The US hypersonic weapons program has reached a major milestone: The Hypersonic Air Breathing Weapon Concept (HAWC) cruise missile, developed by Raytheon Technologies and Northrop Grumman, has completed two successive flight tests.

While many different countries are developing hypersonic weapon systems, and some have even deployed them to a limited degree, the real hurdle to overcome is the creation of a practical and reliable hypersonic guided missile.

The July flight of the HAWC missile for DARPA and the US Department of Defense took place at an undisclosed location and was a follow-up to the previous successful first test on September 2, 2021. Hypersonic flights are not new. They’ve been in the air since the X-15 program in the 1960s. Interestingly, such an improved prototype of an autonomous weapon had two successful flights in a row.

While the 11-month gap between flights may seem long, the Raytheon Technologies/Northrop Grumman team notes that the HAWC program accelerated development through digital engineering, in which the rocket’s virtual twin made numerous computer-simulated flights between two real-world tests. This enables the team to use digital models and real-world flight data to develop new materials, manufacturing processes and aerodynamic shapes best suited to withstand the temperatures and stresses of flight at speeds above Mach 5.

For final testing, the HAWC prototype was moved under the wing of the aircraft and raised to a high altitude where it was released. The solid rocket booster then accelerated the vehicle to supersonic speed and the scramjet was ignited. An engine with no moving parts, the scramjet uses its forward motion to compress incoming air into a shock wave that burns with fuel, generating enough thrust to propel the rocket to five times the speed of sound.

The final prototype had only minor changes compared to the previous flight and met all targets. Data obtained through telemetry will be used to improve digital models using artificial intelligence, machine learning and big data to increase efficiency and productivity as the weapon concept approaches practical implementation.

“Developing our country’s hypersonic capabilities is a critical national imperative and it was an important step forward,” said Wes Kremer, President of Raytheon Missiles and Defense, a division of Raytheon Technologies. “Running back-to-back successful flight tests gives us even more confidence in the technical maturity of our HAWC working prototype.”