Hypersonic Travel: How Fast Can You Go?

    The fastest speed ever traveled by a human is 39,937.7 km/h (24,816.1 mph). This record was achieved by the crew of NASA’s Apollo 10 moon mission on May 26, 1969, as they returned to Earth. It’s important to note that this speed was achieved in the vacuum of space. 

    On Earth, humans have not come anywhere close to these speeds due to factors such as air resistance and the physical limitations of the human body. For instance, the fastest sprinter, Usain Bolt, reached a top speed of 37.6 km/h (23.4 mph).

Introduction

    Hypersonic travel, defined as flight through the atmosphere at speeds greater than Mach 5, is a concept that has intrigued scientists and engineers for decades.

     It promises to revolutionize travel by drastically reducing flight times. For instance, a hypersonic flight could potentially cover the distance from New York to London in just 90 minutes! But how does it work, what are the challenges, and what does the future hold for this exciting field of technology? Let’s dive in.

Understanding Hypersonic Speed

    The term “hypersonic” refers to speeds greatly in excess of the speed of sound, usually meaning greater than Mach 5. To put that into perspective, Mach 1 is the speed of sound, which is approximately 767 miles per hour (mph) or 1234 kilometers per hour (km/h). Therefore, Mach 5 would be around 3,806 mph or 6,126 km/h. That’s about 60 miles per minute, or the equivalent of a four-minute commute from Washington, D.C., to New York!

The History and Progress of Hypersonic Travel

    The concept of hypersonic travel isn’t new. In fact, vehicles have been flying at hypersonic speeds – in excess of Mach 5 – for almost 70 years. The first manufactured object to achieve hypersonic flight was the two-stage Bumper rocket in February 1949, reaching a speed of about Mach 6.7.

Hypersonic flight

    In recent years, significant advancements have been made in hypersonic technology. For instance, the NASA X-43A flew on scramjet for 10 seconds and then glided for 10 minutes on its last flight in 2004. The Boeing X-51 Wave rider flew on scramjet for 210 seconds in 2013, finally reaching Mach 5.1 on its fourth flight test.

The Challenges of Hypersonic Travel

    Despite these advancements, there are still significant challenges to overcome before hypersonic travel becomes a reality. These include:

1. Fluid-structure interactions: At supersonic and hypersonic speeds, aircraft are subjected to aerothermal heating, reducing the stiffness and strength of the airframe and making the structure more susceptible to strong fluid-structure interactions.
2. Propulsion: One of the greatest challenges is the availability of a propulsion system to efficiently accelerate vehicles from rest to hypersonic speed and then cruise at that speed.
3. Materials: The materials used must be able to withstand the thermodynamic loads and intense heat generated from friction and air resistance during hypersonic travel.
4. Heat Management: Managing how hot vehicles get at high speeds is a major technical issue.
5. Aerodynamics: The aerodynamics of a vehicle traveling at such high speeds is another significant challenge.
6. Fuel Efficiency: Hypersonic vehicles must be fuel-efficient to be economically viable.

The Future of Hypersonic Travel

    Despite these challenges, the future of hypersonic travel looks promising. Several startups are looking beyond the speed of sound to hypersonic travel. For instance, Hermeus is an American startup building a hypersonic passenger plane that could travel from NYC to London in just 90 minutes.

    Moreover, Stratolaunch is developing its Talon-A hypersonic research vehicle which will test hypersonic payloads at speeds up to Mach 6. Another company, Destinus SA, based in Switzerland, is developing a hypersonic hydrogen-powered vehicle capable of moving cargo between continents at unheard-of shipping speeds.

Conclusion

    Hypersonic travel holds immense potential for revolutionizing transportation by drastically reducing flight times. While there are significant challenges to overcome, advancements in technology and increased interest from startups indicate a promising future for this field. As research continues and technology advances, we may soon see the day when we can travel anywhere in the world in just a few hours.