A Q&A on hypersonics

Developing and defending against missiles flying faster than Mach 5

An illustration of a hypersonic missile flying over a mountain range.

Hypersonic weapons fly at speeds above Mach 5, or about one mile per second. Extreme speed, maneuverability and ability to fly at lower altitudes make them hard to stop.

Speed. It’s the one word Erin Kocourek hears every day.

That’s because she’s responsible for connecting the people and the programs working to deter and defeat hypersonic missiles – the fastest weapons ever built – and speeding the delivery of hypersonic systems to U.S. forces.

“Our adversaries are testing and flying hypersonic weapons at a pace that is frightening – significantly more flight tests a year than we do and on multiple variants,” said Kocourek, senior director of hypersonic requirements and capabilities at Raytheon Missiles & Defense, a Raytheon Technologies business.

We sat down with Kocourek to discuss hypersonic weapons and how the company is using decades of expertise to develop end-to-end technologies, both defensive and offensive.

Erin Kocourek
Erin Kocourek

What are hypersonic weapons, and why is it hard to defend against them?

Hypersonic weapons are typically classified by their ability to achieve speeds greater than Mach 5 and remain in the atmosphere during flight. 

They fall into two categories: boost glide and scramjet. In a boost glide system, a rocket accelerates its payload to high speeds. The payload then separates from the rocket and glides unpowered to its destination. The air-breathing scramjet relies on high-speed for power. Basically, the air around the missile is moving so fast, the missile takes it in and uses it for propulsion.

What makes hypersonic weapons challenging to defend against, apart from their sheer speed, is their ability to maneuver. They do not fly a predictable flight path, making them difficult to track versus traditional and conventional ballistic weapons that do.

We’re investing in the development of kinetic weapons like missiles, and non-kinetic weapons such as electronics and directed energy to deter, target and defeat hypersonic threats.  

How are hypersonic weapons different from intercontinental ballistic missiles? 

Hypersonic weapons stay within the upper threshold of the atmosphere and do not have a predictable flight path because of their ability to maneuver, whereas ICBMs leave the atmosphere and fly a predictable trajectory. Since hypersonic systems hug the Earth’s atmosphere, they don’t necessarily need to travel as far as ballistic missiles do, so the time to target is less. 

What makes hypersonic technologies hard to develop?

Heat management is one challenge – hypersonic weapons heat up as they accelerate through the atmosphere, so they require airframes that can withstand those blazing temperatures. 

Another challenge is understanding the environment our systems will be exposed to during flight. We can use wind tunnels to emulate hypersonic flight conditions to a degree, but it’s unclear how well these ground tests accurately capture the shock, vibration and thermal stresses that happen in flight. 

We gather vibration data in what are known as “freejet tests” to better understand the environment a scramjet creates for the rest of the system. But this data may not be as exact as we would like because the test article isn’t the same as the vehicle we would fly. Since we are flying these systems for the first time, there’s no historical knowledge to draw from to guide our designs. 

To address these issues, we leverage data gathered from similar government efforts, implement best practices from other programs, and apply margin based on engineering judgment to ensure our designs are robust enough to handle uncertainties.  

How can digital engineering help develop hypersonic technologies? 

Digital engineering allows us to do iterations, real-time changes, incorporating new options and solutions exponentially faster. Building digital twins of actual weapons is much more agile than designing systems on paper. The interconnectivity among design tools eliminates unnecessary rework and offers greater confidence as well as accuracy of engineering predictions. 

As we look to future development, we are using artificial intelligence/machine learning to help predict how the weapons fly and how to build systems to counter them. Our warfighters need industry to move faster, and modeling and simulation play a critical role in accelerating development by allowing us to validate test data.  

Do we have enough engineers to work on hypersonic programs? How do we get more? 

It’s no secret we have a national shortage of hypersonic engineers. Despite all the money we’re investing in this domain, it’s not enough to go at the speed of need. 

Raytheon Technologies is strategizing with national laboratories and agencies on workforce development, and partnering with industry colleagues, academia and STEM organizations to inspire interest in hypersonics and develop curriculum for degree programs. We must recruit the best and brightest to this field because our adversaries certainly are.

We’ve also prioritized training to ensure our workforce is at the cutting-edge of R&D and innovation. Our engineers are becoming hypersonic engineers. 

Should we expect to see more international cooperation?

Absolutely. One company and really one country can’t do the hypersonic mission alone because there aren’t enough sensors, test ranges and wind tunnels in the world to tackle this challenge. 

Bottom line – this threat is not ours alone. The U.S. must partner with its closest allies to deliver these weapons at the scale our warfighters are expecting and on time – in the next five years.  
 

Published On: 08/18/2021