Podcast: Are Supersonic And Sustainability Mutually Exclusive?

Listen in as Aviation Week editors discuss NASA’s recent contract awards to study technology for high-speed airliners flying faster than Mach 2—and the one supersonic project that is still pushing forward, Boom Supersonic.

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Rush Transcript

Joe Anselmo:

Welcome to this week's Check 6 Podcast. I'm Joe Anselmo, Aviation Week's editorial director, coming to you this week from the AEROone aerospace summit in Detroit, Michigan.

With the aviation industry under immense pressure to become more sustainable, one might think that the idea of supersonic passenger travel has gone the way of the pay telephone. After all, flying faster than the speed of sound requires enormous amounts of fuel, not to mention those pesky sonic booms that curtail flying over populated areas.

But supersonic travel conjures a glamour among dreamers that just won't go away. Late last month, NASA awarded contracts to Boeing and Northrop Grumman to study technology for high speed airliners flying faster than Mach 2. And the Boom Supersonic aircraft project continues to push forward, critics be damned.

Here to provide their reality checks are Graham Warwick, Aviation Week's executive editor for technology and Guy Norris, our senior propulsion editor. Both have written extensively about supersonic travel, going back to the days of the Concorde. Guy, why don't you set the table for us, tell us about these new NASA contracts and where we are in supersonic initiatives?

Guy Norris:

Thanks Joe. Well, I mean, you said it correctly right off the bat there. An interest in high-speed flight just doesn't go away. So, this is a great example of it. These contracts were awarded to two teams led by Boeing and Northrop Grumman, and they're part of a broader high speed strategy which NASA has sketched out over the past decade essentially. At the bottom end of it, the lower end, we have the supersonic program, the Commercial Supersonic Technology Program, which of course is the Quesst mission, which is the X-59 low-boom demonstrator. And at the very top end we've got this Hypersonic Technology Project, the HTP, looking at these really sort of high mach cruise numbers of eight to nine, which is very much a sort of multi-role military/commercial study.

And in the middle you have this kind of high supersonic market which NASA has thought industry is driving the sort of desire to go there, whether it's military or commercial. But in the meantime, there's this sort of big gap between Mach 2 and Mach 7, which is right there in the middle. And these contracts which NASA awarded are part of this drive to cover that gap.

And what we really should say is that the dual role here is vital. I mean, you think, well, what is NASA even doing here? It's technology driven. It's something which is really aiming to support US supremacy in high speed flight. And NASA sees its role as trying to make this sustainable. Anyway, I'll just quickly tell you about the contracts themselves.

What they're really looking at is the key items like airframe, power, propulsion, thermal management, composite materials, all of the really hard, tricky parts of going fast through the atmosphere. And we should sort of say that the Boeing team, for example, includes Exosonic, which listeners might've heard about, also developing their own supersonic ambitions. GE Aerospace is a propulsion provider. Georgia Tech, the University of Texas, Systems Design Laboratory from Georgia Tech, Rolls-Royce and Northrop's team includes Blue Ridge Research and Consulting, Boom Supersonic, which we'll talk about in a little while and Rolls-Royce again. So it's a really active time.

Joe Anselmo:

So Graham, when these contracts were announced, you sent a private email to Guy and me that I'm going to now tell the world about. You said, ‘What the heck is NASA doing going forward with supersonic studies when the challenge this industry is facing, the overwhelming challenge these days is sustainability.’ And NASA had an answer for you, didn't they?

Graham Warwick:

Yeah, I'm not sure it said what the heck, it may have been slightly more expletive than that. I was surprised and frankly disappointed. I think the messaging was not very good. This came out round about the same time that Eurocontrol in Europe put out what they call a think paper, where they just looked at how hard it is to decarbonize long haul aviation, right? So long range, large airplanes. And it's an interesting think paper. They look at what would a totally electric A380 look like? What would a solar electric A380 look like? And they're all ridiculous. You can't power these big long range airplanes with electricity or solar or anything like that.

But we have to be focusing the industry's attention on how we tackle long haul aviation. It is a major source of aviation's emissions and it is truly the hardest possible piece of aviation. Aviation is hard to decarbonize, long haul aviation is even harder to decarbonize. So when I saw this supersonic announcement, I literally rolled my eyes saying, ‘What are these people smoking?’ And the truth is they have to do this. Their charter is to cover all aspects of aviation, so they have to look at high-speed aviation. Also, they are really the custodians of the US expertise on hypersonics. In the interregnum, all those years when the US military was not interested in hypersonics, it was NASA that kept the flame alive. It was their research that allowed to keep the skills, maintain the skills that are now being put to work to produce hypersonic defense systems. So there is a reason why NASA is focused on this.

But I would have to say that they're doing it because they have to do it. I would question whether or not there is really a market there in the long term. But also to say they are not ignoring or doing this to the exception of something else. They have a program that they're about to launch, a project they're about to launch, which is looking at, they're going to go out to industry and ask for ideas for decarbonization, sustainable aircraft in the 2045 plus timeframe. Now you've got to realize that this is the second stage of an effort they've been doing for decades now.

The first stage of where we kind of we are now, it started in 2008 when they started looking at what they then called N+3, which was kind of like the next generation of single aisle airplanes. They said ‘What's the best we can do by 2035 to get a significant reduction in emissions from a single aisle airplane?’ The result of that was the sustainable flight demonstrator, which Boeing is developing, the X-66, to flight test the Truss-Braced Wing. Which if the Truss-Braced Wing works at that full scale, will give you a 10% efficiency improvement just from the wing before you do anything else to the rest of the airplane.

So that was the end of that process started in 2008, 20 years later, 2028, they plan to fly the sustainable flight demonstrator. Well this new effort they're starting, which is called Acces, it's A-C-C-E-S or something like that. Anyway, it's to move that deadline to 2045 plus and see what other technologies they can bring in that would start to improve the decarbonization of short haul aviation, short and medium haul with single aisle, but also start to really tackle that long haul. So this is really where we need industry to come together and start to come up with some innovative ideas for how we decarbonize long haul aviation. It's going to take longer to do it. It's going to take a lot more effort to do it, but if we're not careful, it's going to be the piece of aviation that is going to be the hardest. It's still going to be out there as being not really decarbonized other than by sustainable aviation fuels.

So I think we have to say, okay, NASA can't take its eye off high speed, has to maintain its skills in hypersonics, but really its focus needs to shift now to how to decarbonize long haul.

Joe Anselmo:

Guy, back to supersonic. Graham talked about NASA looking at 2045 and beyond. Let's come back to 2023 because Boom is actually planning on flying a supersonic demonstrator. So tell us a little bit about that.

Guy Norris:

While all of these advanced studies are going on, we should remind our listeners of course that there is plenty of activity going on right now. All of it focused in the Mojave Desert in California where, as you quite rightly said, Boom is preparing to fly the XB-1, which is the subscale demonstrator for the Overture airliner, which it's developing for entry into service by the end of this decade. XB-1 just recently received its FAA permit to fly, and that really does clear the way for the beginning of flight test for this demonstrator. Now it's kind of curious, just to remind people, it's about a 71-foot-long, very slender delta, it's trijet, it's a hot little ship, but it doesn't exactly look like the revised Overture airliner. But nonetheless, it's going to do a lot of useful work for Boom, the most particular way, proving that it can build and fly an aircraft. Anyway, so that's something which may be happening in the next few weeks or months. The key thing about what's going on right now is of course, while Boom is getting ready to fly the XB-1, NASA is also right there getting ready to fly the low-boom demonstrator, the X-59. So kind of curiously within the space of years since Concorde was retired 20 years ago, within the space of a few months literally, you've got two new civil supersonic aircraft getting ready to fly. We should just briefly mention the X-59 timetable is of course later than NASA wanted. It was originally due to fly two years ago, but right now it's under test at Lockheed Martin and they're troubleshooting some kind of subsystem flight control computer and hydraulics issues. But nonetheless, we should be seeing both of these aircraft in the air hopefully within the next few months.

Joe Anselmo:

So Guy, I’ve got to ask you, everywhere I go, Paris Airshow, the supplier conference I'm at right now in Detroit, people roll their eyes when you talk about Boom. There are so many skeptics that just don't think this project is going to make it. Why is that?

Guy Norris:

The problem is that traditionally when you've looked at every single aerospace development, whether it's been subsonic or supersonic, it's been underpinned by a huge amount of industrial strength, history and development history, particularly for example, in propulsion. The key to all of these developments is an efficient, working propulsion system.

And I think the skepticism over Boom is not so much in the fact that it can bring 21st century design and systems and structures capability to the problem of a viable supersonic flight. It's in propulsion. That's where the real long pole is in this tent. And it's part of whether you buy into Boom's argument or not, that they've also come up with a new way of attacking this problem with a purpose designed engine that, let's face it frankly was never done for Concorde or any of the other supersonic commercial attempts anyway before. This is why the jury is really still out. There's a lot of skeptics to see whether a non-traditional approach and a non-traditional propulsion team can pull this off.

But the design approach is interesting, there's no denying that. And they're looking at something which has never really been attempted before. So until they prove otherwise, you cannot 100% say that it's impossible. The other aspect is the market size. And it's worth bearing in mind that even for this higher Mach question that NASA is pursuing with the high speed program that we've just talked about, part of the work that they did before they even went to industry was they approached Deloitte Space Works and I think another, SAIC I think, to look at the business case. And as a result of both of those studies they came back with, yeah, there is a market out there. And as we've said earlier, people just are continuously interested in high-speed flight.

And I should say that one of the interesting things about both of the surveys that came out was a bit like Boom. What they suggested was that rather than having a hundred seater aircraft, which was the Concorde size, average size, what you would look at is something that seats between 20 and 50 seats in this case. It's a much smaller aircraft, but it means that your load factor is generally ... the average load factor on Concorde was 50 or so percent sometimes. With a smaller aircraft and a market like this, you could look at around 85% load factor. And because of the difference, it means that the production size and the market itself, instead of 20 aircraft, which is the Concorde total real viable commercial market, you're talking at least 300 aircraft they think for a much smaller size aircraft.

And I think as much as we're talking about the technology, it's the approach to the market here, which is different for both the NASA programs here as well as people like Boom. And the key challenge against all of these though is as we mentioned at the beginning, is sustainability. NASA for all we've said earlier in the podcast here, they have realized that that's different as well this time. That you're looking at emission standards, flight shaming, speed and noise limitations, and even export controls. ITAR is a thing which didn't exist when things like Concorde were being developed. So it's a very different world and a different approach.

Joe Anselmo:

I wanted to wrap by asking Graham about what you just mentioned, supersonic travel and sustainability, but before I do, Guy, we should note that Boom has taken conditional orders from multiple major airlines, right?

Guy Norris:

Yeah. And I think that it's interesting that you're beginning to see United and American, they're talking about the Boom acquisition when they talk about their fleet plans now, it's not something kind of, which is a sort of airy fairy comment that maybe we might or we might not. They are actually being recognized now as part of the future program plans. And JAL of course, Japan Airlines. So you do have this long-term interest which won't go away in serving a market that still exists. It's just a question, how big is it in reality and whether the technology can really justify the sustainability challenge.

Joe Anselmo:

Graham, take us to the finish line. When I think of supersonic air travel and sustainability, they just seem so at odds with each other. I mean, is this really even possible?

Graham Warwick:

I seriously doubt that they are compatible. And the trouble is that we're in a point in the market in social society where we really don't know the answers. We don't know whether sustainable aviation fuel will be regarded as enough to meet aviation's public obligation to sustainability. And I mean that because sustainable aviation fuel, you still release carbon when you burn sustainable aviation fuel, there are what they call tailpipe emissions. You are accounting for those carbon emissions in the life cycle of the fuel. You are getting the feedstock for the fuel from a source that either absorbs carbon dioxide naturally like trees and other sort of vegetation, or you are capturing the carbon either from industrial emitters or from removing it from the atmosphere and using it in the production of fuel. So if you can close that lifecycle, you can theoretically get to a net emissions of zero and possibly even sub-zero. It's possible you could be removing carbon in some of these processes which are still not mature enough today. Mathematically you can say, I remove carbon when I fly the airplane.

What we don't know at this point in time is what is the public's reaction to that message? Will they look at what aviation is doing, will they look at sustainable aviation fuel and will they give aviation credit for that lifecycle argument where we are emitting at the time we fly, but we're removing carbon in other places? And that's the bit we don't know. It's just too early to say whether the public's going to accept that argument.

But when you look at what United are doing as part of this whole thing, Boom is only just a very small piece of what United's doing. They've invested in carbon capture, companies that are going to pull carbon from the air. They've invested in fuel companies that are going to use captured carbon to produce sustainable aviation fuel. And if you use electricity to generate that fuel, then you are reducing the total emissions of the lifecycle. So the problem is, will the public buy that argument or will they simply say, that supersonic airplane's burning three times as much fuel and will they just say no? And it goes to the supersonic argument very specifically because not only are they burning more fuel, however it's produced, their target market is the Business Class to First Class on subsonic airplanes today. That's why they can get away with looking at a 20 seat airplane or a 50 seat airplane because the ticket price is going to be Business Class or First Class.

ESG reporting, environmental, societal and governance reporting, is going to put pressure on the big corporations to make sure that the corporate travel, which is a source of a lot of that revenue, meets ESG goals. So even if you are going to put your executive on an airplane to fly them somewhere, there's going to be a mathematical equation saying getting that executive from A to B is going to have this carbon footprint versus this carbon footprint. And that's where I think it doesn't matter whether you've got one market for supersonic over water, or a much bigger market if we go supersonic and fly, I don't think it matters. In the end it's going to be, are we going to be allowed, is the public, is society going to allow us to fly supersonically? And I just don't think we know. We don't know how bad things are going to get. We don't know what society's reaction is going to be. So it's very hard. You could do all the market studies you want, but I don't know if you can answer that question.

Guy Norris:

And sorry, I just wanted to quickly say, I think people want to go fast and they're sick of trudging across the Pacific Mach 0.8, they want to get there quicker and they're fed up with being held back in the 20th Century.

Joe Anselmo:

Well, thanks to both of you for an enlightening conversation. Unfortunately, that's all the time we have for today. But we know from our web metrics that our readers and our listeners just can't get enough of supersonic. And I know the two of you will continue to cover these stories.

If you look at the description for the podcast, you'll see a link to the gallery put together by Guy Norris and I that features 10 Aviation Week and Space Technology magazine covers going back 60 years, highlighting the history of civil supersonic programs.

Finally, special thanks to our podcast producer in London, Guy Ferneyhough. If you want to listen to some of our sister podcasts, I recommend you check out Aviation Week's MRO Podcast. Recent episodes have covered airlines bringing back their Airbus A380s from storage, as well as issues with Pratt & Whitney's GTF engine. You can find the MRO podcast wherever you're listening to this one. That's it for today. Thanks for your time and have a wonderful week.