What is it Like to Travel at Hypersonic Speed?

While the dream of commercial hypersonic travel may seem far from reality today, the exploration and understanding of hypersonic speed are paramount in the field of aerospace engineering. Hypersonic speed, defined as speeds greater than Mach 5 (five times the speed of sound), represent a realm that few have experienced in its entirety. Despite the absence of publicly available hypersonic civilian aircraft, various rocket-powered vehicles have pushed the boundaries of speed and technology.

The Fastest Air-Breathing Manned Aircraft

One of the most notable and fastest air-breathing manned aircraft is the Hypersonic vehicle, which has a top speed between Mach 3 and Mach 4. This vehicle, while not being part of regular civilian airlines, has paved the way for advancements in hypersonic technology.

What is Hypersonic Speed?

Hypersonic speed is much more than just a fast way to travel. It's a domain where aerodynamics, propulsion, and materials science must all converge to create a reliable and efficient means of transportation. The transition from subsonic to hypersonic speeds occurs at Mach 5, and it's a journey that is both challenging and fascinating.

Experience of Hypersonic Travel

Traveling at hypersonic speeds is not an everyday experience. Unlike the supersonic Concorde, which cruised at Mach 2, hypersonic craft are typically rocket-powered, which means they produce significant noise and vibrations during their acceleration phase. Astronauts and pilots in rocket-powered vehicles, such as the X-15 and the Space Shuttle, have reported feeling engine rumble and force akin to a strong gravitational pull.

Astronauts and Pilots' Experiences

Astronauts aboard the Space Shuttle experienced extreme conditions during reentry, when they encountered temperatures of up to 1,650 degrees Celsius and speeds of Mach 25. During this period, they felt forces up to three times the force of gravity. Similarly, pilots of the X-15 reached speeds as high as Mach 6, which also involved significant acceleration and deceleration phases. These intense experiences are primarily associated with the high-g force during launch and re-entry rather than during steady hypersonic cruising.

The Concorde and Supersonic Flights

While the Concorde did not travel at hypersonic speeds, it serves as a useful comparison. Concorde flights, which cruised at Mach 2, had a smooth experience for passengers and pilots. The transition to hypersonic speeds requires much more advanced technology and infrastructure, making its commercial realization a distant goal.

Astronauts' Perspective on Hypersonic Travel

Astronauts and space explorers experience hypersonic speeds as they travel into space and return to Earth. Upon liftoff, astronauts often experience G-forces of up to 11 Gs, which can last for half an hour. As they climb and reach orbit, they experience near-zero gravity. However, during de-orbit and re-entry, they encounter a similar G-force to what they experienced during launch, as they decelerate towards the planet.

According to renowned physicist Albert Einstein, acceleration and gravity are essentially equivalent experiences from a physical standpoint. Therefore, the main times when people feel the effects of hypersonic speed as a force equivalent to gravity are during acceleration and deceleration phases. This observation is made by an interested amateur enthusiast, but it aligns with fundamental principles of physics.

As technology advances, the possibility of hypersonic travel for civilians becomes a more tangible reality. Advancements in materials, propulsion systems, and aircraft design are pushing the boundaries of what is possible. While the experience of hypersonic travel may continue to be limited to a few select individuals, the promise of speed and efficiency it offers is exciting for the future of aerospace.