Main Engine Cut Off - T+176: The Flight of Starship SN8

Episode Date: December 14, 2020

Starship SN8 took flight last week on a mostly-successful mission to test its final descent phase. I share some thoughts on the test, the state of Starship development, and what that all means for the near future of Starship.This episode of Main Engine Cut Off is brought to you by 36 executive producers—Brandon, Matthew, Simon, Lauren, Melissa, Kris, Pat, Matt, Jorge, Ryan, Donald, Lee, Chris, Warren, Bob, Russell, John, Moritz, Joel, Jan, Grant, David, Joonas, Robb, Tim Dodd (the Everyday Astronaut!), Frank, Julian and Lars from Agile Space, Tommy, and seven anonymous—and 438 other supporters.TopicsOn the Spectacular Flight of Starship SN8 and the Future of Starship Development - Main Engine Cut OffStarship | SN8 | High-Altitude Flight Test - YouTubeSpaceX on Twitter: “Starship landing flip maneuver”September 2019 Starship Update - YouTubeU.S. Transportation Command to study use of SpaceX rockets to move cargo around the world - SpaceNewsEpisode T+149: Let’s Talk About Starship with Tim Dodd, the Everyday Astronaut - Main Engine Cut OffStarship SN5 Flew, So Let’s Check In on Some Predictions - Main Engine Cut OffSenate bill offers NASA only a fraction of requested lunar lander funding - SpaceNewsThe ShowLike the show? Support the show!Email your thoughts, comments, and questions to [e-mail] @WeHaveMECOListen to MECO HeadlinesJoin the Off-Nominal DiscordSubscribe on Apple Podcasts, Overcast, Pocket Casts, Spotify, Google Play, Stitcher, TuneIn or elsewhereSubscribe to the Main Engine Cut Off NewsletterBuy shirts and Rocket Socks from the Main Engine Cut Off ShopMusic by Max Justus

Hello and welcome to Main Engine Cutoff, I am Anthony Colangelo, and I want to talk about the incredible flight of Starship, serial number 8, last week. I'm sure if you're listening to this, you've probably seen at least a clip of this. If not, pause this right now at least a clip of this. If not, pause this right now, go watch this full test. I've got the link in the show notes, because I want to unpack what we saw during the test, a little bit about what it means for Starship overall, and where we're heading in the future with the things that Starship is involved in currently, where it's going, you know, not just because of this test,

but because of the direction of Starship development down in Boca Chica. The test of SN8 had to be one of the most interesting, exciting, and truly spectacular flights that I've seen in a long time. Spectacular in terms of it being a spectacle to behold. This was the flight that was originally supposed to go to 20 kilometers, and then that got moved down to 15, and finally down to 12 and a half. And this is really the test of the final descent phase of Starship, from the aerodynamic capabilities, using the body flaps to guide itself to the landing site, to pulling off that landing flip maneuver, and then firing up the engines to touch down safely. And this is the first attempt at that, right? We've seen hops before. We've seen Starhopper. We've seen serial number five and six do 150 meter hops.

So we've had some experience with Raptors in flight from those flights. But this was the first one to fly it on a vehicle that looked like Starship, what Starship will end up being. And to do these final descent capabilities of Starship, this is the test they need to run. So it was an interesting test to watch for a couple of reasons. Number one, SpaceX was definitely trying to keep things tame on the way uphill, right? This was a test of the descent capabilities and the landing capabilities of Starship, not necessarily the ascent. Starship will, it'll always launch on top of Super Heavy, at least per current plans. I guess in the future that could change, as always, but it didn't seem like, and I've seen

some talk of this online, that the vehicle itself was aerodynamically stable to really push it hard on the way uphill. So they had a very slow liftoff. They had a couple of engine shutdowns during the flight up. They first shut down one engine, then a second engine, and they got to apogee on just a single engine before they shut that down to fall back to Earth. I don't even know if the Raptors were running at 100% on launch. They looked like they were working well, but was that 100% throttle? If so, they probably couldn't have lifted the propellant necessary to get to 20 kilometers. So I didn't hear a final figure on how high this actually got, but we assume that they got to 12.5 kilometers or so. But given the low thrust to weight ratio

that it looks like on the initial liftoff, I'm not even sure they could have gotten enough propellant in there to get to 20 kilometers. Or maybe they could have, and they just had the Raptors turned down to keep it at that thrust to weight ratio. It could also be that the vehicle structure came in mass-wise above what they were planning for the first landing flip test. A lot of variables that could go there. But whatever the case was, they were really keeping it tame on the way up, a very slow flight up to Apogee. And then they cut the engines, flipped to that belly flop maneuver, and started coming back in for landing. As we've seen on the test, if you listen to me up front to say, go watch this again, even if you've seen it, you probably want to go watch it again right now.

They were really successful the whole way down, right? A lot of this was then posted in the media about Elon Musk's Mars rocket blows up because that gets a lot of clicks and all, but you know what? You and I know that this was an incredibly successful test for what SN8 was trying to do here. They made it way further into the test than a lot of us thought they would. Of course, it did explode upon landing, but the failure seemed to be the initial reports were that they lost a little fuel pressure, so there wasn't as much fuel getting into the combustion chamber. You saw one engine flame out at the end, and then the second was burning green, which is the engine-rich mixture ratio from burning through the engine, basically. It was all locks at the end there, and lost thrust entirely, so it landed hard and exploded.

But to even get to that point so successfully was a really big deal for them and the failure mode is something that if you're not confident in the SpaceX team's ability to fix that failure mode I don't know if you've been watching SpaceX for the past decade that is a thing that they know very well the Raptor engines are maybe the best and most refined part of Starship at this point in time so not worried about that failure getting fixed. And as Elon Musk said, they put the crater in the right spot. They actually made it to the landing pad. So they really proved out that entire final descent of Starship with this test here. Now, before Starship can take on advanced mission architectures that involve refueling and

the whole nine yards that we've seen, SpaceX needs to solve the three big technical challenges to make Starship a reusable vehicle to at least orbit and back, right? Low Earth orbit is famously halfway to anywhere in the solar system. That's even more true when you have a vehicle like Starship that relies upon refueling to do all of the things that they've set out to do with it. So they need to solve these three main tasks. Number one, survive re-entry heating on the way back from orbit. Number two, aerodynamically guide yourself back to the landing site. And then number three, land softly under propulsion of these extremely high performance rocket engines. Those are the three main phases of flight, but the transition between each phase are massive challenges in their own right.

Transitioning out of the heating phase into the aerodynamic phase, that involves, you know, still flying supersonic. You've got a lot of different dynamics there depending on how the heat shielding works out. And then the transition between phases two and three is the landing flip that we saw them pull off here. So when you look at these three phases, it's inarguable that the SpaceX team that Elon Musk and crew have built out, it's hard to argue that they are not the best in the known universe right now at number three, landing softly under propulsion of high performance rocket engines, especially on Earth. SN8's flight was to pick off number two, that aerodynamic

guidance back to the landing site. And they were able to do that, including the transition between two and three, the landing flip. So they made it through a lot of this. The one that's left, surviving re-entry heating on the way back from orbit, and then the transition between that and the aerodynamic phase, that might be the biggest challenge of them all. We've seen on some of these hop flights and then this flight here, they've flown a couple of heat shield tiles bonded to the vehicle. It's probably a test to see how their bonding holds up. So we know that they're working on that problem. They have some ideas in flow. They're producing these heat shield tilings. We've seen a lot of them on different vehicles. So that is definitely in progress. They also have super heavy underproduction, which is the booster portion of the Starship

system. That is required before they're really able to test the heat shielding and the orbital capabilities of Starship. But they have a lot of other Starships in production down in Boca Chica. Unfortunately, serial number nine tipped over the other day in the high bay. It looks like they got that backup rate, but what damage there is and if that can still fly is unsure. But there's a bunch of other ones in flow. So I'm sure we'll see more flights like SN8 did before they get to that orbital attempt. But once they have Super Heavy ready, once they've got an entire slate of heat shields applied to a starship, they're going to ping one of these off to orbit and see if they can start picking off that phase one issue of surviving re-entry heating. That is going to be the gnarliest

challenge of them all, I'm sure, and one that's extremely fun to watch, as this test was as well. But all in all, they are making incredible progress through that test phase of, you know, this portion of Starship development. Now, what was probably the most meaningful part of what we saw in this test last week is how closely the actual flight matched the simulation shown during Musk's Starship update back in September of 2019. You remember he did that update while he was standing in front of

what was then Mark I, and they showed this simulation off of the final descent phase, you know, Starship at terminal velocity, then doing the landing flip, and even the engine gimballing that we saw. All of that matched the actual flight, almost frame for frame. If you put these side by side, it's tough to tell the

difference between, you know, is this a recreation of the flight? Is the flight a recreation of this? Hard to tell which way it's going because they match so well. And while that sounds like, yeah, that's silly, duh, that indicates that SpaceX has a really strong sense of this vehicle, including the dynamics experienced during flight, the control necessary to pull that all off. That kind of thing wasn't necessarily the case when they started doing this with Falcon launches and landings. They learned a lot more in the process of flying that than it seems like, you know, they went all of a sudden from 150 meter hop straight to this really complex flight back to the landing pad, and it matched what they

had simulated so well. So that says a lot about the relative state of the SpaceX team on Starship. You know, a lot of other organizations out there, even SpaceX in some cases themselves, they'll show simulations or worse, artistic renderings of what a proposed vehicle will do, but fewer go on to actually fly that and then have that turn out, you know, in this frame-for-frame comparison way to match what they showed off previously. There's always some changes there, and I'm sure there will be changes to Starship in the future. There always are, but the fact that from over a year ago to now, they match so well, that should inspire confidence that SpaceX is not just making up what this vehicle is capable of. They really have a good understanding of what Starship

can do and what they want to do with Starship. And that means a lot in the era where it's in the mix for NASA's human landing system contract to take humans to the moon. It's under consideration by various parts of the US government for point-to-point delivery systems of cargo, maybe even people. Obviously, they have their own Mars ambitions that are the kind of end state of all of this. And that confidence that you should have because they're showing that they know what they're doing at Starship, that should give you a lot of confidence in all of those goals. And it really is meaningful to pushing those all forward. There's another reason why it's amazing that it matched so well to the simulation that was shown off over a year ago. Because this is the first time in a year-over-year

period that Starship has not drastically changed its look and its architecture. They're really dialing this in now. If it's stable from, you know, 14 months separated, it looks like the same vehicle. It's much more refined now, but it looks like the same vehicle. It's not the massive difference that we've seen. Diameter changes, and they've changed from, okay, we're going to have three aerodynamic surfaces, two, back to three, to two again. So the fact that this is the first year-over-year period with very minimal changes and more refinements than changes at that, that means a lot that they are really settling in on what Starship looks like and how it works. Someday I'll convince somebody to send me Elon Musk to talk about the day the decision was made

to switch to the stainless steel Starship, because it's hard not to think back and think about where the program would be because of that decision. If that went differently, where would we be? The old carbon fiber days of Starship, that had a different pace to it. You know, it was a lot more intensive in setting up a production facility out in LA. They had all this tooling there. They ended up destroying that and going down to Boca Chica. And they've just been welding stuff together nonstop for, you know, a year and a half. There's a great story there to be told about how that all went down internally.

The rationale for the decision is out there, and it's been talked about a lot, but I want to hear the details of the internal debates there. What were the debates? How were the ideas competing for what seemed like months or years alongside each other? When, how, why was the final decision made? There's a lot of juicy details there because it does seem like a major divergence point. They trashed that carbon fiber tooling that they had out in LA. They moved down to Boca Chica with all this stainless steel, and they changed their pace

tremendously with Starship. So I really want to hear that story someday about how things change with that because you know not only was starship very flexible back in the day when they were early on in the process of designing and figuring out what this thing was it's hard not to separate that from you know maybe this internal debate about how they should build the thing and once it was switched to stainless steel they kind of narrowed in on what the design was for quite a while and now that they're narrowed in on what the design was for quite a while. And now that they're narrowed in on it and iterating on a single design, I think that says a lot as to why they're making such good progress, you know, over the past year or so. So before we get into the rest of this, I need to

say thank you to everyone out there supporting Main Engine Cutoff over at mainenginecutoff.com slash support. There are 474 of you supporting the show every single month. I'm so thankful for your support. And this episode was produced by 36 executive producers. Brandon, Matthew, Simon, Lauren, Melissa, Chris, Pat, Matt, George, Ryan, Donald, Lee, Chris, Warren, Bob, Russell, John, Moritz, Joel, Jan, Grant, David, Eunice, Rob, Tim Dodd, the Everett Astronaut, Frank, Julian, Lars from Agile Space, Tommy, and seven anonymous executive producers. Thank you all so much for the support. You're really keeping this thing going. We've had a lot of growth lately. I've seen a lot of people jumping in the Patreon. So thank you all so much. And a lot of them are jumping in for Headlines, which is a special show that I do. It's an entire

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But I'm talking about every single story in space over there that matters to listen to. So if you want to stay up on space news, if you want to really stay up on what my thoughts are on all the space news, that's to listen to. So if you want to stay up on space news, if you want to really stay up on what my thoughts are on all the space news, that's the place to go. And it helps support the show and keep it going. So once again, mainenginecutoff.com slash support. Thank you all so much. Waste steel, not time. That is the mantra that SpaceX is following down in Boca Chica. And like I said, I want to hear about the

story behind that day the decision was made to go with stainless steel. But since then, waste steel, not time has been the calling card. It's easy to shrug off the earlier vehicles that we've seen out of Boca Chica as mock-ups like Mark I, or flying test stands like Starhopper, or otherwise not very capable with serial number 5 and 6. Some or all of that was accurate, I'm sure. I don't know what the inside of Starhopper looks like, but I guarantee you it doesn't look a lot like what the insides of serial number 5, 6, or 8 look like. But it's hard not to be impressed with the rapid increase of capability and fidelity that we've seen from Starhopper all

the way to SN8. The idea here is to continue to produce vehicles, and each one you learn, hey, we missed this detail, or we didn't fully consider how these things interact. We need to improve these areas and refine those. You're learning a lot at that point where you're building out a vehicle, and it's kind of integral to the design process that SpaceX is following with Starship. They have an architecture in mind. They have the general concepts of how this is all going to fit together. They obviously have a production flow to have all this hardware flowing into Boca Chica. So there's a lot of refined details under the surface, but think about how much more fidelity they're figuring out as they're actually putting all these things together. It's easy to think

it's just tanks and steel welded together, But there's, you know, all these different parts and components that are coming in from production facilities elsewhere, and being integrated there. And that integration process is where you're learning a lot about how it all goes together. You know, there's all these avionics and flight systems, there's internal plumbing for the header tanks, there's actuators for body flaps, there's heat shield tiling, as we talked about, there's so much going on there, but it's all getting integrated at every single point in time. So you're knocking down risk in the future as you do that. Each time you do that, you're verifying that what you're laying out there is actually going to all work together and make a complete

system. So the general idea is that steel is a lot cheaper than people time. And if you've even with a massive amount of planning and design time, you still learn so much when you actually get into hardware when you're building and testing vehicles. So if wasting a few starships worth of steel each year saves you, you know, five years of planning and design time it's worth it and when i say wasting starships that might not be fair because they are reusing them star hop star hopper is now like an infrastructure tower there's like radar and cameras and a pa system i think they eat lunch under it as well the former body flaps are now like they're making roofs out of them for you know snack bars or

whatever so there's plenty of ways to use this steel in other ways, but it's not a big deal when they say, oh, SN9 tipped over. Well, you know, good thing we have a spare and they roll out SN10. So I think what SpaceX is showing here is something that I try to remind myself a lot when I'm working on projects. The best way to get overwhelmed is to try and solve everything all at once. And the best way to work instead is to have a roadmap, have a vision, and constantly check your work against that as you make progress. You've got to just refine your direction and your trajectory to get to your vision as you're making progress, because the path that you take in the physical world when you're actually building something is going to be a lot different than what was in your head before that. And SpaceX is doing

that all in a really tight cycle to iterate quickly. So some vehicles come off and you're, they come out of the high bay and you're like, the hell is that thing? Like that doesn't really look like a lot, but then the next one comes out and it's got a little bit more and it's got a little bit more. And then you step back and you realize the fidelity of SN8 is way higher than what you were seeing the months previous. So where is Starship going from here? Let's talk a little bit about future plans because Starship's involved in a lot right now. Aside from SpaceX's own plans for Starship, which are obviously ultimately Mars, but in the shorter term, they're trying to replace the Falcon 9 and heavy vehicles. And a lot of that is due to their own capabilities

that they want to have, which is launch a massive amount of Starlink satellites at any given time. But they also want to have that fully reusable launch system to replace the Falcon vehicles, have cheaper launch services, and overall increased demand for getting things to space. But the big thing on the horizon right now for Starship is the NASA human landing system. This is the contract to take humans to the moon as part of the Artemis program. There were three bidders in the initial round that won, SpaceX with Starship, Dynetics had their lander, the really low lander with the attachable fuel tanks on the side, and then there was the national team from Blue Origin, Lockheed Martin, Northrop Grumman, and Draper. They're working on, you know, what looks like a very tall vehicle with Blue Moon, the Ascent vehicle from Lockheed Martin, the Tug from Northrop Grumman.

All of those are in the base period right now, where they're working with NASA on their design, defining out what the capabilities of the vehicle would be and a bunch of other, you know, initial planning and stuff like that. Originally, a down select to two of those systems was supposed to come in February. The election might have changed that and likely will have changed that, but where we are in the process right now, NASA requested for the upcoming fiscal year, the one we're actually in right now but don't have a budget for, as always, NASA requested $3.2 billion. The House bill funded the landing system at $600 million. The Senate put it at $1 billion. If a budget were

to pass, it would be somewhere between there. Let's call it $800 million. Is $800 million enough to downselect to two systems? Is it enough to downselect to just one? Does it get stretched out even longer? Is there a plan still to even land on the moon with Artemis? All of that is going to be figured out not just through the budget process, but what the incoming Biden administration wants to do with NASA generally. So I think over the next six months, eight months, we might have a little bit more of an idea of where that's actually going to go. So I would be shocked if there was an official down select in February. And I would be even more shocked if they down selected to two,

you know, with full funding, maybe they'll down select to two and do another small contract to push it a little further, but not yet commit the massive amounts of funding for landers that would be necessary. But what's important for Starship in that is every single day that a down select is not made

or even every day there is a down select is not made, or even every day there is a down select but isn't a huge budget, that's a win for SpaceX. They are massively investing in Starship themselves right now, and they're making a lot of outwardly visible progress pretty relentlessly down in Boca Chica. So the later the down select is made, or the later the budget is made available, the further along they'll be with Starship. They'll have proved out an increasing amount of the architecture. Things that people would say is they're crazy, they're never going to work. The stuff that we hear with SpaceX all the time, right?

We're used to the goalposts being moved with SpaceX from the Falcon days where it was, oh, they'll never be able to reenter the atmosphere. They'll never be able to fire engines into supersonic retropulsion. They'll never be able to land, never be able to land on a boat. They'll never be able to relaunch one, never be able to launch one, you know, twice or three times. Now they're up to seven. That kind of stuff has always been there for SpaceX. And it's going to be there for Starship too. But now that they've done this SN8 test, one less thing looks crazy about Starship. So if they're going to keep doing that,

and months down the line there's going to be decisions being made, a lot less about Starship is going to look crazy. If they start getting to the point of orbital tests and show some promising results on the heat shield, the atmospheric entry, that would be a huge win. You know, the complexity beyond launch and entry are arguably equal with the other bids that are in the running for the NASA human landing system. The fact that refueling is an essential part of Starship, it does mean that launch and reentry and Earth landings are part of the human landing system bid for SpaceX. But if they were able to solve that piece, the complexity against the other systems looks, you know, arguably similar. You've got Dynetics that has fuel tanks that can be swapped out or refueled or whatever it is. The Blue Origin team has three elements that need to be launched separately on different vehicles. They need the

rendezvous and dock somewhere between here and the moon. And all of them are due to fly on launch vehicles that have not yet been flown. They're all still in development. So there's a lot of similarities in terms of the complexity of all of these bids. Once you get beyond, you know, just say once we're in low Earth orbit, where are the relative states of these architectures? They all have similar, you know, pros and cons. But what's a huge factor is self-funding. Ifa is in this budget constrained environment if there isn't a lot of budget available to actually push these things forward how much you are funding yourself is going to be a huge factor in the nasa decision

dynetics i'm pretty confident to say would not be building this lander if they're not funded by nasa spacex is definitely funding this lander even if they don't have contracts from NASA. Look at them right now. They got $135 million from NASA for this base period. Who knows what that was going to, but they are taking all sorts of investment cash because they are cash hungry between Starship and Starlink, and they're putting a ton of that into Boca Chica. The only chance that SpaceX has for real competition in the space of self-funding is if Blue Origin decides they want the human landing system to exist for their own purposes. Bezos could decide to fund the development from Lockheed, Northup, and Draper.

It's a big ask from, you know, Bezos, but when you look at how much NASA was requesting for the landing systems and how much Bezos is putting into Blue Origin every single year, he certainly could say, I'm going to contract with Lockheed, Northrop, and Draper to build the parts of the system that we had teamed up on while Blue Origin continues on Blue Moon. Because Blue Origin is working on Blue Moon regardless. They have the cargo version that they want to fly. They have some contracts, you know, they're in the running for some commercial lunar payload services contracts from NASA. They have this different variant that would be human landing capable. So I'm pretty confident that they're going to be building out Blue Moon. It's the other pieces of the architecture that, you know, they could fund. I don't see it as likely, but I'm saying it is a possibility. And that's really the

only chance that there is for SpaceX to have real competition in terms of self-funding. Now, there's a chance that some of that company contribution stuff could actually be made public through some of the documents that are going into this round of bidding for the human launch or the human landing system. So we might see some of this, but that is going to be a big factor, especially heading into this year where budgets are uncertain and progress needs to be made. That's going to be a huge piece here. So that is why this delay or whatever it is, if it's a delay or just a budget constraint, that is a really good sign for SpaceX in terms of winning that contract round, because they're going to keep making this progress on Starship. They're going to keep

pushing forward. And each day that they push forward, they're in a better position to win than somebody who isn't showing that outward progress or doesn't have as much development going on internally because of these different self-funding levels. So that's where I'll leave you today with my thoughts on Starship. A great day out there at Boca Chica for SN8, and one that will go down in history for sure. But until next time, thank you all for listening so much. Thanks for your support at mainenginecutoff.com slash support. If you've got any questions or thoughts, email me anthony at mainenginecutoff.com or hit me up on Twitter at WeHaveMiko. Once again, thanks for listening,

and I'll talk to you soon.