Commercial aviation has been pursuing a difficult promise for decades: flying faster than sound without making that progress a problem for those on the ground. The obstacle is not only the speed, but the shock waves that generates a supersonic aircraft and that can be perceived as a sonic boom. The X-59 was born to test an alternative: reaching those speeds with an acoustic signature that NASA hopes will be much more discreet. NASA is not yet talking about commercial routes, but it is about a step designed to address one of the great barriers to this type of flights.
The most recent advance came last Friday, when the X-59 exceeded the speed of sound for the first time during a test flight within the Quesst mission. According to NASA, pilot Jim “Clue” Less took off and landed at Edwards Air Force Base in California on an 81-minute mission. The plane reached an approximate maximum speed of Mach 1.1, which the agency places in this flight at about 1,150 km/h, at an altitude of about 13,200 meters. It was an important milestone, but still within a testing phase focused on testing its flight qualities.
The test of the most discreet supersonic flight enters its decisive phase
The important thing, therefore, will not only be what happens inside the plane, but what is heard from below. Quesst is designed to demonstrate a technology capable of softening this phenomenon until it becomes a lighter sound knock. The next part of the plan involves flying over American communities and collecting the reaction of people exposed to that sound. The agency will then share those results with national and international regulators to inform future data-driven noise standards.
That is why the first supersonic flight is not an arrival point, but rather the beginning of a more demanding phase. The next step will come in the following days: a first test in “mission conditions”, with a cruising speed of Mach 1.4, which NASA places around 1,490 km/hand an altitude of about 16,800 meters. The data matters because these are the basic conditions that the agency contemplates for future flights over inhabited areas in the United States. Before asking people what they have heard, the aircraft has to demonstrate that it can operate stably in that regime.
Behind the X-59 there is not just a striking shape or an isolated commitment to recover supersonic flight. NASA recalls that it has been studying this field for more than seven decades, with special attention to the noise associated with these flights and ways to make it more discreet. The Quesst mission combines advanced simulations, wind tunnel testing, schlieren photography and computational fluid dynamics to anticipate how the air around the aircraft behaves. The current phase has to verify something very specific: whether this entire design works in flight with a full-scale supersonic aircraft.
The ultimate goal is not for the X-59 to end up transporting passengers, but for its data to help open a door that has been practically closed for decades. The information collected will be shared with national and international regulators to contribute to news noise standards based on data, not just the historical experience of the large noises associated with supersonic flight. The agency also plans to provide design tools and technology for future quieter supersonic aircraft. If the plan works, manufacturers would have more confidence to explore commercial concepts capable of flying fast without disturbing the ground as much.
As we can see, the X-59 has crossed an important line, but the Quesst mission still has its most relevant tests ahead. First you will have to get closer to the conditions planned for these test flights over inhabited areas, and then you will come to the verification that really matters for the future of the program: knowing if that sound shock is acceptable. A good part of the value of NASA data will be played there.
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