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Exactly, the two untested things were stage zero (all the new ground infrastructure) and stage one (booster).

I think it's clear one of their biggest lessons is that the construction of the launch mount is wrong, and it REALY needs a flame diverter. Take a look at this photo: https://mobile.twitter.com/LabPadre/status/16490627841670307...

That massive hole in the ground should not have happed, and I suspect that was not an expected possibility. It is a very costly mishap and could mean completely rebuilding the launch mount. With the excavation and rebuild, that could be months or even as long as a year.

On top of that there was significantly more debris making its way to South Padre, the political fallout (pun intended) will be significant, and could cause issues with launch licenses going forward.



>That massive hole in the ground should not have happed, and I suspect that was not an expected possibility.

Interestingly, this post predicting exactly this kind of damage was flagged on HN just days ago: https://news.ycombinator.com/item?id=35590279

I think it's unlikely that SpaceX wasn't aware of the damage that would be caused. They have a pretty good engineering team, and that aspect didn't involve an anomaly, it was the vehicle operating as planned at launch. But admitting the inadequacy of the launch facility would've undoubtedly led to significant delays. Fortunately for SpaceX, the rocket blew up, which will draw media attention away from the damage on and around the launchpad.


There were multiple unexpected "energetic events" seen by observers apparently due to some of the engines failing around liftoff. These "energetic events" could have contributed to greater than expected downward force under the launchpad. If correct, it seems positive that the excess energy was directed downward still permitting the liftoff. That the ship was able to continue the flight through Max-Q and up to MECO and starting the separation spin maneuver seems like a very positive sign. I believe they've already started construction of upgraded launch facilities which include fire trenches and water deluge systems. This first launch facility was basically a V 0.1 test and it appears to have done its job of getting a Starship test article in the air. It's important to remember their development strategy is pipelined and intentionally test-to-failure with multiple improving prototypes in simultaneous parallel construction. Today's test ship was already several versions old.

Also, the rocket didn't exactly "blow up", it apparently lost attitude control during the separation spin maneuver and couldn't achieve the parameters necessary for stage separation. The subsequent rotations appeared to be attempts at automated attitude recovery. The eventual termination was a controlled FTS initiated when SpaceX determined the flight was unrecoverable. I found it incredible that a supersonic rocket about twice as big as anything humans have ever launched was able to rotate several times at around 1300 Mph and over 100,000 ft altitude while maintaining structural integrity. Fortunately, it appears they were able to delay detonating the controlled demolition charges long enough to receive the vital telemetry data that was the entire reason for today's test. That this early prototype managed to load fuel, pressurize, ignite engines, clear the tower, reach MaxQ, MECO, start the separation turn and then down link all the data makes it a massive success from SpaceX's perspective. Everything after MaxQ was pure bonus territory. The engineers at SpaceX must be thrilled to be ingesting all that sweet data from hundreds of internal sensors and start comparing real-world performance against their simulation models.


> I believe they've already started construction of upgraded launch facilities which include fire trenches and water deluge systems.

Ah, so excavating the launch tower was intentional; demo tower 0.1 to make room for tower 0.2!


"test-to-failure" means that when you realize you may have made a mistake, you don't automatically scrap all your work to fix the mistake before continuing down the development path. You complete that prototype and test it because there are a thousand more mistakes to discover. Even if the known mistake will for sure result in a catastrophic failure, there may still be a large window of opportunity for productive mistake discovery before that for-sure failure ends that test run. You want to discover and fix mistakes in parallel, not serially.

Obviously there are judgment calls for when a mistake might prove too costly even in a test run. But manifestly SpaceX has damn good judgment in that regard. If you don't like how the sausage is made, just avert your eyes; don't complain about how ugly the sausage making process is.


when life hands you engine-rich exhaust..


... you make enginade?


That made my day.


From the launch commentary, the rocket is designed to do a 180 at that altitude for the separation event. So a couple extra rotations isn’t going to hurt anything. Additionally, air density at 100k ft is ~1/80th of sea level, which helps.


You mean it should have separated on a 180-flip? Boosting rocket all the way there to break and start orbiting in opposite direction? No way. F9 doesn't do that. The booster should have flipped without starship. That was mistake on commentator side - they were talking all the time like everything is normal. Even when we all saw it started to twist, commentator sayd something like: waiting on separation.

Anyways, the stress rocket experiences in a position like that is such that they break up, because its not designed for positions like that - we have seen that on failing rockets videos. This one did multiple flips with upper stage attached that shouldn't be there on rotation. And thats great :)


This is kind of dumb. SpaceX not only was aware of the damage that would likely be caused, but there are already steel pieces of a flame diverter that arrived a couple of weeks ago at Starbase: https://twitter.com/CosmicalChief/status/1644405156132290560...

They intentionally chose not to install it yet to accelerate the launch (it has been two years without flight testing, they need more data and this booster needed to be gone). It's a perfectly fine decision, it just means more repair after this inaugural flight than normal. If the cost of the repair is less than the cost of delay (and delay impacts Starlink, various payload customers, and especially NASA's Artemis program), then you're a poor manager if you choose delay.

The media have largely been completely ignorant about this kind of testing. Exception being those who have space as their main beat, like Space News, etc. Everyone in the space industry pretty much understands the concept of a test regime that has a high probability of failure. They understand that it's about an order of magnitude cheaper and about 3 times faster than the usual defense contractor "failure is not an option" approach. That's why you had such supportive comments from the NASA Administrator and anyone else who is actually in this industry.


It sounded like Elon also put a decent probability on the rocket exploding on the pad. In that case, the flame diverter would likely have been destroyed anyway.


> I think it's unlikely that SpaceX wasn't aware of the damage that would be caused.

"SpaceX" isn't a unified mind. It's not even a hivemind, no company is.

We keep saying "company knew about X", but it's a such a mischaracterization of how companies, or any group of humans, work. Yes, some people in the company might have known it, but for various reasons, be it poor communication, mistaken assumptions, willful ignorance, or what have you, that information wasn't acted upon. Companies have complicated and chaotic dynamics. We Do Not Have An Algorithm For Truth.

In effect, "Company knew about X" is practically a meaningless oxymoron.

Yes, the "company" may be the "responsible entity", but as a century of corporate history demonstrates, that doesn't mean very much in practice, as the individual people within the company who might theoretically be tagged can weasel out of consequences.


My issue with this take is that companies have used leverage and lobbying to get to define when a company isn't a single entity and when it is not, always in their advantage. For example, a company is involved in a human death: the company is suddenly not a single entity and is instead simply part of this complex system of moving parts out of which emerged a human death. As another example, a corporation wants to donate to politicians (for "reasons"): the company is suddenly a single entity and even individual (!) who has constitutional rights to political donations.

Companies flip flop back and forth between them being a collective and individual at will and to their singular benefit.


1. Company is doing good --> Company is a single, good individual doing good

2. Company is doing bad --> Someone inside the company must have been bad, company would have prevented it but was powerless, because #1


Or maybe they estimated the chances of the launch pad being entirely obliterated during the launch attempt as pretty high and didn't want to invest more money into it than absolutely necessary?


Turns out they were indeed right! The hole is Boring Company-worthy.

Joking aside, the test was successful, but the missing concrete and what seems to be 50 meters of sand below it is a problem for the next test launch schedule. The pad they’ll need for reusability will be as impressive as the rocket itself.


Interesting article. He doesn't really speak of a large hole in the ground and huge chunks of debris flying around though. More of the effects of the heat and sound energy on wildlife which is not quite as obvious.

He raises some good points indeed, not sure why it was flagged at all.


Given what have happened in the past few years, we (as a whole) are less tolerant to alternative ideas.

IMO, we (as a whole) should spend less time spreading ANY information online, use more time to think before speak


> we (as a whole) are less tolerant to alternative ideas.

It’s not just that though, certain topics are lightning rods, and Musk is particularly devisive.


> IMO, we (as a whole) should spend less time spreading ANY information online, use more time to think before speak

When it comes to insensitive tweets vomited out over the internet I totally agree. Though even those of us more considerate can contribute to this by simply not following people who do that. I'm personally not even using Twitter at all and I never did even before Musk took it over. I find the signal/noise ratio way too low there and anything really interesting there makes Hacker News anyway. But anyway that's a tangent.

So, if you read something that really makes you think: "Wow that's really an insensitive hot take", just block the person from your feeds, no matter who they are. Especially if it's not the first time. Makes your life a lot more relaxing. And it's more effective than wishing that haters are gonna stop hating.

However this particular article was thoughtful and came with a lot of explanations, diagrams and source links. It was pretty hard criticism of SpaceX and the FAA but it was not agressive or flaming. To me it seems pretty well thought out and it gives balance to a complex story by showing a side to it I wasn't aware of yet. Not saying the story itself is balanced, but it gives balance to the other media which are overwhelmingly positive and don't cover the ecological side at all.

In other words, this is not the thing that should be cut from being spread online, in my opinion.

The author has clearly written about this before but that doesn't necessarily invalidate them or make them biased. They can also simply be right and been ignored so they keep writing about it. When you 'go fast and break things' it's important to consider the things you are breaking, even if they are not very obvious. One of the questions that comes to my mind is: "Why is this thing even in the middle of protected habitats?"


Lately HN has been critical of dissent against certain ideas, with flagging and mass downvotes used to push certain narratives.


I read that article shortly before it was black-holed. When I was done, I wanted to read some of the discussion around it. When I saw that it was nowhere to be found, I distinctly remember thinking “what the hell is going on with this place?”


I couldn’t find a way to unflag it once it was flagged?

You’d expect it to stay fine if 20 people don’t think it should be flagged and 10 others do.


I think you'll find that Hacker News can be quite hostile to something viewed as "alternative" information, especially if it relates to certain companies. I found the article quite interesting and actually quite informative and evidence driven.


I mean, I thought it was nonsense, and we shouldn’t let the feelings of a bunch of birds stand in the way of the largest rocket launch in history.

But the discussion around it was valuable, and as said before, some of the topics raised by the author were actually issues.


> expect that this comment will be massively downvoted and flagged

Well, yes. It’s in the guidelines: “Please don't comment about the voting on comments. It never does any good, and it makes boring reading.”

https://news.ycombinator.com/newsguidelines.html


Quis custodiet ipsos custodes?


The gist of the comment is not on the downvotes of that particular comment in and of itself, as much as the overall behaviour of HN and using itself as a data-point to support the hypothesis. At the time of writing I made a prediction on the behaviour of HN. I did not make a comment about the votes of a particular comment after the fact, therefore, I am clear.


> gist of the comment is not on the downvotes of that particular comment in and of itself

The gist doesn’t matter. You commented on being downvoted. That’s against the guidelines and gets flagged. Your comment is stronger without the throwaway bit at the end.


Sure, let us remove it and see how bad things go.


There has always been some of that on HN. But the ideas which get downvoted have slowly shifted over time.

I’ve been on HN for well over a decade. I remember it being more startup focused, and more libertarian politically. My perception is that it became a bit woke for awhile, but now the backlash to that sort of thinking has happened in earnest.

We have all the comments going back to the start of the site. I’d love to see an analysis of what HN believes and how it has changed over time as a new generation has joined the community.


When you say 'we have'; you mean access to scrape, right? Or have they already been put in a file format?



Thank you!


I still don’t understand why that post was flagged so quickly.


> SpaceX's Texas Rocket Is Going to Cause a Lot More Damage Than Anyone Thinks

It might be the over-the-top title didn't do it any favors. It's in a gray zone between truth and click bait.


And yet here we are in a thread discussion how the rocket did more damage than anyone thought.

That article was always going to be flagged, strictly because of its content. Maybe it could have snuck in with a headline like "Great news, SpaceX wisely found ways to launch rocket 20% more powerful than they planned for", but I doubt it.


The title is a completely reasonable and accurate reflection of the opinions that the author presents. If there’s disagreement about the opinions, that’s what discussion is for. I think this kind of thing is indicative of hn being on a bit of a downward slide.


This is disingenuous when you consider that it's not really over the top, and less subjectively, mods have other tools available to them, like renaming submission titles.


With hindsight, we can now actually conclue that it was in fact, over the top. They claimed that buildingds would be destroyed and neighboring communites would be scarred for life.


When a post is flagged enough by users, it's hidden without interventions from mods. They can bring it back, though.


A 10x-100x increase in sound beyond approved levels, intentionally skipping or lobbying to skip approvals, ignoring environmental impact, and using designs as if they were approved when it was really earlier, much different versions are not examples of gray areas.


Fair point, there's definitely some hyperbole there. "More than anyone thinks" would mean the author doesn't think it will damage as much as he's saying either.

Sort of implies the article was hyperbole, which it was.


[flagged]


Considering one of the possible outcomes was for the whole thing to blow up on launch pad, the crater and debris storm were nothing.


Maybe… the tower is still standing but one has to wonder if the foundations are in good shape after this amazing rock throwing performance.


> it's unlikely that SpaceX wasn't aware of the damage that would be caused

If there is a material chance you won’t clear the tower, building an elaborate pad is overkill. I disagree that a new mount means months of delays—SpaceX has been building these faster than legacy operators.


They'll need one that won't turn to a hail of debris and a crater though, that may be somewhat more work.


> need one that won't turn to a hail of debris and a crater

They have these. At their permanent launch sites. This is a test site. That the rocket reached max Q suggests this isn’t a problem needing solving right now.


It most certainly didn’t reach its planned max q, not with 6 motors out and the rest with nozzles dented by rocks at ground escape velocity.


> most certainly didn’t reach its planned max q

One usually throttles down around max Q, so it's unclear from outside.

> rest with nozzles dented by rocks at ground escape velocity

Now we're speculating beyond the data. (Actually, we have counterfactual data: it reached max Q. That doesn't happen if you have mis-shaped nozzles causing flow separation.)


Earlier you seemed to imply that you could achieve max Q with six engines out by not throttling down as much. Why does the same not apply to overcoming possibly dented engine nozzles?


It reached some max Q. I’m not convinced it reached the absolute Q value they hoped for.


I think it is a bit premature to assert that the launch pad caused the engine failures.


Thanks for posting that link. I found the article informative and actually well-written and driven by evidence and examples.

It is really striking to me how people are willing to throw the environment under the proverbial bus and literal rocket in order to further some false idea of improving humanity. We're actively killing a live planet, currently the only planet known to be able to house human and life in general for that matter, to reach a dead planet on the whims and wishes of paper billionaires.


Maybe we could get minerals and stuff from space instead of digging up nature


Ignoring the complexity of accomplishing that, such an enterprise would cost an immense amount of material and pollution. Also, it would not stabilize or decrease mining on Earth.


no one thats been following the test campaign for Super Heavy is surprised by the damage. the damage to the pad has been documented after the 3, 14, and 33 engine Static fires in the run up to launch. I believe they said SpaceX has been experimenting with different concrete formulations in the repairs after each static fire. There has also been photos of what appears to be flame diverters on site at Starbase, and I think they have even done a crude test fit of them under the OLM at some point recently.


I don't follow space stuff nor space x but I was quite surprised not to see the usual water flooding system


Yeah, I think it's been surprising to a lot of people. There have been a lot of questions among people who follow space as to why they didn't start with a flame diverter and water deluge system.

I guess they felt the delay to install one would be too long, and they really wanted to get this launched? Or maybe they had reason to believe they'd get away with it... seems implausible given the forces involved.


A month in the lab will save you an hour in the library, as the saying goes.


I wonder whether all that debris was a factor in the engine failures?


Hopefully the data will work that out. Raptor 1 seemed to have quality control issues in that some percentage of engines would fail, hopefully this isn't also the case for Raptor 2 or at least can be worked out.


It was expected. They have moved deluge equipment from Canaveral and have partially installed it, which they wouldn't have done if it wasn't expected to be needed.


Came here to point this out.

The dark ages still lure within us.

I thought that article raised some valid points, but fanbois gonna fanboi and don't dare you speak wrong of their master.


If nothing else, Musk has a lot more entertaining method of boring tunnels now than those slow tunnel boring machines.


Surely considering what the Saturn V launchpad used - a rather huge hole in the ground lined with concrete and an insane amount of water being released to dampen sound and damage ???.


Why do things like this get flagged? Who decides which topics aren’t allowed for discussion on HB


Come to think of it; I never saw the water deluge system come to life... did it?


There is no deluge system, yet. But the aftermath of the launch today shows it really is needed


I think this non deluge system was 100% intentional as a cost saving measure to just see if the asset acquired clearance from launch tower. The next iteration of launch will have one.


Seems like the author was closer to the truth that HN gave him credit for: https://www.youtube.com/watch?v=thA8jlgcJ-8


I dont think it was close to the truth at all.

They predict shattered glass,damaged foundations of beachside homes, and people scarred for life by the launch.

This was hyperbolic fearmongering. The actual launch was very close to baseline expectations. The lack of launch pad flame channels was common knowlegle, and no great insight.

This entire blog is dedicated to environmental complants about SpaceX operations. If there had been flame channels, the author would instead be writing about how they are pointed at sensitive environmental habitat.


Would strongly disagree. Reading the article it doesn't sound like fear-mongering at all.

In fact their concerns about FAA cutting corners in allowing SpaceX to build such a facility seem quite legitimate. Especially if they are passionate about protecting sensitive environment habitat which is a voice that we need more of in this world.


Is there evidence for widespread property damage in neighborring communities and are the individuals scarred for life, as the author predicted?

I think we need fewer such passionate voices who place such a high value on a handful of birds and am glad they are largely ignored.


So this needs to be stressed: the only reason the area around Starbase is protected habitat is because SpaceX built Starbase there. Because space launches fall under FAA and thus Federal regulation, the area around them becomes Federal land and subject to Federal environmental review and protection. This is the same reason Cape Canaveral is surrounded by protected wetlands - it's because the Cape Canaveral launch complex is there.

But that's predicated on the facility existing. If SpaceX hadn't bought that land - and they did buy it - it was for sale - then those wetlands would not be protected habitat at all.


I wasn't aware of that. Can you recommend further reading?


> pecially if they are passionate about protecting sensitive environment habitat which is a voice that we need more of in this world.

Environmentalism is one of /the/ largest talking points in current discourse.


Are you still of the opinion that the article was not close to the truth at all? Windows were shattered, the highway next to the facility was damaged and is still closed, Port Isabel was showered with dust and debris, and more.


Try this exercise:

Go through that article to find every specific prediction you can (e.g. broken glass & damaged foundations in the town 8.5km away). Then compare these to what happened.

When I tried it, I found that they were more incorrect than they were correct and the biggest harms predicted were the things they were the most wrong about.


the wide angle makes it look a lot further away from the rocket than they really were - The camera is about 440m away from the rocket.

The damage shown in the video appears to be entirely caused by debris while the article was suggesting possible property damage ("shattered glass and damaged foundations ... from a miscalculated sonic blast") to towns 8500m away - 20 times further


To come back and admit that I was wrong:

"In Port Isabel, a city about six miles northwest where at least one window shattered, residents were alarmed. " from [0] posted to HN [1]

I stand corrected - the warning article was pretty accurate

[0] https://www.nytimes.com/2023/04/21/us/spacex-rocket-dust-tex...

[1] https://news.ycombinator.com/item?id=35651757


Wow! You can see the chunk nail the corner of the NASASpaceflight stream van (on the left of the frame) at 0:15.

Unlucky hit! But I guess lucky it missed the camera gear.

The team was chuckling on the stream about how they opened the vehicle windows for airflow to the electronics gear inside... but SpaceX helped them open it even more.


I agree with this assessment and probably the biggest problem in the test. After that, they still have a fair way to go on Raptor reliability; I was a bit disappointed with the number of engine outs: clearly the engines have not arrived. I think the big win of the day was the overall resilience of the vehicle. It seemed to handle (what looked to be) possibly explosive engine failures and kept going and stayed intact... even through the tumbling.

I think this is a case where the engineers can look at the numbers and calculate for a limited variety of well defined (and foreseen) scenarios, but that they continue to fail to have an intuitive sense of the power of the thing that they built. Given the complexity of the real world, they can "engineer" themselves into an undue sense of certainty about what will happen when they light a rocket of this power... and I think we see the result of that. As an aside, this is precisely where I think we'll some of the biggest failings for LLM based AI... it can get you some nice words to describe a situation and may be able to do all the calculations... but having that gut feeling that maybe there's more to a situation than the numbers would have you believe is still something that humans can do better (though not SpaceX this time around).

In closing, if I had a binary choice of "successful" or "unsuccessful" for this test... I'd still probably call it successful. But only just; it's a very qualified success given some of the test parameters SpaceX had set for themselves.

(of course we could find out about even more damage to "stage 0" which might shift my assessment... but we know that they're in the process of putting in a deluge system at least already, so I'm being a bit more charitable regarding expectations than I might otherwise be.)


> After that, they still have a fair way to go on Raptor reliability

I suspect the debris from blowing a whole in the ground was the biggest contributing factor for the engines out. It looked like at lease 4 we're gone before it left the pad.


Isn't it pretty unlikely that this debris, flying against the exhaust, can reach the engines with significant energy?


That's my thinking, but ignition is a staggered 6 second duration, so there's at least a window for adverse directional flow.

But looking at that pad and the damage to it- without deluge dampening, I bet the RC spalling might have been a bigger issue than just ground blowback.

Put a blowtorch to some concrete a and watch how quickly trapped moisture starts causing miniature explosions and flying shrapnel.

But that's just my first uninformed impression.


They have special concrete now which shouldn't explode from moisture. But apparently it didn't hold up at all. I don't think anyone expected this.


The output power of a rocket is different than a blow torch. The sound pressure alone is near or above atmospheric pressure. That concrete is being exposed to vacuum and more than 1atm pressure fairly rapidly. The heat on top of that and if the concrete has any moisture, the water inside is going to rapidly sublimate and condense several times a second. That is on top of the concrete being slammed into by an entire atmosphere of pressure in the meanwhile.

There is a reason that NASA dumps a few million liters of water under their rockets.


My understanding is that one of the Starship prototypes were damaged by flying debris during a static fire. I think the available evidence points towards it being possible.

https://www.youtube.com/watch?v=jM61ZkUoO4U

> About 2 secs after starting engines, martyte covering concrete below shattered, sending blades of hardened rock into engine bay. One rock blade severed avionics cable, causing bad shutdown of Raptor.

https://twitter.com/elonmusk/status/1328742122107904000


Assuming that this photo

https://twitter.com/LabPadre/status/1649062784167030785

is real, I guess not. What used to be in that crater couldn't just move sideways, it had to go up to get out of the hole. Engine exhaust hit the center of the crater, dislodged rocks, pushed them away radially and up the sides of the hole.

Four of the six engines later seen to have gone dark were in the outer ring. Coincidence?


Rocket "engines" aren't like engines in your car. The bell and the plumbing for it is the engine. There's not too many moving parts besides a pump. Any sort of damage to the bell can cause a failure.

The bells are cooled by pumping super cold fuel over them, a rock hitting those thin lines of fuel could rupture a line, or divert on causing a failure in the bell which eventually (seconds) ends in an engine rich fuel mixture.


Considering the energy they have comes from precisely that exhaust, I don't think so. I'm pretty sure some pieces would make it through.


> but having that gut feeling that maybe there's more to a situation than the numbers would have you believe is still something that humans can do better

In my life experience so far, humans having gut feelings it 99% of the time complete nonsense. But people forget the 99 times and that one time their gut was right they tell that story forever about how smart they were.


Correct gut feelings are just your subconscious running the numbers without bothering you about it. A human having a (correct) gut feeling that the numbers are wrong just means that the human has not chosen the correct numbers to look at, or possibly that a human has made an error in telling the computer how to calculate the numbers.

Yes, computers are really good at making calculations, but we have to tell them which calculations to make, so there's still (will always be?) a weak link in the chain.


Like survivor bias.


> I was a bit disappointed with the number of engine outs

Who knows if they were controlled tests, you need failures to understand the reliability domain. Engineering is about handling failure, not success. You learn very little from success, esp with so many free variables.


Reminds me of the flash memory cells SSD's are made of - overprovision them because some are going to become/or is bum anyways.


The Raptor issues may well be just a symptom of the concrete issue; large chunks flying up into complicated plumbing isn't ideal.


This will be more of an issue on landing (the moon, mars, mercury, the bricks in red square).


Not necessarily; low gravity plus lighter weight means much, much lower thrust on landing in those locations. F9 lands on the drone ships with one engine, for example. It also looked like today's launch involved a hold-down period while they lit them all; that wouldn't be the case for landing either.


I hadn't known that. Is that a center engine?

Intuitively it seems like more would be better so that in the case of that engine failing you could use the other engines to push up and maybe light another engine.

Of course, if there's two engines and one fails, it's going to tilt. Same with 3, though to a lesser degree. 4 engines lessen it even more, etc. etc.

Or maybe they can detect a bad center engine on descent (it doesn't light or flame is detectably not the right) and then go to outer engines. Or drop it in the ocean. Hope there aren't people on that one.


> Intuitively it seems like more would be better so that in the case of that engine failing you could use the other engines to push up and maybe light another engine.

The landing F9 first stage is so light even one engine at minimum throttle has a thrust-to-weight ratio greater than one; they can't throttle it down enough to hover. Three lit engines would send it shooting back up rapidly.


I was under the impression that there's no hold-down or clamping of the booster for this vehicle. The clamps are disengaged around T-10 (maybe T-15?).


The booster is securely clamped to the launch stand. However the starship is only resting on top of the booster - the two parts of the ship are not clamped together.

Launch clamps are released on command of the engine computer - i.e when it detects that sufficient engines are running correctly it commands a clamp release.

Note that Starship Booster's outer engines are actually started using feeds from the launch pad. They need power and pressurized nitrogen from ground equipment to start. The outer engines are not able to restart once off the ground.

So the clamps are required to keep the vehicle in place until all the engines that will start have had a chance to do so. They're also useful if there is an abort during engine start so the vehicle remains secure.


> However the starship is only resting on top of the booster - the two parts of the ship are not clamped together.

That isn't what it looked like to me when it made what, 3 go arounds?


I may be incorrect and they are now using explosive bolts. I've seen those mentioned elsewhere.

However the engines were on the whole time, producing >1G of thrust along the direction of the booster. So that force is going to hold the StarShip and the booster together. But you would expect some lateral force from air friction to push the stack apart at some point.


Might just be the thrust-to-weight being under 1 while they light the engines, but it visibly sits there for a signifcant amount of time, much more than you'd get with a landing suicide burn.


Then what holds the rocket down while the engines are spooling up?

Could possibly this explain why there was so much lateral movement of the booster before it cleared the tower?


That makes sense, but on mars? Full payload, very little atmospheric drag, little atmosphere to keep the blastolith from scrubbing the bottom of the vehicle. I am talking generically since presumably the first stage won't be landing on mars.


Mars is far off enough it's entirely speculative on how they'll handle this. Drop some robot bulldozers first? Specialized landers for landing pad construction crews? Bring the heavy cargo via a separate non-atmospheric craft built in Earth orbit? Hover from height for a while to blow debris off a rocky flat spot?

I don't have the answer, but IMO cheap mass to Earth orbit is the biggie that enables a whole bunch of options.


There was an idea of adding aluminum powder to exhaust and hovering a little over the pad, so that you deposit a solid metal surface where you intend to land.


You missed the moon solution - use engines high off the ground (most of the way up the ship) for landing.

Another idea (not starship specific) is to introduce cement (or similar) into the engine burn to build a landing pad from middair.


Lower pressure could help help the exhaust spread more.


they’re not going to land with all the 30+ engines turned on and they won’t need the same amount of thrust since the first stage is gonna be mostly empty. Plus they won’t land the first stage on the moon or on mars.

And the plan is to grab the first stage before it touches ground anyway. So this is mostly an issue on liftoff.


> clearly the engines have not arrived.

I think Raptor2 as an engine has definitely arrived. Igniting and running this many at the same time has some work remaining however.


Pretty sweet that they got to test 33 Raptors at a time. You can find failure modes approximately 33 times faster that way.


There was a time where people questioned if 33 of them packed in like this would work at all. Pretty impressive that it does and survives multiple engine failures.


Plus the combinations.


> After that, they still have a fair way to go on Raptor reliability

They seem to have worked fine individually and in smaller groups. There could be issues with the plumbing, which they seem to be iterating on quite a lot with the newer boosters.


One of the response to that tweet has a before pic for comparison: https://twitter.com/intrepidpursuit/status/16490707601981317...


Woof, that's a hole! Yeah I completely forgot "w", all the stage 0 stuff. There's only so much you can test with wet dress rehearsals, at some point you need to just launch a fully loaded rocket from it and see how it behaves.

> On top of that there was significantly more debris making its way to South Padre

Tim Dodd got coated in dust and sand (probably pulverized concrete) kicked up from the launch well outside the exclusion zone (iirc his studio is just over 5km). That's not just a bad sign from the engineering and politics/perception point of view, but I'm sure EPA has some feelings on that amount of rapid unscheduled geology.


> Tim Dodd got coated in dust and sand

i don't see that being that big of a deal, winds blowing west to east and no one would have ever even thought about it.


I had a long history of supporting live events like this. One of the most common phrases we heard from the engineers was: "Well... that didn't act like the model"

That is why we test real things in the real world. While the rocket did not operate as expected, so much information from this launch is going to go back into engineering.


Thinking about this a little more, that was the longest duration burn with all engines. I imagine it's a bit like water behind a dam, a small leak very quick grows into a catastrophic failure.

A small fault in the concrete slab grew into a catastrophic blow out. I worry about the integrity of the massive concrete piles they put in.


I was surprised to see so much equipment right next to the launch vehicle in the video. Would all that have gotten damaged during the launch?


Need to see the numbers before passing judgement. Dirt is cheap compared to concrete. Depending on how many cycles the concrete is expected to last it may be cheaper both short and long term to just have "ablative dirt" and bulldoze around afterwards "reloading" the launcher. There's also other variables like how long it takes for the engines to stabilize and the launcher to release the rocket, weight of rocket, etc that would go into it.


It wasn't "ablative dirt". It was a massive reinforced concrete pad that was pulverized and blown to kingdom come.


The issue is that that dirt and rocks flying around damages all the other expensive equipment at the launch site. There is going to be some very dead kit down there. They can't do that every time.

But big dust clouds also upset people, and SpaceX can't afford to fall out with the locals.


> dirt and rocks flying around damages all the other expensive equipment at the launch site

It’s a test pad. The equipment HN’s armchair aerospace engineers are proposing be installed would have been that expensive equipment.


Locals? Don't they own 99% of Boca Chica by now?


South Padre, about 5 miles away has been covered with a layer of dust.


I was on South Padre Island watching the launch, and I was stuck in traffic on South Padre Island for almost an hour afterwards, and I did not observe this.

It’s possible that some of the dust reached South Padre or Port Isabel, but neither seemed to be “covered” in it.


It's not just dust it's pollution and it's going to cause long-term health problems.


Methane rocket exhaust is steam and CO2. Where did the "pollution" come from?

Are you suggesting they buried polluted dirt in the launch pad to distribute later?

It's just like construction dust. It's unpleasant and inconsiderate but it's not highly toxic or a pollutant.


I mean the concrete dust that got airborne as it was being blown apart. It's airborne silica and is toxic which is why construction workers wear masks when producing it.


What? This is quite the claim to make so confidently.


It's been wild to see people here try and spin this as a success story, because the rocket launch was missing things known to be required and the end result was as you mentioned. Massive destruction of the surrounding area which is going to require months of rebuilding and tons of $$$.


Because they achieved what they were trying to do? They said if it got 50 seconds into flight it was a success and it did. No Spin, they literally mentioned this objective before the flight, it's more wild for people to suggest that it wasn't despite it exceeding it's objectives.


I listened to Musk give a QA about this last week before the initial launch date. He very clearly defined success as reaching orbit, and stated that success wasn’t likely.


Pouring more concrete is not very expensive. It takes a month to cure completely, but the next test is multiple months out regardless. By that time they'll have the deluge equipment installed.




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