For listeners who aren't as familiar, walk us through what you're working on at Hermeus and why it's important for the world.

We're trying to radically accelerate aviation by building high-speed aircraft: initially uncrewed aircraft, and eventually, hopefully, aircraft that fly people around the world much faster. All of our work today is focused on solving problems with the Department of Defense to ensure we've got a world that we all want to live in and want to fly around quite a bit in the future, when these super high-speed airplanes are ready for us.

We take a very iterative approach to development. A lot of our core engineering team comes out of SpaceX, and they've brought what they learned through Falcon 9, Starship, and Starlink development and are now applying that to airplanes.

If we take a quick step back on the technology itself, can you give listeners a refresher on the core differences between hypersonic flight, supersonic flight, and the air travel we all experience today?

I'll start with where we are today. Today we all fly around the world at Mach 0.8, so eight-tenths the speed of sound. That's about 600-some-odd miles an hour.

For supersonic, the best example for most people would be the Concorde. That flew at Mach 2, so twice the speed of sound. The technologies we're working on are focused on hypersonic travel, which is generally accepted to be about five times the speed of sound or faster. So if Concorde was a 2x to 3x speedup in transportation, what we're building now is a 5x to 6x speedup in transportation.

Where are we in the evolution of hypersonic flight? Have we worked on hypersonic flight before and failed? Is Hermeus the first swing, to your knowledge? And by extension, what are the tech enablers allowing you to build this company right now?

From a hypersonics perspective, there have been lots of hypersonic systems over the course of history. Any vehicle reentering the Earth's atmosphere from orbit is traveling hypersonic. The Space Shuttle, Apollo, Gemini, all the capsules, Dragon today: those are all technically hypersonic vehicles. But they're basically coming straight down. The same goes for intercontinental ballistic missiles. Those are also technically hypersonic vehicles.

The thing that has started to come up more recently, especially in the DoD world, is hypersonic vehicles that stay in hypersonic conditions for extended periods of time. That would be boost-glide vehicles, which are boosted up by solid rockets and then fly as a glide vehicle above Mach 5 for very long periods of time and very long ranges. And then also air-breathing hypersonic vehicles. Again, most of those on the military side are boosted by solid rockets up into the Mach 5-plus regime, where they turn on their air-breathing engines, so scramjets. That's where the technology development focus has been in hypersonics for the past two decades.

What we're trying to do is bring reusability to hypersonic vehicles that fly for long durations in the atmosphere. The closest we've seen to that would be the SR-71, which is a Mach 3.2 aircraft. So we're going for a vehicle that's about 50% faster than that. The core enabler is really the engine technology: being able to take an existing off-the-shelf gas turbine engine and push it up to about the Mach 2.5 to Mach 3 range.

Once you get into that range, you can start a ramjet engine, which functions the same as a jet engine but doesn't have any moving components. It uses shock waves to compress the air. You transition to that and ride it up between Mach 3 and Mach 5. Put all that together in one engine, and now you've got a system that can go from not moving on the ground to Mach 4 to 5 at 80K to 100K feet. That's the key enabler. Then there are all sorts of other airplane things around that: high-temperature airframes, thermal management, and all those things. But the engine's the big differentiator.

It's interesting to reflect on why humans haven't taken certain existing pieces of technology and pushed the frontier until somebody decides to plant their flag in the ground like you have and say, "We can actually do this. Let's go for it." What has been holding us back to date?

Nobody's really tried doing this stuff in the private world. Most of this type of development work has been done within government research labs and places like that, where the incentives are very different. Accountability and ownership are very different too. It's much more in the science world, versus, "We'd better actually get this thing into a product quickly so we can have an actual, real company."

That's the fundamental framework that drives how we've set up the technology stack we're investing in, the milestones we've set along the way that we've hit, and what we have ahead. It's really focused not on, "Let's go build this cool technology and see if it works." It's, "What is the customer problem we're trying to solve?" Then you work your way back: you've got a problem, now you've got a solution that's built on top of a tech stack, and you have to go de-risk that tech stack to create the product that solves your customer problem. When you work from that perspective, it drives a different kind of strategy into the roadmap, but also a very, very different sense of urgency.

You and the team made the pretty intentional decision, as you've mentioned the DoD a few times, to take that initial swing at the DoD and the US military. Why start there? Why is that the right test bed to prove out the work you and the team are doing?

We looked at some of the problems and challenges the US government has. Hypersonic flight testing is one where we've been pretty poor in our rate of flight testing in very high-speed conditions, especially relative to other countries: Russia, China, and others.

Let's talk about that real quick. What is the state of the global hypersonic race? Where does the US stack up against others?

All right, I'll give you my hot takes on this. Let's talk about Russia. Russia's really good at marketing. They've built some things, but they tend to punch above their weight. You have to remember their economy was the size of Texas before they invaded Ukraine and were sanctioned to hell. They've done some cool things, but generally most of the things in the Russian arsenal that you see claimed as hypersonic weapons are really ballistic missiles, for the most part. There are some air-breathers and other things.

But I think China has really hit their stride. Their approach has been very much, "Let's go build and test and fly these things, get data, learn, iterate," which is great. I think we should be doing more of that. It's how we built the fundamental culture of our company as well.

From a government perspective, when you have an authoritarian state, you can basically say, "We're going to go do this. It doesn't matter how many times we fail. We're just going to keep going." That's possible. Within the government setup and culture that we have here, it's really tough to do that. When Congress holds the purse strings, they tend not to like to watch things fail. It's a very different incentive structure. That's generally why, in government-driven development programs, you see a much slower pace, because everybody's saying, "We've got to get this right. We've got to get this right. Can't fail. Can't go wrong." And when you start doing that, especially while trying to push the boundaries, you end up not getting the data or the learnings you need to actually build the right things and figure out which of the right problems to solve.

I think that's the unlock of capitalism, and it's what you're seeing broadly in the defense tech ecosystem: people bringing private capital to bear to extract problems, develop technology, and deliver products that solve those problems. Not saying, "Hey, DoD, we'll just be a contractor. We'll do what you tell us." No: "We're going to learn your problems, figure out the solutions, and then deliver products that solve those problems." I think that approach is super critical in the global geopolitical competition we're in.

So perhaps as of right now, the US is behind in the development of hypersonics, but hopefully, as a result of companies like Hermeus, we're accelerating fairly quickly.

I think that's a reasonable opinion to have. You can just look at the rate at which they're testing and the rate at which we're testing. There's plenty in the public domain about that, and it doesn't paint a very rosy picture for us.

Two last things. First, I want to talk about what success looks like for Hermeus over the next three, four, or five years from an autonomous hypersonic point of view. Then I want to talk about what success looks like for hypersonic flight, period, in the longer term. Walk us through how you're thinking about those two things.

If I look at the five-year horizon, success looks like Hermeus aircraft in the US Air Force and our allied fleets, flying missions, deterring aggression around the world, and helping maintain air superiority in an incredibly cost-effective way. That's really the goal we're shooting for in the near term.

As we get into the 2030s and start getting into super-long-duration, long-range hypersonic flight, that's when we start to hit the commercial market for the technology stack we're building. Seeing people fly on really fast airplanes and actually start to shrink the world again in an economically viable fashion, built on top of the tech stack and business we've built solving DoD problems: that's where we want to be, which is pretty exciting.

But we have to earn the right to even really talk about the commercial side. It's incredibly difficult just to build an airplane, let alone design it, certify it, produce it, operate it, and maintain it. Commercial aviation is an incredibly difficult thing. There's a reason there are only a couple of companies, built up over the past 50 to 100 years, that do it. So we've got a long way to go before we can really claim we're going to build a commercial aircraft. It's certainly out there on the roadmap, but we've got to take care of business on the DoD front first.

And I would imagine even then, very likely, you'd start on a graduated basis. You could start and experiment a little bit with supersonic, rather than going straight to hypersonic.

This is why we built an airplane that can do nothing other than take off and land. That's the first step, so you'd better get that right. The next step for us is supersonic. That's hopefully coming up later this year with Mk 2.

AJ, congrats again on a really impressive Mk 1 test run a couple of weeks ago. It's great to have you on, and I appreciate the work you and the team are doing at Hermeus. Thanks so much.

Awesome. Very glad to be here.