Nasa X59 makes history with first supersonic flight: Science explained

Nasa successfully flew its experimental X-59 aircraft at supersonic speeds. Learn the science behind how this unique design replaces sonic booms with a quiet thump.

In Short

• Nasa X-59 achieves first supersonic flight at Mach 1.1 speed.
• A unique aerodynamic shaping prevents loud sonic booms from merging.
• Future tests will evaluate public perception of quiet supersonic sound.

Nasa has officially entered a new era of aviation. On June 5, the experimental X-59 aircraft successfully broke the sound barrier for the first time, marking a monumental shift in how we might travel across the skies in the future.

This historic flight is a giant leap for the Nasa Quesst mission, which aims to replace the jarring noise of traditional supersonic flight with a gentle thump.

BREAKING THE SOUND BARRIER QUIETLY

For decades, flying faster than the speed of sound, known as supersonic flight, was synonymous with a deafening sonic boom.

When an aircraft travels faster than sound waves can move, it creates a pressure wave that crashes into the ground as a thunderclap.

This disruptive noise has historically led to global bans on supersonic travel over land.

The X-59 is designed to change that. Instead of a loud boom, the aircraft aims to produce a soft thump, no louder than a car door closing in the distance.

During its test flight at Edwards Air Force Base in California, the aircraft reached a top speed of Mach 1.1.

In simple terms, Mach 1.1 means the plane was flying at 1.1 times the speed of sound, or approximately 713 miles per hour (1,147 kilometres per hour).

By successfully hitting these speeds, the team has proven that the X-59 aircraft is performing exactly as intended. This process of gradually increasing speed and altitude is called envelope expansion.

It allows engineers to test the safety and structural integrity of the aircraft at every stage, ensuring that the machine is ready for the rigours of high-speed travel.

THE SCIENCE OF THE QUIET THUMP

To understand the genius of this design, one must look at how the aircraft is shaped. Imagine an object moving through the air. At slower speeds, air molecules have time to move out of the way.

However, as an aircraft approaches the speed of sound, these molecules no longer have time to react, causing them to pile up. This creates a high-pressure shockwave.

A conventional supersonic jet has a blunt profile that forces air to compress into one massive, powerful shockwave. Think of it as pushing a large wall of air that smashes into the ground all at once.

Nasa engineers designed the X-59 with a radical, elongated shape. Its nose alone is nearly 30 feet long. This unique geometry prevents those air pressure waves from merging together.

Instead of one massive shock, the X-59 creates a series of smaller, weaker waves that stay separated as they travel toward the ground. By the time they reach an observer, they feel like a soft sound rather than a window-rattling boom.

Additionally, the engine is mounted on top of the aircraft to use the body of the plane as a shield, directing noise away from those on the ground.

These advancements represent a triumph of computational fluid dynamics, a field where researchers use powerful computers to digitally shape every curve of the aircraft to manage these sound waves.

The team is now preparing to push the aircraft to Mach 1.4, which is about 925 miles per hour (1,488 kilometres per hour), in the coming days.

As the X-59 continues to push boundaries, it brings us one step closer to a world where speed and silence coexist.

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