The future of hypersonics research

Greg Scofield, director of Purdue Applied Research Institute’s Hypersonics Laboratory

Greg Scofield describes his 2022 return to Purdue University as “coming back home.” That’s understandable, given that he’s spent most of the last decade there. Now, he sees mentoring the next generation of engineers as a large portion of his job leading Purdue Applied Research Institute’s Hypersonics Lab. The lab specializes in assessing manufacturing techniques, as well as all kinds of hypersonic testing from thermo-mechanical to high-speed propulsion. It also focuses on building a workforce and completing test, manufacturing and design activities under contracts from industry and government.

I chatted with Scofield about the lab’s accomplishments so far and what’s next.

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Q: What are the similarities and differences that you’ve seen switching gears from industry to academia?

A: There’s a lot of similarities between industry and what we’re doing with PARI. One of the things I love is we kind of split the difference between what academia does from a benchtop, laboratory scale — usually at the small scale — fundamental science and basic research, to full-scale production that I was used to on the industry side.

PARI gets to work in this cool middle ground where we’re taking that early-phase discovery, those early TRL [technology readiness level] and MRL [manufacturing readiness level] discoveries and advancements, and move that up the chain to where we can transition it over to a large prime contractor or a large industry partner to be able to make, instead of ones and twos, hundreds to thousands of these. I love being able to work at the interface of academia and industry and government.

We get to train students on how to move technology through that development cycle. But the other neat thing about working in this environment is the fact that our students, our staff are prototyping full-scale systems. We’ve designed and built a scramjet that flew on the ground at the same flow conditions as the X-51. We’re working with major primes in industry to scale up components that will eventually fly on systems.

Boeing built four expendable X-51A demonstrators for the U.S. Air Force, one of which flew for three and a half minutes under scramjet power in May 2013, the final flight of the program. — MC

We get to do a lot of the rapid prototyping. We get to advance the state of some of this early-phase technology to a place where it’ll eventually affect our warfighters, our allies and partners as well. We’re a little closer to the action when it comes to being able to work on real systems than you might be able to be purely on the academic side of things.

Q: It sounds like you might be later in that process than some labs, but earlier in the process than most industry research. Is that accurate?

A: That’s pretty much spot on. Where we really sit in that development cycle is taking a technology that may work in the laboratory, in a controlled environment where you can get rid of some of the things that would happen out in the field and really understand at the basic physics, basic chemistry level. You can prove that concept in the laboratory scale. Where we sit is just a little bit past that, where now we’re looking at what happens when we throw in an environment that would be more indicative of the real world.

A good example is some of our wind tunnel testing. On the early side of development, you’re often doing modeling and simulation to look at how will a vehicle perform in flight, but it’s difficult to model and simulate everything and get that accurately. We can take prototype models, physical models and actually put those into a large-scale wind tunnel or high-pulse wind tunnel and test those at Mach numbers ranging from Mach 4 all the way up to Mach 25 and beyond. There’s not many places in the world that can do that, let alone in a university setting. We’re able to test and build and design things at a scale that very few academic institutions have the capability of doing, but then we’re able to continue to interface with industry in such a way that actually begins to affect the way they produce the next generation of their system or their vehicle.

Q: Is it challenging to find the projects that need the research work but that are relatively close to applicability?

A: It can be challenging in that everything at this scale doesn’t always pan out. But that’s the nature of research and development: that some things work well, some things don’t work well, but you’re continuously trying to understand why something doesn’t work so you can inform your next round of testing and hypotheses.

In our case, for the most part, we’re trying to partner with industry where they can bring their problems to us and we can help solve them. When we look at industry, research and development is really expensive. Internal research and development dollars are prized. If you’re a company, you want to know that when you take your IRAD [independent research and development] money and invest it in something, you’re going to get the most bang for your buck. It’s difficult for some companies, particularly small- and medium-scale companies, to have all of that depth of knowledge in-house.

That’s where a place like Purdue, like PARI really can shine is we have this great bench of experts — faculty members across a variety of disciplines that all work interdisciplinary projects together — and we can take those faculty, those graduate students and staff and harness that intellectual capital that the university brings and apply it to a problem in industry. When they come to us and say, “Hey, we’re having this trouble with this portion of a hypersonic vehicle” or something isn’t going as planned, we can harness that intellectual expertise and drive forward a solution without them having to have that deep staff in-house.

Q: That’s a great segue into how you set the lab’s priorities. It sounds like that really is a conversation you’re having with industry and government.

A: Absolutely. When we look at a new project that we want to start, there’s certainly some areas where we say, “Hey, this is something that we believe we’re leading in.” We’re doing a lot of ceramic printing, for instance, and I truly believe we’re a national and global leader in that technology.

There’s certainly other areas though where we’re taking direction right from the warfighter, right from industry representatives and partners. A good example of this is metal additive for next-generation systems. We can print new geometries that we could never print before, and so we’re looking at how do we create new alloys that we can use to further the capabilities of these systems. Same thing with lightweighting of systems for propulsion, and we’ve again done a lot of work in scramjets in our team and rely heavily on some of the Purdue faculty expertise there to be able to design new cooling technology for scramjets that ultimately comes from our partnership with industry. It’s certainly from a priority standpoint walking hand in hand with our partners in industry and government to guide the work that we’re doing.

Q: Is there some consistency to what those needs are?

A: Absolutely. When we look at the nation’s priorities, it’s a new hypersonic capability that’s deployed that our warfighters can use. But cost is a massive driver there. When we talk about priorities, there’s technological priorities and then there’s economic priorities. You could have wonderful technology and never be able to field it and deploy it because it’s too expensive. That’s a big problem our nation faces.

When we look at our priorities in terms of the projects that we’ve actively got going on within our facility, I’d struggle to think of one that doesn’t have cost as a major driver. Whether it’s government or industry, both are interested in how do we drive down the cost of manufacturing, validating and verifying and fielding these systems — and maintaining them, frankly, once they’re fielded. Cost is that thread that connects all of our programs that we’re working on. It’s truly what’s going to make the difference for the warfighter. If these systems are all exquisite and we can only produce a few of them at astronomical cost, we can never use them or we can’t use them in numbers that matter.

Q: Beyond cost, can you describe another priority or two?

A: Working so closely with the Purdue workforce is a giant priority for us. President [Mung] Chiang’s goal is to make Purdue the premier national defense university in the country. I think we’re doing an absolutely great job of solidifying our place there through these massive investments in hypersonics and propulsion and in defense generally. With that comes being a university that’s excited to work in the defense space. One of our big priorities as a hypersonics lab within PARI is creating pipelines of students that transition over to government, they transition over to industry, they transition over to academia in certain instances too, where they have hands-on experience with testing, with manufacturing, with design, with modeling and simulation of all of these next-generation hypersonic systems and even in some cases current systems that are being developed.

That’s something that we hear time and again from industry and government: We need students coming out of these universities that want to work in defense, that have clearances. Our facilities and our projects enable us to clear students and move those students into industry with a secret, a top secret clearance. If you think, as a company, you want to bring on a student to support a classified program, it could be months to sometimes upward of a year where that new employee is sitting on the bench waiting for their clearance. That’s something that we can begin to alleviate further upstream and begin to ensure that when those students enter the market or the industrial base, they’re ready to go day one.

Q: Can you share a little bit about what you feel most proud that the lab has accomplished?

A: One of our biggest successes was the program that kicked off our hypersonics research and development at PARI. We had a contract through OSD ManTech [the Office of the Secretary of Defense’s Manufacturing Technology Program] routed through the Naval Surface Warfare Center – Crane Division that ultimately was five projects within that program, all hypersonics related, that really kicked off our facility, the research that we were doing, getting students involved and developing a lot of the technology in our facility.

We did everything from scramjet design, build, test. The vision for that program was to help set up our facility that we’re working in, which is our HARF facility — the Hypersonics and Applied Research Facility — and specifically the manufacturing space in that facility.

Within the HARF, we have the manufacturing center, which we call the HAMTC Center, the Hypersonics Advanced Manufacturing Technology Center. And then we have two hypersonic wind tunnels, the HYPULSE wind tunnel and the Mach 8 quiet wind tunnel, which is still under construction. HYPULSE is active; the HAMTC space is now fully active. The vision for this space was we want to take our manufacturing, our testing, our design work and put it all in one place. Right now, if you look at how hypersonic vehicles are assembled and built and designed, it’s often done in disparate locations across the country. Just the time it takes to go from a concept to a prototype to a test can be very long because it’s not only coordinating teams, but you’re taking a part, you’re shipping it across the country to new machines; you’re shipping it to another part of the country to be heat treated; you’re taking it back to an assembly plant.

The vision here was vertical integration and specifically utilizing advanced manufacturing to enable that. We have a variety of additive manufacturing technologies. We have a variety of coatings and heat treatment technologies and testing capabilities all in one facility, as well as large-scale wind tunnels that are also within our facility. Ultimately, that enables us to go from a design to a fabricated prototype to a test all in a matter of weeks to months.

One of those projects that initially kicked off our contract with the Navy through OSD ManTech was a scramjet demonstrator. This thing was about 7 feet long, a couple feet in diameter. It was a large system — student-designed, student-built and then students tested it, all at PARI and Purdue. It took roughly 30 days on a printer to build that entire system. It had geometries that you couldn’t traditionally manufacture. We flew it at the same flow conditions as the X-51 on the ground. That’s an example of the Navy and ManTech making an investment to stand up a facility that can increase our ability to rapidly prototype, it can increase our ability to demonstrate some of this technology quickly and then transition that over to companies to be able to take it and run with it into a production environment.

Q: How do you find or build the workforce that you need? It sounds like there’s a cultural piece on campus that you think is important.

A: It’s very easy at Purdue. The students here are excited. They care about national security and defense. There’s a huge population here that has some personal connection to the military, to the defense industry, whether it’s family members, themselves, friends that work in this space. So we don’t have to do a tremendous amount of recruiting and pounding the pavement to find people who are interested.

We’ve set up structured programs to be able to create that pipeline of cleared workforce that’s going to go into the defense industry. We’ve got what we call our PARI Scholars program, which is a partnership between PARI and the Engineering Undergraduate Research Office. One of the primary things we hear from industry is, “We love to be able to do research with you, but we’re also after your students.” When we hear that, we say, “Excellent, we can help you with that. What are some topic areas that you want us to tag students to and develop a workforce around?” Oftentimes, there’s things in industry that aren’t perfectly taught in classroom settings. We are able to take whatever that tradecraft might be, think of it almost like a capstone project and advertise through the PARI Scholars program directly to students.

Q: You’re working closely with hypersonics on a regular basis. What do you think is the promise of that technology?

A: This is a technology that’s here to stay. From a defensive capability standpoint, it provides options to the warfighter that enable deterrence and ideally prevent a Cold War from ever becoming hot. There are things that these vehicles can do that, frankly, make them very difficult to stop. From a deterrence perspective, that’s a huge, huge advantage that it gives us compared to traditional ballistic missiles.

Long term, when we think of hypersonics, everyone likes to think of how cool would it be if I could travel from New York to Tokyo in just a couple hours. Eventually, there’s applications for non-defense areas as well.

Q: What do you think is the biggest challenge? It sounds like it might be cost.

A: The cost of these systems is the real hurdle. We can develop fantastic technology. We can develop technology that lowers the cost of these systems, new materials, new algorithms, new microelectronics. But often it’s the contracting process; it’s the many steps that we have to move through to go from a design ultimately to a deployed system that drives that cost. If you’re a large defense company, it’s going to drive the size of your contracts department, it’s going to drive the size of your legal department, it’s going to drive the size of your finance department. We start stacking that on top of itself, and that drives up the cost of the vehicle beyond just the material cost. That’s a huge issue.

There’s the technological side too where we are working with very, very custom materials, one-off systems, systems that were designed as demonstrators that maybe didn’t have mass production in mind. How do we go from we need a specialty material to be able to accomplish this mission to we can produce these by the truckload? There are industry providers out there that are capable of this. We have some of those pieces in place. It’s just we need these systems to be designed with that in mind from the beginning to some extent.