Let’s be honest, we all want commercial supersonic flight. Long-haul flights can be soul-destroying, and traveling just a few hours to spend the weekend on the other side of the world would fundamentally change travel forever. Yet, while a taste of the future of travel was shown with the Concorde, it was soon ripped from grasp as manufacturers grapple with the huge drawbacks of supersonic flight. Particularly, the rather difficult problem of sonic booms.
Now, Lockheed Martin and NASA’s answer to the ever-prevalent sonic boom issue, a new supersonic plane design called the X-59 Quiet SuperSonic Technology aircraft, has returned home after months of ground tests, and the outlook is positive. Testing whether the aircraft could survive the intense stress it would be under at supersonic speeds, NASA have stated that phase is now complete and they need to do a few further tests before it can begin its first flight, pushing us one step closer to commercial supersonic travel.
Created when an aircraft passes through the sound barrier, a sonic boom is the result of compressed pressure waves at the front and rear of the aircraft merging into a singular shockwave as they can no longer get out of the way of each other before they reach the ground. Many people believe that a sonic boom only happens when the aircraft first passes into Mach 1 (above 767 miles per hour or 1,235 kilometers per hour, which is the speed of sound), but this is false – the shockwaves are heard by everyone the aircraft flies over.
The crack of a bullet is the same effect as a sonic boom, although on a much smaller scale. This noise is already enough to cause hearing damage in veterans, but make that shockwave bigger – say, the size of a jet – and it is capable of causing structural damage and noise of up to 120 decibels. It is therefore not viable to have commercial airliners flying overhead that constantly shatter windows in its path, and so supersonic flight above land is prohibited.
So, to create an airliner that can scorch across the world at above Mach 1, engineers must quieten the boom.
The X-59 was an aircraft concept that computer models predicted would produce a much quieter sonic boom, which NASA calls a “sonic thump”. While still not ideal, the design significantly reduces the noise and potential damage created by a sonic boom, which both Lockheed Martin and NASA hope will allow the ban on overland supersonic commercial flights to be lifted.
If the tests succeed as planned, the X-59 will be debuted above communities as early as 2024, says NASA. They then hope that the X-59, and the sound measuring technology used in its creation, will pave the way for overland supersonic flight.
“With the X-59, we want to demonstrate that we can reduce the annoying sonic booms to something much quieter, referred to as ‘sonic thumps,’” said John Wolter, lead researcher on the X-59 sonic boom wind tunnel test, in an earlier statement.
“The goal is to provide noise and community response data to regulators, which could result in new rules for overland supersonic flight. The test proved that we don’t just have quieter aircraft design, but that we also have the accurate tools needed to predict the noise of future aircraft.”