Hypersonic technology is the next step in aviation and defense. But what is it, exactly? How does it relate to supersonics? And what effects will hypersonic technology have on the future of flight and warfare? To find out more about how hypersonic technology works, and how it could be used, RSnake spoke with Dr. Leon Vanstone, rocket scientist and CEO of VerdeCode. Vanstone explained that hypersonic engines open up new possibilities for space travel, flight, and even mining. Hypersonics are also being used in the military; China and Russia both have hypersonic missiles in their arsenals.
Hypersonic vs. Supersonic
Both hypersonic and supersonic speeds are faster than sound. Supersonic is usually understood as a speed of Mach 1-4 and hypersonic is Mach 5 and above. At hypersonic speeds, objects are traveling so fast that the air molecules around them start breaking apart or becoming electrically charged. The speed of sound is the speed that sound waves move through a substance (air or water). At 32 degrees Fahrenheit in dry air, sound moves at 1,086.9 feet/second. Supersonic and hypersonic speeds are measured using the Mach ratio named after physicist Ernst Mach. It compares the speed of a fluid (air counts as a fluid in this case) with the speed of sound in that fluid. Mach 1 is the first supersonic speed, then Mach 2, and so on. While it’s rare, some vehicles have gone as fast as Mach 9.6. Though some military aircraft fly at supersonic speeds, supersonic flight was banned for civilian travel in the 1970s because of the noise it makes – the “sonic boom.” Today, NASA is actively experimenting with quieter supersonic technology that only makes a “sonic thump.”
The Significance of Hypersonic Technology
To many, hypersonic technology represents a huge leap forward from our current
capabilities. And it’s big money. The hypersonic tech market was valued at $4.98 billion
in 2020 and is expected to more than double by 2030.
Space Travel
Hypersonic engines could make it easier and less expensive to get to outer space. With
current technology, vehicles are launched using huge rockets that are very heavy.
Vanstone explained, “A 1000-ton rocket would have 400 tons of oxygen inside it. Liquid
oxygen. For reference, that's pretty much the weight of the ISS (International Space
Station). A decent-sized rocket taking off basically carries the ISS.”
Once the very heavy rockets have served their purpose, they fall into the ocean, never to
be used again. It’s not a very efficient or cost-effective way to make multiple trips.
With hypersonic travel, a single vehicle could be used multiple times to carry people or
equipment into space. This could open up new possibilities like innovative space
research, space mining, or even space tourism.
Faster International Travel
Some companies are also interested in hypersonic travel on earth. Imagine going
around the world in just one hour. International travel would be forever transformed. And
it has the potential to produce fewer emissions. Some of the companies developing
hypersonic planes are also exploring the use of hydrogen to power them. Hydrogen
doesn’t produce carbon dioxide when it burns, so it’s considered an environmentally
friendly fuel.
Mining
In his chat with RSnake, Vanstone showcased a hypersonic engine made by the
company he worked with at the time, Hypersciences, that could launch projectiles at
hypersonic speeds. Vanstone explained the engine could be used for mining and
building underground infrastructure for geothermal energy.
If a hypersonic engine were embraced for these purposes, it could transform those
industries. One of the main problems with geothermal energy is the initial infrastructure
cost. If a hypersonic projectile could punch into the earth faster than the drills we have
today, geothermal energy could become more available.
Defense
Hypersonic flight is also attractive for defense purposes. Many countries including the
United States of America have made and tested hypersonic missiles.
Hypersonic missiles have the advantage of stealth, and can be launched over long
distances. Unlike ballistic missiles, they are maneuverable. This makes their path
difficult to predict. Some say a hypersonic missile attack would only be noticed minutes
before a strike.
Types of Hypersonic Vehicles
So far, hypersonic engines are most popular for planes and missiles.
Planes
Currently, the only hypersonic plane in existence is a Chinese drone called the WZ-8. It
can reportedly fly at speeds up to Mach 7.
A few companies are working towards hypersonic passenger planes for international
travel. While this is a compelling vision, the technology is likely still years or decades
away.
NASA is also researching hypersonic technology with the intent of using it for space
exploration. Space planes could one day be a reality, though the research is still
evolving.
Aeroballistic Missiles
These are dropped from planes and powered by rockets to hypersonic speeds. They
then detach and cruise to their targets.
Hypersonic Glide Vehicles
Although these may sound relatively innocuous, they are actually hypersonic missiles.
Russia and China both have them in their arsenals.
Hypersonic glide vehicles (HGVs) are launched with rockets or ballistic missiles high up,
almost into space. They then detach and zoom along at hypersonic speeds towards
their targets.
Hypersonic Cruise Missiles
A hypersonic cruise missile (HCM) is defined as a missile that powers itself for the
duration of the flight and keeps a constant speed of at least Mach 5.
This technology is more complicated since it requires one or more engines to operate
both at hypersonic and subsonic speeds. Russia has an HCM called the Zircon.
Challenges and Risks
Hypersonic technology has its downsides.
As a cutting-edge technology, it is very expensive to develop. Companies that create
hypersonic tech put a high price tag on it. Hypersonic vehicles require special materials that can take very high heat. Facilities to test the technology are also expensive.
There are also a number of problems with hypersonic flight. Since a vehicle is traveling
at such high speeds, it’s incredibly vulnerable to even slight changes in the atmosphere.
Vanstone said, “Rain at 5000 miles an hour. That's a bullet. Hail is definitely. These are
real problems if you want to fly these vehicles.”
A hypersonic plane would also have to navigate both hypersonic and subsonic speeds.
Vanstone explained that scramjet hypersonic engines can only operate at hypersonic
speeds. Ramjet engines only work at supersonic speeds. How then is a plane to
accelerate from a full stop to a hypersonic speed and decelerate again?
Hypersonic missiles pose their own set of problems. Since the missiles are so difficult
to detect, current American defense systems need to be upgraded to protect against
potential threats from countries with this technology. There is also pressure for the U.S.
to develop its hypersonic capabilities in order to compete with China and Russia, which
has resulted in an arms race.
The Takeaway
Hypersonic technology is exciting, but engineers and other scientists have a lot to figure out before people climb in hypersonic planes ready to take them to far-flung countries or into outer space. And the current focus on developing hypersonic missiles is concerning. For a full discussion on hypersonic technology, and to find out what a rail gun is, check out RSnake’s conversation with Vanstone today!