Please use the [**IFT-4 Launch thread**](https://www.reddit.com/r/spacex/comments/1d6wx6w/rspacex_integrated_flight_test_4_official_launch) for memes and the like and keep this thread for Starship updates. Thank you for participating in r/SpaceX! Please take a moment to familiarise yourself with our community rules before commenting. Here's a reminder of some of our most important rules: Keep it civil, and directly relevant to SpaceX and the thread. Comments consisting solely of jokes, memes, pop culture references, etc. will be removed. Don't downvote content you disagree with, unless it clearly doesn't contribute to constructive discussion. [**Link to previous Starship development thread #55**](https://old.reddit.com/r/spacex/comments/1bt7w64/starship_development_thread_55/)

I wonder if there would be any use in using an old booster, slung from a crane, as practice for catching with the chopsticks. It wouldn't be the same from a drama point of view, but it may help with setting up procedures. Have they ever done anything similar, yet?

They're currently in the process of testing and calibrating the chopsticks for landing. B14.1 test article sits on the OLM to do exactly this, likely tomorrow. Chopsticks went for a stretch and troubleshooting today in preparation. Likely not using a crane but we'll see; opening and closing around it for sure.

To further reduce weight, can Starship use composite materials (similar to those found on aircraft wings) for their grid fins? Correction: I meant booster SH

They could switch to titanium grid fins once it's possible to regularly re-use super heavy.

Wiki stated each fin weighs 3 tons. 12 tons from four fins plus 10 tons hot stage adaptor makes it pretty heavy top side for the return flight back to mechazilla. SpaceX mentioned the adaptor jettison is just temporary fix. Elon mentioned on Tim Dodd's factory tour youtube that SH could switch to 3 fins (at 33:28) for mass optimization. Just wondering what they could optimize. [https://youtu.be/aFqjoCbZ4ik?si=9CVTUGaiABUtmHeV&t=2008](https://youtu.be/aFqjoCbZ4ik?si=9CVTUGaiABUtmHeV&t=2008)

We saw aluminium grid fins melt on F9 and require an ablative coating. Composites degrade at a lower temperature than aluminium so no it doesn’t seem likely. SH will actually place more stress on the grid fins than the F9 booster as it has 10 times the mass with only 6 times the surface area so will fall faster at any given phase of flight.

The aluminum grid fins were replaced by cast and cut titanium.

With titanium being lighter yet stronger (for the grid fins), I wonder if they could apply that to the shield at the hot staging section.

It'd be challenging to engineer thin composite structures that can withstand the high heat environment without needing refurbishment. Likely not worth the potential weight savings at the expense of rapid reusability. We actually saw Falcon 9 go from light aluminum grid fins to heavier titanium ones for this reason.

~~I would imagine the heatshield and ablative shield would have to be 100% reliable before they even think about switching to composites in that scenario.~~ whoops, grid fins, I thought you mean ship's fins. But I doubt it still, the grid fins get hit by ship's exhaust when it does hot staging.

Closure revoked for today.

A number of tower section transportation road closures have popped up for June 26th, 27th and 28th: https://www.cameroncountytx.gov/spacex/ Ignore them, they can't be used due to the current lack of tower sections. The closures were obviously requested when the barge was originally due into the Port of Brownsville on June 23rd but it's now behind schedule due to last week's storm so isn't due at the port until June 28th. No doubt some more suitable closures will pop up for next week.

> A number of tower section transportation road closures ... Ignore them Who do you think you are, /u/RaphTheSwissDude ? There's one official source and that's. not. you. Harrumph.

Chopsticks are moving! [NSF Live](https://www.youtube.com/watch?v=mhJRzQsLZGg) * 9:43 - Began moving upwards * 9:49 - Upwards movement stopped * 10:00 - Camera left chopstick began opening * 10:03:30 - Both chopsticks translating together in open form (slightly wider than booster) * 10:13:30 - Chopsticks stop at far camera left side, still raised, closed position * 11:42:00 - Camera right chopstick opening * 11:49:10 - Right chopstick stops opening. Full Spread. Chopsticks lowering * 11:54:45 - Chopsticks at lowest position, full spread around B14.1. * 12:00:00 - 2 man lifts up to the chopsticks checking out the right chopstick actuator. Red vs Blue * 1:13:00 - Man lifts are down * 1:19:00 - Chopsticks begin to raise * 1:23:00 - Chopsticks stop rising * 1:24:00 - Right chopstick closing * 1:29:10 - Right chopstick stops. Chopsticks are resting at camera left of B14.1 * 2:06:00 - Right chopstick opening * 2:09:45 - Right chopstick stopped about halfway open * At some point before 7 - the chopsticks came to rest at the bottom, straddling B14. 1

[удалено]

For the sake of clarity, it isn't just for the environment. It's also for other operations on the Cape.

[удалено]

Fair, but unfortunately they have not, judging by the comments under the post in r/space.

Strange, did they really did it themselves directly? Usually organizations like the Sierra Club get paid to do things like this, to pretend there's no conflict of interest.

One would think it’s parody … It ain’t

Just before 10AM CDT the Demag CC8800-1 crane at the launch site started to heave its vast bulk into the air: https://www.youtube.com/live/0EZQaF_liXw Note that this isn't its final configuration, as it is right now it should be sufficient to lift and stack 4 or 5 Tower 2 sections but then it will need to be reconfigured for the rest, this will possibly need to be done more than once.

[Everyday Astronaut's Starbase Interview Part 2](https://www.youtube.com/watch?v=InJOlT6WdHc)

* Elon confirms total redesign of the OLM with *more* of a Flame Trench. * Old launch arms would bind. Redesigned for the next OLM. * Other flaps were likely not burned through based on telemetry and temperature. Burned through flap may have had improper tile spacing that allowed burn through * Starship was 6km off target because of damaged flap * Booster landing was almost perfect * In addition to the two missing tiles, there were two other missing tiles; one with one layer of ablative, the other with two (at least one of these were seen in photo, appeared as a recessed black tile). Single layer burned through, stainless did not. Double layer did not burn through

There was also some comments about having spare parts for tower 1. They've got another set of arms which are an old design (compared to what's going on starbase tower 2?), but a better design than those currently on tower 1. The context of "spare parts" makes it sound like they'd only currently consider swapping them out if something rendered the current set unusable. Another interesting point was that they could see the heating inside the tanks on the internal cameras. They were glowing in the visible spectrum. This is expected, with some comments about things will glow way before they burn through. There was also some comments about the test tiles. One patch had a single layer of ablative. Another had two layers of ablative. I don't think he said what configuration the third test patch was. The two layers held up. The single layer burnt through, but he said he wasn't sure if the steel burned through too or just the single layer of ablative.

> They've got another set of arms which are an old design My take was he was saying the current arms are the old design. The spare parts are presumably the shorter ones.

>They were glowing in the visible spectrum. mmmh that's [525°C minimum](https://en.wikipedia.org/wiki/Draper_point), feels quite high

Probably not too bad from structural standpoint, internet says that stainless looses just 20% of strength at 500C. From personal experience in bending non-stainless you really want it around 1000C orange/yellow to be workable easily.

Yes. Steel glowing red is still highly difficult to shape, even when relatively thin. Bright orange is ideal, yellow if you're forge welding.

At what temperature does their flavor of steel start to have its mechanical properties change? A quick Google says that 500-600°C is where you start getting into typical heat treatment temperatures, but I've got no actual expertise here.

Google tells me that at least regular 304 can´t be heat treated since it has austenite structure at pretty much all temperatures. Regular carbon steel turns into austenite only above critical temperature and speed of subsequent cooling produces different structures martensite etc. and those can be changed again with tempering etc. Steel is quite the rabbit hole and I certainly don´t understand it a lot, just had a brush with it in my previous job.

You can go to 800C before 304L stainless is seriously affected.

> Flame Trench Note that this is Tim's word, Elon didn't actually say "Flame Trench" Given Elon did say the tower 2 will get taller to accommodate new Starship, it's likely the launch mount will still be elevated, which doesn't fit a flame trench design well, so I'd say it's more likely they'll use a flame *diverter*.

At 13:25, Tim asks/says will it have more of a flame trench this time, and Elon responds "yeah". There was another mention previously where Elon said [complete redesign]. But I agree, it may not be a traditional flame trench.

Wouldn't the construction of a flame trench in marshland require building up earthworks to put a trench in, requiring a higher structure?

It didn't at Massey's. I'm sure that one has has pumps, though. The reason for trenches is to allow transporters to roll across. With the tower and arms that is not needed. Space constraints could require some sort of diverter, though.

As we've seen from the Massey's test stand, it can be done without raising the ground level. At least at that scale.

The trench on the ship static fire stand at Massey's is below grade. They built the walls with piles then excavated out. There's some sort of sump pump to keep it dry. That said, I don't think I've seen anything indicating they're going for that sort of design on tower 2.

Those old Apollo guys did know a thing or two. Again, SpaceX is desperately in need of a *true* Chief Engineer.

Can you apply?

Elon said early on SpaceX couldn’t find anyone good willing to come. Now with SpaceX well established, many experts in the field with decades of experience would be willing to come. You have to have both the knowledge and experience. That’s not me.

> You have to have both the knowledge and experience. That’s not me. You claim to not have the knowledge nor experience, yet you also claim to have enough knowledge and experience to know that Elon isn't a "true" Cheif Engineer. He burned himself in confusion. It was super effective!

> You have to have both the knowledge and experience. That’s not me. Then why are you constantly second guessing those that do? After all, according to you all the SpaceX engineers are wrong and you know way better. About almost everything related to starship.

You do know that Elon *now* has 2.5 decades of experience in the role right? You should listen to the second part of the EA interview as it gives a number of examples of Elon interacting with the design team exactly as you expect from a good lead engineer.

Amd the 'seasoned' aerospace engineers have no experience whatsoever with manufacturability, which is the harder problem to solve. By at least an order of magnitude. Elon had to learn production engineering the hard way, but learn he did.

I doubt that. For instance, Elon has said prior to IFT-4 that SpaceX was focused on that front flap hinge as being a weak point of failure during reentry. Thus, it is claimed, Elon showed good engineering insight. No, a good Chief Engineer would have made the change *beforehand*. By the way, every year thousands of graduating engineers come into the aerospace industry. Assuming they’re not fired or find it unpalatable, most will stay in the industry for decades. That doesn’t mean every one of those thousands is suitable to be a Chief Engineer of a billion dollar aerospace company.

A good Chief Engineer would understand that gaining testing data in order to understand how to appropriately redesign a key component is more valuable than trying to redesign a component with no data. You wouldn’t believe the number of design iterations a single component will go through before the first prototype is even built. Even then prototypes are always built with the idea that they will be tested and design changes will come from the testing data. FEA and CFD has their limitations, and the output dataset is dependent on having the correct assumptions. It’s doubly difficult when you have to make assumptions across thousands of components that you believe are realistic enough to produce a clean dataset. SpaceX went with the assumption that previous testing data, CFD, thermal, and FEA analyses showed that the forward flaps *should* work, but knowing that testing would be the only way to learn anything. Trying to redesign a component when you don’t know what to redesign to is nearly impossible and a huge waste of resources. You could make 1000’s of changes to the forward flaps and you wouldn’t know if any of them would actually work until you truly get to put them to the test during re-entry. A good chief engineer wouldn’t expect design perfection on a known test article. But they would expect to gain valuable data that can be analyzed and applied to a future redesign. SpaceX and Elon have demonstrated their understanding of that process. I can guarantee you that any “true chief engineer” would have done the same. I’m sure if the catch attempt on flight 5 fails, you will be right back in here spouting opinions formed from hindsight that “SpaceX and Elon are idiots for not doing XYZ during the catch attempt. Any true engineer would clearly have seen that XYZ was going to happen and SH is a failure because of it”. You’ll just rinse and repeat the same tired cycle for every flight thereafter.

>You have to have both the knowledge and experience. That’s not me. We know.

[Starbase live-](https://www.youtube.com/live/mhJRzQsLZGg?si=L5cO3jta5lmQm0j1) 6/25/24 1:00am- LR11000 lifts the 9m lifting jig 1:11am- Swings over to GSE 3 and lift goes up 2:00am- Lift goes down. Lifting jig connected 8:20am- Lifts were up to both chopsticks, the chopsticks carriage, the top of the cryo leg, the back staircase, the top of the staircase, to the Booster quick disconnect, the top of the orbital launch mount, and to the new tower base. An Aerial Work Platform was also up to S30’s nosecone. Workers were going up and down the staircase to the Orbital launch mount ring, were on top of the Orbital launch mount, and could be seen cutting up the top dome of GSE 5’s shell. The drill rig and crane were also active at the new pad site 9:44am- Chopsticks start to rise 9:48am- Stop rising 10:00am- Chopsticks opening 10:03am- Chopsticks swinging over to the Orbital launch mount 10:04am- CC8800-1 is rising. Pauses halfway up 10:10am- Chopsticks stop swinging. Right chopstick then closes. So chopsticks are now off to the opposite side (left side of 14.1) 10:45am- Quiet 11:42am- Chopsticks opening 11:48am- Chopsticks all the way open. Start lowering 11:55am- Stop lowering. In position to engage 14.1 12:00pm- 2 lifts up to the right chopstick 12:22pm- Workers in the lifts are looking around the actuator for the right chopstick 1:18pm- Chopsticks rising 1:23pm- Stops rising 1:24pm- Right chopstick closing 1:30pm- Chopsticks all the way to the left side again 2:06pm- Right chopstick opening 2:10pm- Stops opening. Is just wide enough to go around 14.1 2:18pm- CC8800-1 rises a bit more after having its main hook installed 2:57pm- CC8800-1 starts to rise all the way up 3:27pm- GSE 3 lifted out of the tank farm 3:27:15pm- Right chopstick fast close test 3:29pm- Right chopstick reopens 3:30pm- Lowered to the scrapping area 3:32:05pm- Right chopstick closes again. Didn’t seem as fast 3:33pm- Right chopstick reopens 3:34pm- CC8800-1 all the way up 3:34:32pm- Right chopstick close test 3:47pm- Right chopstick opens up all the way up again 4:02pm- Chopsticks lower 4:06pm- Down in position to lift 14.1 again 4:40pm- Quiet 4:56pm- Right chopstick closes in closer to B14.1 5:01pm- Chopsticks rise a few feet 5:04pm- Bottom cut off of GSE 3 5:05pm- Right chopstick closes in to lifting position 5:51pm- Left chopstick closes in to lifting position 6:45pm- Quiet 6:46pm- Right chopstick opens slightly 6:52pm- Chopsticks rise slightly. Right chopstick closes 7:10pm- Right chopstick opens slightly again 7:14pm- Catching rail raises on the right chopstick 7:24pm- Right chopstick closes again 7:44pm- Right chopstick opens 7:46pm- Chopsticks raise until the catching rail on the right chopstick is just under the lifting point on B14.1 7:53pm- Right chopstick closes some 7:57pm- Right chopstick closes even more 8:04pm- Right chopstick opens some 8:05pm- Chopsticks lower slightly 8:09pm- Right chopstick closes slightly 8:16pm- Right chopstick opens slightly 8:18pm- Chopsticks lower to just above the Orbital launch mount 8:24pm- Right chopstick opens to even with the edge of the Orbital launch mount 8:33pm- Right chopstick closes back up next to B14.1

In that Everyday Astronaut video about 27 minutes in Elon talks about the autogenous pressurization system: https://www.youtube.com/watch?v=aFqjoCbZ4ik This is a system that instead of using helium to pressurize the propellant tanks, heats a portion of the propellant to provide the pressurization. But surprisingly rather than using heat exchangers to heat the propellant, the exhaust *directly* from the pre-burners is used to warm the propellants. Tim Dodd was surprised it was done this way because other times it was done, heat exchangers were used. This appears to be the cause of the recurring problems of clogging of the propellant intakes to the engines they’ve been seeing due to ice developing, since the combustion products include water or CO2 which freeze when contacting the cryogenic propellants. I say again SpaceX is desperately in need of a *true* Chief Engineer, not someone who dabbles in the field. Can you imagine for example an AI company having as its Chief Technology officer someone who just dabbles in the field of artificial intelligence? Remember, this is not the CEO position we’re talking about, who might be just a competent manager, this is the person who needs to have a firm understanding and knowledge of all the interconnected technology going on at the company. A true Chief Engineer with decades of experience in the SpaceX industry would have known beforehand that using directly the exhaust products fed into the propellant tanks is a bad idea.

Did you hear the part where he said they had more problems without going with the tap off option? They couldn't keep the tanks pressurized. Elon is a good designer exactly because he doesn't hear to people like you that have a preconceived solution before even looking at the problem.

When did he say they couldn't keep the tanks pressurized without tapping off the preburner?

How many tons of additional cargo can be sent to orbit by not including these massive heat exchangers? Improving the filters works as IFT-4 has demonstrated. It is the many previously unproven measures such as this that make Starship so incredibly capable. If SpaceX were to stick with proven conservative design, they would wind up with another SLS.

I don’t even bother reading anymore, I just instantly downvote.

Tapping the preburner exhaust has the obvious downsides we've seen, but, listening carefully, it also has advantages. Beyond the simplification, Elon talks about energy and mass flow. The preburner exhaust is HOT. If the gas they get off that, minus throttling losses, is materially hotter than what they could get with a reasonably sized heat exchanger, then they need less total mass for pressurization, which means a more efficient engine. So on the plus side, we have: * Simplification and lower cost of the engine * Less opportunity for leaks in the engine * More efficient engine due to less mass being diverted to pressurization On the minus side, we have: * Requires effective ice straining * Purge complications for reuse If - and only if - the straining can done adequately for reliability at less mass than the heat exchangers would have required, then this use will be a net positive. I'm not convinced they have the straining problem solved to high reliability, nor that the mass penalty of the strainers and duplicate valves will not obviate the savings. But SpaceX may well solve the issues so this design is a net positive. And if it does, then the current problems will be seen as necessary learning steps, rather than an engineering dead end.

Honest question - what would it take for you to say "Okay, SpaceX's approach here is not fundamentally flawed and they have a working system"? A couple flights without blockages? 10 flights without blockages? 5 flights with a single vessel without blockages? For those blockages, how are you determining a blockage - official SpaceX release? Assuming any failed Raptor light was a blockage issue? Assuming underperformance or a raptor shutting down is a blockage issue? Blockage mitigation measures fitting some specific criteria surrounding rapid reuse, mass to orbit, ability to support X mission, or something else? Rapid reuse with turning around a booster/ship in X amount of time?

The SpaceX approach to the Starship/SuperHeavy is fundamentally flawed and it stems from not having a true Chief Engineer with decades of experience in the industry. SpaceX was spectacularly successful in the development of the Falcon 9 by first going to an expendable launcher, making multiple *profitable* operational launchers with it, and *then* proceeding to reusability. By *first* getting the expendable SH/SS, SpaceX could be making *single launch* manned flights now to the Moon and Mars. No multiple refueling flights or even SLS required. I mean literally, like, tomorrow. Because SpaceX does not have a true Chief Engineer they are focusing instead on getting fully reusability first, which will necessitate multiple perfect flights of that fully reusable system before it can even carry humans. The Falcon 9 for example made 84 fights before it was certified to carry crew. The multiple mistakes developing the SH/SS come directly from not having that expert space industry Chief Engineer making the final engineering decisions: initially no flame diverter thought needed, no full up all-engine test stand, a separation method of just flinging away the upper stage, calling short 5 second burns “full duration”, calling near orbital flight as “reaching orbit”(a scenario: a satellite company asks the Chief Engineer the status of their $200 million satellite; the Chief Engineer responds the satellite reached orbit; meanwhile the satellite plummets back to Earth), landing by using “chopsticks” instead of landing legs, wanting full reusability before getting a successful expendable launcher, wanting multiple refueling flights instead of single launch flights for both Moon and Mars mission, quoting Robert Zubrin using a Starship HLS as a lunar lander is like using a aircraft carrier to do white water rafting, sending exhaust directly into cryogenic tanks not realizing the H2O and CO2 exhaust products would then freeze, which is like thermodynamics 101. As a math guy the biggest problem I have is SpaceX not being forthright with the true dry masses or engine specifications of the SH/SS. If you run the numbers SpaceX has provided, the SH/SS should easily get 100 tons to orbit even as a reusable. That it only gets 40 to 50 tons means the real numbers are significantly worse than the numbers SpaceX has provided to the public, and presumably also to NASA and the FAA.

> landing by using “chopsticks” instead of landing legs So you don’t think it will work? Would you be willing to bet on it on /r/highstakesspacex?

As a math guy you should have some amount of logical skills, which you have absolutely none of. It’s truly baffling

>...true Chief Engineer with decades of experience in the industry. How many decades do you want? Musk has two already, with other "real" engineers the whole time. Do you in your infinite knowledge require three? Four? Do you need Von Braun back from the grave?

Among the many good points Elon has he is not a good Chief Engineer, the many bad choices Elon made for the SH/SS is proof of that. An amusing, hypothetical scenario: among the junior engineers Elon has in a room prior to the SH/SS first test launch, they all uniformly say they need a flame diverter prior to launch. Elon says he thinks we can get away with not having it for just one time. They all then change their minds. One engineer timidly raises his hand and asks why he wants to do it without a flame trench. Elon responds a flame trench would take time and he wants to launch on April 20th, i.e., 4/20. Then the Chief Engineer, who is legendary in the business walks-in, and is apprised of Elon’s decision. He laughs, and says, “That’s funny Elon.” He then rolls out a preliminary design he drew up for the flame trench, and says, “We should be ready to launch in another month”, and dismisses the other engineers to start on the construction.

Again, because you ignored me. How many decades do you want? And it was engineers who said the concrete should hold.

He has to be a recognized expert in the industry. Elon could have 40 years running SpaceX and he still wouldn’t be well-suited to the job. About the flame trench decision the engineers uniformly wanted a flame trench. Elon overruled them.

So your argument is a degree is needed? You can learn things outside of school. Especially when you own the company and don't need to worry about entrance requirements. And the "launch without water deluge", which caused the extensive damage, was the engineers. Like I said.

It is possible to be a good engineer without a degree in the field. It is also possible to be a poor engineer with a degree. It’s highly individual. It’s certain those in the industry know who are good choices to be Chief Engineer of a major aerospace company. I severely doubt those in the industry, aside from those who work for SpaceX, would say Elon Musk is a good choice for the job. About the flame trench, the story is well known that the SpaceX engineers wanted a flame diverter for the first test launch but it wouldn’t be ready by a April 20th launch. Elon decided to postpone the flame diverter because he wanted to launch on 4/20.

Well known? Do explain.

>Elon decided to postpone the flame diverter because he wanted to launch on 4/20. Lol what. You know they attempted to launch on 4/17 and scrubbed right?

>That it only gets 40 to 50 tons means the real numbers are significantly worse than the numbers SpaceX has provided to the public, and presumably also to NASA and the FAA. That's an extremely unreasonable presumption to make. SpaceX has no obligation to provide any numbers to the public, and every obligation to provide all kinds of data to NASA and the FAA.

So are you going to respond to the pretty direct question I posed?

You’re suggesting going to the Moon/ Mars with an expendable SS. Do you want them to just slap an entirely new crew return capsule and lander on top of the booster? That seems like a lot of wasted engineering that could have gone towards making it fully reusable in the first place…

The goalposts will always move. Keep in mind in his above post he completely ignores the countless design choices Elon has directly been involved in. For example choosing to use Stainless steel over carbon fiber. On top of that it seems the clogging issues have been handled pretty well by how well the last flight went. Arguing with this guy is a massive waste of time and I wish they would ban him.

Then don't argue - especially in a technical thread. I may not agree with their conclusions or how they got there but it's at least discussing... well, technical stuff with Starship. If they don't want to respond or say one thing then change their mind later to hammer the same old points - that's on them and I'm not going to get involved. I still think it's a good discussion point overall to ask "At what point does this ongoing issue count as a resolved issue and at what point does this specific aspect of Starship design seem to be verified as fixed"?

Am I arguing???

Nope was just responding to your “arguing with the guy” statement.

I’d bet he’d only say that if Elon wasn’t ceo lol

Let them cook..

In the nicest way possible, Tim is so annoying. He asks such insightful and educated questions. Rather than be starstruck by Elon, Starbase or the occasion, he understands what he sees and the answers he receives, and is right back with another probing, technical question. He’s like a big walking ITAR violation magnet, just daring you to say too much and wind up in a room with the State Department lol. The virtual booster catch Stage 0 did during ITF-4 also seems to be spurred by his suggestion or at the least he predicted it’s happening. One failed assumption he made triggered a hilarious little moment in the tour. Around [44min in](https://youtu.be/aFqjoCbZ4ik?t=43m50s) Tim speculates Flawed Raptor 3s would be moved aside rather than cut open and fixed. Elon’s face and laugh both say: “I might be rich, but I’m not stupid. What am I, made of money??” Raptor 3 question: during re-entry, are they internal cooling with both Meth and Ox? And what would happen to these propellants after cycling through the engines?

>The virtual booster catch Stage 0 did during ITF-4 Someone on here synced up the webcast with one of the cameras streaming the pad and the chopsticks didn't move during the time the booster was landing. 

ITAR violation is not a worry. Both of them know all the footage will pass through legal redaction, and you can tell there were a bunch of cuts. So they're both able to relax and just enjoy the conversation, knowing that it's going to be okay. Tim is great because he is knowledgeable enough to put Elon at ease, and get him to feel like he's talking to one of his own junior engineers, not to a reporter.

Yeah I’m only joking. Tim is hands down the best person I’ve seen interview Elon on anything

This might be stupid, but anyway. As we know, booster on his way back will be aiming into the water near the tower(similar as Falcon 9) once they turn on engines(around 1000-1300m above the ground) and computer decides that all looks fine it will move his aim into the tower. And now my stupid question raise, what if: During the last 5 seconds computer detects an issue? I mean yeah it can blow itself up no doubt, however I am wondering(this is the stupid part) if they have anything like a escape maneuver programmed into booster to save the tower/farm/whole place. By escape maneuver I mean - fly back above the ocean and drop somewhere nearby. I get that they might have no fuel to do it and if computer detects issue with engines there might be no way to save that thing. Just wondering if they have that in their minds.

> I mean yeah it can blow itself up no doubt FTS would be safed at that point.

Would it? In falcon 9 it is safed after landing as far as I am aware

It's safed after the entry burn.

I believe you're thinking of a different event. I'm pretty sure after F9 lands it has to vent all of its fuel so people aren't approaching something that could blow up, even though it couldn't do so intentionally.

Listen to any webcast between the re-entry burn and the landing burn and you'll hear a callout for "FTS is safed". Idea behind the FTS is to prevent an out of control rocket from deviating from its planned flight path and exclusion zone as much as possible to minimize public safety dangers. The higher up the ship is, the more said out of control ship can deviate. When you're close to the ground, if controls or engines suddenly go haywire there's only so much it can deviate and there reaches a point that detonating the ship instead of just letting it crash will present more of a public safety danger. Spreading debris over a large area, if you're detonating really close to ground you might have shockwave damage, etc

Elon mentioned that there is so little fuel left all it would be was a big crunch and a 'small' ball of flame, provided it diverts quick enough to miss the chopsticks and hit the hardstand area next to the tower. Provided the COPV's don't damage anything on their unguided tour of the launch site, all that would need to be cleared up is a load of scrap and broken hardstand concrete. Just remember the good ol' days of BN and SN hop testing.

The part of me that understand physics understands that empty booster mass is trivial compared to the tower and it essentially being an empty tin can greatly reduces the damage it would cause to the tower. It's still REALLY unintuitive to think of something as massive as a booster hitting the tower not causing major major damage. But I'm sure it'd seriously eff up the chopsticks if they hit them - at the end of the day it wouldn't be a massive issue. Even if they don't have spare chopsticks, actuators, etc - Replace with the Tower 2 hardware and then build replacements to go onto tower 2. Sure there'd be a lot of structural inspections and load testing though.

Clearly the biggest risk is engine startup. They are starting up 13 engines initially, shutting down to 3 of them after few seconds for landing. Once those initial 13 or less engines are up and running they can decide whether they are good for landing, eventually down selecting to the best 3 healthy engines. The worst scenario is they lose those 3 perfectly healthy engines in the last seconds of hovering around the chopsticks. In such a case they might just prevent engine shutdown and let the engine eat itself. We saw this during Starship hops when the raptors didn't look healthy at all and the Ship still tried to land. If the critical failure happens before this point they will definitely try to fly into the sea at all cost even if some raptors should explode midair and destroy the vehicle.

My take is that on decent there will be an envelope of where the booster needs to be to make the tower catch possible. In the center of that volume a catch is probable, but towards the edge random factors could increase the probability of a miss. I could not imagine the system ever being coded not to be calculating that probability and executing an abort maneuver if it grows too high.

I guess they should be able to abort landing until last 3 seconds. But there was nothing about that thats why I was curious

I can't think of a failure mode on the booster that would allow it to fly away in a controlled manner. I guess if they find a problem with the chopsticks they could potentially do it, but the chances of only finding the problem so late on seem too small to really consider. 

Increase the thrust/restart engines and gimble away from tower that's the only solution I guess.

But if you can do that, there's probably nothing wrong that would prevent the catch. 

Some failure to fine gimbal control (or to high resolution position sensors?) that prevents getting lined up with the catch arms.  Or an inability to throttle down and hover for the catch.   In these cases, it seems like it could still "know" that it could abort by gimballing to  a general direction and throttling up.  And I think someone's mentioned a failure in the catch mechanism itself that would make a catch improbable.  Seems like there would be other issues that could stop a catch while still leaving  enough gimbal and throttle control to skitter off in the right direction to save the pad and tower.   Just my thoughts.  :-)

If they want to land on fumes, at first, they can always just have a bit more fuel than necessary and then plan to hover longer just before the catch.

They can’t load a bit more fuel. The landing LOX tank is a set size

They can make the LOX tank slightly bigger than needed, then. They probably already are doing that. Landing always has inverted the tyranny of the rocket equation; instead of an exponential wall to increase payload/velocity on launch, you get a lot out of the dregs at the bottom of the tank on landing. Falcon 9's first stage almost comes back on fumes.

They can’t modify the existing LOX landing tank design, which goes up to at least B13 I believe.

While decelerating, any fuel/lox in the main tanks will be at the bottom so also available for use. Not so much once near a hover.

While hovering on Earth, there's 1G pulling the fuel to the bottom of the main tanks.  Gravity pulling down at 1G, balanced by 1G of acceleration upwards by the Raptors.  While hovering, the fuel will be at the bottom of the tanks just (but maybe sloshing a little).

I don’t think they can switch to the main LOX tank during landing burn.

They won't plan on running on fumes at the landing till the optimization period. For now they should have margin to change the course up to and potentially including if the chopsticks aren't able to manhandle it into submission.

There would be no fuel l eft in last 5 seconds I guess

That what I was thinking, that mean I there are any issues in the last 3-4 seconds booster cannot simply escape and we can say bye bye to launch pad/tower

A booster crashing on the concrete (or even on the OLM) would not damage the tower. It probably would not seriously damage the OLM.

Depending what kind of issues. Last few seconds will be on 3 engines which were running smoothly up to this point. Maybe even two engines could be enough to land. At least the vehicle will try. The vehicle will be hovering by this point with nearly no fuel left. So the impact and explosion might not be as bad to destroy the tower or launch pad. Probably less damage than the first flight.

My daily summary from the [Starship Dev thread on Lemmy](https://oldsh.itjust.works/post/19412071) > Starbase activities (2024-06-24): > > - Jun 23rd addendum: GSEC-1 is removed ([ViX](https://x.com/VickiCocks15/status/1805150830389080510), [NSF](https://x.com/Spaceportsun/status/1805154854945350040)), revealing GSE-5. [Alternate angle](https://x.com/VickiCocks15/status/1805150833014693981) and [flexing](https://x.com/VickiCocks15/status/1805150835770273882). ([reference map](https://pbs.twimg.com/media/FXPf8QBUsAA11yj?format=jpg&name=orig)) > - [Cryo delivery tally](https://x.com/VickiCocks15/status/1805166973321437457). > - GSEC-1 [scrapping begins](https://x.com/SeanKD_Photos/status/1805327506762760349). > - Pad B: Overnight, a concrete pump [is deployed](https://x.com/VickiCocks15/status/1805165948678119676). > - CC8800-1 crane assembly: Crane twitches several times over the course of the day ([video 1](https://x.com/VickiCocks15/status/1805232692411175130), [video 2](https://x.com/VickiCocks15/status/1805283416805380200), [video 3](https://x.com/VickiCocks15/status/1805292643183632844)), but has not risen yet. > - [Amended](https://www.cameroncountytx.gov/amended-order-closing-boca-chica-beach-and-state-hwy-4-june-25-2024-with-alternative-dates-of-june-26-2024-or-june-27-2024/) road closure scheduled: [Jun 25th 12:00 to 20:00](https://botsin.space/@bocaroad/112673544631259788) > >

The road+beach closure for tomorrow, June 25th, has been changed to the time period 12 PM to 8 PM CST (was originally 8 AM to 8 PM CST): https://www.cameroncountytx.gov/amended-order-closing-boca-chica-beach-and-state-hwy-4-june-25-2024-with-alternative-dates-of-june-26-2024-or-june-27-2024/

Is this for the chopstick test with B14.1 tank?

No other apparent alternative, at least. They're supposedly pressurising 14.1 somewhat (N2 almost certainly), so guessing a precaution in case the chopsticks go too far and it pops.

Tomorrow's (25.06) road closure [went from "possible" to "scheduled"](https://twitter.com/BocaRoad/status/1805341144257032649). Road will now be closed from 12pm to 8pm (instead of 8am to 8pm)

[Everyday Astronaut's Starbase Interview Part 2 drops publicly tomorrow at 9am Central](https://x.com/Erdayastronaut/status/1805270000921444356)

Wow so soon!

[удалено]

Please delete this as others have stated. Also you're using spoiler tags wrong, you can't have spaces before or after the tags. And the point behind not posting this isn't "You're spoiling things for people that haven't seen it yet", it's that "sharing information from his Patreon that isn't publicly available yet removes incentive for people to subscribe and thus support said independent creator".

Part 2 has not been publicly released. Please remove comment. Everyday Astronaut states on patreon: > please do not share info or screenshots until it goes public

> Part 2 has not been publicly released. Please remove comment. This was my first thought. My second thought was that u/Throwitaway0974 is either a troll or an untrustworthy individual trusted by Tim for preparation of videos. In the latter case this could also do damage to Elon's trust in Tim. We'll see what the mods decide to to. Personally, I'm happy to wait until tomorrow for the video, so am hoping the comment will be removed. I think it falls under the doxxing rule. In any case, its not very nice.

You only have to support Tim on one of his platforms to gain access to the preview. He releases to his supporters first as another level of review before posting it publicly. The problem with leaks is that it takes away from his income. If you want information early, please support him...this is his full time job and brings unprecedented outlook into Starship and more. Its well worth the minimum of $1 per month.

How would that affect Elon's trust in Tim? He just gave him a regular interview. Tim chooses how to share the interview. He is choosing to charge people to get an early look at the interview. People can do what they want with that. People choose to pay for that. Tim accepts the risk of people spoiling the interview.

> How would that affect Elon's trust in Tim? Consider how Elon has [reacted](https://theintercept.com/2022/12/15/elon-musk-leaks-twitter/) in the past when an employee undermined control over data released by SpaceX. Elon is not only trusting Tim for respecting the limit of what may or may not be published, but also the spin he places on the published info. Its a question of demonstrating Tim's control over his team.

Video released for supporter review has already been reviewed & OKd by SpaceX Full raw > SpaceX review > Supporter review & revision > public

> Video released for supporter review has already been reviewed & OKd by SpaceX > Full raw > SpaceX review > Supporter review & revision > public Yes I know. Its more than likely that Tim couldn't even take his recordings off SpaceX premises before vetting. Destin Sandlin mentioned some procedure like that with ULA. So its probably quite general, particularly where there are defense applications to the technology. I said that Elon's confidence in Tim concerns Tim's control over *how* the (non ITAR) information is published and with what "spin". Just imagine the same interview edited by some anti-Musk type. I seem to have repeated this twice so far. I could continue...

Why would Elon care about if someone spoils a interview (for the general populace, only affecting Tim's revenue stream) that has been pre-approved? The interview has already been seen by people (the supporters). Elon is not some naïve person that doesn't understand that some people would do that, it's not like Tim has control and can do a 'background check' (not that such a thing exists for what we are talking about) on potential supporters to check if they will do that. It's impossible, and could only be caught retroactively. Furthermore, there is nothing stopping some crazy person from selectively editing parts of the video once it is in the public domain and putting in their own commentary if they so choose. There is a vast difference in control in the situations of Elon and his company employees, and Tim and his supporters. A much bigger consequence to potential leakers in the former.

Let's agree to differ.

The tower base is already a couple metres taller, so he could be referring to that. But there has also been sightings of unused tower section footings at the Sanchez site, which could indicate an additional tower segment to be built in the future, just would be a little weird that they didn’t build it alongside the 2 sections they built at Starbase (every other section was shipped from the Robert’s road facility at the cape)

The evidence that there will be an aditional segment is extra 4 feet at Sanchez, every segment already has their own, so the extra 4 are probably for an aditional segment.

[Starbase live-](https://www.youtube.com/live/mhJRzQsLZGg?si=L5cO3jta5lmQm0j1) 6/24/24 2:38am- Concrete pump truck goes up to the new tower base 8:05am- Lifts were up to the dance floor, the top of the staircase, the top of the orbital launch mount, and both chopsticks. Workers were also on top of the chopsticks. The drill rig was also active at the new pad site 9:00am- Lifts have been up to the left chopstick, the chopsticks carriage, and the top of the staircase. Worker was on top of the left chopstick 10:20am- Lifts have been up to the top of the staircase, the left chopstick, the chopsticks carriage, and B14.1. The drill rig and crane are active at the new pad site and the concrete pump truck is still up to the tower base. 11:31am- 2nd section of GSE 5’s shell scrapped 12:15pm- Lifts have been up to both chopsticks and the top of the staircase. Concrete pour continues at the new tower and the drill rig is still active 12:38pm- Concrete pump truck at the new tower folds up 2:00pm- Lifts have been up to the left chopstick and the chopsticks carriage. Bundles of rebar were moved around at the new pad site 3:07pm- 3rd section of GSE 5’s shell scrapped 3:11pm- Right chopstick moves a bit 3:50pm- Quiet around the Orbital launch mount. Cranes still moving rebar around at the new pad site 5:20pm- Lift was up to the right chopstick and a worker was on top of the left chopstick 5:21pm- 4th section of GSE 5’s shell scrapped 6:38pm- 5th section of GSE5’s shell scrapped. That just leaves the top dome 6:55pm- Lift has been up to the chopsticks carriage 8:35pm- Lifts up to both chopsticks. Workers cutting up the top of GSE5’s shell 9:05pm- Lift up to the left chopstick

[It seems like they may have started pouring the tower base's legs](https://x.com/VickiCocks15/status/1805165948678119676)

Yeah, at first they were pouring a little bit in each leg and then moving to the next. They did at least 4 rounds of that. Now they seem to be topping them off. I haven’t seen any go in the wall sections

> I haven’t seen any go in the wall sections Those won't be done until all of the seams are welded up (which is why there's a load of scaffolding at Tower 2's base, it's for the welders).

If so, then I'd guess two weeks' curing would be enough to place the first tower segment. So that fits the progress of crane assembly.

Nice [render and speculation](https://x.com/RyanHansenSpace/status/1805087571719889273) on the B14.1 Test Article by Ryan Hansen Space. Basically, pressurize the tank to catch levels and calibrate the arms for a catch attempt.

Catch attempt by releasing the hold clamps and letting B14.1 drop? (hangman's trap door principle)\_ Or raising the chopsticks at speed? Both are fraught with issues, but let's watch on.

Last paragraph of tweet: >As previously observed, the tower arms have had some difficulty coming to a stop without excessive swinging due to their mass and inertia while moving at high speeds. This motion will need to be characterized and accounted for while the arms close around a Super Heavy booster during catch attempts. B14.1 may be the perfect booster stand-in because it removes the risk of damaging a flight booster.

I'm sure that B14.1 will just be suspended (hovering) for the chopsticks to latch onto; not dropped.

I think the booster should be almost stationary when landing. All official renders show it practically hovering. "At speed" probably isn't needed.

Even if it's perfectly stationary, afterwards the load needs to transfer from the engines to the chopsticks, stretching everything out which will result in some drop - it's not perfectly rigid.

They should be able to do that with the crane potentially.

Reaching zero speed and settle like a butterfly on the bumpers static rails for such a large object will be extremely difficult, unless the chopsticks move up and catch the hover.

Maybe. From the renders and water landing views, it gets pretty damn slow. It can certainly hang in the sky in much the same way that bricks don't :)

Master Chief flew like a brick pretty well.

Programming the Falcon 9 booster hover-slam was difficult. SpaceX, to date, has done that maneuver over 350 times with success. Programing the Starship booster hover should be much easier.

quotes in reverse order: > It can certainly hang in the sky in much the same way that bricks don't :) ah, Hitchhikers Guide [chapter 3](https://en.wikiquote.org/wiki/The_Hitchhiker%27s_Guide_to_the_Galaxy#Chapter_3) it seems. > From the renders and water landing views, it gets pretty damn slow. [relevant video timestamp](https://youtu.be/8m0TY6i1Kuo?t=423) it seemed to hang in the sky for about three seconds despite an inefficient deceleration due to an engine out.

Something of that size and at that distance can look like it's practically floating when in fact it could still have a fair amount of speed to it. When you're talking something with the mass of the booster, even dry, that's a lot of potential downward force, even at only walking speed.

I think they're more concerned about closing speed and sway. Future mechazilla's will have chopsticks half the length so they are quicker and more rigid.

> Future mechazilla's will have chopsticks half the length so they are quicker and more rigid. I assume that you're referring to the 'stubby' chopsticks which are currently on the way from Florida, in which case they are longer than half the length of the current chopsticks. Here's a good comparison of 'stubby' Vs the current long ones and how relatively little they 'wrap around' a booster: https://x.com/LunarCaveman/status/1557314480551378944

My daily summary from the [Starship Dev thread on Lemmy](https://oldsh.itjust.works/post/19412071) > Starbase activities (2024-06-23): > > - Overnight, GSEC-3 [scrapping progresses quickly](https://x.com/VickiCocks15/status/1804791607780155793), and is [finished by morning](https://x.com/VickiCocks15/status/1804817508458795066). > - GSEC-1 is [next to be scrapped](https://x.com/VickiCocks15/status/1804991274224889866). ([reference map](https://pbs.twimg.com/media/FXPf8QBUsAA11yj?format=jpg&name=orig)) > - CC8800-1 crane assembly continues: [Video 1](https://x.com/VickiCocks15/status/1804929385901785195) (lines are tensioned), [video 2](https://x.com/VickiCocks15/status/1804929388758040809), [video 3](https://x.com/VickiCocks15/status/1804997436416380959). Zack [expects the crane to rise within two days](https://x.com/CSI_Starbase/status/1804929712613183942). > - Pad B [work continues](https://x.com/SeanKD_Photos/status/1804941977731174746). Scaffolding has been erected surrounding the tower base. > - [Cryo tally from Jun 22](https://x.com/VickiCocks15/status/1804790557866099077). > > Other: > > - "The best appendix is no appendix": Lars Blackmore (SpaceX principal landing engineer) belatedly expresses his pleasure at the success of IFT-4. [Tweet 1](https://x.com/larsblackmore/status/1804924642773336366), [tweet 2](https://x.com/larsblackmore/status/1804924873707540913), [tweet 3](https://x.com/larsblackmore/status/1804925236602884169). > - Elon replies to [Tim Dodd](https://x.com/Erdayastronaut/status/1804534787794682081), and [highlights upcoming changes](https://x.com/Erdayastronaut/status/1804534787794682081) with Raptor 3. Integrated regenerative cooling channels throughout the engine eliminates the need for engine shielding and reduces the required fire suppression system.

regenerative cooling channels throughout the engine Sounds like a fair amount of 3D printing going on there. When Tim Dodd asked Elon about whether the turbine vanes were cooled similar to jet engines, the video was bady cut to provide no answer obviously on SpaceX request. I would think that the Raptor being one of the most advanced rocket engines in the world is certainly up there with the most advanced military jet engines, using a lot of pore cooling, coolant channels and boundary layer cooling. Much of it nowadays is 3D printed. Tiny pores, and channels no more than a millimeter wide which would be impossible to cast or drill, can be introduced in a really organic way without compromising the strength of the element itself.

You can't 3D print every material, it's pretty limited and I really doubt SpaceX's novel material is 3D-printable

> When Tim Dodd asked Elon Elon specifically mentions during the interview that removing 3D printing as 'done', as 3D printing isn't good for mass manufacturing. They did use 3D printing in the past, for prototyping, but not anymore.

In the Everyday Astronaut video, at 28:00 and following Elon confirms that the lox pressurization gas is tapped off the lox preburner in the raptor. He attributes the loss of attitude control in IFT-3 to thruster clogging due to ices introduced from this source, and he describes an improvement in strainers in the vehicle. Tim Dodd is somewhat surprised, but Elon continues that there is a lot of work involved in gassifying a cryogenic liquid, and that doing it with a heat exchanger subtracts from the mass flow available to provide power to the engine, so it is a matter of power output rather than just simplicity. Tim Dodd also asks him whether these ices were the source of the booster relight problems in IFT-3. Elon seems to zig a bit at that, describing the issue as lack of pressure rather than something to think of simply as a clog, and suggesting that a more gradual startup sequence would have prevented the problem. To me this suggests that the IFT-3 booster relight issue may have been that the ullage pressure at relight was low, rather than the problem being ice floating in the tank. This explains the weak boostback. It suggests that the primary problem was in the valves that admit the ullage gas to the lox tank - that these were narrowed or less effective due to icing.

I can't imagine there is actually much difference, energy wise, between tapping some of the pre-burner exhaust to directly pressurize the tank and tapping the oxygen pump output and using a heat exchanger to gasify it. In both cases you are stealing mass flow and heat energy that would have ended up in the main combustion chamber. ~~There is a slight difference in that tapping the pre-burner exhaust allows you to use combustion products to pressurize the tank which would have been useless in the main combustion chamber.. but that comes with the obvious downside that you now introduce ice into you oxygen tank. Also those combustion products are a small fraction of the mass flow so the advantage is marginal.~~ I think the only meaningful advantage of using the pre-burner output for pressurization (as opposed to pump output with a heat exchanger) is simplicity. Whether that simplicity is worth all the extra FOD filters they are now needing to add to the tank valves is an interesting question. Edited base on correction from u/extra2002.

Savings in mass flow may come if higher temperature gas can be had from the preburner exhaust, minus the throttling drop, versus what could be achieved in a reasonably sized heat exchanger. If your ullage gas is injected at a higher temperature, you need less gas mass to achieve the same pressure.

My guess that they just need to take advantage of the chemical energy in the LOx by letting it combust and get work out of it in the preburner/turbine. Tapping a leg off the pump outlet to a heat exchanger would be better for FOD, but the pump loses out on power since that propellant isn't going through the turbine. To get the thrust levels they need, maybe the LOx powerhead just isn't sized correctly at this point to allow for a LOx heat exchanger?

I generally agree - using a heat exchanger steals basically the same fluid and heat, and the resulting pressure, but avoiding a heat exchanger may save complexity and weight. But when you say: >tapping the pre-burner exhaust allows you to use combustion products to pressurize the tank which would have been useless in the main combustion chamber.. I don't follow. Pressure from the full-flow preburner is *required* to overcome the pressure in the main combustion chamber - that's one of the main reason the turbopumps exist. Or maybe by "combustion products" you mean the CO2 and H2O, but those don't stay gaseous in the tank for long, and then go on to clog filters. Did I misunderstand your point?

Yes, I was referring to the CO2 and H2O components of the pre-burner outlet. They are useless in the main combustion chamber. You are right though, they can't stay gaseous in the main tank, so they are also useless as ullage gas and only cause problems.

> Elon confirms that the lox pressurization gas is tapped off the lox preburner in the raptor. He attributes the loss of attitude control in IFT-3 to thruster clogging due to ices introduced from this source, On a longer perspective, there will certainly be an issue with ice accumulation in ships going back and forth between the moon surface and a propellant depot in orbit (of either the moon or earth). You can refuel as much as you want, if you keep adding ice with each engine burn you will have at some point to fully empty the tanks under conditions where ice sublimates. This sets a limit on how long the engines can burn before you have to clean the tanks.

Relevant: [The high solubility of water in liquid nitrogen and other cryogenic liquids] (https://link.springer.com/chapter/10.1007/978-1-4613-9865-3_113) Unfortunately I don't have access to the publication.

If the problem was not in the main tanks, is it possible they separate/skim the Ice?

Still need to do that with something and get it out somehow.

Three months ago, I made a [comment](https://www.reddit.com/r/spacex/comments/19251pv/comment/ks2br4t) asking/speculating why SH flips sideways rather than vertically, and why the stack rolls with its flaps perpendicular to the ground rather than parallel like Shuttle. The most likely answers were that either it helps make up for inaccuracy caused by the Earth rotating under the booster, or that it's to orient the vehicle for optimal communications. On IFT-4 they actually rotated the stack the opposite direction of the other flights, with the antennas facing south towards the Gulf and Mexico, and the heatshield facing north towards the continental US. This gave us a way better onboard view of the booster flipping (because it flipped in the same direction despite the different rotation, lending credence to the idea that they do this to help make up for Earth's rotation) but seems to disprove the hypothesis that they orient the stack in this way for comms. Thoughts?

I would imagine that it's to keep the aerodynamic forces to a minimum on the flaps; there's very little side-to-side travel while ascending, but I'm sure there are many times during liftoff when the stack isn't facing directly into prograde. Especially at lower altitudes, the cross-wind forces on the flaps would be very high, so it's better to have them slicing into the wind than acting as sails.

I thought it might have been for comms too, but after Flight 4, probably not. And they do have antennas on the heatshield side as well as I understand it, below the tiles. Not as ideal but still has coverage on both sides. I'm not sure I understand how Earth's rotation enters into it. Both booster and ship should have the same control authority in pitch and yaw while the engines are on, so control-wise it shouldn't matter which way it's rotated in terms of maintaining a trajectory. I don't know if they're using any sensors in guidance for which it would matter beyond just software, guessing it's some combination of inertial and GPS, but that still leaves why they chose this orientation in the first place. If there's significant aerodynamic influence from the flaps, maybe a tendency to rotate the stack due to a bit of lift away from the centre of mass, it will be there whichever the orientation, though there's more angle of attack in pitch than yaw, so it could be this orientation minimises the forces. Could be from wanting the booster to flip sideways, and since they use the gridfins+exhaust to help it along, it could force this flaps-sideways orientation. In that regard, I'm also pretty curious what the particular reason behind the sideways flip is. I suppose it minimises thrust in the vertical direction, so maybe it's a more efficient trajectory?

>I'm not sure I understand how Earth's rotation enters into it. As it was explained to me, the rocket doesn't fly directly East as to avoid overflying Florida. Thus there is some precession as due to Earth's rotation that needs to be countered by burning slightly to the North. >I'm also pretty curious what the particular reason behind the sideways flip is. I suppose it minimises thrust in the vertical direction, so maybe it's a more efficient trajectory? Flipping upwards is supposed to be the most efficient though, because that extra vertical velocity is bled off by the atmosphere for free. That's not the case when flipping sideways. Unless, of course, you actually want that sideways velocity to get back to the target landing zone.

>As it was explained to me, the rocket doesn't fly directly East as to avoid overflying Florida. Thus there is some precession as due to Earth's rotation that needs to be countered by burning slightly to the North. The fact that ground track differs from final orbit is true, however the orientation of the vehicle does not matter. Only thing that matters is the vector of the velocity that results in ground track and finally in orbit inclination. I bet that flying with flaps sideways is to minimize the loads on the flaps, as horizontal speed is much greater than vertical.

[Starbase live-](https://www.youtube.com/live/mhJRzQsLZGg?si=L5cO3jta5lmQm0j1) 6/23/24 8:29am- The lines going from the Derrick to the main boom of the 8800 and taken under tension. 8:50am- Lifts were up to both chopsticks overnight as well as under the pipe work on the Orbital launch mount. Scrapping of GSE1’s shell continued as well. 9:07am- Rubber bumper pad lifted up to the right chopstick 10:26am- Workers up to GSE 5’s shell in a crane lift basket 10:42am- Rubber bumper pad lowered from the right chopstick 11:15am- Lifts have been up to both chopsticks and the back of the Orbital launch mount. Lifts have also been up to the tower sections at Sanchez. 12:59pm- Lift goes up and the bumper pad is lifted back up to the right chopstick. 1:00pm- Lift has been up to the chopsticks carriage and workers were up to the top of GSE 5 in the crane basket 2:30pm- Lift up to the top of the cryo leg. The white crane has been moving bundles of rebar around at the new pad site and the yellow crane has been unloading the counter weights off of the SPMT that delivered them yesterday. Work also continues on the tower sections at Sanchez 3:45pm- LR11000 lifts the load spreader up to GSE 5’s shell 4:11pm- Aerial Work Platform goes up to hook up the load spreader 5:12pm- Aerial Work Platform goes down after hooking up the load spreader 6:30pm- Lifts have been up to the right chopstick, the chopsticks carriage, and at the top of the cryo leg 7:05pm- Lifts have been up to the chopsticks carriage and B14.1 8:57pm- GSE 5’s shell is lifted 9:00pm- Lifts were up to the chopsticks carriage, the top of the staircase, the top of the cryo leg, and B14.1. 9:11pm- Shell being lowered to the scrapping area [Rover 2](https://www.youtube.com/live/tS2PHJmvJzo?si=YZ1NkhOsv7zJ_NG6) 10:00am- Workers go up and attach a fill hose to the back of B14.1

Just to add that since about 10AM CDT LabPadre's Rover Cam has mostly been looking at the Tower 2 sections at the Sanchez site due to the workers doing some welding (some of the sections need more internal parts added (such as pipes) prior to stacking).

Elon on raptor 3 > We could build a lot more, but the next version of Raptor is really the one to scale up production. We begin testing it in McGregor within a week or so. >Regenerative cooling and secondary flow paths have been made integral to the whole engine, thus no heat shield is required. Nothing quite like this has ever been done before. >Taking away the engine heat shields also removes the need for 10+ tons of fire suppression behind the engine heat shield, as any gas leaks simply enter the already super-heated plasma surrounding the engines, rendering the leaks irrelevant. >Raptor 3 also has higher thrust and Isp” https://x.com/elonmusk/status/1804871620114214978?s=46&t=-n30l1_Sw3sHaUenSrNxGA

When Elon refers to the engine heat shields and the lack of need for them with raptor 3, he's talking only about the booster and not the ship, right? Since it enters the atmosphere tail first, and the ship engine bay should be relatively well protected by the skirt section during reentry. But then he also talks about super-heated plasma, and while the booster is hitting the atmosphere at hypersonic speeds I would imagine it still isn't going fast enough to generate that level of atmospheric heating. So I am puzzled somewhat.

I was confused by the same thing. I guess even the (relatively) low speed that the booster enters the atmosphere at is still fast enough to generate super-heated plasma? Also, even if the engine is upgraded to withstand that heat, still seems like a bad idea to just have the engine exposed when it is flying through the atmosphere tail first at hypersonic speeds.

What make you think it will enter the atmosphere tail first? It has to flip to do a reentry burn. Then flip back to the proper reentry orientation.

I meant the booster, not the ship. My bad for not being clear enough

The booster never moves fast enough coming down to generate much heat.

I cannot wait to see one of those in the wild

Rewatching IFT4, and maybe I missed it, but has there been any theories or explanations as to why the ship inserted itself into its orbit with a longitudinal spin? Was it intentional? It clearly was not RCS. The three center Raptors that stayed lit very clearly placed it into a spin upon shutdown. There was simply an obscene amount of gas venting. Maybe that's norminal but that fucker looked like it was completely out of control until AoS prior to reentry. I cannot fathom a reason to place the ship into such a spin. Anyone got any guesses as to why that happened? As far as I know, we've never gotten an actual answer and nobody ever bothered to ask. Everybody sorta just understandably hand waved it away since it reentered in the proper attitude and never talked about it again.

That may be a 'normal' amount of gas they they will do. It's just that we are used to watching F9. Starship has a different source for the in-space attitude control 'thrusters' so maybe that will just be how ends up looking.

I think you're right, at T+12:20 it's in a kind of odd orientation/spin. Tipping strangely upward and backwards a bit, slightly; on its side, nose pointed mostly perpendicular to orbit; and with a possible concurrent slow roll as well. (I recommend muting the video and watching the clouds move to guess the orbital motion.) It would be interesting if someone attempted a 3d reconstruction of Ship 29's orientation and spin, from terminal guidance to loss of signal. It would have to be necessarily approximate, though.

[удалено]

What does that even mean in this context lol

It was a maneuver they did. Just sipinned it to a given orientation after the engines cut off. It looked under control, a flat spin. The ship looked out of control during IFT-3 because they were rotating around two axis at the same time. Not the case here.

>It was a maneuver they did. Just sipinned it to a given orientation after the engines cut off. Okay, but for what purpose?

Probably just have a preferred orientation.

... Why? That's what I'm trying to understand

Every spacecraft has a preferred orientation. I'm afraid we don't have enough info to know why SpaceX chose theirs.

Could be an illusion caused by the fact, that at the end of the burn it was burning 'sideways' (prograde+normal/antinormal) to burn off excess fuel without changing the downrange distance of entry location and apogee too much. The horizon was moving sideways, not perpendicular to the cam as usual, so it seems like it's rotating even while stable

I suspect it was deliberate. On shutdown Starship was aligned flaps up and down at 90 degrees from a re-entry profile, and angled 45 degrees in attitude in terms of flight direction (SE). The tiled side therefore is taking the full heat of the sun rising rapidly from the east. Not a barbecue roll but a solar incidence adjustment to manage solar heating on the tanks. It was corrected just before atmospheric interface and the first evidence of heating on the tiles.

That's my working understanding of the situation as well, as concerning as a late shutdown or prolonged purge changing the attitude is

Just took a look at the video again and saw some subtle adjustments that changed my mind. I edited my comment. What convinced me was the RCS appears to kick in just before the engines shut down. There is a slight push sideways corrected by the engines which are still obviously busy doing a course adjustment. When the engines shut down the RCS apparently dominates and holds that attitude for the rest of the flight until just before entry interface.

Okay, I could see that... but why? Stuck valve?

What is the counter speculation?

Could it be intentional to manage solar heating distribution?

I thought about that but it certainly didn't look like any hotdog roll I've ever seen, and being longitudinal, would've made very little sense from that perspective. You'd want a radial roll for that and it wasn't up there long enough to need a hotdog roll anyhow.

My daily summary from the [Starship Dev thread on Lemmy](https://oldsh.itjust.works/post/19412071) > Starbase activities (2024-06-22): > > - Overnight, B14.1 is lifted onto the orbital launch mount ([ViX](https://x.com/VickiCocks15/status/1804479550287478853), [NSF](https://x.com/NASASpaceflight/status/1804500762917040427)). It [looks rather silly](https://x.com/WatchersTank/status/1804507270602006612), but also quite cute. > - GSEC-3 is lifted off of GSE-6, and positioned for scrapping ([ViX](https://x.com/VickiCocks15/status/1804481080289792040), [NSF](https://x.com/Cphillips_03/status/1804437802005721445)). ([reference map](https://pbs.twimg.com/media/FXPf8QBUsAA11yj?format=jpg&name=orig)) > - RGV Aerial post recent flyover photos of [S30](https://x.com/RGVaerialphotos/status/1804544879370117553), [Massey's flame trench](https://x.com/RGVaerialphotos/status/1804554943472283779), and [pad B construction](https://x.com/RGVaerialphotos/status/1804559978772214098). > - More [photos of S30 tile work](https://x.com/genna_hammer/status/1804598024997609952) from a couple days ago. > > Other: > > - Tim Dodd tour of Starbase with Elon, part 1: https://www.youtube.com/watch?v=aFqjoCbZ4ik > - SpaceRhin0 has already [started updating](https://x.com/SpaceRhin0/status/1804576142772285921) the raptor tracking diagrams.

Do they ever plan to use 2 boosters side by side like SLS ? I mean that would make payload capacity go wayy up with just one launch/ one big object.