X-59 QueSST: NASA’s Silent Supersonic Jet

For decades, supersonic commercial travel has been grounded over land due to the disruptive shockwaves known as sonic booms. NASA is working to change that with the X-59 QueSST (Quiet SuperSonic Technology). This experimental aircraft is designed to fly faster than sound while generating only a gentle “sonic thump,” potentially opening the door for a new era of rapid passenger flights across the globe.

The Problem with Current Supersonic Flight

To understand why the X-59 is necessary, you have to look at the history of aviation regulations. In 1973, the Federal Aviation Administration (FAA) banned civilian supersonic flights over land in the United States. Other nations followed suit. This ban was largely due to the Concorde.

When an aircraft like the Concorde breached the sound barrier, it pushed air molecules aside with such force that they formed shockwaves. These waves merged as they trailed the plane, creating a double bang loud enough to rattle windows and set off car alarms on the ground. Because of this, supersonic travel was restricted to ocean routes, which limited the economic viability of faster-than-sound commercial planes.

The X-59 is not a prototype for a commercial airliner itself. Instead, it is a data-gathering machine designed to prove that an aircraft can break the sound barrier without disturbing the public below.

Engineering the "Quiet" Thump

Lockheed Martin Skunk Works, the legendary division responsible for the SR-71 Blackbird, built the X-59 in Palmdale, California, under a $247.5 million NASA contract. The design philosophy focuses entirely on aerodynamics that prevent shockwaves from coalescing.

The Shape

The aircraft looks unlike anything else on the runway. It measures 99.7 feet long and 29.5 feet wide. The most striking feature is its nose, which accounts for nearly a third of the plane’s total length (about 30 feet). This elongated nose creates a specific airflow that keeps shockwaves separated.

The Engine Placement

Engineers mounted the engine, a General Electric F414-GE-100, on top of the tail section. This unusual placement directs the exhaust upward and away from the ground, further preventing shockwaves from reaching the surface as a loud boom. This engine generates 22,000 pounds of thrust, allowing the X-59 to cruise at Mach 1.4, or roughly 925 miles per hour, at an altitude of 55,000 feet.

The Metric: 75 PLdB

The goal is to reduce the noise on the ground from the standard 105+ decibels of a Concorde-style boom to just 75 Perceived Level decibels (PLdB). NASA compares this sound level to a car door slamming twenty feet away. In a busy city, residents might not even notice it.

The External Vision System (XVS)

One of the most unique challenges of the X-59’s design is pilot visibility. Because the nose is so long and tapered to maintain quiet aerodynamics, there is no forward-facing window in the cockpit. A real window would disrupt the airflow and ruin the sonic profile of the jet.

To solve this, NASA developed the eXternal Vision System (XVS). The pilot relies on a 4K monitor in the cockpit that displays stitched-together images from two cameras mounted on the nose and one under the plane. This creates an augmented reality view, overlaying flight data directly onto the visual feed. It is one of the few times a pilot will fly a supersonic aircraft solely by reference to instruments and video screens for forward visibility.

The Mission Roadmap

The rollout of the X-59 is just the beginning. NASA has outlined a three-phase plan for the Quesst mission.

Phase 1: Flight Readiness

This phase occurs at the Armstrong Flight Research Center in California. It involves extensive ground testing, engine runs, and the initial first flight. Engineers will verify that the aircraft handles correctly and that systems like the XVS function safely in the air. This phase ensures the plane is airworthy before it attempts supersonic speeds.

Phase 2: Acoustic Validation

Once the plane is proven safe, pilots will fly it over the test range at Edwards Air Force Base. NASA will use thousands of ground-based recording devices to measure the actual sound reaching the desert floor. They need to confirm that the “thump” actually registers at 75 PLdB as the computer models predicted.

Phase 3: Community Response

This is the most critical phase, slated to begin around 2025 or 2026. NASA will fly the X-59 over several selected U.S. cities (the specific locations have not yet been publicly finalized). Residents in these areas will be surveyed to see if they heard the aircraft and if they found the noise disruptive.

Changing the Rules of the Sky

The ultimate product of the X-59 program is data, not the plane itself. NASA intends to deliver the results of the community response surveys to the FAA and the International Civil Aviation Organization (ICAO).

If the data proves that supersonic flight can be quiet, regulators may switch from a speed-based ban (no flying faster than Mach 1) to a noise-based standard (no flying louder than X decibels). This regulatory shift is the “green light” that aerospace manufacturers like Boom Supersonic and others are waiting for. It would allow airlines to offer flights from New York to Los Angeles in 2.5 hours rather than 5, transforming domestic travel.

Frequently Asked Questions

How fast will the X-59 fly? The X-59 is designed to cruise at Mach 1.4, which is approximately 925 mph at its cruising altitude of 55,000 feet.

When will the X-59 take its first flight? While schedules in experimental aviation often shift, NASA and Lockheed Martin are targeting the first flight for late 2024 or early 2025, following the completion of vibration and engine tests.

Can I buy a ticket to ride on the X-59? No. The X-59 is a single-seat experimental demonstrator. It will never carry passengers. Its purpose is to test technology that will eventually be applied to commercial passenger jets.

What creates the “thump” instead of a “boom”? A standard sonic boom happens when shockwaves from the nose and tail of a plane merge into two distinct, loud pressure waves. The X-59’s shape spreads these waves out so they never merge, resulting in a soft rise in pressure rather than a sharp explosion of sound.