The design and testing of the X-59 Quiet SuperSonic Technology (QueSST) aircraft will attempt to prove that the latter is possible. NASA is attempting to prove that commercial supersonic aircraft can be constructed in such a way that the loud sonic boom they generate can be replaced with a much more tolerable sonic “thump.” Theoretically the sonic boom laid down by supersonic aircraft can be turned into a noise similar in magnitude to the noise generated by slamming a car door. It is believed that the general public, pets, structures and insurance companies will be able to endure this major reduction in noise on a regular basis.
Sonic booms are tough to eliminate. The boom happens when shockwaves are produced by an aircraft as it pushes its way through the air and displaces it as it approaches, or exceeds, the speed of sound. Sonic booms are simply a change in pressure but they generate enormous amounts of energy. Most booms generated by aircraft are in the vicinity of 110 decibels, which is similar to the sound energy of a nearby explosion or thunder released by a lightning strike, and they are just as surprising.
NASA has designed the X-59’s testing into three phases:
1) Design (completed) and construction (continuing) of the aircraft. After Lockheed Martin has completed assembly of aircraft, it will enter, what I was told to be, a 10-flight validation program completed by Lockheed Martin before the aircraft is handed over to NASA. These initial flights will include a check-out of the aircraft and validation of safety and expected performance. This will hopefully be happening at the end of this year or early 2023. The pandemic has slowed everything down on this project.
2) NASA will test the X-59 to validate its acoustic signatures. At this point, the flights are slated to be flown in the vicinity of NASA Armstrong and Edwards Air Force Base. The data from these tests will hopefully prove that the X-59 is capable of regular operations in the National Airspace System. The flights will also validate the testing equipment used to determine the impact of the “sonic thump” expected from the aircraft.
3) The X-59 will fly over selected communities across the United States to gather data from the general public to determine their opinions of the noise generated by the aircraft. At this point, I imagine this will be happening in 2024 or 2025 and will continue for a couple of years. I have not heard if the specific communities have been selected at this point. I imagine that the aircraft will travel around the country taking advantage of geographic and population density issues that will certainly affect the magnitude of the “thump” laid down by the aircraft.
At this point, the X-59 test program mission is set to end in 2027—taking into account any delays. Data gleaned from the project will be presented to rule-making and regulatory bodies for evaluation. If the program is successful, the hope is that new aircraft can be designed and evaluated by the noise they generate and not on an arbitrary speed limit.
