircraft Programme (EAP) in the 1980s, which tested core systems for the Typhoon fighter, and BAE Systems' current technology demonstrator for a future combat air program, the human element in testing and feedback is still considered crucial.
These ongoing X-plane initiatives, both in the US and internationally, underscore a continued commitment to pushing the boundaries of flight technology, whether focused on reducing noise pollution or developing advanced military capabilities.