From the moment Chuck Yeager broke the sound barrier for the first time in 1947, zipping from New York to Paris in less than three hours became every travelers dream. Its a dream that shattered as soon as everyone realized supersonic flight was really annoying for people on the ground. Thats why NASA and Lockheed Martin created the X-59 Quesst, which was designed with an aerodynamic profile that would reduce the eardrum-breaking boom to a dull thump. NASAs upcoming test flight was supposed to be the first silent supersonic flight in historythen January 28 happened.Thats when the startup company Boom Supersonic flew a supersonic flight over the Mojave Desert, in California, using a radically different approach that was theorized decades ago but only now has been possible thanks to new engines and computers.[Photo: Boom Supersonic]The company announced the milestone February 10. The testing of its Boomless Cruise technologyrecorded with a sophisticated microphone array by NASAshowed that its XB-1 demonstrator aircraft broke the sound barrier three times without generating a sonic boom that reached the ground. This is the first time a plane has achieved this.On our first flight, we expected to break the sound barrier without a sonic boomthat was our prediction, Blake Scholl, founder and CEO of Boom Supersonic, tells me. We broke the sound barrier three times: on the first flight, no boom; and on the second flight, three more times. Our forecast was no sonic boom, and thats exactly what we had.Rather than redesigning the physical airframe of the airplane to redirect air and reduce the supersonic shock volumelike the X-59the company bet on taking advantage of using a physical phenomenon called Mach cutoff, using powerful computers and software to carefully change the airplanes speed and altitude depending on the weather around it.[Photo: Boom Supersonic]Mach cutoff is a phenomenon where a sonic boom, instead of traveling directly to the ground, bends upwards and dissipates into the atmosphere. There is a boom that comes off the airplane, but it makes a kind of U-turn in the sky, Scholl explains. And as long as the boom is coming off the airplane at the right angle and its high enough, you can think of it as the bottom of the U never touches the ground. And as long as the bottom of the U never touches the ground, theres no audible boom.This phenomenon occurs because the sonic boom refracts upward due to temperature and wind gradients affecting the local speed of sound, just as how a pen appears to bend when passing through a glass of water because the difference in the density of water and air affects how light propagates.The NASA X-59 [Image: Lockheed Martin]Unlike the X-59s low-boom approach, Boomless Cruise aims to entirely eliminate the boom at ground level. The X-59 is designed to manage the shockwaves through its airframe design, aiming for a gentle thump. The way the engine is placed, and the fact that theres no cockpit breaking the flow of air, its Pinocchio nose reduces the sonic boom.Scholl says the approach works, but theres still a boom. With Boomless Cruise, there literally is none. During its first supersonic flight, XB-1 reached a top speed of Mach 1.12, demonstrating that the theory works. The data collected during XB-1s supersonic runs allowed Boom to validate their sonic boom models and refine the algorithms that predict the operation within Mach cutoff. The successful flight test validated that this works.[Photo: Boom Supersonic]What were doing is well-known physics thats been around for a long time, Scholl says. The key to making it a reality now lies in advanced engine technology and sophisticated computing capabilities, which were unavailable in the past. The Concorde could have done it, but its engines werent powerful enough and they required afterburning to reach supersonic speed. The kind of computing power thats needed to do what the XB-1 did during its two flight tests also didnt exist. So, fast-forward 50 years, computers, weve got great weather data, and weve got engines that are powerful enough to fly supersonic without afterburners.[Photo: Boom Supersonic]The future of supersonic flightAfter validating Boomless Cruise technology, the company is planning to build its supersonic airliner. It will utilize the Symphony engine, which is specifically designed for enhanced transonic performance, to enable Boomless Cruise for commercial flights. Symphonys enhanced transonic thrust will allow its commercial airliner, called Overture, to surpass the sound barrier at altitudes exceeding 30,000 feet. This altitude is sufficient for Mach cutoff physics to function.According to Boom Supersonic, Overture will use the companys secret sauce: an advanced autopilot system that continuously optimizes speed for the Boomless Cruise based on real-time atmospheric conditions. This is what allows it to avoid the sonic boom. This dynamic adjustment is essential because weather conditions, particularly temperature and wind, significantly affect the speed of sound and the behavior of the sonic boom.[Photo: Boom Supersonic]If all goes as well with the demonstrator, the only major hurdle will not be technical but legal. Just as NASA is trying to do with its Quesst program, the company will need to convince lawmakers to allow for supersonic flight from coast to coast, over the continental United States. Hes convinced it will happen. Its a very simple regulatory change. We should have a noise limit, not a speed limit, he tells me.Boom Supersonic also notes on its site that Overture is not designed as a low-boom aircraft, and [they] do not expect to certify it for unrestricted supersonic flight over land. This means that, over sea, the airplanes speed will be unrestricted, reaching Mach 1.7. There will be no speed limit because the sonic boom doesnt matter over the ocean, and flying from Paris to New York will be twice as fast, taking only about 3.5 hours versus the current 7 hours. Over land, however, the future aircrafts speed will be restricted to Mach 1.3 to avoid the booms, Scholl says: Sometimes, as low as 1.05 and sometimes as high as 1.3. Usually, itll be between 1.1 [and] 1.2. Thats 50% faster than current commercial planes, which will get you from New York to Los Angeles in around three hours rather than six.Whatever happens with regulations, with this successful display, Boom Supersonic has demonstrated that it can be done. We will need to wait and see if it reaches the point in which we will enjoy quiet, affordable, and sustainable supersonic travel. And perhaps restart the era in commercial aviation that the Concorde brought to the world.