[[Home|🏠]] <span style="color: LightSlateGray">></span> [[Interviews]] <span style="color: LightSlateGray">></span> December 19 2021 **Insider**: [[Peter Beck]] **Source**: [Everyday Astronaut](https://www.youtube.com/watch?v=gcuOSXjevGs) **Date**: December 19 2021 **Article Summary**: https://everydayastronaut.com/neutron-update-interview-with-peter-beck/  🔗 Backup Link: https://www.youtube.com/watch?v=gcuOSXjevGs ## 🎙️ Transcript >[!hint] Transcript may contain errors or inaccuracies. **Tim Dodd:** Hi, it's me, Tim Dodd, the Everyday Astronaut. Rocket Lab recently showed off plans for their next rocket Neutron. Neutron is a medium lift methalox-powered carbon composite rocket with a propulsively landing reusable first stage that features a super cool integrated payload fairing. Now their announcement video is amazing, but I still had a lot of nerdy questions that I couldn't wait to get the answers to. So join me as I chat with their founder, CEO and CTO, Peter Beck. Peter Beck, how are you doing? **Peter Beck:** Good, thanks, Tim. **Tim Dodd:** Huge congratulations on the awesome Neutron announcement. It looks amazing, honestly. I have to say it right up front, I'm really excited about this rocket. How are you feeling about it after all the feedback and everything? You pretty excited to get going on it? **Peter Beck:** Yeah, I mean, look, you know, it's taking a tremendous amount of learnings over many, many years and hard lessons and hard-won lessons and, you know, transferring that into something that we think is gonna be pretty important for the future. **Tim Dodd:** Yeah. It definitely looks like it's gonna be a good competitor in that class. I mean, eight tons to orbit. That's a pretty nice sweet spot. You even talked about maybe you're open to the option of expending it at 15 or 16 tons to orbit. ### Expending a Reusable Vehicle **Tim Dodd:** Is that correct? **Peter Beck:** Yeah, yeah. I mean, obviously, it would be a sad day to watch a reusable rocket get expended but, you know, there'll be some missions, I'm sure, that are warranted. You know, at the end of the day, it will have a life. So, you know, you may as well run the end of life missions as expendable. **Tim Dodd:** That's absolutely true. And that's interesting to think looking that far forward, you know, that, yeah, at some point, the fleet of vehicles, you know, they'll get old and retire and you can send them off in a proper, you know... That's a proper sendoff, I feel like, you know? **Peter Beck:** It is. (laughs) **Tim Dodd:** So you guys have had a lot of really interesting and unique design decisions in this vehicle, stuff that, you know, I don't think I've ever seen before, which is always exciting. So I wanna go to a couple of them. First off, I think one of the things that most people are talking about... ### Integrated Payload Fairing **Tim Dodd:** that's really exciting is I love the four-petal, you know, the opening design of your fairing and how it stays attached to the first stage. That is super cool. How far are you along in the design of knowing like how to actually open that and close that? What types of systems are you looking for in that? **Peter Beck:** Yeah, so I mean, there's still a little bit of a trade going on between four petals and two petals at the moment. So we hope to have that closed by the end of this year. But I mean, the fundamental, you know, ethos around that is not having to go and pick them up or not having to deal with them in any other way. I mean, the best solution for, you know, reusing fairings is to just hold them on, you know, and keep them. There's a bunch of really fundamental decisions that drove a whole lot of things with the vehicle. And, you know, we sat down right at the beginning, we said, "Look, the vehicle must be able to be turned around in 24 hours." And although, you know, I don't anticipate ever turning the vehicle around in 24 hours, just that constraint, you know, created, you know, a whole lot of design decisions that needed to be resolved and made. And what you see is basically, you know, the result of some of those really difficult constraints and the fairing's been one of them. Because you can't turn a vehicle around in 24 hours, if you've gotta, you know, put new fairings on, or go and collect new fairings out in the middle of the ocean. So, you know, a whole bunch of things really came down to that 24-hour turnaround. **Tim Dodd:** Yeah. I love the idea of it staying with the first stage, that makes so much sense. I guess that makes me think, you know, I guess, why is it not more common to have fairings be ditched even at stage separation anyway? You know, with most boosters and vehicles? I kind of, I guess, maybe falsely assumed that we're still slightly too low in the atmosphere. There's still- **Peter Beck:** Correct. The dynamic... **Tim Dodd:** Yeah, there's still some dynamic- **Peter Beck:** Dynamic pressure heating. **Tim Dodd:** Yeah. So does that mean you're gonna have to do a little bit higher altitude separation and things like that? How's that actually change that? **Peter Beck:** Yeah, look. Yeah, well, I mean, as you know, like a launch vehicle is just one giant engineering compromise, and it's really about enabling you to be able to compromise in certain areas. And that's where materials played such a massive important role for us. Because if you can remove so much mass out of the structures, and all of a sudden, you know, you've got more scope to do things like coast for a little bit longer and, you know, deal with that dynamic pressure and that heating a little bit later, and you can add more structures also to deal with that as well. So yeah, it all comes down to mass at the end of the day. It's the biggest challenge you need to solve. **Tim Dodd:** Yeah. And so that brings up the beautiful upper stage concept... ### Hung Second Stage **Tim Dodd:** of being hung, basically, by the payload separator, right? **Peter Beck:** Yeah. **Tim Dodd:** So it's under tension under acceleration of the first stage, which allows you to not have to worry about compression, but then that brings up the question of how, you know, it will be under compression during acceleration of the second stage anyway, is that just such a low-powered second stage? It will never quite, you know, reach one, two, three Gs? Or how does that work then? **Peter Beck:** Well, I mean, so that the tanks are always pressurized to give you, you know, enough NPSH on the suction sides of your pumps. So, you know, the dominant load case in an upper stage is that pressurized load case. So, you know, when the tanks are pressurized, the thrust that's reacting into that structure is well less than the pressure, you know, those tanks are pressurized to. So, you know, think of it like sitting on a balloon. If the balloon's pumped up enough, then you know, it's no big deal. But, you know, it's a really important element, that upper stage, because as we're going through the design, we really started trading our reusable upper stage. And it's a really tough trade. And, you know, never say never, but for us, where it made the most amount of sense is if you look at the relative sizes of the first stage and the second stage, the second stage is tiny, but yet the second stage is doing, you know, as with most rockets, the first stage is just getting you through the soup, the second stage is doing a lot of work. And, you know, the reason why the second stage is so tiny is because it's just so ridiculously light. You know, like Centaur is a good example of this, right? Centaur is kind of a hung stage as well and it's in thin, thin stainless steel. So imagine a center, but make that out of carbon fiber, which is one quarter of the mass of the stainless steel. And, you know, you end up with an upper stage, which is super high performance, which is, you know, what you really want in an upper stage. But the other advantage for that is that there's no material in it either. So it's super cheap. It's not like there's a large mass of carbon composite material and it's very, very inexpensive to produce. And then when we use the automated, you know, tape laying or fiber placement, it's just almost unfair because, you know, you can lay a tank down and we measure it on how many meters a minute of tank are we producing, not how many meters an hour or meters a day, it's like meters a minute. **Tim Dodd:** Wow. **Peter Beck:** So, you know, you can produce this at a very low cost, very high performance structures. And, you know, the dominant load case in a launch vehicle is, you know... Obviously, you've got your tanks that are pressurized and that's a very dominant load case. But especially on a larger launch vehicle, the thing that you're better most with is buckling. So if you look at like a lot of launch vehicles, either they've got their isogrid, or they've got lots and lots of stringers on the back of the thin panels, and that's really, you know, the thing that you're battling with all the time is these buckling loads. So (clears throat) with carbon, you have so much stiffness and a much thicker wall thickness for, you know, a relative mass that you can deal with these buckling cases without having to put internal structure in behind it. And that, once again, it just simplifies things. If you have a look at it, you know, lots of launch vehicles, you'll see just a sea of kind of either welds or internal structures, you know, up the side of it to deal with that buckling load case. **Tim Dodd:** That brings up a good point. Yeah, I guess I had never considered the bigger right. I mean, looking at, you know, chassis, the isogrids of most vehicles makes it look so complex on the inside of the fuselage, you know, inside the tanks. But, you know, there's also always gonna be like bafflings, and things of that nature, of course, too. But yeah, I guess, I never considered that. But back to the second stage, is that still running? Is that also running on methane as well? **Peter Beck:** Yup. ### Second Stage Engine **Tim Dodd:** So basically, the same engine on the second stage as the first, but vacuum optimized, of course. **Peter Beck:** Vacuum optimized. **Tim Dodd:** Wow, so that'd be a pretty powerful second stage too. I mean, just physically powerful, 'cause that might be almost an overpowered second stage, similar to the Merlin. **Peter Beck:** Yeah, no, you did write about that where we continually... It's kind of a nice problem because the problem feeds also directly into the landing burn engine as well. Those kind of upper stage and landing burn engine has similar thrust and throttle requirements. So that's at least a nice thing. But the challenge is, yes, you know, especially near the end of burn, that upstage engine's throttled right back. **Tim Dodd:** Yeah, yeah, I can imagine. 'Cause you're looking at, you know, in one meganewton engine, you know, that's up there. You know, it sounds like a very familiar class community, you know, compared to Merlin and things like that too. ### Why Methane? **Tim Dodd:** I'm curious, with a clean slate design, you know, you ended up at methane and it seems like, you know, years past, we had never touched methane and now everyone's doing methane. Why is Rocket Lab doing methane? What were the design decisions there? **Peter Beck:** Yeah, no, that's a good question. So really, what it came down to is reusability, ultimately. Because the composite structures are super light, you don't pay at all really for the extra or the reduction in density and the increase in tankage. It's a very good trade versus ISP. So that's a great trade. But ultimately, what it came down to is reusability. And if you think about, you know, LOX/kero is a great combination, but one of the challenges with that is coking and sooting. So, you know, through the region channels and especially through, you know, the pre-burners and bits and pieces in the turbo machinery, it's just a heck of a job to de-scunge that you know, every flight. So once again, you know, it came down to the 24-hour theorem, like you're not gonna de-scunge all these engines in 24 hours. Whereas if you look at a methane engine, especially in a GG cycle, you know, you could eat your lunch out of the GG, you know, pre-burn after you run an engine. So ultimately, that's what drove the decision into methane, nothing else. It was purely, how do we actually get reusability in these engines and reliably, and just not have that coking issue? **Tim Dodd:** But also as far as cost of operation, methane is a relatively cheap fuel too though. So that's not a bad... Compared to RP-1, correct? **Peter Beck:** Yeah, yeah, but I mean, yes and no. I mean, it's one of these things that are like hidden costs, you know, per pound, it's cheap fuel, but actually, by the time you have all the infrastructure required to deal with it, and to contain it and flare it and all the rest of it actually is like everything in the rocket industry, in the launch vehicle industry. You know, that's where the real cost lies. You know, if I drew you a graph of what it costs to launch an Electron, you know, the only like a relatively small fraction of it is the cost of the materials, like the build of materials. It's much, much more expensive to fly a vehicle than actually, you know, to build one. **Tim Dodd:** Yeah. **Peter Beck:** When you amortize everything over all of the launch infrastructure and everything like that. That's why if you look at Neutron, there is no strong back, that's just deleted. And if you look at, you know, the pad, it's a very, very simple, clean pad. That's because all of that infrastructure, it's really significant cost to operating a launch vehicle. And that was the reason why it's a return to launch site. ### Why No Barge Landing **Peter Beck:** You have any idea what it costs to operate a ship? (Tim laughs) Like, I mean, it's way, way cheaper for us to fly out for Electron to fly it with a helicopter than it is to put a ship out there for a couple of days. It's just ridiculous. Marine assets are so expensive. So if you land on a barge, then you know, you have to operate that Marine fleet. And that becomes very, very expensive. So return to launch site once again. Let's delete out that element. So it's actually the operational costs of flying a rocket is what actually is the majority of the cost in it. It's kind of funny to sit and watch new rocket companies really, really focusing on like the build of materials of the rocket and, you know, taking every dollar out of that. And sure, that's a great thing to do, but that's not where your costs really come from when you actually operate a launch vehicle. **Tim Dodd:** Well, I think that's something that you guys have a perspective on compared to some of the other new players in the table is actually launching an operating vehicle. You know, that's something that your expertise will show through there, you know, putting efforts into probably where it matters long-term compared to, you know, the short-term gain of really worrying about each and every little bolt, you know, the cost of each bolt. So that brings up a good point though. As far as operating a helicopter, I think of that as very expensive, you know, and it is, a helicopter is expensive. But if you're saying it's like much cheaper- **Peter Beck:** Cheap. **Tim Dodd:** Compared to- **Peter Beck:** It's like $5,000 an hour for an S92. The Bell 429 that we operate is like $3,000 an hour. And in order, you know, to get out to the rendezvous point, it's like two and a half, three hours flight. So it's like 60 to $70,000 for the ship just to sit in the port, not even going anywhere, (Tim laughs) just to have the luxury of the ships sitting in the port, it's like $60,000 a day. **Tim Dodd:** What? **Peter Beck:** And yep. And that's just a little ship. That's a tiny little ship. It's not like, you know, giant ship. You would be stunned at how much it costs to operate Marine assets. **Tim Dodd:** No. Okay, I am stunned to know how much it costs to operate- **Peter Beck:** That's why we don't have a barge because it's just horrifically expensive. **Tim Dodd:** Wow, okay, touche. Oh, I know you love helicopters, but that's another mark towards goodness in helicopters, I guess, I had no idea. Okay, so I gotta get back to that second stage and all that stuff, too, because... **Peter Beck:** Yeah. ### How to Human Rate Neutron **Tim Dodd:** So it's inside the payload fairing during ascent. Super cool. How is that gonna work though? You know, you're still talking about human rating this, and having this be something that could be, you know, operating for human space flight. I guess, how far are you into thinking about that or considering that when you have an encapsulated payload fairing like that? **Peter Beck:** Well, so this is a thing for a capsule, the capsule is generally the fairing anyway. So you just remove actuated fairing halves or petals for a crewed mission. So, you know, there is no fairing requirement there. So the capsule becomes a fairing. **Tim Dodd:** And the second stage is hung below, right at the line of where the payload fairing... Okay. **Peter Beck:** Yeah, yeah. So if you look at the load, I mean, this was all done on a whiteboard, and it's like an engineer's and a structural analyst's dream. ### Structural Loads **Peter Beck:** Because if you actually draw out the load path, you know, you have your payload, and your job is to get the load from your payload into the tank walls, that's kind of a structural analyst job, is in the most efficient way possible. And when you're typically doing that through a traditional rocket, then you get it out into the rocket tank walls, and then you've gotta push it through your second stage, and then you gotta push it through your separation planes and down into your first stage and ultimately react it. Whereas if you think of the concept with Neutron, literally, your payload cone goes directly to the hard point of the fairing opening points, which is, you know, a structural hard point for the vehicle anyway. And then everything else below that is just sort of hung off that structural hardpoint. So it's an incredibly efficient way to transfer all those loads ultimately into the tank walls in a really, really short load path. **Tim Dodd:** Wow. Yeah. That's actually really cool when you think about it. So I guess another question with those fairings and things like that is, is there any chance that, you know, at subsonic speeds, you could reopen those on re-entry... ### Fairings as Drag Brakes **Tim Dodd:** (Peter laughs) and landing and use them as drag brakes, basically? **Peter Beck:** Yeah, so that was the original plan. So we didn't have any of those kind of fins at the top, the canards at the top for any kind of range adjustment. And the original plan was, you know, to open those fairing petals, that's why there's four of them, and try and do the cross range with that. But the loads just get insane, like the loads just get ridiculously insane so quickly, and you fall off the trade very, very quickly. And, you know, the design of the vehicle is such anyway that, you know, it's almost like a re-entry capsule in its design. And you notice it's very wide at the base and then, you know, narrowing up. So that does a majority of the work anyway, but we just couldn't get enough authority with the petals to do, you know, cross range. And also, we couldn't really react the loads efficiently, everything gets too big. **Tim Dodd:** And especially, probably at hypersonic speeds, I'm guessing they're pretty well on the wake of the vehicles as well, it's probably hard to get any reasonable control out of them that way, too. **Peter Beck:** Yeah, yeah. And in those flow regimes, you know, you get all sorts of crazy shock-shock interactions, and, you know, fin is just so easy, right? It's so well understood. And, you know, it's a very, very simple problem to solve. But when you've got these kind of, you know, funny shape things dragging out in the wind and shock waves attaching to them all over, that just gets really, really complicated to analyze and make reliable. **Tim Dodd:** Now, have you already designed how to actuate and control those fins? Are those gonna be electronic or electric, you know, electric motors, or have you not quite gotten that far into design yet? **Peter Beck:** You know, they'll be most likely electrohydraulic. So we do a lot, obviously, we're very familiar with electric things, so electrohydraulic will be most likely the solution. Very simple. **Tim Dodd:** Yes, very simple and very quick, too, and those are good things for, yeah. ### Fixed Legs Heating / Details **Tim Dodd:** For re-entry now, you know, with that kind of blunt-bodied design and everything, how it kind of folds in and all that stuff. It is interesting that the legs do protrude in front of the shock plane. Do you have to worry about their plumes, you know, their bow shock, is that going to interact and make this spiky point right in the middle of the engines or something like that that you guys have to worry about? **Peter Beck:** Yeah, I mean, there's a lot going on down there as you kind of alluded to, and, you know, we'll do some more CFD to really try and understand that. But I mean, we have a lot of learnings from Electron as well. I mean, it's a very simple blunt bottom end. But, you know, even on Electron, there's some really weird heating spots that you see, you know, around and in-between the nozzles. We basically get stagnations, you know, from the flow and get really, really hot spots. So yeah, I mean, actually, the bigger challenge with the legs is not re-entry, it's actually ascent because as you're ascending and your plume's expanding, your legs get impinged by the plume. **Tim Dodd:** Yeah. **Peter Beck:** And that's actually the dominant thermal case on ascent rather than actually re-entry. **Tim Dodd:** Really? Okay, yeah. That actually makes a really good point. And it looks like there is some amount of shock absorption kind of built-in to the ends of the legs there. **Peter Beck:** Correct. **Tim Dodd:** I'm assuming the bottom of them will probably not be... You know, those have to be something high, like you said, high temperature, you know, and probably pretty strong. The very bottoms, will they still be carbon fiber or have those likely be some kinda metal? **Peter Beck:** Yeah, I mean, so, I guess, the reacting structure will most likely be composite and will run a hot skin. You know, we can get really, really efficient interactions of the structures by making kind of a cold structure and carbon, and then, you know, a hot skin either with thermal protection systems or even just a hot skin. **Tim Dodd:** Yeah, yeah. **Peter Beck:** But the whole point of these legs, I mean, the way the design came about is we started off with something that looked more like a rocket and kind of parallel in a sense, and it's one of these things that sort of all happened in like 20 minutes. And, you know, we're drawing on the whiteboard, and I was working on the legs at the time and the legs were driving me insane because, you know, I just hate mechanisms. Mechanisms suck at the best of times, let alone, you know, when you've gotta build them super light and... But anyway, it was kind of driven out of that. It's just like, "Well, how can we avoid just not having legs?" And then it's like, "Well, let's make the base wide enough, so we don't need legs." So we did a quick calc, and it's like, "Yeah, we need about seven meters in diameter of the base." And then what is the optimum shape from there on? And we ended up with kind of a traffic cone, or it looked very similar to like, you know, the Delta Clipper or DC-X kind of, you know, that traffic cone, that single-stage-to-orbit vehicle. Actually, that is the most efficient structure to transfer all the loads and it's the most efficient structure. And then we did some arrow on it. And actually, it turns out that, you know, a cone like that is great for entry. There's plenty of examples of that. And help manage all of the thermal loads as we're descending. Having that, you know, decreasing diameter means that the pressure gradient across the vehicle is also decreasing, so you don't get shock waves attaching, and it all kind of made sense, you know, pretty quickly. So, you know, somewhere, there's a picture of all of us standing around a whiteboard with a traffic cone. (Tim laughs) Ultimately, that's what it evolved into. **Tim Dodd:** And you don't have to worry about those legs. ### Wing Strakes **Tim Dodd:** They almost look like wing streaks on two of the sides appear to go pretty much all the way up. So they are kinda streaks. You can use that a little bit as aerodynamic lifting. **Peter Beck:** Yeah, yes. Cross range and down range, get that right to get your trajectories for that final time. **Tim Dodd:** And those lifting points aren't so... I mean, they look like, you know, if it's flying backwards, engines first, it does appear that, having the legs out already in front of it seems like a bit of a no-no aerodynamically almost, having them so far forward. But I assume with the mass of all the engines right there, that your center of mass is quite far forward, too, though. **Peter Beck:** Oh, it's way back. Oh, especially with a lightweight carbon structure, it's like, yeah. **Tim Dodd:** Yeah. **Peter Beck:** It's way, way down there. **Tim Dodd:** The center of lift is way back, yeah. **Peter Beck:** Yeah. And the thing is because the structure is so light, you've got this wickedly awesome ballistic coefficient with no mass. So, you know, the reason why we're able to be really efficient with return to launch site is because we have like this really great ballistic coefficient with low mass. And, you know, it looks like jumping off of the roof with an umbrella versus jumping off the roof, you know, holding a golf ball in your hand. It makes all of the difference and it makes it much more efficient to do the return to launch site trajectory, you don't eat so much propellant. **Tim Dodd:** Yeah. So you won't have to do as much of a boostback burn, you can kinda fall short of the landing pad essentially, and basically glide back more or less almost, to a degree. **Peter Beck:** Yeah, yeah, I mean, the boostback... ### Light Mass is a Win **Peter Beck:** I mean, firstly, light mass is just a winner everywhere. Like I often talk about the spiral of doom for rockets where, you know, you add a little bit of, you know, inert mass and you've gotta add, (clears throat) excuse me, you've gotta add more propellant and you have to add a little bit more inert mass and this just spirals away. **Tim Dodd:** Yep. **Peter Beck:** Well, if you can invert that spiral of doom, then it's all awesomeness. And a lightweight structure is kind of like that. Because if you have a super lightweight structure at the end of that burn, then, you know, the amount of Delta-V you need to impart to it, or the amount of energy you need to impart to it to get that Delta-V is much, much lower. So that's awesome. You win there. Versus, you know, having to slow down a big heavy stage, and then turn it around. And then on re-entry, you know, you can use the atmosphere to do a lot of the work for you, just like we do with Electron. Because the ballistic coefficient's in the right place, the mass is so low, so the atmosphere does a lot of work. The heating's not nearly as high, you know, it's just all goodness. Like light structures is just wonderful. **Tim Dodd:** It's just a win-win all around. **Peter Beck:** Yep, yep. Takes all the pain out of propulsion, everything. ### Re-Entry Burn **Tim Dodd:** Yeah, so are you not having to do an entry burn or some kind of burn similar to Electron? You can just do your boostback burn and let the atmosphere do the rest? **Peter Beck:** Yep. So there's one boostback burn and then one landing burn, that's it. **Tim Dodd:** Wow. So you're just gonna let that... So yeah, that again, speaks to, I'm assuming, you know, carbon composites. I have to admit, it's pretty amazing that you've gotten away with it with Electron, too. With no active aerodynamic control to just using cold gas thrusters, to continue to, you know, properly orient the stage. It's been amazing to see that it's been returning, you know, so cleanly, that's been awesome. **Peter Beck:** Yeah. **Tim Dodd:** It looks easier than it is. (both laughing) **Tim Dodd:** Like I can only imagine the amount of work that you guys have to do for that. But I wanna talk more about Archimedes, ### Archimedes Engine **Tim Dodd:** because this is going to be your first vehicle that's not either, you know, just pressure-fed or electric pump-fed, you're now looking at gas generator. Congratulations, I guess. (laughs) I don't know if congratulations isn't calling it, but that's gotta be kinda scary. Are you worried at all about having to develop a gas generator engine for the first time? **Peter Beck:** No, I mean, it's a gas generator. I mean, I might've had a different... If you see it, like we're gonna run a full stage, you know, float cycle, then now I'd be worried, but it's GG. **Tim Dodd:** Yep. **Peter Beck:** Like the pump side of the equation is no different. You know, we've got electric motors and Electron running pumps. But whether it's a turbine... You know, so the pump heads and the knowledge that it takes to build good pumps is already gained. And, you know, the GG cycle is, you know, such a well understood in arbitrary, simple cycle. And this is kind of the point is like, where do you put your innovation and where do you put your expertise? And if you have a lightweight structure, then you don't need to push propulsion. And that was kind of the point. So, you know, Archimedes is the boringest engine that we can build in a lot of sense. We're not pushing the boundaries anywhere in that engine. So, you know, it's like GG Methalox. Ho-hum kind of an engine. **Tim Dodd:** Yeah. Pretty, pretty conservative all around. **Peter Beck:** Yeah, yeah. **Tim Dodd:** Really? **Peter Beck:** But actually, that's what you want though. And that's what you want, a reusable launch vehicle. I mean, do you wanna sit in, you know, a 787 or you know, a jet, and look out at the wing and look across at an engine that's like safety factor 1.01, (Tim laughing) or do you wanna look, you know, out on your wing at a safety factor of 1.5. **Tim Dodd:** Right. **Peter Beck:** And this is fundamentally what it comes down to. Like a rocket is just a giant engineering compromise, and you just have to choose where you're gonna eat the pain and you can choose it in propulsion. You can choose it in structures. You know, where is the bit that's gonna destroy your life? (Tim chuckles) **Tim Dodd:** That's a good way of looking at it. And you guys are definitely... I mean, you've known how to do the carbon composite so well, obviously, you've proven that you're kinda the kings of the composites end of the structures. So, you know, like you keep saying that, it makes so you don't have to do as much heavy lifting with the engines, you don't have to do as much. **Peter Beck:** Yup. **Tim Dodd:** It's making your lives easier on that end as well. So it is interesting. Tom Mueller really wanted to do a methane Merlin. SpaceX Propulsion Engineer, **Peter Beck:** Yeah. **Tim Dodd:** Tom Mueller, really wanted to do a methane Merlin. And it's fun to see that you guys have kinda come to what is similar to a methane Merlin, a similar class engine, you know, gas generator. Yeah, it's gonna be really fun to see, because I think that actually makes a lot of sense for your vehicle. What's- **Peter Beck:** Yeah, yeah. **Tim Dodd:** And so, as far as other design decisions with that, I mean, have you looked at... Obviously, yeah, you can't scale up electric pump-fed that much, you know, as you kinda mentioned in the video. It just doesn't close. But had you considered closed cycle at first or anything, or did you just pretty much go, this is... Was it pretty obvious when you guys got into it? **Peter Beck:** It's super obvious. I mean, like I said, at the end of the day, this is about a reusable launch vehicle. And in propulsion, you need margins, you need structural and thermal margins. That's what you need. So, you know, pushing into any of the more exotic cycles. If we had to go there, because we couldn't get the structures, you know, where we wanted them, then that's your only choice. And look, I even spoke to Tom earlier this year and said, "Look, Tom, this is what we're gonna build." And he's like, "Yes, that's exactly the right thing to build." (Tim laughs) So, you know, at the end of the day, this is about, you know, a reusable workhorse, and you can't build something that's super reliable and super reusable when you're pushing up against, you know, the margins of materials and, you know, the margins of everything really. So from a propulsion perspective, the key here is, you know, just keeping all of the limits well within check and not trying to push the boundaries. ### Injectors **Tim Dodd:** Yeah. I like that. Do you already know things even like, you know, what type of injector you're using, how low it can throttle, and all that stuff, or is that all still kind of to be determined? **Peter Beck:** Yeah, yeah. Yeah, no, no, I mean, you know, the methane is obviously a gas liquid injector, so, you know, that's very well understood, that kind of geometries, you know, that you want to run with those, you know, kinds of phases of propellants. And, you know, we'll leverage heavily on our 3D printing. So, you know, all the lessons we've learned with 3D printing, hundreds of Rutherfords, the majority of that engine will be 3D printed. It's a different engine, but really, once you build a few engine, it's all but the same. I mean, you can get your thermal balance, and then just sort of, you know, single element injector testing, and just sorta go from there. This feels very kind of turn the crank. **Tim Dodd:** Sorry. Did I hear you say liquid gas injector? Is that because the methane will burn? **Peter Beck:** Yeah, methane. **Tim Dodd:** Yeah, will boil off in the active region channels, is that right? **Peter Beck:** Correct. (crosstalking) **Tim Dodd:** That's the gas. **Peter Beck:** Yep. **Tim Dodd:** Gotcha. **Peter Beck:** Yeah, yep, yep. **Tim Dodd:** Okay, yeah. I guess, I didn't know for sure, you know, if it boils off of that point or not. I assumed it would, but yeah. So obviously, active region, which is par for the course, are you gonna be doing swirl injectors or, you know, shot with a traditional shower head, like impinged injectors or pintle? Or can you give us any of those details? **Peter Beck:** Well, let's just say, I mean, if you had one gas and one liquid propellant, you know, that there's some obvious choices around injectors. **Tim Dodd:** Okay. You didn't say what you did when I asked about electronic, it's a very good injector. (laughs) So I'm getting- **Peter Beck:** It is a very good injector, yeah. Rutherford is an amazing engine. That is just such a high screaming performance engineers. It's quite incredible, really. And you know, it's not a copper-lined engine either, so, you know, it's a pure 3D printed Inconel engine. So generally, as you shrink the engine, you know, cooling especially gets harder and harder because you've got tremendous amount of obviously, heat flux, but very small surface area to deal with it. So, you know, to have such a high-performance engine in all stainless steel and small, it's a real credit to the team. **Tim Dodd:** I guess. Let me ask you this then, if you don't mind. ### Cooling the Engines **Tim Dodd:** In that term, as far as trying to cool, like a throat of Rutherford, do you do any film cooling at the throat where you have a little holes? **Peter Beck:** No. **Tim Dodd:** Nothing? **Peter Beck:** Nope, nope. Nothing, no. **Tim Dodd:** It can just handle the heat load? **Peter Beck:** Yeah, I mean, the injector geometry, the team has spent a lot of time and a lot of work on that. They had little nuggety, little grunted sizing. They're very impressive. **Tim Dodd:** Is there some film cooling as far as additional, you know, fuel injectors around the outer perimeter of the injector face or something? **Peter Beck:** Yeah, you know, most engines will run some film cooling. So there's a small amount of film cooling. And in fact, if you look at... Well, actually, you can look at just about any rocket engine on an upper stage on like refracturing metal alloy nozzle, like a niobium nozzle, you can see the dark spots. So you'll notice that it's kind of on a nozzle, there's this kind of dark spots that run around the periphery. Well, those are actually, you know, the locations of the injectors up in the thrust chamber. And that's where the film cooling injector kinda lies in line with one of those dark spots. **Tim Dodd:** Oh, I always thought that was from just the fins that kinda hold the manifold. I guess you don't have them, but you don't have a gas turbine manifold on Electron because it doesn't have a turbine. **Peter Beck:** No, no. **Tim Dodd:** Interesting. So that's just from the pockets basically of the film cooling. **Peter Beck:** Yep. **Tim Dodd:** Okay, I'm so glad I have someone to ask this, sorry, I'm working on it. The reason I'm excited about cooling is I'm working on a video about, you know, why rocket engines don't melt, because it is pretty amazing (Peter laughs) to have that much heat contained within walls that should, by all accounts, it should melt the walls every time. So it was pretty amazing that you engineers get to figure out how to keep the engines from melting. And, you know, with the F1 engine having such drastic film cooling, especially, you know, because it uses the turbine- **Peter Beck:** Yeah, the GG into the- **Tim Dodd:** Yep. **Peter Beck:** Yep. **Tim Dodd:** You really see that distinct flame front below the nozzle exit. You know, you can see that dark thing. But I even noticed that, you know, with like the RD-180, closed cycle, you know, you can still see little spikes coming out from the bottom of the nozzle that are kind of those dark spots, you know, at sea level. I couldn't tell if those were a little bit of flow separation, you know, the flame getting pushed in, or if that would indeed be from some of the film cooling. Do you happen to know? **Peter Beck:** I'd have to go and take a look at it. I'd have to have a look and see. Yeah, I'm not that familiar with the, yeah. **Tim Dodd:** I'll send you an image and I'd be curious to get your thoughts on it. 'Cause I'd be very curious. **Peter Beck:** Yeah, yeah, yeah. **Tim Dodd:** What type of film cooling, or what exactly that is. **Peter Beck:** Yeah. **Tim Dodd:** Yeah, if you don't mind. **Peter Beck:** No, and the other thing that plays into this is the injector pattern as well. So the injector pattern can make those kind of shapes around the periphery of the nozzle. ### Vertical Integration **Tim Dodd:** Oh, that's very cool. That's very cool. Okay, so a few more things, if you don't mind. **Peter Beck:** Yeah, yeah, yeah. **Tim Dodd:** You know, I'm guessing this whole vehicle will live its life basically vertical. **Peter Beck:** Yes. **Tim Dodd:** You know, likely just stay vertical the whole time, right? **Peter Beck:** Yeah. Well, infrastructure sucks, remember. So anytime you've gotta build something to break it over, then, you know, it's a whole piece of machinery or the whole maintenance schedule, and a whole team to maintain it and operate it and all the rest of it. So, you know, the concept here is to not break it over. And of course, you know, structurally, it kinda hurts breaking those things over. You've gotta support them gently and all the rest of it. And so it's just an operational end, and OPEX nightmare. So if you can avoid doing all of that, then you're in a far better position. **Tim Dodd:** So how do you get it from... Are you still planning? 'Cause last time we had spoken, I think you had said you were planning to build most of these at Wallops actually, was your plan or something along that? **Peter Beck:** At the launch site. **Tim Dodd:** At the launch site. **Peter Beck:** At the designated launch site yet to be announced, but yes. ### Where They'll Build Neutron **Tim Dodd:** Oh, okay, okay. **Peter Beck:** Yep. So yes, you know, we removed that constraint immediately. That always seemed to be the dumbest constraint you can imagine as like the dome of the rocket is set by the lowest bridge between California and Florida. **Tim Dodd:** Right. **Peter Beck:** That's not a good engineering trade, you know, to have a deal with. So yeah, right from the very beginning of the program, we just released all constraints on diameter. **Tim Dodd:** So you'll build the rocket at the site, roll it out vertically, and assumingly, integrate vertically, obviously, with a payload. **Peter Beck:** Correct. **Tim Dodd:** I'm guessing, you know, if you have a quick turnaround time, you ought to still bring the rocket back in, you know, to the payload integration or the facility, and then roll it back out. Is that correct? **Peter Beck:** Yep, yep. **Tim Dodd:** Okay. **Peter Beck:** Yep. **Tim Dodd:** Well, that's not too bad though, I mean. (laughs) **Peter Beck:** That's the whole point, right? **Tim Dodd:** Yeah. **Peter Beck:** Is the minimum amount of facilities and operations possible. **Tim Dodd:** Yeah. **Peter Beck:** And you trade a lot for that, right? I mean, you know, just a strong back, for example. Not having a strong back and an umbilical tower means you have to run all of the upper stage filling lines up the length of the first stage and it's all mass, you know, eating mass all over the show. But you know, operationally, it just makes huge gains operationally. And if you have super lightweight structures, then you can actually afford to trade in some transfer pipes up the side of the vehicle to fuel the upper stage. And all these kinds of things. So, as I mentioned, it's a giant kind of suboptimal engineering compromise. But you know, giving yourself the best set of constraints, you know, messes everything. **Tim Dodd:** So does that mean those streaks are... Did you kinda say that those are also raceways of sorts? ### Second Stage Umbilicals **Peter Beck:** Correct. Yep, 100%. **Tim Dodd:** Cool. **Peter Beck:** Yep, one propellor on the either side. Yep, yep. **Tim Dodd:** Oh, wow. Yeah, so then that attaches to the... The second stage has its own basically umbilicals that attach to the first stage and you fill it up through there. **Peter Beck:** Correct. So in the interstage, if you will, there's a vertical umbilical between the first stage and the second stage. And that's actually the umbilical breakaway for the upper stage. **Tim Dodd:** Hah, wow. Okay, so, I mean, these are all... You have a lot of new things that I don't think I've seen be used too often. How are you feeling about your timeline? I know you're originally aiming... ### Timeline **Tim Dodd:** for some kind of structure-ish next year, 2022. Engine, hopefully, firing by 2022, and still looking to maybe be flying by 2024. Does that seem like a reasonable timeline? **Peter Beck:** Well, I mean, as reasonable as building any rocket... Look, I mean, we're pushing super hard. And look, there's new stuff, but none of that's like kind of risky or development, heavy or challenging. Like if you stand back and you say, "What are the things that drive time in the development of a launch vehicle?" It's always propulsion. Propulsion is always the last thing to turn up at the launchpad, no matter what. So, you know, if you can start off with, you know, a really simple well-trodden path of propulsion system and development program that's not doing anything new there, then that kind of solves half the problems. You know, just because we're running some internal umbilicals and bits and pieces, it's just no big deal. And a lot of the stuff that's in Electron scales very, very well to Neutron. So, you know, vent relief valves and all that sort of stuff. Whether it's two inches or 12 inches, it just doesn't matter, right? And in some cases, it's a lot easier to build something bigger than smaller. Yeah, so there's a lot of stuff. Avionics just pulled it across. There's a bunch of stuff that's kind of really long lead time, that's kind of done. But the one thing I will say in the development of Neutron to date is it is way easier. Now I'm probably gonna live to regret this. (Tim laughing) So maybe, let's not put a hat on this one. (Tim laughing) But thus far, it is way easier to develop a larger launch vehicle than a smaller one, because the mass constraints are just not there. I mean, you know, we really care in Electron about 10 grams. We really care about 10 grams. Neutron, I don't even care about 10 kgs. So it's a totally different, you know, situation to be in. You know, we will debate with ourselves to add one pressure transducer on Electron, because it's a measurable impact to payload. Whereas with Neutron, you're not even gonna have that debate, you just put another one on there. So there's a lot of things that, you know, small launch vehicles that are just super, super hard, that on a larger launch vehicle get, you know, much, much easier. **Tim Dodd:** And so just to kinda wrap things up and round things up here, 2025, you know, we're looking four years down the road, you're predicting that obviously, Constellations will continue to grow and be more of a thing. ### Neutron VS Competition **Tim Dodd:** So you're building kind of this Constellation launch vehicle. How are you feeling like, you know, by the time 2025 comes around, do you think you'll be pretty much in the sweet spot compared to the competition or you're gonna be still competing against Falcon 9, New Glenn will likely be flying by then? Yeah, you must be feeling pretty good then that you're kinda hitting the right place, the right time and everything. **Peter Beck:** Well, I mean, put it this way. Building a rocket, you can measure the amount of time that it's gonna take off your life. So there's no point in doing that unless that you think you can be competitive, otherwise, you've just burned a hole in your life for no reason. So, no, we're pretty confident. I mean, I think we've been okay at picking the market niches to date, and we see a real opportunity in that class. You know, obviously, there's some very large launch vehicles that are gonna come online at some point in time. But fundamentally, you know, even if you have a super large capacity, it's kinda like Electron. You know, Electron is flat out with lifting customers that, you know, a lot of people would say, "Oh, well, they will just go and rideshare." But rideshare doesn't actually, you know, meet their need and meet the objectives of the business plan. So, you know, having huge amount of capacity doesn't necessarily solve the problem, it's actually about getting the right massive payload to the right orbit in the right timeframe that builds businesses. And ultimately, that's what we think Neutron is gonna be very, very successful at. And I'm sure, you know, we'll compete with a bunch of others in the marketplace over time. **Tim Dodd:** Yeah. So I guess you probably don't have any kind of pricing idea yet, ### Pricing **Tim Dodd:** or do you sort of have a price in mind of what a target you're trying to hit per launch? **Peter Beck:** Yeah, we do. But like we say, you know, we would not even be undertaking this program if we didn't think that we're gonna be very competitive on that element, and you can stand back and you know, look at the design and look at the architecture. And as I said, at the beginning of this, if you wanna draw a graph of what it costs to actually put something in orbit, you know, the cost of the rocket, the bottom bit, is relatively small compared to everything else. And then if you look at Neutron, like it's a flat pad, there's no barge. All of the things that really, you know, add significant cost just aren't even there. So that's what gives us confidence that we think this is going to be, you know, very unique vehicle in the marketplace. **Tim Dodd:** Well, as you mentioned too, even with Electron being overbooked already, just even with, you know, things that should be rideshare missions. Rockets are almost never packed to the brim, you know, with their full capacity. **Peter Beck:** No. **Tim Dodd:** You know, most of the time, they're flying well below their capacity. **Peter Beck:** Correct. **Tim Dodd:** You know, eight tons is- **Peter Beck:** And by the way, you don't get a discount for that as a customer like whether you fill the rocket or you don't fill the rocket, when you buy the rocket, the cost is the same. **Tim Dodd:** Right. So if you have a cheaper ride, period, that's the bottom dollar, the amount of the check is what matters most to the customer at the end of the day. **Peter Beck:** This is where the whole cost per kilogram metric falls over. It's a great metric, you know, that accountants and bankers can understand very easily. But the reality is that almost nobody buys like a rocket on a cost per kilogram basis. **Tim Dodd:** Yeah. **Peter Beck:** It is, how do I get this particular mass to this particular orbit in this timeframe, and what's the lowest cost that I can do that for? **Tim Dodd:** Yes. And that's something that I think us, you know, armchair individuals, accountants and YouTubers, I guess, love the cost per kilogram thing. (Peter laughs) You're right, we don't see those behind the scene things, and it's sometimes confusing to see, you know, a customer maybe choose a more expensive rocket or, you know, something like a Proton or something like, "Well, why did you do that?" But it's like, "Well, if it can get our payload into space a year earlier, you know, or whatever, all these extra things that we just don't see at the end of the day, you know?" **Peter Beck:** Yeah. **Tim Dodd:** At the end of the day, it's total cost and total cost comes down to as well as, you know, if I put my Constellation in this particular orbit, it's much more cost-effective of generating revenue versus, and this is where Electron, you know, does so well, yeah, I can go on a rideshare, but I'm gonna be in the suboptimal orbit and I'm not gonna be able to generate as much revenue in the lifetime members. My spacecraft is much, much shorter, and it's gonna take me much longer to generate revenue. Or I can pay a bit more on Electron and get to an optimum orbit means I can generate revenue faster. The quality of the revenue is higher. So, you know, this is how satellite operators look at it, is they look at what is the total cost here, not just a cost per kilogram to get my satellite in orbit. **Tim Dodd:** And that's what makes you different than me. (Tim laughing) I love your expertise. It's really fun talking to you because I feel like you've gained a lot of knowledge having run Electron now. A lot of the operational cost and how you do things efficiently and, you know, you just turned a rocket around and your launchpad around, and flew 21 days back to back. That's impressive. You know, you're definitely getting those gears moving. So it's been really exciting to see you guys do that. I'll just round up here. What are you looking forward to next year the most? ### What's Exciting in 2022 **Tim Dodd:** 2022, what are you most excited for? **Peter Beck:** Well, I mean, it's quite ironic really, because I used to travel to the US every three weeks from New Zealand. And, you know, it got to a point where it's a bit of a drudge. I haven't been to the US for nearly two years. So the thing I'm looking forward to the most in 2022 is they're letting me out of this country is I can get on a plane and come to the US and actually see the factory that we built there that I've never even been into, and visit all of, you know, the incredible company, and people that we've partnered with over the last year or so. Actually, 2022, for me, I just can't wait, you know, to get up to the States, and just, you know, burn a whole bunch of time up there. It's gonna be great. **Tim Dodd:** That's awesome. That's good to hear. Well, maybe I'll run into you then when you're upstate side and I'll come and say hi. **Peter Beck:** Sounds good. **Tim Dodd:** All right. Well, Peter Beck, thank you so much for taking time to chat with me, and I'm really excited for what you guys are working on. It sounds like it's gonna be a really exciting couple of years here. **Peter Beck:** Thanks, Tim. Yep, no, it's gonna be a wild ride. ### Outro **Tim Dodd:** All right, thanks Peter. **Peter Beck:** Cheers. **Tim Dodd:** Thanks again, Peter, and the rest of the teams at Rocket Lab for allowing me that much time with Peter. I just love asking him deep questions because he has just really good answers. I really, really like hearing from him. Let me know if you guys have any questions or thoughts in the comments below. I'll try and answer some of the questions in the comments if I see them, but also be sure and stick around because I have a new video coming out about why rocket engines don't melt. And I think, hopefully, you'll learn something from this one because I learned quite a bit doing the research for it. It's a super fun and interesting topic. I owe a big thank you to my Patreon supporters for helping make everything we do here at Everyday Astronaut possible. If you wanna gain access to our exclusive discord channel, some exclusive live streams and early access to videos, head on over to patreon.com/EverydayAstronaut And while you're online, be sure and head over to our web store where you can find merchandise like this, our awesome new space shuttle-inspired hoodie. Now this is actually inspired by the first four space shuttle missions spacesuit, that was the S1030A, which is the space shuttle ejection suit. And it is actually based on the SR-71's flight suit. So I love this, it's got all these nerdy little details, like what they had on the suit. You can find that as well as a lot of other fun stuff up at our website, but you'll also notice we have our new RD-171 long sleeve shirt and short sleeve shirt, as well as our RS-25 space shuttle main engine shirt, and our R-7 Soyuz shirt as well. You can find all of those and lots more at everydayastronaut.com/shop Thanks everybody, that's gonna do it for me. I'm Tim Dodd, the Everyday Astronaut, bringing space down to Earth for everyday people.