Podcast: The U.S. Hypersonics Program Matures

In the last few weeks, Aviation Week editors Steve Trimble and Guy Norris have learned new information about several U.S. hypersonic weapons efforts. Listen in as they tell executive editor Jen DiMascio about the developments, which include the revelation that the Air Force is studying intercontinental-range hypersonics that could be nuclear-armed and confirmation of the creation of a multi-mission platform with a multi-cycle engine that could be the path toward a SR-72 intelligence-gathering vehicle.

Beyond those potential future programs, they discuss the construction of a new Dynetics facility in Huntsville, Alabama, likely to be the first U.S. factory that will be able to produce hundreds—perhaps even thousands—of hypersonic glide vehicles in the coming years.

Don't miss a single episode. Subscribe to Aviation Week's Check 6 podcast in iTunes, Stitcher and Google Play. Please leave us a review.

Below is a rush transcript of Aviation Week’s Aug. 25, 2020, Check 6 podcast.

Jen DiMascio:               Hi, and welcome to the Check 6 Podcast. I'm Jen DiMascio, the executive editor for Defense and Space, and I am here with Defense editor, Steve Trimble, and technology editor, Guy Norris. And we're here because, in the span of a couple of weeks, our knowledge of the U.S. hypersonic weapons program has significantly expanded, and a lot of these disparate pieces that we have been tracking are falling into place. Steve you've been at the forefront of reporting a lot of these developments. Can you summarize the highlights?

Steve Trimble:              Right? Well, just to give you an update across the entire spectrum because it's a huge portfolio. So let's go back to March. That was the last flight test, hypersonic flight test that the Defense Department has carried out. That was with a block zero common hypersonic glide body, and that's the glide body that's going to be the front end for the Army's long range hypersonic weapon and the Navy's intermediate range conventional prompt strike, which is a sea-launched missile. That was a successful flight test. It was later described by President Trump as the SuperDuper missile. We were trying to figure out what that was, but according to CNN's reporting, that's what he was referring to at the time. So that was that program.

                                    The Air Force, meanwhile, has got a couple of different programs ongoing. One is the AGM-183, an air-launched rapid response weapon (ARRW). It's a Lockheed Martin design for both the front end and the integration. And they did a captive carry flight test that appeared to be pretty successful just a couple of weeks ago and they're moving that into flight test with the front end, actually incorporating the design from the tactical boost glide program from DARPA. That was supposed to be an independent, separate effort. Well, not quite. They are linked, but that was supposed to be a separate flight test program, but they've now folded that into the ARRW vehicle design and will continue testing that through ARRW. So that's all of the tests.

                                    Also, the Hypersonic Air-breathing Weapon Concept (HAWC) program, is the next set of flight tests that are supposed to be happening. That's the hypersonic air breathing weapon concept, which is basically a Scramjet powered cruise missile. There's a Lockheed version and a Raytheon version. We know back in May that Lockheed attempted to do a captive-carry test with its version of the HAWC missile, but there was some kind of failure during the flight test. We still don't know exactly what it was, but it appeared to be somewhat damaging, but since then, we've heard nothing about where they're going with that, except for the fact that the Air Force, a few weeks ago, launched a follow on program to develop an operational prototype of a Scramjet powered cruise missile that would be a follow on to the HAWC program.

                                    But in the competition, the Air Force basically selected three companies a couple of weeks ago to form the competitive field for the follow on HAWC missile. Those three companies are Lockheed, Raytheon and Boeing, which of course the interesting part there is Boeing. Lockheed and Raytheon are heavily involved in the ARRW program and the [Tactical Boost Glide (TWG)] program and the HAWC program, but Boeing has been shut out, so this gives Boeing a chance to come back into the hypersonic weapons arena. At one point, Boeing of course, was the champion, especially in the air breathing propulsion space with the X-51 program. If you go way back, I'm sure Guy could chime in on these programs would be the space shuttle and X-15 with Boeing's legacy companies of course. So that brings us up to speed with where we are right now.

Jen DiMascio:               Okay, and then in the last couple of weeks, you've stumbled onto a few really interesting stories, one of them, this week. Can you tell us what's happening with the Air Force, and what new weapons down the road they might be looking at?

Steve Trimble:              Right. So the big disclosure came this week that we found out that the Air Force Nuclear Weapons Center briefly published a request for information (RFI) on the government's acquisition website, betasam.gov. The RFI was about future upgrades for an ICBM that sounded a lot like the ground-based strategic deterrent, which is going to replace the Minuteman III, and one of the upgrades that was listed in the RFI was for a hypersonic glider. It was seeking thermal protection systems for an intercontinental range hypersonic glider. And that would be a new and big and very controversial step. If this actually becomes an acquisition program, it would violate a current Defense Department policy that would prohibit a nuclear version of a hypersonic glide vehicle or a cruise missile. But in the broader context, Russia and China have already started developing ICBM HGVs.

What's been interesting is that Russia has already deployed a nuclear armed hypersonic glide vehicle on an intercontinental ballistic missile. In fact, the SS-19, the hypersonic glide vehicle called Avangard became operational as Russia declared in December of last year. China has not been quite as public about their plans for a nuclear or even intercontinental HGV, but the then-head of U.S. Northern Command, Gen. Terrence O'Shaughnessy, wrote in testimony to Congress in February, that Northern Command understands or believes that China is currently testing in an intercontinental range hypersonic glide vehicle, perhaps for the DF-41, which is also in development right now.

                                    And so the U.S. is actually outlier among the major nuclear powers in that it doesn't yet have a hypersonic glide vehicle development program for a nuclear ICBM missile, if you believe in the Northern Command testimony in February. So, this new development from the Air Force Nuclear Weapons Center indicates that there is perhaps some interest, long term, in developing that capability the Ground-based Strategic Deterrent (GBSD). In fact, just yesterday Gen. Richard Clark who's the head of strategic systems and nuclear deterrence for the air staff at Headquarters Air Force did say, he told me specifically that there is not a threshold requirement for a hypersonic glide vehicle in the GBSD program. But of course, all the acquisition programs set up threshold requirements and objective requirements, and he would not speak to what the objective requirements are for the Hypersonic Glide Vehicle (HGV). But certainly the RFI, which has since been removed from betasam.gov, because it contained information that was for official use only, it probably should never have been posted there in the first place, that RFI suggests that perhaps one of the objective requirements would be a hypersonic glide vehicle.

Jen DiMascio:               That's really interesting, Steve, and I'd like to talk more about that, but there have been so many developments I want to move on to another expanded role for hypersonics and that is this missile that you've been writing about called Mayhem. What would that do? How would that expand the mission and the types of technologies that the Air Force is working with?

Steve Trimble:              Well, it would certainly a add a really cool new name for a hypersonic weapon program, I like the name Mayhem. But we just found out about this last week, and again, it was another RFI that we weren't expecting. It came out of the Air Force Research Laboratory. Now it's only for a demonstrator, it's for an expendable demonstrator vehicle that would be powered by an air breathing hypersonic propulsion system. Initially, we thought that that meant a Scramjet. I should say that one of the main features of this vehicle is that it could host at least three different payloads and that suggests a fairly large vehicle and perhaps a multi-mission vehicle that could perform intelligence missions, attack missions, be something a lot more than just a hypersonic glide vehicle that is essentially just a missile.

                                    But as we looked for this program in the budget justification documents, we didn't see anything quite by that name, but we did see something called the multi-mission cruiser, which we hadn't noticed earlier. That is an Air Force Research Lab (AFRL) program that was supposed to be launched in fiscal year 2021, and it's described as a multi-cycle engine program and AFRL, just yesterday, confirmed to us that Mayhem is the multi-mission cruiser.

So we know that it is linked to this idea for a multi-cycle air breathing propulsion system. And that has some really interesting implications that I think I'd let our air breathing hypersonic propulsion system expert on staff going to in a little further detail. So over to you Guy.

Guy Norris:                   Yeah, all right, thanks Steve. Yeah, it is bewildering Jen, what's going on here. There so much activity across air breathing and boosted vehicles right now. But just before we go any further, my view is that Mayhem is not a missile. It may well end up becoming a bit so by accident when it gets lost in the sea on its trial, but I think essentially we are talking about a flight demonstration, a test vehicle. Really as Steve mentioned, it's the beginning really of the next phase of maturity for this technology, because it introduces for the first time, the idea of a much longer range air breathing element, which is integrated potentially from a runway start, all the way to hypersonic speeds.

                                    So it's not necessarily a case of dropping this off the wing of say a B-52 and firing the button and off it goes. This thing is the beginnings of what the Air Force has been dreaming of, really since the X-30 onwards. And we should say that there's been a lot of work going on in the background, probably leading up to this. Both NASA on the civil side and DARPA on the military side, have been working programs in the U.S. for several years now on the combined cycle engine that we would need for, that presumably would be at the core of Mayhem.

                                    So just to quickly remind people what that is, you're talking about a jet engine, essentially, which would be a turbine that would allow the vehicle to go from a standing start to a speed of Mach 3-4. At that point, which again, one engine being able to do from zero to Mach 4 is pretty significant. We have seen, in the past through programs like DARPA’s High Speed Turbine Engine Demonstration (HiSTED), other high-speed turbine programs, the fact that you can push turbines to that limit, you can do it. It's been proven, it's just what happens next.

Steve Trimble:              But in the normal cutoff for a turbine engine, we'd be Mach 2.2 or so, is that right?

Guy Norris:                   Well it really depends on what the literature says, but we've seen evidence that people have pushed turbines beyond Mach 3, and I'm not just talking about, obviously SR-71 with a turbo ramjet idea, but really a small compact turbine engine has, if that has the ability to go beyond the Mach 3 range. And there's work obviously underway already to increase that with, for example, reaction engines working on pre-cooler technology. Earlier tests Pratt & Whitney did to basically condition entering these turbines, really fools them into thinking that they're going a lot slower. And so it's all about air temperature and the operating condition in that engine.

                                    So anyway, back to the basics. You'd have this turbine engine as the beginning phase. It would then transition to this Ramjet mode and the Ramjet itself would then transition to Scramjet as you go from beyond Mach 4 through to Mach 5 and onwards.

                                    DARPA's program, the advanced full range engine was really the driving force, the focus really for a lot of the U.S. military research in this area. DARPA began really, the main run-up to this four years ago, and in 2017 awarded Aerojet Rocketdyne a contract and we were not sure if there was another one also competitively awarded, but Aerojet Rocketdyne certainly spoke about that at the time. So yeah, this would be about the right time, assuming that things went well in that area, to begin moving this into a flight demonstration phase. And AFRL, of course, with this multi-mission cruiser Mayhem vehicle, is painting that picture.

                                    And one last thing Steve, sorry, I'm just going to mention this, is that of course, Lockheed, when they unveiled to us several years ago this idea of an SR-72, also outlined their vision for using the same kind of Turbine Based Combined Cycle (TBCC) combined cycle capability, really is the fundamental power system, foreign ISR vehicle, whether it would be crewed or not crewed. And under the plan, they outlined by 2020, by now, they would be testing a subscale flight demonstrator. Now if that's happening, it's definitely in the black world, we don't know about it. But we've had reports, none of which have been verifiable, that vehicles have been seen, but it's again, at this stage it's all a bit of a mystery. So Steve, sorry. Did you want to jump in there?

Steve Trimble:              Nope, I was just going to ask if everything is pointing towards SR-72 but you just answered that, so.

Guy Norris:                   Okay.

Steve Trimble:              Yeah.

Jen DiMascio:               As a multi-mission aircraft or an intelligence aircraft, how has it recoverable on the other end?

Guy Norris:                   Well, that's a good question. So at the moment, the Mayhem itself is considered expendable, right Steve? I think that's-

Steve Trimble:              Yeah.

Guy Norris:                   But that's just the demonstrator and as I said, it could go off into separate directions. You could use this cycle for an expendable vehicle, of course. But the big goal about it, obviously, is to be reusable because you obviously increase your operational envelope enormously by having something that you don't have to rely on a mothership or whatever to launch it, but also you can dramatically expand your range capability and flexibility by flying at different speeds for different regimes and so forth. However, the longer term goal would be to bring this thing back and to grow it in scale and get to the size where you are literally talking about an SR-71 type vehicle, or at least a vehicle that does that mission, or did that mission. So you're not going to throw that away, you're going to bring that home.

Jen DiMascio:               Thanks Guy. As we're talking about the technology really maturing and rapidly, one of the other big stories is about technology actually maturing to the point that production might begin. Steve, can you catch us up on your conversation with Dynetics this week?

Steve Trimble:              Sure. And this is really the consequence of the hypersonic push by the Defense Department. For 60, 70 years, the entire industry has been this cottage sector that has supported experimental vehicles every other year, maybe a couple a year in the best of times. Very bespoke, unique designs that are not meant to be industrialized. And that's what's changing. Whether it's hypersonic glide vehicles or hypersonic cruise missiles, the time has come now to start industrializing those systems for when they become operational, at least in the U.S.

                                    So there's two different strands to this in the hypersonic glide vehicle area. There's the Army and Navy program where the glide body is being assembled in Huntsville by Dynetics and then there's the Air Force ARRW program where the glide body will be assembled, we think and are pretty sure about this, in Palmdale at Lockheed's Site 10 campus, which is part of Skunkworks. In Huntsville, they have built the facility for the hypersonic glide body factory. And they're just in the process of completing the building. They plan to open the production area for the sub-system component assembly in October. And then by mid-December, open up the final assembly testing integration part of the building.

                                    That's where they're going to bring in the control modules for the elevons. There's four elevon control surfaces on the common hypersonic glide body and the control module for that is being supplied by Raytheon. General Atomics Electromagnetic Systems is coming in with sub-assemblies and electronics and cables and then the Army, interestingly is actually supplying the thermal protection system to Dynetics on a separate contract. All of that will be coming together in December with the second unit of the common hypersonic light body. That's where it will be produced.

                                    The first unit is actually being assembled right now in Albuquerque at Sandia National Laboratories. Dynetics is the contractor for that, but they are essentially shadowing the Sandia workforce as they assemble the first one, and then the Sandia workforce will go from Albuquerque to Huntsville and shadow Dynetics employees as they build the second and all the way through the 20th, which is currently the contract that Dynetics has to produce the first 20. So that is where things stand with the industrialization on the Army, Navy and Air Force side for the hypersonic glide bodies. But Guy can also talk about his recent interview with the Aerojet people, Aerojet Rocketdyne on the air breathing side.

Guy Norris:                   Yeah, well thanks Steve. Yeah, and in fact, it's air breathing unboosted because they've of course, got a long, long history in both areas really. But yeah, so paralleling what Steve was saying there, and of course, a lot of this does seem to be based in Alabama and Arkansas and Florida, the Southeast corner there. But much of the industrialization focus that Aerojet Rocketdyne is doing is building on a lot of these early programs too. Glide Breaker, DARPA, Op Fires, both another DARPA program, the Advanced Full Range Engine, which we just talked about and HAWC. I mean, those are only the things that we know about that they're involved in. But they've basically opened, last year they opened an advanced manufacturing facility in Huntsville, which is really beefing up their new capabilities for booster, essentially the booster side of things, but also will be aligned to any air breathing work, I think, in the future.

                                    And they also just opened up this engineering, manufacturing, and development facility in Camden, Arkansas, which is really expansion of again, existing side of their work, which they do the standard missile-three, the Terminal High Altitude Air Defense, and the GBSD that Steve just mentioned. But they know that hypersonics is coming. It's part of the plan for this facility and as part of this overall strategy, they've also acquired a company called 3DMT in Florida, which is this additive manufacturing specialist, and that seems to be really going to be part of their Scramjet philosophy. They know that they're going to have to build lots and lots of these things and make it incredibly... The thing about Scramjets is they're very, very precisely built. There's very little room for error. So when you build these things, you have to make them absolutely the same every single time and additive manufacturing is probably the best way to do that and do it at cost as well. So it's a key element of their strategy and it'll be good to find out more.

Steve Trimble:              There has been some other elements on the side too, that I've found interesting. As they try to industrialize this, the idea that they really want to build hundreds or thousands of these things. Maybe dozens per year to begin with, but by the end of this decade, I mean really pump out these things like they would do with a JASSM or AMRAAMs, where it's really in batches of hundreds or thousands. And the way to do that is really to, well I mean, we're not exactly sure how they're going to do that, but there are companies that are lining themselves up to compete for those things.

                                    Spirit AeroSystems is a really good example. Back in January, they announced the acquisition of FMI, which had supported the space shuttle program and other rocket booster programs with very advanced composite 3D manufacturing assembly techniques. You combine that with Spirit AeroSystems's mass production capability on the commercial side and you get potentially a pretty interesting combination of very advanced, very exotic material technology with mass production aircraft manufacturing know how that Spirit AeroSystems has. It could be really interesting.

Guy Norris:                   Sorry yeah. Thank you. One last question and that's a really good link. One thing I was going to say regarding Steve's earlier story about this idea of a hypersonic glider on the front of an ICBM, part of the huge technical challenge of that is it's going to be even greater than having to deal with the massive heat fluxes that you get on the shorter range systems. And Steve mentions this in his original story, he's talked to people who've said that we're talking about potential thermal flux capability here of 7,000 degrees, Kelvin, so over nearly 6,700 plus degrees C. And I just thought it'd be interesting to give you a little idea of how that compares. The space shuttle, at its peak temperature deals with about 2,900 degrees Fahrenheit. The Orion crew vehicle, which is hurdling back from the depths of space is a little bit more, 3,400 degrees.

                                    So you can see, there's a delta there. It's a massive Delta really, in terms of thermal capability. And I thought it worth also pointing out that both the space shuttle and the Orion crew vehicle are blunt bodies, essentially. The space shuttle, less so, but there's a lot of area over which to distribute that heat. The thing about a hypersonic cruise vehicle is you're talking about a very pointy little thing and so that really amplifies the massive engineering challenge of that. And you're talking about not only prolonged exposure, but you're talking about different types of exposure. Re-entry remember, really these big heat fluxes for reentry vehicles is encountered at about 250,000 feet during that initial plunge into the atmosphere.

                                    What we're dealing with the cruise vehicle potentially is all sorts of prolonged exposure, not only from re-entry, but also in the denser atmosphere lower down where you get a different type of frictional heating. The amount of frictional heating for space reentry vehicles is actually quite small, especially at that initial re-entry point. But if you're now dealing with... because there's no way for the autobiotic temperature release, but once you get down into lower depths of the atmosphere for prolonged periods, you've got another set of thermal requirements to deal with. So anyway, I just wanted to point out that this is no easy task.

Jen DiMascio:               So does that mean the timeline for that piece of the potential hypersonic program is pushed far out into the future, or are engineers up to that task and are they close to solving those issues?

Steve Trimble:              Well, so we don't know yet necessarily for ARRW for example, because they haven't tested it yet in flight. So as soon as they actually start doing the flight testing, which actually was supposed to start last year. And for HAWC actually. Both were supposed to be tested in 2019, but they weren't and they won't tell us why. But yeah, that's what we're waiting for is to see whether or not these things actually work. And those are the most advanced systems. When you talk about ARRW and HAWC, those are the most sophisticated, most complex and also in the case of ARRW, is in a regime that we've never actually had a successful flight test before.

                                    The common hypersonic glide body is a little bit different. It's based on the design that actually dates back to the late 1970s. They've had, since 2011, four tests. Three were successful. The one on successful tasks had an issue that was unrelated to the actual glide body itself and so it seems to be a much more mature system, but also less capable, less sophisticated, less advanced, less survivable, but still pretty good. I mean, I'm not criticizing it, but it's a notch below the kind of technology they're pursuing for Aero, for example. So once we get into the flight test, we'll find out whether or not they've done their sums correctly in the analysis and in the wind tunnel testing, but they seem very confident about it.

Jen DiMascio:               Wow. So much progress seems to have been made quickly. I mean, you're talking... where are we now relative to Russia and China? I know Guy, you'd written a couple years about how the U.S. program had really fallen behind and there's been this tremendous investment trying to catch up. Are we making up that lost ground?

Guy Norris:                   Yeah. Well, I mean, I think certainly in terms of testing, we're finally getting to the stage now where there's a tempo of activity. I know we've had a few hiccups and stalls along the way with the issue that we were just reporting on about. The B-52 mishap with the captive carry tests. So I think from a test perspective, I would say, yes, there's lots of positive signs. From an industrial perspective equally you can see people are getting themselves organized. It's a footing across the spectrum. What we really don't know yet is the results. The flight testing actually has to start, the live of flight testing. And secondly, these more ambitious programs have to really step up. We've done decades of research behind the scenes. Now it's the time to really begin integrating a lot of that technology together in a real flight demonstrator.

                                    This is the early signs. Steve story picks that up this week. We've finally seen that they're stepping up to get that on the record. So I'd say we've still got a long way to go with nowhere near really yet matching, I don't think, certainly on the pace of testing, but we're getting there. Steve?

Steve Trimble:              Well, and I would just add that, absolutely. That's all correct and I just add that bottom line is Russia has a deployed hypersonic glide vehicle. We're two years, at least from getting there. Actually, almost two and a half years, if everything goes correctly with ARRW. And then the long range hypersonic weapon would follow in 2023 and IRCPS in 2025. So we're a bit behind them in that sense. But if you look at the industrialization, that's really where I see the U.S. industry catching up in a very important way with these facilities and with this infrastructure and this capacity that they're building out now, they are getting to a point where they could mass produce these weapons. I'm not sure I've seen the same sort of industrial capacity. Well, I don't know if they've got this, but I'd be surprised if Russia and China were that far along with that.

Jen DiMascio:               Well, I think we will leave it there. Thanks for joining us for a really interesting discussion on this week's Check 6. We'll be back again next week so please download it on iTunes and if you like what you're hearing, give us a positive review.


Jen DiMascio

Based in Washington, Jen previously managed Aviation Week’s worldwide defense, space and security coverage.

Guy Norris

Guy is a Senior Editor for Aviation Week, covering technology and propulsion. He is based in Colorado Springs.

Steve Trimble

Steve covers military aviation, missiles and space for the Aviation Week Network, based in Washington DC.


Great discussion...I would have liked to see some visuals along the way instead of all dialogue...e.g. what do the various hypersonic concepts look like? Or show a picture of the new Dynetics facility
Great podcast - Thanks!