NASA's X-59 project, aimed at developing a silent supersonic aircraft, has reached a crucial milestone with the completion of the flight readiness review, paving the way for future flight tests. This promising advancement could transform air travel by reducing the noise of sonic booms.
Artistic illustration of the X-59 in flight over land.
Credit: Lockheed Martin
An independent committee at NASA evaluated the safety of the X-59 project for the public and personnel during ground and flight tests. This thorough assessment of potential risks and hazards ensured the necessary safety before proceeding to flight tests.
The flight readiness review is an initial step in the flight approval process. According to Cathy Bahm, NASA's Low-Boom Flight Demonstrator project manager, it is a process aimed at identifying the necessary actions to address before moving on to the airworthiness and flight safety review.
The X-59 project, in collaboration with Lockheed Martin, seeks to transform the sonic boom into a quieter "thump." This development is central to NASA's Quesst mission, which could eventually enable commercial supersonic flights over land, banned for over 50 years due to the noise of sonic booms.
The X-59 team still has significant milestones to achieve before flight begins. Upcoming steps include ground tests on system integration and electromagnetic interference. Although the X-59's design is innovative, it incorporates proven components from other aircraft, like the landing gear from an F16.
NASA's X-59, shown in this illustration, is designed to fly faster than the speed of sound while producing softer sonic "booms." To test the public's perception of this noise, part of the Quesst plan includes flying the X-59 over several communities to evaluate the residents' reactions.
Credits: Lockheed Martin
Brad Neal, chairman of the X-59 airworthiness and flight safety review committee, emphasizes that while these systems come from existing aircraft, they have never worked together before.
The sonic boom
A sonic boom is a sound shockwave generated when an object exceeds the speed of sound (approximately 767 mph) in air. When this object, such as an aircraft, crosses this speed barrier, it compresses the air molecules in front of it, creating a shockwave that propagates outward and backward. This shockwave manifests on the ground as a loud noise, similar to an explosion.
This phenomenon occurs because the aircraft is traveling faster than the sound waves it generates, forcing these waves to compress and form a conical shockwave called a Mach wave. When it reaches the ground, this wave is perceived as a boom. Sonic booms can be heard over large distances and can cause disturbances and damage, including vibrations and broken windows.
The Mach wave can be visible when the sound barrier is broken in a moisture-laden environment. The compressed air condenses the water present in the atmosphere, forming a mist, making this compression visible.
To mitigate these negative effects, ongoing research aims to reduce the intensity of sonic booms. NASA's X-59 project is an example, aiming to replace the boom with a much less disruptive "thump." These advancements could allow the reintroduction of supersonic flights over land, currently banned in many countries due to noise disturbances.