Will Purdue Close the Hypersonic Weapons Gap with 3D Printing?

Purdue University is developing a new hypersonics center that is meant to create high-temperature materials—and it’s bringing along a number of high profile partners to help. The University’s Hypersonics Advanced Manufacturing Technology Center (HAMTC) will work with Lockheed Martin, GE Additive, Dynetics, Aerojet Rocketdyne, GE Edison Works, Boeing and others on the technology. The Uni will initially get $18 million to close the weapons gap in hypersonics.

Mike Sangid (Purdue University photo/Vince Walter)

I’ve stated before that making hypersonic craft with current stage materials is a bit like trying to make an aircraft out of Play-Doh. Our current materials are too costly and are not capable of performing at the high-temperatures and pressures created by traveling five times the speed of sound. This is a sentiment echoed by Michael Sangid, executive director of HAMTC, who is trying to change this with the new center.

“When you heat up 3,000 degrees Fahrenheit, small differences in expansion can cause large stresses between components made of different materials that may result in failure of hypersonic vehicles. At HAMTC, we can essentially increase the temperature capabilities of materials via new compositions, create new manufacturing routes to produce complex geometrical designs, and join these dissimilar materials together, in order to meet the requirements of hypersonic environments. We’ll have researchers and students work on real industrial and defense problems, while at the same time advances and transitioning innovations in high temperature materials and cutting-edge additive manufacturing,” Sangid said.

HAMTC will be colocated with the $41 million Hypersonics and Applied Research Facility, which features a Mach 8 wind tunnel and the hypersonic pulse (HYPULSE) reflected shock/expansion tunnel. About these Sangid explained, “We are vertically integrating our design/build/join/test capabilities here in our building. With the HYPULSE and Mach 8 tunnels, the idea is we can shorten the development cycles because we’ll not only have every step in the process under one roof, but we’re going to have the talent under one roof, as well.”

Chris Schuppe, general manager – engineering and technology, GE Additive:

“The potential and opportunity for additive manufacturing in hypersonics is huge. We are honored to be part of Purdue’s team supporting the Department of Defense in manufacturing research that will advance U.S. national security and competitiveness; we value results-driven, industry-academic collaboration in industrializing additive. Our team – many of whom are Purdue alums – are excited to get started.”

John Ferguson, an aeronautics and astronautics graduate student, prepares to measure the thermo-mechanical strength of prototype materials for hypersonic vehicles in the Advanced Computational Materials and Experimental Evaluation Lab. (Purdue University photo/Vince Walter)

This program is a much-needed shot in the arm for the hypersonics efforts of the U.S. The country has been pioneering in the field for decades now, making craft that can exceed the speed of sound for a number of minutes or seconds. But recent tests of hypersonic weapons by China and Russia have gotten a lot of U.S. planners worried. It would seem that China is much further than the U.S. in hypersonics. Indeed, it is being described as a ‘Sputnik moment’, in reference to the U.S. was completely surprised by the Soviet’s ability to launch and orbit a satellite. Similarly then, it was feared that the enemy was far ahead of the U.S. in the space race. Now, just like then, the U.S aims to catch up.

The U.S. has a tradition of being overly alarmed at enemy’s capabilities, highlighted by the fact that, for decades, the country thought that there was a “missile gap” in which the U.S. trailed the Soviets in intercontinental ballistic missile (ICBM) technology, capability, and numbers. This turned out to be untrue. So, perhaps, now the nation’s military leaders are also overreacting to a few tests. In this case, however, the country could very well decide to err on the side of caution, not only to feed the military industrial complex, but also to guard against a threat that will be almost impossible to counteract if borne out.

Missile tracking and defense systems, such as the Patriot or Iron Dome, as well as general military planning is all based on a subsonic or supersonic world. Russia’s Skyfall hypersonic missile is a nuclear-powered weapon with a global range, indeed, it could patrol for a long time before choosing to land somewhere. China’s own tests have demonstrated that they can have a modicum of guidance over their hypersonic vehicles, with one vehicle release another hypersonic one while in flight. Meanwhile, the U.S.’s most recent tests have failed. It’s as if the country is trudging along on foot and the near-peer rivals have brought cars to the war. In a hypersonic world, a missile could be launched at a speed too fast to intercept and, within a few minutes, come down anywhere on the planet.

This would make the U.S. vulnerable. Indeed, its carrier groups could be struck by such missiles or its cities attacked and the world’s superpower could do nothing to stop them. This is why hypersonics are so valuable to the Chinese and Russians. They can’t catch up to the military might of the U.S. overall. The US has been spending more on defense than anyone else for decades now. However, revolutionary new kit could make most of the U.S. arsenal outmoded. Crucially for Beijing, the U.S. could not make a credible threat to China to stop an invasion of Taiwan if China had hypersonics. If the People’s Republic believes this, then it stands to reason that it will spend tens of billions on its hypersonics dream. For Russia, it can be relevant with a strategic weapon once again whilst most of its arsenal is being held together by duck tape, sweat, and hope.

Intermetallics, bulk metallic glasses, dispersion steels, new superalloys and more materials will need to be developed to make hypersonics viable. Ceramics and completely new classes of materials will be needed for engines and all surfaces. At stake is the ultimate high ground, space, and the ability to strike with impunity globally.

As we wrote about two years ago, hypersonics will be bring AM into the fore once again. Machining very hard materials is sometimes impossible and always lengthy and costly. Meanwhile, saving a little weight has a huge impact on a vehicle as expensive and capable as these hypersonic craft need to be. 3D printing can make optimal weight saving structures, reduce part count, and optimize component properties and surfaces while working on difficult-to-machine items. Therefore, a major role is reserved for our technology on what is shaping up to be a modern arms race.