NASA will demonstrate its plans to test its Quiet Supersonic Technology (QueSST) over United States communities this week in Nashville.
NASA’s X-59 aircraft
Supersonic flight, or flying at speeds greater than the speed of sound, is commonplace for military aircraft. But, commercial airliners have been somewhat restricted over land due to the associated “booms” that come with this kind of flight.
Called “sonic booms,” these are a sequence of shock waves produced by supersonic aircraft that combine to form two deafening booms that can be heard for miles around. Overland, these booms make unacceptable noise levels for the public.
While there have been some successes in the past, with the likes of the now long-retired Concorde, she was banned from conducting flights over land. Since then, on the whole, there have been few attempts to make the supersonic flight the norm for commercial airliners.
But, if means could be found to reduce the noise generated by these aircraft, especially over land, it could drastically shorten travel times. This is where aircraft like NASA’s planned X-59 aircraft could prove revolutionary for air travel.
Fitted with something called Quiet Supersonic Technology (QueSST), this sonic boom-reduction technology is being developed to make supersonic flight over land a real possibility in the future.
The X-59 measures 94 feet (29 meters) in length and has a 29.5-foot wingspan (9 meters). Like the Concorde, the aircraft has a long, pointed nose cone that obstructs forward vision. This obstruction will be made up for by an improved flight vision system, which is most likely made up of 4K cameras.
The Concorde’s 105–110 Perceived Level Decibels (PLdB) on the ground are much higher than the Lockheed Martin-designed aircraft’s target of 75 PLdB. According to its designers, the boom produced by this aircraft shouldn’t be any louder than the thump of a car door.
To put these levels into perspective, a whisper is about 30 dB, normal conversation is about 60 dB, and a motorcycle engine running is about 95 dB. Levels consistently over 70 decibels can damage human hearing, and over 120 decibels can cause severe damage to your eardrums.
NASA is set to showcase the X-59 at the Grand Hyatt Nashville Hotel this week
According to NASA Langley Research Center’s Gautam Shah, its features will be discussed when he presents “NASA Quesst Mission – Community Response Testing Plans” at the 183rd Meeting of the Acoustical Society of America.
As part of the meeting taking place between the 5th and 9th of December 2022 at the Grand Hyatt Nashville Hotel, the presentation will be held on December 6 at 10:50 a.m. Eastern U.S. in the Summit Broom.
The X-59 aircraft, according to Shah, “is intended to validate and demonstrate the design tools and technologies that make it possible to design an aircraft with a different shape that alters how supersonic shock waves behave.”
“Instead of coming together to be heard as a loud boom, the shock waves do not merge. They rapidly weaken, resulting in a sound more like a soft thump,” he added.
NASA will fly over several American cities and towns to test the theory and determine how the public would react to various noise levels; Shah and his team will measure the aircraft’s sound and perform surveys of the general population.
The organization wants to inform an overland supersonic sound standard by giving this knowledge to regulatory bodies.
After 18 months of testing to ensure the aircraft’s performance and safety, the first flight of the X-59 is scheduled to occur in 2023. NASA plans to carry out four to six community tests around the country between 2025 and 2026 to provide the results to regulators in 2027.
The mission website has more information. Additionally, NASA has created the Quesst Mission Supersonic STEM Toolkit, which features acoustics, flight-related activities, and learning resources.