NASA's Quiet Supersonic
For decades, commercial supersonic flight has been stuck on the ground—at least over land. The deafening shockwaves caused by breaking the sound barrier led to strict regulations that banned aircraft like the Concorde from flying at full speed over populated areas. NASA is now aiming to change those rules forever with the X-59, a unique experimental aircraft designed to turn a sonic boom into a quiet sonic “thump.”
The End of the Sonic Boom
The primary hurdle for supersonic travel is the noise. When an aircraft flies faster than the speed of sound (Mach 1), it pushes air molecules aside faster than they can escape. This creates shockwaves that merge together as they separate from the plane. When these merged waves hit the ground, they create a startling, thunder-like explosion known as a sonic boom.
This noise pollution is why the United States banned civilian supersonic flight over land in 1973. To lift this ban, regulators need data proving that a plane can fly faster than sound without shattering windows or startling residents. This is the sole purpose of the X-59.
NASA’s “Quesst” mission (Quiet SuperSonic Technology) uses the X-59 to demonstrate that careful aerodynamic design can prevent shockwaves from coalescing. Instead of a loud double-bang, people on the ground should hear something more akin to a car door slamming down the street or distant thunder.
Engineering the X-59
The X-59 is not a prototype for a future airliner. It is a distinct, one-of-a-kind experimental jet built by Lockheed Martin at their famous “Skunk Works” facility in Palmdale, California. Every inch of its geometry is engineered to manipulate airflow.
The Long Nose
The most striking feature of the X-59 is its length. The aircraft is 99.7 feet long, but the nose alone accounts for roughly 30 feet of that length. This needle-like nose is critical. It spreads out the shockwaves generated by the nose and the wing, preventing them from combining into a single, high-intensity front.
The Hidden Cockpit
Because the nose is so long and tapered, there is no place for a forward-facing window. A traditional windshield would create drag and disrupt the supersonic flow. Instead, the pilot sits deep within the fuselage and relies entirely on technology to see.
NASA developed the eXternal Vision System (XVS) to solve this. It consists of a 4K monitor located where the front window would normally be. Two cameras mounted on the nose and one below the fuselage stitch together a high-definition view of the world ahead. This effectively gives the pilot an augmented reality window, overlaying flight data directly onto the video feed.
Engine Placement
The engine intake is mounted on top of the aircraft, rather than underneath. This is a deliberate choice. By placing the General Electric F414-GE-100 engine (the same engine used in the F/A-18 Super Hornet) on top, the structure of the aircraft shields the ground from the shockwaves created by the engine inlet. This further ensures that the sound reaching the ground remains quiet.
Measuring the Sound
The standard measurement for sonic booms is Perceived Level decibels (PLdB). A Concorde supersonic boom registered around 105 PLdB, which is loud enough to be physically felt and potentially cause minor structural damage to glass or plaster.
The X-59 targets a noise level of 75 PLdB. To put this in perspective:
- 105 PLdB: Thunder overhead or a chainsaw nearby.
- 75 PLdB: A car door slamming 20 feet away or the sound of basketball dribbling.
At this lower level, the sound blends into the background noise of daily life. If successful, the X-59 will cruise at Mach 1.4 (925 mph) at an altitude of 55,000 feet while remaining barely noticeable to anyone standing below.
The Quesst Mission Timeline
NASA has broken the project down into three specific phases to ensure they gather the necessary data for the Federal Aviation Administration (FAA) and international regulators.
Phase 1: Aircraft Development and Testing
This phase covered the construction and initial rollout of the aircraft, which occurred on January 12, 2024. Following the rollout, the team began a series of ground tests, engine runs, and taxi tests to ensure all systems function correctly. The first flight is the capstone of this phase, proving the aircraft is airworthy.
Phase 2: Acoustic Validation
Once the X-59 is flying, NASA will fly it over the Armstrong Flight Research Center in California. During these flights, thousands of sensors on the ground will record the acoustic signature of the plane. NASA needs to verify that the “thump” produced in the real world matches the computer models and wind tunnel data they have been studying for years.
Phase 3: Community Response
This is the most critical step. Starting around 2025 or 2026, NASA will fly the X-59 over several select U.S. cities. The specific cities have not yet been announced to avoid biasing the results.
Residents in these areas will act as citizen scientists. NASA will ask them to provide feedback on what they heard (if anything) and how annoying they found the noise. This human data is what regulators require. If the data shows that the 75 PLdB thump is acceptable to the public, the FAA may replace the current speed limit (Mach 1) with a noise limit. This would open the door for companies like Boom Supersonic to build commercial airliners that can cut flight times from New York to Los Angeles in half.
Why This Matters for Travel
If the X-59 succeeds, it will change the economics of global travel. Currently, supersonic flight is only viable over oceans (like New York to London). However, a vast number of lucrative flight routes are over land. Being able to fly at supersonic speeds from San Francisco to Washington D.C., or London to Dubai, requires permission to break the sound barrier over populated terrain.
The X-59 represents a shift from “speed limits” to “sound limits.” By providing the data needed to change the law, NASA is paving the way for a new era where cross-country flights take two hours instead of five.
Frequently Asked Questions
Will the X-59 carry passengers? No. The X-59 is a single-seat experimental aircraft. It is a technology demonstrator strictly designed to gather data. It does not have room for passengers, cargo, or commercial amenities.
How fast can the X-59 fly? The aircraft is designed to cruise at Mach 1.4, which is approximately 925 miles per hour. It will fly at an altitude of 55,000 feet.
When will the X-59 fly for the first time? After its rollout in January 2024, the aircraft entered extensive ground testing. The first flight is expected to take place later in 2024, subject to the results of ongoing safety checks and engine runs.
How much did the X-59 cost to build? NASA awarded Lockheed Martin a contract valued at approximately $247.5 million to design, build, and deliver the aircraft. The total cost of the Quesst mission, including testing and community overflights, is higher and spread over several years of operation.
Does the X-59 have a window? The pilot does not have a forward-facing window. Due to the long nose, the pilot uses the eXternal Vision System (XVS), which uses high-definition cameras and a 4K monitor to provide a view of the flight path. There are, however, side windows and a canopy glass above the pilot.