Elon Musk Explains Updates To Starship And Starbase (Everyday Astronaut, 2022)
Questions on ElonsFAQ asked in this interview (2)
Transcript
0:00Tim DoddHi, it's me, Tim Dodd, the everyday astronaut. Welcome to Starbase Texas. Today we're going inside Starbase with the ultimate tour guide, Elon Musk. He's going to take us through the High Bay to see where starships are assembled.
0:11Tim DoddWe'll also see the new Mega Bay under construction and talk about SpaceX's plans to get this rocket flying. Now I must warn you, some of the things we talk about are pretty technical, but I've got a handful of videos to help you understand what we're talking about.
0:24Tim DoddThere's links in the description to those videos. And stick around because in the next videos we're going to go up the launch tower. Then we'll see the new Raptor 2's UPC close and personal and talk about the Falcon 9's Merlin engine in great detail.
0:36Tim DoddAnd if you happen to find this video valuable, consider dropping a super thanks as a tip or become a channel member or a Patreon supporter for early access and to help show your support.
0:45Tim DoddAll right, let's get started.
0:58Elon MuskSo we're making good progress with the, the Mega Bay over there. So that should be done in a month or so.
1:08Tim DoddThat's tricky. The scale from. Because perspective wise, right here, it almost looks the same, you know, just from our perspective, but it's, it's about
1:19Elon Musk30, 40ft taller. Okay, so it's, it's more about just, you know, in this case girth is more important than length because we just need, we need to be able to construct more ships and boosters and you can see like, like the, the High Bay there is, it's okay if you've got like maybe two or three works in progress, but like maybe have two or three workstations in, in this, in the High Bay, in the Mega Bay we can have like really almost a dozen, maybe at least 10 workstations.
2:00Tim DoddHoly cow.
2:01Elon MuskSo that's why the sort of width and length are more important there, especially as we try to really get the production line going. We need more workstations. The high bay here is okay for making for a low production rate, but as you go to a higher production rate, you just need more workstations.
2:21Elon MuskYeah,
2:28Tim DoddAnd so that's booster, right? Yeah, or half a booster. Half a. Half a ship, it looks like.
2:38Elon MuskYeah, exactly.
2:40Tim DoddLooks like you do have those, your vents there, the cold, the cold gas or the ullage gas vents.
2:47Elon MuskYes, well, we're using the ullage gas for attitude control. So instead of having separate attitude control thrusters, were using the ullage gas itself for attitude or reaction control. So basically for attitude control, once you're in orbit, or basically when you're in a vacuum, you don't need the impulse needed is very low.
3:11Elon MuskSo in earlier design iterations, we had a separate cold gas attitude control system with nitrogen bottles. But that actually doesn't make a lot of sense since we've got a bunch of ullage that we're going to vent anyway.
3:26Elon MuskSo might as well use the ullage gas for basically attitude control and small delta V changes on orbit. Yeah.
3:39Tim DoddOkay. I have to admit, you taught us to question your constraints. So that makes sense to me for the booster, you know, Cause the booster doesn't need to do it.
3:49Tim DoddBasically the second you turn the engines off, it's gonna need to want to vent a lot of its stuff anyway. And that also corresponds with its first flip. But for a starship, like with docking maneuvers and stuff, how does to me in my head, the Venn diagram of needing to depress a tank and the Venn diagram needing to do an orbital maneuver don't always have a huge amount of overlap, or is it not a concern?
4:14Tim DoddIs it always going to be on
4:15Elon Musktap when the ship gets to orbit? You're going to have still a pretty high pressure in the oxygen and fuel tanks, which are autogenously pressurized. So you've got hot gaseous oxygen and sort of hot methane, but you have a lot more ultra pressure than you don't need.
4:41Elon MuskYou actually don't need any more ullage pressure. So like you've got more, you've got more pressure than you need. Okay. So and, and the, the, the deorbit and the landing burns are done with the header tanks.
4:56Elon MuskSo you actually want to vent the main tanks down to just above atmospheric pressure. Well, really.
5:06Elon MuskYou want, you want to have enough pressure in the main tanks for structural stability. So it's like this. So it's pressure stabilized, but not any more pressure than is needed for pressure stabilization for atmospheric entry.
5:20Tim DoddRight.
5:21Elon MuskAnd it's going to. But when it gets to orbit, it's going to have really a lot more pressure than is needed for atmospheric entry. So we would in any case end up venting the main tanks down to the pressure needed for reentry.
5:37Elon MuskOkay. And so we'd be tossing that gas away. Okay.
5:43Tim DoddSo if it's free, you might as well use it.
5:46Elon MuskYeah, we're going to dump the gas anyway. So then, so then why have separate tanks and everything? You might as well use that gas
5:52Tim Doddfor,
5:55Elon Muskyou know, attitude control and small maneuvers. And then even then we'll still end up dumping the remaining gas that's not needed for entry.
6:08Tim DoddOkay, so because of that last statement, you'll be dumping it anyway. Definitely kind of.
6:14Elon MuskYeah. Actually when you look at the whole design, it actually, it's just like obviously it was pretty dumb to have a separate cold gas reaction control system because we have excess ullage gas.
6:32Elon MuskAnd if we simply have main tank vents that vent in the direction that you'd want, then there's no need to have separate ullage thrusters. You can literally just use the vents.
6:50Tim DoddSo at some point those will probably have like, almost like an Apollo style, like four, four way set of nozzles or something. Right. Or because right now they're just facing prograde, basically.
7:04Elon MuskYeah. So that would be for settling thrusters, basically those ones up there.
7:09Tim DoddOkay.
7:10Elon MuskAnd there's, there's side thrusters that you don't see on right now that will be added. So side vents and. Yeah.
7:22Tim DoddSo I, I, it just still surprises me that they're not doing, you know, like capturing and doing some kind of high pressure or higher pressure, you know, hot gas thruster anymore when you have.
7:32Elon MuskNo, the hot gas thruster was definitely over engineered and unnecessary. So just using ullage gas for, for basically for, for small thrust is the obvious move in this case.
7:49Elon MuskSo in retrospect, the obvious move, it's much more efficient than having separate cold gas thrusters.
7:57Tim DoddWell, I guess now that I think about it, there probably hasn't. There's never really been a rocket where the upper stage or the actual spacecraft is 99% a giant empty tank or a drained tank.
8:07Tim DoddEvery other vehicle, space shuttle, very small amounts of just the OMS pods basically and that stuff. But there's never really been a vehicle that's on orbit where it just went through a, you know, four or five minute burn and now it needs to.
8:22Tim DoddYeah, that actually is really, really interesting. That's so crazy.
8:28Elon MuskSo it's, it's, it's a significant optimization mass and cost savings to use the ullage gas for attitude and reaction control than to have separate coal gas thrusters.
8:40Tim DoddI love it.
8:42Elon MuskI'd say that's like one of the biggest improvements that we've made.
8:45Tim DoddI gotta admit. That was when you were talking about the last time and I kept thinking about it.
8:49Elon MuskI was actually used, I was just, it was literally occurred to me in real time. It occurred to me while I was explaining it to you. I was like, wait, what are we doing?
8:59Tim DoddIt was one of those things that kept just being like, that can't be Right. But you're. Yeah, I mean, it is. It seems to be.
9:07Elon MuskYeah. We kind of went through this exercise for the ship, and I was like, wait a second. We should do that for the booster as well. And that just occurred to me, literally, while I was doing the interview with you.
9:20Elon MuskLike, okay, do you mind saying a few things? Or what do you think we should. I don't know.
9:29Tim DoddYeah. I want to see Elon's interviewing skills.
9:32Elon MuskWell, I mean. So this is Joe Petrozalka. He's head of booster engineering. And I don't know if anything you want to say. You pointed things and described what's new
9:50Tim Doddon, like, seven and stuff. What are some of the new things you guys are working on on booster
9:53Elon Muskseven, which is down at the pad right now? It's been quite an improvement over the first boosters that we built, 4 and 5. We simplified a lot of things.
10:02Elon MuskLike, there was a lot of. You just learned when you put things together the first time. We were able to get rid of a lot of it and combine a lot of it.
10:09Elon MuskIt's got some new arrow features, so it's got upgraded grid fins, and it has chines or strakes on the side of it. And those are going to make the reentry performance much better.
10:17Elon MuskSo we'll be able to actually come in at a lower velocity and get higher precision when we're coming in for the tower catch. So we're really excited to try that out on there.
10:24Tim DoddOkay, then I got one for both of you guys. Why are the strakes or whatever the Chinese. Chinese. Why aren't they 180?
10:33Elon MuskSounds like wind chimes.
10:33Tim DoddYeah, or like chimes.
10:35Elon MuskChimes would end chimes.
10:38Tim DoddWhy aren't they 180 degrees to each other? It looks like they're about 140 or something offset.
10:42Elon MuskYeah, they're about 120, actually. And what they do, it's not about just increasing the wingspan, if you will, it's about getting the area of the cylinder of the rocket to pressurize.
10:54Elon MuskSo those features help the rest of the rocket pressurize. So it's more than just the area of those chines. You actually get more net drag on
11:01Tim Doddthat section of the vehicle at an angle.
11:03Elon MuskRight.
11:04Tim DoddNot. Yeah, okay. So you're. So you're basically using that to increase, like, the overall surface area when it's coming at some kind of angle of attack.
11:12Elon MuskAnd so the booster is very. It's very bottom heavy with all of the engines down there. And so you're trying to actually add Drag area down there as well.
11:20Tim DoddYep.
11:21Elon MuskAnd when you do that, that can let the booster pitch up higher.
11:23Tim DoddYes.
11:24Elon MuskOtherwise, if you don't have the Chinese, it wants to just come in feet first, it's still going to come in pretty butt in first. A little. Slightly less. Well, you can pitch it up to 10 or 20 degrees.
11:34Elon MuskYeah. Much more control authority.
11:36Tim DoddAnd further. And cross range.
11:38Elon MuskAs Joe was saying, it's a little bit more than just increasing the cross section of the vehicle because you're not increasing the integrated pressure profile on the base. So you've got the sort of.
11:54Elon MuskThe experienced wind is hitting the cylinder of the vehicle and then it's rolling around the cylinder and it's kind of like losing pressure as it rolls around. By having the Chinese be not at 180 degrees but a little lower down, we're catching more of that air that's escaping.
12:15Elon MuskOkay. And so technically you actually have slightly less cross sectional area, but you have more integrated pressure at the base.
12:23Tim DoddGotcha. Let's keep moving quick while this machinery is firing up.
12:27Elon MuskSo these are very primitive shines. Yeah. We can do way better first attempt. And I expect to change them. Yeah. A lot over time.
12:33Tim DoddWell, one of the things that I love about it is that you're covering up the COPV's that. So it's both. Both a COPV aero cover. Double use out of it, which I love.
12:43Elon MuskI do fear that makes us less rigorous about getting rid of COPVs, but
12:48Tim Doddmore complacent that they have a hole
12:50Elon Muskas many as we wanted under them. So they were still a force. Okay, good. But like, if, say like what are optimized shines, you'd actually want them to get bigger as you get closer at the bottom.
13:02Tim DoddYeah.
13:02Elon MuskWider at the bottom. They begin to start looking like chip flaps. Yeah. Let the simulation run away.
13:07Tim DoddEspecially. Especially as you're coming in, like you said, with such a big amount of mass and basically a dry can above it, you'd really want the center of pressure to be as low as possible.
13:16Elon MuskRight. Yeah.
13:18Tim DoddSo that brings me to another question then. You're still. I'm curious why you guys are still sticking with grid fins instead of like a more traditional stabilator or some kind of canard or something.
13:28Tim DoddYou know,
13:30Elon Muskthis is a frequent topic of conversation. Exactly. This is a. We discuss this a lot. I mean, essentially like our optimization right now is getting to orbit. So there's.
13:44Elon MuskYeah. So we know how to use grid fins from Falcon 9. Grid fins are much more consistent than flaps as you go from hypersonic to supersonic to transonic to subsonic.
13:59Elon MuskSo you're going through these different marker regimes and grid fins are much more consistent than a wing or a, a wingy thing. So especially as you go subsonic, the center of pressure on any kind of flat surface shifts significantly when you go from supersonic to subsonic.
14:23Elon MuskSo but you know, could you be lighter than a grid fin? I think there's a good chance you could be. There's also another factor which is the, the actuator power needed to turn a grid fin is much less than is needed for to turn a wing.
14:43Elon MuskA sort of a wing like thing of similar. Yeah. Especially as that, as that center of pressure changes, it increases the torque on the motor. Right. You're necessarily. Yeah, yeah.
14:53Elon MuskYou're necessarily going to be ordered so short that even if the center of pressure changes, it's not far from the rotator.
14:58Tim DoddYes.
14:59Elon MuskAnd so the total torque required does not change dramatically throughout your mock machine transitions. Yeah, yeah. We are constantly talking about do we have the right number of grids?
15:09Elon MuskAre they designed correctly? Yes. So like we're not saying we're right to be clear. Like we're, we're definitely not optimal optimal. But we, it'll work. Like probability of working is good and it's one less problem to solve.
15:26Elon MuskIt's also there's like, we obviously don't need four. Like.
15:34Elon MuskI think we could probably get away with two. Definitely not more than three.
15:39Tim DoddWell, your old, the 2016 like original OG, you know, its had three. And I remember that being a pretty unique design consideration, you know.
15:48Elon MuskYeah. The sheer number of iterations that this vehicle has gone through is insane.
15:52Tim DoddBefore it, even before it even hit the pavement, it had already iterated like so many times. Well, I started questioning, you know, why for me I always thought the grid fin was a lot of it was being able to retract them on ascent, you know, get them out of the windstream.
16:05Tim DoddBut now that you're not retracting them, I was like, well that and then also, you know, the actual mass savings, you know, 50% of your, the mass of a grid fin is perpendicular to your control motion, you know, your control authority.
16:18Tim DoddSo I always wondered if like they, how that would the trade would be on just. Yeah. Compared to like a normal wingy thing.
16:25Elon MuskYou know, if you know your position well and you know your winds well, you can in theory have a ballistic arc when you do your boost back burn. That is very accurate with, with nothing.
16:41Elon MuskExcept and we tried this in the early days of Falcon 9, but the problem is any small asymmetries on the vehicle will cause it to go crazy. Basically it'll spin up and start flapping around and it'll just start oscillating and rotating.
17:04Elon MuskDynamic stability becomes a concern. Yeah, exactly. So technically you don't actually need massive surfaces. You just need to be able to take out the asymmetries of protuberances on the vehicle and any error that you have with respect to position or your boost back impulse.
17:29Elon MuskYeah.
17:29Tim DoddAnd even wind conditions and things like that, I'm sure micro.
17:32Elon MuskYeah, so you really don't. The control surfaces you need are actually not very big and we've shrunk the grid fins significantly from where we started out. So they're much lighter.
17:49Elon MuskYeah, but like even with grid fins we really should be moving to aspirationally two grid fins, but certainly not more than three. And the third one can be small
18:03Tim Doddlittle vestigial guy in the. I like just imagining a tiny little guy.
18:07Elon MuskYeah. So.
18:14Elon MuskWe have actually this is the liquid oxygen tank section for booster eight. It's coming along very quickly right behind booster seven. And then the ship 24 nose comes. So this is the ship that we hope to pair with booster seven for our first four.
18:29Elon MuskWh.
18:34Tim DoddIt's looking so much more refined already than even S20. Oh, can we see the door on the back side of it?
18:47Elon MuskCorner? Yeah. I mean it's not going to blow your mind.
18:51Tim DoddYou'd be surprised. Man, the Internet sure loves that door.
18:55Elon MuskYou gotta see the door anyway, so I guess why not? But
19:00Tim Doddbecause you're, you're at this point planning to launch 24 with Starlink version 2 already, right?
19:12Elon MuskYeah, well we'll see. But.
19:23Elon MuskI mean it's just like I said, it's not going to blow your mind here. You know, it's basically it's like we call it the PEZ dispenser and it's kind of like that.
19:33Elon MuskIt's the Starlink satellites are, you know, in this rack which looks like a friggin PEZ thing because they're like, you know, kind of like rectangular, just like a pez.
19:46Elon MuskAnd they're stacked inside the nose cone, inside the fairing. And since they're low profile, we only need really a small door. With a small door we can use pressure stabilization.
20:02Elon MuskLike we can retain pressure in the fairing so we can at least partially pressure stabilize the nose cone or fairing. And then we don't have a humongous hinge door like.
20:18Tim DoddYeah, like you might later on with larger pieces of cargo. And things like that.
20:22Elon MuskYeah, we can make a giant door in the future. But this allows a small door weighs a lot less than a giant door.
20:29Tim DoddYeah, yeah.
20:31Elon MuskIt's a simple sensor we could come up with for.
20:34Tim DoddI feel like it's just bagging the hammer.
20:36Elon MuskIt can go wrong, to be clear. Yeah. Like if the mechanisms inside jam up, that'll be pretty embarrassing.
20:41Tim DoddRight, right, right. But it looks like it's just begging to have like two big googly eyes with a, with a funny looking grin there, you know, or something.
20:50Elon MuskSo we are, we are incurring some complexity for the sort of the racking system inside. Because you've got to have a racking system. So it's more complicated than a PEZ dispenser.
21:02Elon MuskBut it's the general principle.
21:04Tim DoddIs it like spring loaded then or hydraulically loaded or something?
21:06Elon MuskOr. It's a bunch of electric. It's electric and with a bunch of mechanisms
21:20Tim Doddand they just like roll themselves out and just zip out the door and. Sorry.
21:26Elon MuskIt's inspired by pallet stacking technology. Yes. Like I watch YouTube videos of a pallet stacker. Exactly. Industrial pallet stackers. It's the same basic principle. They don't look super simple, but they do work.
21:44Elon MuskAnd so it's the same basic mechanism. I mean there's some risk of you're loading it in at 1G and then you're unloading it at 0G. So you could have some situation where you're unloading a mechanism and because you unload the mechanism, it now binds.
22:05Elon MuskRight. Like. So that's a risk that we. That's hard to test for.
22:08Tim DoddYes.
22:08Elon MuskYeah.
22:10Tim DoddWhat, so this. So you're planning to actually do your first set of Starlink version 2s on this vehicle? Or wait, is this 25 or 24?
22:21Elon Musk24.
22:21Tim DoddThis is 24, which is currently scheduled. Ish. To be the first orbital attempt. Right. So you are. So has a plan changed to go from kind of a suborbital to an orbital launch if you're going to be trying to pop out a couple Starlinks?
22:36Elon MuskNo, we're always going to get. Our next launch is always going to be orbital.
22:42Tim DoddIs it full orbital? Not.
22:43Elon MuskYes. Okay.
22:44Tim DoddSo that would.
22:45Elon MuskWell, yes. I mean, yes, for a little while
22:49Tim Doddthere was talk about like B4 and stuff and S20 back in the day doing like a. Just shy of orbit, you know, on the reentry by Hawaii and stuff like that.
22:56Tim DoddNever quite reaching.
22:57Elon MuskIt's. It's still. It's basically orbit. Okay. Yeah. There's no Real difference.
23:00Tim DoddMouse fart. Between the.
23:01Elon MuskYeah. I mean, you could just. It's the difference between. I mean, you're going like 3/4 the way around the Earth. You're. Yeah.
23:09Tim DoddI mean, it was literally like 30 meters per second difference or something tiny. It's hilariously small.
23:14Elon MuskYeah. It's extremely. Yeah. It's essentially orbital velocity. So there's just no point in doing, like. Why not? Why do an extra loop around the Earth, you know, and. And have another.
23:26Elon MuskThe orbit burn. So. But if you're really like. I. I wouldn't say that. There's like, high confidence that the first flight will work. I think there's a good chance that it does not reach orbit, that there's an issue with the booster or stage separation or the ship doesn't start or.
23:44Elon MuskAnd then even if it does get to orbit, there's the probability that the ship makes it down intact is also not super high. This is why it's entering over the Pacific and unpopulated area.
23:58Elon MuskSo if there is an issue, it's not a danger to people.
24:02Tim DoddYep. So one of the things that a lot of people were asking about after or, you know, once we started seeing the heat shield tiles is why they aren't scaled like a dragon or like.
24:13Tim DoddLike a roof shingle, where they're slightly overlapping and tapering and thickness. You know, why are they just have the gaps and everything? What's.
24:25Elon MuskI mean, you know, this. There's more than. There's multiple ways to approach this. So it's not that like a single approach couldn't work. You could have a shingled approach.
24:39Elon MuskThe thing that will happen, or should in theory happen here is that when the tiles get hot, they will expand and tighten the gap. So the gaps that you see here should be smaller when the tiles heat up.
24:57Elon MuskAnd, you know, you're really not going to see a lot of heat going down through those gaps is our expectation. So shingling does not seem to be important. You could be wrong about that kind of around the vehicle as opposed to trying to burrow into it.
25:18Elon MuskRight, right. Yeah.
25:19Tim DoddThe flow is not coming straight in at those gaps.
25:22Elon MuskIt's like it's. Yeah. I mean, we'll be coming in at an angle similar to the shuttle, like, I don't know, 60, 70 degrees. So sort of like if the ground is the surface of the Earth, we're sort of coming in like that.
25:35Elon MuskYeah. And it's a balance between generating lift. Like, for a reusable heat shield, we want to minimize the peak heat load. So the peak heat Load is going to determine if we melt the tiles or not.
25:50Elon MuskAnd if you melt the tiles, they're not very good for reuse. So we're kind of balancing between generating lift and. Yeah. So there's atmospheric density, velocity and you don't want to have like be going fast in high density air.
26:16Elon MuskThat's going to be.
26:17Tim DoddYou want to kind of stay up in the upper atmosphere for a little bit longer than you would with.
26:20Elon MuskYou want to slow down as much as possible in the thin upper atmosphere. So you'll. You minimize peak heating. That's the best to go. Minimize peak heating.
26:29Tim DoddWhich is pretty much what designed the whole shuttle's airframe almost Was that that peak heating and the controlling that peak. That peak. Q yes.
26:40Elon MuskSo we're going to learn a lot from this first entry. Like I said, if there's any issues the ship will not, you know, if there's unexpected heating in some places then the ship will fail on entry and that'll be that.
27:03Elon MuskYeah.
27:03Tim DoddIs there any talks speaking of failing and reentry and all those things. Have you guys. There were rumblings for a little bit that you guys. Someone was talking about flying ship 20 still or S20 just on a suborbital.
27:16Elon MuskYeah, we've moved on.
27:19Tim DoddFor my sake. Man, those, those suborbital flights were so fun to watch because it was so slow. You gotta feel it, you know, that much longer when it's just sitting there, you know, ascending for several minutes.
27:29Tim DoddLike I've never seen anything like.
27:31Elon MuskThose flights are cool. But like this we think we've learned, you know, what we needed to learn really with the suborbital flights. Yeah. And there wasn't really much to learn.
27:41Elon MuskSo best to focus on getting to orbit. Okay.
27:45Tim DoddI mean yay. But also should be quite excited about the. Yeah, it's true. Yeah. Those 33 Raptors I think we'll put on a pretty. That'll make up for the slow, slow, gentle climb.
27:55Tim DoddWill be 33 shaking everything.
27:58Elon MuskI think what'll seem pretty. Pretty odd or like strange is that the starship orbital stack is going to come off the pad very fast. Yeah. So yeah it's to going a high thrust weight.
28:11Tim DoddWhat's its approximate thrust of weight?
28:13Elon MuskI mean it should be like 1.4 ish. Maybe 1.5. Around 1.5. Yeah.
28:18Tim DoddThat's like Ariane 5 speeds with those SRBs. Once that those light. That thing just shot off shoots off the pad, you know and yeah, that'll be like that.
28:27Elon MuskI mean it's.
28:29Tim DoddYeah, that'll be disorienting to see something that big just accelerating that quickly. You know, it'll.
28:36Elon MuskFor a reusable vehicle, you actually want to have a higher thrust to weight than an expendable vehicle because thrust weight below one is not doing anything. So your propellant is not being useful below thrust weight of one.
28:50Elon MuskSo you actually want to have a higher thrust to weight for a reusable vehicle than for an expendable. For an expendable vehicle, the cost overwhelmingly is in the vehicle itself that you are losing.
29:04Elon MuskBut for a reusable vehicle, if it's, you know, rapidly reusable and completely reusable, the cost of propellant is the single biggest cost of the flight. And so you want to have a high thrust to weight so that more of the thrust is useful.
29:20Elon MuskYeah, so, so high thrust to weight
29:23Tim Doddratio literally is, is financially beneficial purely on the, on the, you need less fuel to do the same amount of work.
29:30Elon MuskLike this may sound sort of mercantile, but it's actually the thing to optimize for is cost per ton to orbit. Like, you can't cheat if you get cost per ton to orbit.
29:48Elon MuskIt's not about what the mass ratio is or the ISP or anything. So we're aiming for, you know, to have a great mass ratio, great ISP everything. But it's really what is your fully considered cost per ton to orbit.
30:01Elon MuskAt the end of the day, the fully considered cost per ton to orbit is the optimization. And any given technology is only relevant to the degree that it produces cost per ton to orbit.
30:12Tim DoddSo thrust to weight ratio might matter more than ISP as long as it makes for a lower cost per ton to orbit.
30:20Elon MuskYes.
30:20Tim DoddSo the trade offs always end up with does it decrease the cost per ton to orbit? And that's what matters.
30:27Elon MuskInspirationally, we don't always get right. But the thing that really matters is minimize cost per ton to orbit and then for Mars or the moon, minimize cost per ton to the surface of the Moon or to the surface of Mars.
30:42Elon MuskAnd just to give you a sense of just how much we need to improve it, it's really insane. Like right now, the cost per useful landed ton to the surface of Mars is in excess of a billion dollars.
31:00Elon MuskYou can't count the heat shield or the parachute or the useful stuff. So the landing system's mass does not count, only the. Like in the case of the rovers, it's really just the rover that is the useful thing.
31:16Elon MuskSo if the rover weighs a ton then, and it costs a billion dollars to get there, it's a billion dollars per ton to Mars and that's. That's roughly you know what it currently costs.
31:34Elon MuskNow in order to make life multi planetary and have a self sustaining city on Mars that number will have to improve to I think probably under $100,000 a ton.
31:53Elon MuskThat would be 10,000 times better than the current state of the art. To put things into perspective, how much of an improvement is needed? Not 10,000%, 10,000 fold.
32:10Elon MuskThat's what Starship is intended to do. Be 10,000 times better than the current state of the art.
32:17Tim DoddSo orders and orders and orders of magnitude.
32:20Elon MuskIt's a lot of orders of magnitude, but it is. We're not breaking any laws of physics. It is possible to do that.
32:28Tim DoddShould we. Can we see up at the top or is there anything to see up there right now?
32:33Elon MuskNot really anything. See, I mean I think we probably shouldn't take pictures of the inside. Not that it's super interesting but I think we got to be cautious about like pictures of the inside of.
32:48Elon MuskSo.
33:06Tim DoddWhere's the lifting points on. On this one now you can see
33:11Elon Muskthe lugs up there. I mean I'm not super. We need to move those lifting points. Those are not in a good position. So you don't want to have lifting points where the heat shield tiles are.
33:24Elon MuskWe need to move lift points to where the heat shield tiles or not.
33:30Tim DoddAre you still hoping to catch the ship too with the arms or what's the. I mean you are right.
33:37Elon MuskYeah.
33:39Tim DoddHow are you gonna catch it? I guess. Are you going to do the same thing with the tiny little nubs like the booster?
33:47Elon MuskYeah. I mean it'll be very similar to the booster with. Now in the case of the ship because we need to have heat shield tiles that go more than 180 degrees.
33:56Elon MuskA little more than 180 degrees. We'll have to have the. The catch points kind of like flip out.
34:02Tim DoddOh cool.
34:03Elon MuskBut it'll otherwise be stays in the. In the le lee of the wind. Like you either have to. I mean there's. You either have to have it. Have a pot with heat shield towels pop out or have something that's in the leeward side that, that swings out one of the two.
34:18Tim DoddAnd you can't just have the. You can't catch them by the. The nose fins.
34:24Elon MuskYou. Well, you sort of could.
34:32Elon MuskWell like what you're seeing there. That doesn't have heat shield tiles. Will need to have heat shield tiles.
34:37Tim DoddYeah, yeah.
34:38Elon MuskSo everything's going to have heat shield tiles that just. You see Like a steel part at the base of the. But that'll have to have tiles on it. What if it's.
34:45Tim DoddIf it's attached. If the mounting point would be attached to somewhere on the leeward side of the. Of the flap, and the flap could rotate more than 180 degrees.
34:53Tim DoddIt could get in line with this. It could be the same mechanism that does the quickie thing. Could be just the flap itself.
35:02Elon MuskI'm not sure I understand what you're saying.
35:04Tim DoddBut if the, the catch ball thing is on the leeward side of the flap and the flap can go beyond 180 degrees.
35:12Elon MuskOh, that's.
35:14Tim DoddMan, we're talking high.
35:15Elon MuskThat's not the problem you want us to try to solve. The, like a huge challenge we have is the, the hot gas seal.
35:22Tim DoddOh, right. You'd move that.
35:24Elon MuskYou don't want to over. Over center that.
35:27Tim DoddYes.
35:27Elon MuskIf like, frankly, the, the thing we need to do I think is move the forward flaps more towards the leeward side. This is a major internal debate, but there's a massive amount of optimization possible with the forward flaps.
35:44Elon MuskThey're in the wrong position. They're the wrong size, wrong position, wrong location. But they will work.
35:51Tim DoddYeah, they're a start.
35:53Elon MuskYeah, they'll work, but they're far from optimal. What are the.
35:59Tim DoddUnder those one. Heat shields. You see the little, those like yellow puck things?
36:04Elon MuskWhat are those? Are those special or something just like temperature sensors? Oh, I think so. Either temperature or radio. I'm not sure. So either the antennas or temperature sensors.
36:22Tim DoddWell, what, what else is new since last time we were out here?
36:28Elon MuskWell, we're, we're building the, the mega B.
36:48Elon MuskIt.
37:19Tim DoddWhat got your gears turning now?
37:22Elon MuskNo, just there's a. I mean, there's a lot of improvements to make with the ship. Ship and booster design. But anyway, right now the important thing is just to get to orbit with, you know, some reasonable payload.
37:37Elon MuskAnd then we have a whole series of improvements that we plan to improve the performance the payload orbit. So. But I really am not a fan of our forward flaps.
37:54Elon MuskLike every time I look at them, it drives me crazy because they're so suboptimal.
38:00Tim DoddWell, your rate of innovation and your rate of iteration, those will be different sooner rather than later, I'm sure.
38:08Elon MuskYeah, I mean, it's. There's a potential scenario where we can delete the forward flaps entirely. The shuttle didn't have four flaps.
38:18Tim DoddRight. So. And that's because you're using dihedral control to control mostly pitch. And you can still do a little Bit of yawn roll with just a pair. So. Huh.
38:37Tim DoddBecause it's mostly about your center of pressure.
38:40Elon MuskRight. So center of mass and center of pressure. It's a seesaw. So you can just think of these things like the. You've got a seesaw and your center. It's like your center of pressure, like the winds, the, the air is hitting the vehicle and you have a center of pressure.
39:08Elon MuskIt's like where's that air going to push the vehicle? If you add up all the wind pressure, if you're pushing it with your finger, what's the center of that force going to be?
39:26Elon MuskAnd then you've got your center of mass, which is a similar thing but for mass. So you've got like, you've got these sort of two seesaw things. Center pressure, center of mass.
39:38Elon MuskIf you have big forward flaps and big rear flaps, you can have a much more variation in where your center of mass is going to be and also what your angle attack can be and how you.
39:49Elon MuskWell, you control the vehicle and different Mach regimes and in the face of like a lot of wind shear, wind buffet.
40:02Tim DoddBecause there was that again Soviet, like, I don't remember what it was called, the Mole or something that just had a dihedral wing on the back. It's supposed to be like a mini shuttle for them.
40:12Tim DoddLike a two passenger shuttle.
40:13Elon MuskBuran, you mean, what was that? The Buran?
40:15Tim DoddNo, not Buran. No, it had a, like it's, it had foldable wings and they basically the only thing is those are fixed. They weren't dynamic, you know, so it's not like they controlled its pitch, but it basically had a really, was supposed to have a really high angle of attack during initial ascent.
40:30Tim DoddAnd then the back flaps just folded down. But that was to extend, basically have actual lift and do a horizontal landing. It wasn't necessarily like a dynamic link, but the idea was that you could control your overall pitch.
40:43Tim DoddAlmost like Virgin Galactic's SpaceShipTwo that folds in half. You know how it can change its whole center pressure and everything just in a single thing. But again that's not dynamic.
40:55Tim DoddIt goes from one mode to mode one to mode two. And same with that Soviet one. But yeah, that probably becomes a lot trickier when you are trying to be dynamic and when you are trying to actually pinpoint control your landing.
41:06Tim DoddI'm sure that with just having a.
41:10Elon MuskThe thing that's like really counterintuitive about the starship is that it's not an aircraft, it's falling. Yeah. So we're just constantly Trying to brake as opposed to an aircraft.
41:21Elon MuskThat is an aircraft is trying to generate lift and fly horizontally. We are trying to generate drag and be as draggy as possible when we, when we fall. Yeah.
41:33Elon MuskSo it's a very different optimization than an aircraft. Yeah. So yeah, yeah, it's about, about four times the usable area of the high bay. So it's only a little bit taller, but it's a lot wider and deeper.
41:54Elon MuskAnd so we have a lot more positions for manufacturing the booster or the ship. So if you have a production line, you need a lot of stations essentially for high production.
42:09Elon MuskSo this is intended to have a lot of stations.
42:12Tim DoddIs some of this getting replaced by another building that's like over top of some stuff or is it.
42:19Elon MuskWe are building a permanent building, a permanent factory building and replacing the tents,
42:26Tim Doddbut the high bay is.
42:29Elon MuskWe're not building a building to encompass the high bay. That would be insane. But we are going to be building a permanent factory building and replacing the tents and we start the factory building from that side and kind of build and gradually replace the tents with a, with a, with a large permanent building.
42:47Tim DoddOkay. That's actually currently in the works, I guess. So you're still, you know, there's a lot of speculation obviously with how quickly Florida is ramping up that this might be slowing down, but that doesn't seem to be slowing down too much if you're building and building out here.
43:01Tim DoddYeah, yeah. Hey, by the way. Hi, I'm Tim. Hi. Hey, nice to meet you. Awesome. Yeah. Sorry, what was your name? Andy Krebs. Okay, cool. I do engineering for the non flight hardware.
43:13Tim DoddSo I do the high bays and the factory have the spotlight for those as well as the launch pad.
43:16Elon MuskCool. Stage zero. A lot of the stage zero stuff.
43:19Tim DoddYeah.
43:21Elon MuskBecause the ground systems are. Ground systems, especially inclusive of the tower, are at least as complicated as the. As the stage one or stage two.
43:30Tim DoddYeah, yeah. So should we go check out stage zero?
43:36Elon MuskSure.
43:46Tim DoddThank you, Elon, for all your generous time. And thank you, Ryan Chalinski, for helping shoot and capture this incredible conversation. And I owe a huge thank you to my Patreon supporters for helping make videos like this possible.
43:57Tim DoddIf you want to help me continue to do what I do, head on over to patreon.com/everyday:isyonk and while you're online, be sure and check out our awesome merchandise shop where you can find shirts like this, the RD171 shirts and lots of other really cool [email protected] shop.
44:11Tim DoddThanks everybody. That's going to do it for me. I'm Tim Dodd, the everyday astronaut. Bringing space down to earth for everyday people.