According to Isaacson's biography of Musk, Musk relentlessly challenges the existence of every part in Tesla and SpaceX machines. He's willing to go too far, having to sometimes put a part back in.
Everything in the manufacturing process is also challenged to justify its existence.
This is how he managed to reduce the costs by 90%.
Isaacson’s “biographies” are glorified puff pieces. Musk is as unrecognizable in his as Jobs was in his.
Both Tesla and SpaceX had teams keeping Musk busy on bs just so that the engineering teams could do their work.
The second he took control, we got the cybertruck and the starship, the worse products both companies ever built (or attempted, in the case of the starship).
> Musk relentlessly challenges the existence of every part
This sounds insightful until you find yourself debating with the CEO for the eleventh time about how his high-school understanding of the physics involved breaks down in a particular case.
Musk is very lucky to be moving such quantities of money that his companies are big enough to protect themselves from him, if you ever wonder how Musk would fare on a tight budget, look no further than the Oceangate.
Do you remember when he bought Twitter and fired everyone, and the mass media and employee outcry was that a) the service would stop working and b) he would bankrupt the company, yet a few years later it’s massively more successful than Twitter ever was as a public business?
Regardless your thoughts on Elon, his drug habits, and his political brashness, I don’t think you can say he’s in any way close to the Oceangate guy. There is something legitimately special about him and his collective.
Yes, Twitter is so “successful” Musk had to write off 50% of his “investment” out of the gate, and had to come up with an AI-hyped merger with SpaceX to compensate the banks that went in with him.
The only reason Twitter has more active users is that it removed some of the protections for bots, in particular broad filtering coming from certain country involved in a war.
You don’t think Musk is any close to the Oceangate guy? Let’s review some interesting decisions by his companies then:
- Musk mucking around with the blue checks and the bot filters in Twitter skyrocketed the amount of scams in the platform.
- Tesla uses very strict NDAs and settlement to silence the reporting of accidents
- The infamous electric door handle that locks up Teslas when power goes out was an obvious point of failure, it was ignored, people died, and now several countries have legislation against it
- Reportedly Musk had safety lines and other safety features in the factories removed for serious reasons like “not liking yellow”
- Any understanding of how to parse public insurance data will show you Tesla’s have accident rates that are multiples of other brands
- The Starship, a vessel that is intended for human transport, has no safe abort system, no way to fit one in its current state, and no plans to modify that.
Just a reminder that even a very SpaceX-friendly count (in which flights that did not attempt to land are considered “good”) puts the current reliability rate at <40%.
As a naive boundary, for clearing the 97.5% predicted crew survival, SpaceX would need to fly in the order of 300 good Starship launches.
Twitter is definitely not more successful now than before. So many people left and are gone forever.
I would read a deep dive though into the history of Twitter (with the financials) to understand better and I do get that for a single product company there really is a point at which you give up on finding the next big thing and just optimize on your main thing and you really just need a few dozen awesome people and a rotation of new hires to keep things rolling but not thousands of engineers.
Maybe I’m overstating “massively more successful” but to my understanding “X” has roughly twice the active use count that Twitter did, although that includes Grok.
That said, do you remember these kinds of articles?
> Musk summons engineers to Twitter HQ as millions await platform’s collapse
> “Former Twitter employees fear the platform might only last weeks.” Melissa Ingle: “I don’t see how it lasts the month.” “All signs point to some catastrophic failure of the system, and very soon.”
Elon was firing people left and right and literally physically destroying Twitter’s data centers. I remember hundreds of these hysterical articles and tweets that very clearly did not come to pass. He obviously did something more clever than the authors of these articles expected… is all I’m claiming.
I haven't posted anything on this HN submission yet, but all I'm claiming is that Twitter was so successful under Elon's management that he thought it was better to roll it into SpaceX than to keep it independent. Kind of like solar city was merged into Tesla to bail it out and then it winded down after the acquisition while nobody is looking.
Yes, and Tesla and SpaceX are both ridiculously overvalued by any fair measure.
But we can separate the financial inanity of his empire from the question, which is whether Elon is a capable engineering mind or simply an ‘Isaacson puff piece recipient’.
He also unbanned a lot of people and got Trump back, got to ride the AI wave with Grok, pushed paid subscriptions and implemented paying people for tweeting. I would argue growing the platform by bringing back people that were brought back for violating the original rules is not a win. Nor is attracting people to the platform that follow those people, Nor is riding the AI train.
And even with all of that, the new users, the AI, the paid subscriptions, None none of that actually fixed the major underlying issues that Twitter is not profitable. Jack Dorsey couldn’t fix it and neither did Elon. I think he just realized having a modern media platform he controls is more powerful than it making money. He inherited a platform built by someone else, and keeps the lights on with a skeleton crew. I don’t see that as a success
> yet a few years later it’s massively more successful than Twitter ever was as a public business?
Twitter has certainly been a glowing success at becoming a right-wing propaganda chamber for Musk but as a commercial venture not really. Revenue is down 60% since Musk bought it.
It also doesn't factor in the dramatically reduced costs. It's likely that X is already significantly more profitable than Twitter was. And with less dependency on advertisers, which is a huge win in and of itself.
Look man I'm not a fan of Elon, but it's ridiculous to say the starship is the "worst". It's coming out of early development and has had some minor success already.
It seems to me that partisan/political hate blinds some people so much that they are becoming ridiculous.
"This sounds insightful until you find yourself debating with the CEO for the eleventh time about how his high-school understanding of the physics involved breaks down in a particular case"
Musk has a bachelor's degree in physics from the University of Pennsylvania. While not a full scientist, I doubt that "his high-school understanding of the physics involved breaks down" anytime often.
Have you ever been in such a situation that you describe, or is this just your prejudice speaking? AFAIK the discussions in SpaceX revolve more around things like "can this part be 3d-printed", "do we keep the actuators for part X or can it just stick out into the wind" or "should we use landing legs or not", which have nothing to do with high-school physics and everything to do with actual engineering tradeoffs.
"the starship, the worse products both companies ever built (or attempted, in the case of the starship)."
This is what tells me that you are speaking in bad faith. Starship is not yet a finished product. Judging it now makes about as sense as judging Edison's lightbulb a year before it was introduced into the market.
Starship has several issues to fix, but we can already see that a) the Raptor engines are about the best on the planet, doubly so when considering their extremely low unit cost; b) the vessel itself is very tough and performed well even in really bad situations; c) the heat shield developed a lot and the last Starship (the one which was dragged to the Christmas Island) survived reentry in very good condition; d) the amount of control (belly flops, slowing down to hover) that they have over that huge thing is unique in the history of spaceflight.
> Musk has a bachelor's degree in physics from the University of Pennsylvania.
Clarification, Musk bought a B.A. in physics. In the Paypal S-1 in 2002, [1] Paypal's lawyers claimed that he graduated with a B.S. in Physics and B.S. in Economics in 1995.
Yet the actual degrees subpoenaed from UPenn indicate a B.A. in Physics and B.S. in Economics in 1997, two years later. He could not even remember the year he graduated or the degree he received just 5/7 years after their purported completion. I have yet to meet a single person who actually graduated from college who can not accurately recollect the year of their graduation, have you?
Most likely he did this because he was in the USA on a student visa and dropping out of UPenn in 1995 made him a illegal immigrant which his brother, Kimbal Musk, corroborated in a interview [2].
He was the chief engineer and head of product at SpaceX and Tesla for over 20 years, respectively.
On Falcon 1 and 9 he worked directly on major components of the vehicles.
In Tesla, he was heavily involved in the design of every single product they came out with. He also micromanaged Model 3 assembly automation in 2017-18.
>"According to Isaacson's biography of Musk, Musk relentlessly challenges the existence of every part in Tesla and SpaceX machines."
This removal of surplus-age is common in the automotive industry, and one of the reasons that cars are such an amazing value. It seems like Musk's remarkable ability to achieve cost reductions (at least in the aerospace context) is attributable to his pursuit of vertical integration. Airframers (aeronautical vehicle designers & manufacturer) are bound by the costs dictated by their component suppliers, especially after a configuration has achieved regulatory approval. SpaceX has managed to avoid being 'held hostage' by pseudo-monopoly suppliers.
How does something like this happen despite Ford knowing all the 'secrets' a company like Tesla or the Chinese know? I have a few guesses:
1. Its the structure of the company. In this video the presenter talks a lot about all the hoses and clamp connectors etc. The cooling department thinking they had to stay relevant made sure the car incorporated a design that had all this nonsense.
2. Maybe they didn't put their 'A' engineers on this car. Its plausible: the F-150 is their massive money maker. However this car was supposedly developed under some skunkworks program and yet here we are.
3. Maybe there was sabatoge from elsewhere (suppliers, middle management etc.) You watch a movie like Ford vs Ferrari and while im sure a lot is dramatized, I can't help but think man they were talking about the dysfunction of Ford way back then?!
Then we have Youtube documentaries like this one about the Ford Taurus SHO talking about how they screwed up so much that they had one chance left to get serious...like what? Shouldn't they be serious every day? Thats what the Chinese are doing.
The presenter further added how they had to ship entire engine blocks to Japan so that they could 'fix' them and unlock 80 more horsepower that Ford just left on the table. If factual, this should be a total embarrassment: You had to send your handiwork to a entity with a better reputation so that they could 'fix' your mess?
At some point, you have to acknowledge that the naysayers were wrong: Thinking (especially among the short community) was that Tesla had some cool ideas but their implementation was horrific, they couldn't just make up for 100+ years of institutional knowledge that the legacy companies had. The Tesla cars showed some of this thinking: quite poor build quality, poor after sale support, poor parts network. These things improved over the years but still isn't perfect.
But at the same time you have to acknowledge that the legacies suffer from their own problems that dont put them as far ahead as newcomers as you'd think. Sometimes a lot of that institutional knowledge becomes a liability when a paradigm shift occurs.
yes and no. Like you said, automotive and aviation industries are bound by a lot regulatory and path dependent constraints.
Elon's strength is his willingness to pull the plug and transition away from suboptimal solutions. This is bolstered by his willingness to double down.
Imagine if Boeing said "screw all this recertification technical debt for the 737 MAX airframe, we will start fresh. Customers can take it or leave it"
According to a version I heard, Boeing engineering did say more or less just that, at which point Southwest, the near-monopoly in some regions, said something like, "Oh yeah? Then we'll plan to leave it."
And Boeing upper management overruled the engineers.
There was nothing wrong with the MCAS concept. The implementation of it, however, wasn't very good.
Unfortunately, two of the 3 crews did not understand the runaway stabilizer trim procedure. The 3rd crew did, and landed safely, and the media never reports on that.
The runaway stab trim procedure is a "memory item", meaning pilots shouldn't need a checklist to deal with it.
But doesn’t apply to MCAS because the symptoms and recovery procedures are distinct.
The MCAS system wasn’t documented, pilots weren’t trained on it, it didn’t indicate anything distinct in the cockpit, and it could rapidly put the plane into an unrecoverable attitude where pilots no longer had the physical strength to overcome the forces involved.
I know how the stab trim system works. I worked on it (for the 757) for three years.
Yes, it applies to MCAS.
> the symptoms and recovery procedures are distinct
Nope. MCAS failure manifests itself as runaway trim, and the emergency procedures for it are exactly what is needed to recover from it.
1. the stab trim switches override the MCAS signals. Override. That means the pilot can trim to normal using the column mounted trim switches. The column switches will power the trim back to normal. No physical strength is required.
2. there's a "stab trim cutoff" switch on the console. That turns off the trim system. MCAS cannot bypass it.
The proof is the 3rd MCAS incident. The pilots trimmed it back to normal, and turned the stab trim system off.
That's all they had to do.
This is supposed to be a "memory item". The other two crews did not remember the memory item. Boeing even sent out an Emergency Airworthiness Directive reiterating this information. It was ignored by the EA pilots, who did everything wrong (including overspeeding the airplane at full thrust).
The narrative you wrote is the typical one in the mass media, which is utterly wrong. The proof of that is they ignore the 3rd incident which didn't fit the narrative.
I've talked with two 737 pilots about this. They agree with me, though I knew I was right anyway.
Food for thought: ever wonder why the stab trim cutoff switch is in a prominent place on the center console in easy reach?
You just took Boeing adding a secret system that can cause a plane to crash and then blamed the pilots who were unfortunate to be a victim of malfunctioning sensors and then put all the blame on them because pilots who didn't want to die inside a deathtrap aircraft figured out how to avoid their own death the moment they realized that the MCAS crashes were not an isolated incident?
What exactly are you accusing the pilots involved with the accident of? That they had some perverse incentive to die?
Nope. I wrote: "The implementation of it, however, wasn't very good"
> What exactly are you accusing the pilots involved with the accident of?
Not following the runaway stabilizer trim procedure. This is supposed to be a "memory item", meaning a checklist is not required.
There were 3 MCAS incidents:
1. crew trimmed to normal with the thumb switches, then turned off the trim system. Flew the rest of the flight, landed safely.
2. crew trimmed it back to normal at least 11 times (if I recall correctly) and never turned off the trim system. Crashed.
3. Boeing Emergency Airworthiness directive was sent to all MAX pilots. In a nutshell, it says to restore normal trim using the thumb switches then turn off the trim system. EA pilots instead turned off the trim system while the airplane was pointed down at full throttle. Crashed.
The two 737 pilots I talked to about this both asserted pilot incompetence.
Personally, I assign half the blame on Boeing and the other half on the pilots. Flying is not a joke. Not paying attention to an Emergency Airworthiness Directive is not acceptable.
> "The implementation of it, however, wasn't very good"
It was purposefully deceptive -- Boeing management actively decided to hide its existence from pilots.
The narrative that the pilots were at fault was Boeing leadership covering their ass.
The MCAS symptoms did not match runaway trim. It's not continuous. It stops and starts.
MCAS would also re-activate with a five second delay, just long enough to confuse pilots.
More importantly, deactivating the electrical trim system would make it all too easy to enter a regime where the pilots couldn't physically recover the plane.
This is a Catch-22 scenario: Activate the electrics and be killed by MCAS, or deactivate the electrics and be killed by physics.
I could go through each of your comments in this thread and point out how NTSB crash investigators proved that Boeing was directly or indirectly at fault in almost every aspect, but I don't want to write out ten pages. Others have done so already, more eloquently, and often with more colourful language. Most professional pilots were rightly furious with Boeing.
Boeing's arguments have been mutually exclusive with each other: "Just remember how to operate MCAS... which we hid from you!" and "Just disable the electric trim... which will pit you against forces you can't overcome"... "Which is not a problem because you can turn electric trim back one... but then MCAS will try to kill you again"... "It won't do that because it is dual redundant... an option... that nobody purchased... and we didn't even tell most customers about."
I expect this kind of self-contradictory "logic" from narcissists and sociopaths -- I know one of each and I'm now intimately familiar with the self serving arguments that make no sense, especially in combination.
> The MCAS symptoms did not match runaway trim. It's not continuous. It stops and starts.
I'll pick this one. I've heard it before. Runaway trim is uncommanded movement. It does not have to be continuous, it can stop and start. That behavior can certainly happen with a short circuit or faulty wiring. It's like the speaker connections on my home stereo - the connectors corrode over time, and the sound cuts in an out randomly.
The MCAS behavior absolutely presents as runaway trim behavior. Remember I worked for 3 years on the 757 stab trim system. I know what runaway trim is.
> deactivating the electrical trim system would make it all too easy to enter a regime where the pilots couldn't physically recover the plane.
That's why the instructions provided to the pilots said to use the thumb switches first to restore normal trim. All three crews had managed to do just that to restore normal trim. The second instance the pilots restored it ELEVEN TIMES and it never occurred to them to then turn off the trim system.
You might want to review the first incident. The MCAS system came on 2 or 3 times, and each time the crew used the thumb switches to restore normal trim. Then they turned off the trim system. The flight continued and they landed safely. They knew nothing about MCAS - they just followed the runaway stab trim procedure.
> I expect this kind of self-contradictory "logic" from narcissists and sociopaths
Being nasty doesn't lend credibility to your arguments.
This is exactly correct in the context of the decision as it played out, but stretches and re-engines are very common in commercial airlines. Changing that decision without reinforcing the safety culture probably would have ended in the same place.
Wasn't the whole point of the MAX that they had reached the limit of what their existing design had, but due to the demands of the airlines, as well as their current position in the market, they felt it was an easier idea to extend the lifespan of their already tired design by using software to overcome the physical limitations of the aircraft? I do understand that the airplane would have flown fine without the MCAS system, but then it would not have satisfied all their requirements.
Taking a step back, I think it's more than that. It's just the company structure. It remains to be seen if SpaceX and Tesla survive long term. But if they do, a lot will be attributed to the company structure that Elon designed. When you have a company that does stuff like this: https://www.youtube.com/shorts/1InUlHXv718
You just think to yourself, even if the airplane was completely safe, and they are incredibly safe, this is just not a great look. Both doors accomplish the task but little thought was put into the operator of the door. The little things matter and I notice them more and more everywhere I go with a lot of legacy American companies.
My point was more too highlight his approach to problems, not make the argument that this would have been successful or profitable for Boeing.
In fact, I would say there's probably a very narrow set of circumstances where his back to the drawing board approach can be deployed successfuly.
That said, the 787 Dreamliner remains statistically one of the safest widebody long-haul aircraft in commercial aviation history, which I think is a Counterpoint. It achieves this despite any more globally diverse supply chain, and moving production out of unionized Boeing manufacturing plants.
Safety by Design and design for manufacturability can help eliminate the possibility of quality issues during production.
Sure, that is no accident. Elon seeks out markets ripe for disruptive engineering innovation.
His approach probably wouldn't work as well if you threw him in as CEO of a random company like JC penny or Pizza Hut. Other CEO's are good at different things - like squeezing the extra 0.1% out of a 40 year old brand or product line
Now I'm thinking about him firing the pizza cooks and bringing in a crack team of engineers to redesign the concept of Pizza from first principles.
That's basically what happened at DOGE, there was a hilarious quote from one of the software engineers he brought in that they thought the government would be full of useless and overpaid people, like silicon valley.
Slight aside, he also has driven capability that was challenging to justify existence for, and was later removed re: Dragon 2 propulsive landing via SuperDracos, landing legs, and the ballast sled. I'm sure the Dragonfly programs matured their abort programs, but surely, that was a ton of time and effort wasted.
I find it mind boggling that you can 3d print rocket engines. I thought that the standard line is that 3d printing metal wasn't developed enough for anything serious. Not a mechanical/materials engineer, but if you can 3d print rockets what's off the table? Jet Engines and that's about it I think?
From the article links, I am amused that SpaceX uses cybertrucks to tow their rocket engines around the grounds and not a normal cheaper truck. They also do it in a totally uncovered trailer, which must be good for the guys taking pictures for forums. But isn't that also good for guys taking pictures for competitors / Russians/ China?
> I thought that the standard line is that 3d printing metal wasn't developed enough for anything serious.
This hasn't been true for over a decade. High value relative to weight, highly complicated internal geometry, or repeated need for one off parts are all reasons to choose 3d printing today for production parts.
I think by one way they are referring to cruise missiles i.e. the engine is only used once or twice. Once during test fire, and once in production environment.
3d printing metal has some strength downsides, I'm not sure what it is for the raptor engines, but I've heard other space companies claim ~5% less strength that traditional methods for aluminum structures, but that can be worth it in cases where you are able to make shapes that wouldn't be possible with traditional methods, or if you save enough money by printing it. Rocket engines often can benefit from intricate internal channels and shapes that you can 3d print as once piece with no way to do it via subtractive manufacturing.
It has mild strength downsides, but very severe fatigue and damage tolerance downsides. Knowing this, it makes sense that 3d printing tech would make headway in space industry but not (yet) in aviation
crack growth in metals is driven by microscopic flaws that cause high-intensity but very localized stress concentrations. Over time even low stress levels cause these flaws to grow to the point where they start causing strength problems. Even in traditional aluminum machined parts, increased surface roughness can have a large impact on fatigue life.
3D printed parts are chock-full of these microscopic flaws, porosity, and have horrible surface roughness (most parts you see in production are post-machined to improve the finish). Additionally, the repeated heating-cooling of the layers as they are deposited builds up residual stress in the part. All just due to the nature of how they are manufactured.
Is there a known source of internal flaws/porosity in an otherwise solid part? Presumably laser melting produces a puddle which shouldn't allow for internal pores, as long as it isn't printed too fast (or solidifies too fast, which is why I think most chambers are internally heated to near melting temp).
Re: surface roughness, I can understand that the powder grain size creates a sort of minimal structure size, and can in principle be the start of a crack if a surface grain gets knocked loose. Is that the sort of thing you mean? I can see that for any internal or external surfaces, and a rocket engine combustion is certainly applying a lot of heat and pressure on surface grains. Can this be alleviated by smaller grain sizes, or is there some limit there?
Re: repeated heating/cooling and internal stresses, this strikes me as just requiring standard post-printing stages like tempering to alleviate internal stresses.
I can't speak to the proximal cause of the roughness and porosity, but if you've ever held a raw printed aluminum part in your hand it is immediately apparent.
That said there are processes to deal with porosity like Hot Isostatic Pressure (HIP) treatment that basically crushes all the voids with immense pressure. This does come at the cost of dimensional accuracy though (HIP will compress the part somewhat).
Similarly, annealing a 3D-print to relieve residual stress does work, but it also will cause warping as those stresses are relieved. Again, sacrificing dimensional accuracy. Frontier AM companies have ways to compensate for all of these effects but it's a trial and error process for each part essentially.
At this point you're now stacking multiple processes on each other just to try to get to near-billet properties. Calibration Trials > Print > HIP > Anneal > Machine. The cost adds up quickly. It can be justified especially in non-fatigue-critical applications but it's no free lunch
SLS printers lay a layer height worth of powdered metal and fuse it with a laser engraver. Thee bed lowers one layer and the process is repeated. They don't bring materials used like inconel to full melting temperature, only do what it takes for the metal sand to clump together. That's one source of pores.
I assume you can just anneal or print then recast in sand or whatever, maybe even lostwax with Al as wax, but the point is that porosity in a print itself is inevitable with current powder based tech.
3D printed metal is now as strong as machined metal, assuming an identical alloy. The process has been pretty well perfected.
The strength loss comes from the fact that not all alloys are 3d-printing friendly, so you often have to compromise and you end up with a less than ideal alloy for your application.
Sure, but I mean what's the technical reason a material isn't it 3D printing friendly? Are we talking grain structure here? Is it something that can be at least partly mitigated by some post-printing heat treatments, like tempering?
Some alloys don’t like to be melted. If an alloy has a large solidification range, certain areas can partially solidify without the liquid part keeping up to fill in the gaps so to speak. This leads to solidification cracking / hot tearing. This is a simplification and only one possible cause, but there are literal books written about this kind of thing (I like Solidification by Dantzig and Rappaz). This is also why you see things like friction stir welding for rocket bodies. No melting means no solidification means no solidification issues.
One of the things that 3-D printing allows is a fine honeycomb structure. This comes with a somewhat bigger strength reduction, but a dramatic weight reduction. Less materials is cheaper.
Also subtractive manufacturing requires paying to melt away a lot of metal. 3D printing saves.
I don't know all of the ways in which SpaceX is using
GE9X aircraft engines have 3D printed low pressure turbine blades, so I think the view that jets are somehow exceptional is already disproven. There are real benefits to using additive processes for turbojet/fan applications: many jet components have intricate passages and bizarre shapes to conduct gasses, and they are hideously expensive to manufacture with conventional tools.
The thrust vector control (TVC) subsystem is usually considered a part of the engine. The major change the Soviet NK-33 underwent for a USA model was the addition of TVC, and the engine was named differently, so there are two engines, named differently, which mostly differ by the presence of TVC.
Raptors can be used without TVC. Be that by using differential thrust, or just not needing that - because rocket is controlled using other means, or other engines - it's possible. Tory Bruno specifically explained that he meant - among other things - that absence.
A picture of the engine working on the test stand can be that for the engine - or for the chamber, a significant component of the engine, with or without turbopumps involved.
Tony Bruno, when referring to the partially assembled engine, was complaining about the lack of engine controllers, fluid management, and TVCs [1].
In addition, SpaceX isn’t cheating by not including TVCs. They purposely designed their rocket to need a minimum of them and fully take advantage of the space savings the lack of TVCs affords them.
[1] “So, there is no need to exaggerate this by showing a partially assembled engine without controllers, fluid management, or TVC systems, then comparing it to fully assembled engines that do.”
Oh yeah, Tory Bruno made that gaffe of a comment publicly, and completely unprompted, before he abruptly quit. I had forgotten, but you’re right of course.
TLDW but TVC for rocket engines is usually achieved by like one hydraulic suspension rod each for X and Y axes(Y and Z in rocketry? idk) serving as parts of the engine mounting frame. It shouldn't add a lot to the system.
Yes, that's the usual way. With SpaceX, however, Raptor engines are gimbled with electric actuators.
And yes, the TVC adds very little to the complexity of Raptor 3's appearance: it still looks like science fiction, even when operating in Starship. Had TVC been present in the original SP1 image that had Tory accusing SpaceX of misleading everyone, it would have made no difference.
> TLDW
That video has beautiful shots of Raptor 3 firing and gimbling. It's worth watching.
> And the problems haven’t been completely ironed out: the first launch attempt of Starship’s flight test 13 was aborted automatically by the vehicle’s flight software at T-0 (right before liftoff) this past July when several Raptor 3 engines failed to start
And several engines failed to relight on the booster for flight 13. I believe ice in feed lines is viewed as the most likely cause.
I'm pretty sure that the heat exchanger is going to end up being one part they have to put back in. Pushing CO2 and H2O (both ices at prop temp) into the tanks just seems so ill-advised to me. The amounts of contamination are small, but there are just so many different ways that can go wrong.
> A full-flow staged combustion engine is very complex, and prior to the Raptor only two had been built, neither of which successfully flew on a rocket.
Isn't the Space shuttle main engine / SLS engine a full-flow staged combustion engine?
In SSME, most of the LOX never goes through a preburner.
The SSME uses the same kind of fuel-rich combustion chambers for both preburners. This presents a problem for the oxidizer side because any leaking along the shaft between ox pump and turbine in either direction would be catastrophic. This is resolved by an extremely expensive and complex multi-stage helium-purged rotating seal.
One of the cool parts about most FFSC designs, and the raptor in particular, is that they can afford slight leaking from high pressure to low pressure through any seal in the system and it's broadly safe, and only marginally reduces performance. This allows them to be made much more cheaply.
> There turned out to be less detail available here than I hoped.
I'm surprised the author was surprised that a component of a multi-billion dollar company which is vital to it's future success in the industry and is covered by US regulations governing information export wasn't available as a cut-away diagram.
According to Isaacson's biography of Musk, Musk relentlessly challenges the existence of every part in Tesla and SpaceX machines. He's willing to go too far, having to sometimes put a part back in.
Everything in the manufacturing process is also challenged to justify its existence.
This is how he managed to reduce the costs by 90%.
> According to Isaacson's biography
Isaacson’s “biographies” are glorified puff pieces. Musk is as unrecognizable in his as Jobs was in his.
Both Tesla and SpaceX had teams keeping Musk busy on bs just so that the engineering teams could do their work.
The second he took control, we got the cybertruck and the starship, the worse products both companies ever built (or attempted, in the case of the starship).
> Musk relentlessly challenges the existence of every part
This sounds insightful until you find yourself debating with the CEO for the eleventh time about how his high-school understanding of the physics involved breaks down in a particular case.
Musk is very lucky to be moving such quantities of money that his companies are big enough to protect themselves from him, if you ever wonder how Musk would fare on a tight budget, look no further than the Oceangate.
Do you remember when he bought Twitter and fired everyone, and the mass media and employee outcry was that a) the service would stop working and b) he would bankrupt the company, yet a few years later it’s massively more successful than Twitter ever was as a public business?
Regardless your thoughts on Elon, his drug habits, and his political brashness, I don’t think you can say he’s in any way close to the Oceangate guy. There is something legitimately special about him and his collective.
Yes, Twitter is so “successful” Musk had to write off 50% of his “investment” out of the gate, and had to come up with an AI-hyped merger with SpaceX to compensate the banks that went in with him.
The only reason Twitter has more active users is that it removed some of the protections for bots, in particular broad filtering coming from certain country involved in a war.
You don’t think Musk is any close to the Oceangate guy? Let’s review some interesting decisions by his companies then:
- Musk mucking around with the blue checks and the bot filters in Twitter skyrocketed the amount of scams in the platform.
- Tesla uses very strict NDAs and settlement to silence the reporting of accidents
- The infamous electric door handle that locks up Teslas when power goes out was an obvious point of failure, it was ignored, people died, and now several countries have legislation against it
- Reportedly Musk had safety lines and other safety features in the factories removed for serious reasons like “not liking yellow”
- Any understanding of how to parse public insurance data will show you Tesla’s have accident rates that are multiples of other brands
- The Starship, a vessel that is intended for human transport, has no safe abort system, no way to fit one in its current state, and no plans to modify that.
Just a reminder that even a very SpaceX-friendly count (in which flights that did not attempt to land are considered “good”) puts the current reliability rate at <40%.
As a naive boundary, for clearing the 97.5% predicted crew survival, SpaceX would need to fly in the order of 300 good Starship launches.
Those are just of the top of my head.
Independent web traffic analysis shows that the average X user spends 12 to 14 minutes on the site. It's impossible that these are bots.
Twitter is definitely not more successful now than before. So many people left and are gone forever.
I would read a deep dive though into the history of Twitter (with the financials) to understand better and I do get that for a single product company there really is a point at which you give up on finding the next big thing and just optimize on your main thing and you really just need a few dozen awesome people and a rotation of new hires to keep things rolling but not thousands of engineers.
Maybe I’m overstating “massively more successful” but to my understanding “X” has roughly twice the active use count that Twitter did, although that includes Grok.
That said, do you remember these kinds of articles?
> Musk summons engineers to Twitter HQ as millions await platform’s collapse
Source: https://www.washingtonpost.com/technology/2022/11/18/twitter...
> “Former Twitter employees fear the platform might only last weeks.” Melissa Ingle: “I don’t see how it lasts the month.” “All signs point to some catastrophic failure of the system, and very soon.”
Source: https://www.technologyreview.com/2022/11/18/1063467/former-t...
> Twitter ‘to lose 32m users in two years after Elon Musk takeover’
Source: https://www.theguardian.com/technology/2022/dec/13/twitter-l...
Elon was firing people left and right and literally physically destroying Twitter’s data centers. I remember hundreds of these hysterical articles and tweets that very clearly did not come to pass. He obviously did something more clever than the authors of these articles expected… is all I’m claiming.
I haven't posted anything on this HN submission yet, but all I'm claiming is that Twitter was so successful under Elon's management that he thought it was better to roll it into SpaceX than to keep it independent. Kind of like solar city was merged into Tesla to bail it out and then it winded down after the acquisition while nobody is looking.
Just claiming, you know.
Yes, and Tesla and SpaceX are both ridiculously overvalued by any fair measure.
But we can separate the financial inanity of his empire from the question, which is whether Elon is a capable engineering mind or simply an ‘Isaacson puff piece recipient’.
Isaacson could write the puffiest puff piece about me and I'd still never become a trillionaire.
Merging his companies into one will also reduce his workload. It's a sensible thing to do, regardless of their profitabilities.
> I don’t think you can say he’s in any way close to the Oceangate gu
They both have loud, stupid, and obviously wrong ideas about how hard diving in the sea is or isn't.
He also unbanned a lot of people and got Trump back, got to ride the AI wave with Grok, pushed paid subscriptions and implemented paying people for tweeting. I would argue growing the platform by bringing back people that were brought back for violating the original rules is not a win. Nor is attracting people to the platform that follow those people, Nor is riding the AI train.
And even with all of that, the new users, the AI, the paid subscriptions, None none of that actually fixed the major underlying issues that Twitter is not profitable. Jack Dorsey couldn’t fix it and neither did Elon. I think he just realized having a modern media platform he controls is more powerful than it making money. He inherited a platform built by someone else, and keeps the lights on with a skeleton crew. I don’t see that as a success
X is the 13th largest social media platform with 650m monthly active users. Sounds like a success to me.
But whose success is it? Twitter was ranked 13th largest in 2021 before he bought it. Let that sink in.
Twitter had 362 million monthly users in 2021. X has 650 million today. Looks like X has done well.
Considering he wanted to rescue those poor kids trapped in an underwater cave by building a submarine, the parallels are closer than you'd think...
> yet a few years later it’s massively more successful than Twitter ever was as a public business?
Twitter has certainly been a glowing success at becoming a right-wing propaganda chamber for Musk but as a commercial venture not really. Revenue is down 60% since Musk bought it.
https://www.businessinsider.com/elon-musk-approach-advertise...
The article doesn't mention subscription revenue. I subscribed to X in order to not see ads.
It also doesn't factor in the dramatically reduced costs. It's likely that X is already significantly more profitable than Twitter was. And with less dependency on advertisers, which is a huge win in and of itself.
Apparently 90% of the Twitter staff were simply baggage.
Uh, no, I do not remember how Twitter is massively more successful than it was as a public business. Can you enlighten me?
Look man I'm not a fan of Elon, but it's ridiculous to say the starship is the "worst". It's coming out of early development and has had some minor success already.
Ok, so which is the worst product SpaceX has made? And I don't think the CSAM producing twitter account counts in this context.
Falcon 1 is the obvious one.
The Falcon 1 was a necessary step in learning how to build rockets.
"coming out of early development" that has been going on for almost a decade...
I don't like Musk, butt that's not really that unusual. Starliner has been in development for much longer and still doesn't work.
>Isaacson’s “biographies” are glorified puff pieces. Musk is as unrecognizable in his as Jobs was in his.
i mean, you can also read liftoff and re-entry by eric berger and you will see the same kind of thing being mentioned.
It seems to me that partisan/political hate blinds some people so much that they are becoming ridiculous.
"This sounds insightful until you find yourself debating with the CEO for the eleventh time about how his high-school understanding of the physics involved breaks down in a particular case"
Musk has a bachelor's degree in physics from the University of Pennsylvania. While not a full scientist, I doubt that "his high-school understanding of the physics involved breaks down" anytime often.
Have you ever been in such a situation that you describe, or is this just your prejudice speaking? AFAIK the discussions in SpaceX revolve more around things like "can this part be 3d-printed", "do we keep the actuators for part X or can it just stick out into the wind" or "should we use landing legs or not", which have nothing to do with high-school physics and everything to do with actual engineering tradeoffs.
"the starship, the worse products both companies ever built (or attempted, in the case of the starship)."
This is what tells me that you are speaking in bad faith. Starship is not yet a finished product. Judging it now makes about as sense as judging Edison's lightbulb a year before it was introduced into the market.
Starship has several issues to fix, but we can already see that a) the Raptor engines are about the best on the planet, doubly so when considering their extremely low unit cost; b) the vessel itself is very tough and performed well even in really bad situations; c) the heat shield developed a lot and the last Starship (the one which was dragged to the Christmas Island) survived reentry in very good condition; d) the amount of control (belly flops, slowing down to hover) that they have over that huge thing is unique in the history of spaceflight.
> Musk has a bachelor's degree in physics from the University of Pennsylvania.
Clarification, Musk bought a B.A. in physics. In the Paypal S-1 in 2002, [1] Paypal's lawyers claimed that he graduated with a B.S. in Physics and B.S. in Economics in 1995.
Yet the actual degrees subpoenaed from UPenn indicate a B.A. in Physics and B.S. in Economics in 1997, two years later. He could not even remember the year he graduated or the degree he received just 5/7 years after their purported completion. I have yet to meet a single person who actually graduated from college who can not accurately recollect the year of their graduation, have you?
Most likely he did this because he was in the USA on a student visa and dropping out of UPenn in 1995 made him a illegal immigrant which his brother, Kimbal Musk, corroborated in a interview [2].
[1] https://www.sec.gov/Archives/edgar/data/1103415/000091205702...
[2] https://www.reddit.com/r/EnoughMuskSpam/comments/1az29vs/elo...
[dead]
He was the chief engineer and head of product at SpaceX and Tesla for over 20 years, respectively.
On Falcon 1 and 9 he worked directly on major components of the vehicles.
In Tesla, he was heavily involved in the design of every single product they came out with. He also micromanaged Model 3 assembly automation in 2017-18.
And you know this how? ...
He's dissembling a rumor from Tumblr from an alleged intern.
>Both Tesla and SpaceX had teams keeping Musk busy on bs just so that the engineering teams could do their work.
This is Tumblr origin nonsense, especially given that he's allegedly been involved with Engineering work he's not cleared for.
Neither Cybertruck nor Starship were designed by Musk.
Cut your crap.
>"According to Isaacson's biography of Musk, Musk relentlessly challenges the existence of every part in Tesla and SpaceX machines."
This removal of surplus-age is common in the automotive industry, and one of the reasons that cars are such an amazing value. It seems like Musk's remarkable ability to achieve cost reductions (at least in the aerospace context) is attributable to his pursuit of vertical integration. Airframers (aeronautical vehicle designers & manufacturer) are bound by the costs dictated by their component suppliers, especially after a configuration has achieved regulatory approval. SpaceX has managed to avoid being 'held hostage' by pseudo-monopoly suppliers.
>This removal of surplus-age is common in the automotive industry, and one of the reasons that cars are such an amazing value.
You say that and then a company like Ford releases this as their EV to show the world that they are competitive with Tesla.
[1]: https://youtu.be/C1dQtlrI7uU?t=70
How does something like this happen despite Ford knowing all the 'secrets' a company like Tesla or the Chinese know? I have a few guesses:
1. Its the structure of the company. In this video the presenter talks a lot about all the hoses and clamp connectors etc. The cooling department thinking they had to stay relevant made sure the car incorporated a design that had all this nonsense.
2. Maybe they didn't put their 'A' engineers on this car. Its plausible: the F-150 is their massive money maker. However this car was supposedly developed under some skunkworks program and yet here we are.
3. Maybe there was sabatoge from elsewhere (suppliers, middle management etc.) You watch a movie like Ford vs Ferrari and while im sure a lot is dramatized, I can't help but think man they were talking about the dysfunction of Ford way back then?!
Then we have Youtube documentaries like this one about the Ford Taurus SHO talking about how they screwed up so much that they had one chance left to get serious...like what? Shouldn't they be serious every day? Thats what the Chinese are doing.
[2]: https://youtu.be/5VTRhCC3gZI?t=56
The presenter further added how they had to ship entire engine blocks to Japan so that they could 'fix' them and unlock 80 more horsepower that Ford just left on the table. If factual, this should be a total embarrassment: You had to send your handiwork to a entity with a better reputation so that they could 'fix' your mess?
[3]: https://youtu.be/5VTRhCC3gZI?t=212
At some point, you have to acknowledge that the naysayers were wrong: Thinking (especially among the short community) was that Tesla had some cool ideas but their implementation was horrific, they couldn't just make up for 100+ years of institutional knowledge that the legacy companies had. The Tesla cars showed some of this thinking: quite poor build quality, poor after sale support, poor parts network. These things improved over the years but still isn't perfect.
But at the same time you have to acknowledge that the legacies suffer from their own problems that dont put them as far ahead as newcomers as you'd think. Sometimes a lot of that institutional knowledge becomes a liability when a paradigm shift occurs.
You can always get help from subject matter experts.
yes and no. Like you said, automotive and aviation industries are bound by a lot regulatory and path dependent constraints.
Elon's strength is his willingness to pull the plug and transition away from suboptimal solutions. This is bolstered by his willingness to double down.
Imagine if Boeing said "screw all this recertification technical debt for the 737 MAX airframe, we will start fresh. Customers can take it or leave it"
According to a version I heard, Boeing engineering did say more or less just that, at which point Southwest, the near-monopoly in some regions, said something like, "Oh yeah? Then we'll plan to leave it."
And Boeing upper management overruled the engineers.
Color me skeptical.
There was nothing wrong with the MCAS concept. The implementation of it, however, wasn't very good.
Unfortunately, two of the 3 crews did not understand the runaway stabilizer trim procedure. The 3rd crew did, and landed safely, and the media never reports on that.
The runaway stab trim procedure is a "memory item", meaning pilots shouldn't need a checklist to deal with it.
> The runaway stab trim procedure…
But doesn’t apply to MCAS because the symptoms and recovery procedures are distinct.
The MCAS system wasn’t documented, pilots weren’t trained on it, it didn’t indicate anything distinct in the cockpit, and it could rapidly put the plane into an unrecoverable attitude where pilots no longer had the physical strength to overcome the forces involved.
I know how the stab trim system works. I worked on it (for the 757) for three years.
Yes, it applies to MCAS.
> the symptoms and recovery procedures are distinct
Nope. MCAS failure manifests itself as runaway trim, and the emergency procedures for it are exactly what is needed to recover from it.
1. the stab trim switches override the MCAS signals. Override. That means the pilot can trim to normal using the column mounted trim switches. The column switches will power the trim back to normal. No physical strength is required.
2. there's a "stab trim cutoff" switch on the console. That turns off the trim system. MCAS cannot bypass it.
The proof is the 3rd MCAS incident. The pilots trimmed it back to normal, and turned the stab trim system off.
That's all they had to do.
This is supposed to be a "memory item". The other two crews did not remember the memory item. Boeing even sent out an Emergency Airworthiness Directive reiterating this information. It was ignored by the EA pilots, who did everything wrong (including overspeeding the airplane at full thrust).
The narrative you wrote is the typical one in the mass media, which is utterly wrong. The proof of that is they ignore the 3rd incident which didn't fit the narrative.
I've talked with two 737 pilots about this. They agree with me, though I knew I was right anyway.
Food for thought: ever wonder why the stab trim cutoff switch is in a prominent place on the center console in easy reach?
You just took Boeing adding a secret system that can cause a plane to crash and then blamed the pilots who were unfortunate to be a victim of malfunctioning sensors and then put all the blame on them because pilots who didn't want to die inside a deathtrap aircraft figured out how to avoid their own death the moment they realized that the MCAS crashes were not an isolated incident?
What exactly are you accusing the pilots involved with the accident of? That they had some perverse incentive to die?
> put all the blame on them
Nope. I wrote: "The implementation of it, however, wasn't very good"
> What exactly are you accusing the pilots involved with the accident of?
Not following the runaway stabilizer trim procedure. This is supposed to be a "memory item", meaning a checklist is not required.
There were 3 MCAS incidents:
1. crew trimmed to normal with the thumb switches, then turned off the trim system. Flew the rest of the flight, landed safely.
2. crew trimmed it back to normal at least 11 times (if I recall correctly) and never turned off the trim system. Crashed.
3. Boeing Emergency Airworthiness directive was sent to all MAX pilots. In a nutshell, it says to restore normal trim using the thumb switches then turn off the trim system. EA pilots instead turned off the trim system while the airplane was pointed down at full throttle. Crashed.
The two 737 pilots I talked to about this both asserted pilot incompetence.
Personally, I assign half the blame on Boeing and the other half on the pilots. Flying is not a joke. Not paying attention to an Emergency Airworthiness Directive is not acceptable.
> "The implementation of it, however, wasn't very good"
It was purposefully deceptive -- Boeing management actively decided to hide its existence from pilots.
The narrative that the pilots were at fault was Boeing leadership covering their ass.
The MCAS symptoms did not match runaway trim. It's not continuous. It stops and starts.
MCAS would also re-activate with a five second delay, just long enough to confuse pilots.
More importantly, deactivating the electrical trim system would make it all too easy to enter a regime where the pilots couldn't physically recover the plane.
This is a Catch-22 scenario: Activate the electrics and be killed by MCAS, or deactivate the electrics and be killed by physics.
I could go through each of your comments in this thread and point out how NTSB crash investigators proved that Boeing was directly or indirectly at fault in almost every aspect, but I don't want to write out ten pages. Others have done so already, more eloquently, and often with more colourful language. Most professional pilots were rightly furious with Boeing.
Boeing's arguments have been mutually exclusive with each other: "Just remember how to operate MCAS... which we hid from you!" and "Just disable the electric trim... which will pit you against forces you can't overcome"... "Which is not a problem because you can turn electric trim back one... but then MCAS will try to kill you again"... "It won't do that because it is dual redundant... an option... that nobody purchased... and we didn't even tell most customers about."
I expect this kind of self-contradictory "logic" from narcissists and sociopaths -- I know one of each and I'm now intimately familiar with the self serving arguments that make no sense, especially in combination.
> The MCAS symptoms did not match runaway trim. It's not continuous. It stops and starts.
I'll pick this one. I've heard it before. Runaway trim is uncommanded movement. It does not have to be continuous, it can stop and start. That behavior can certainly happen with a short circuit or faulty wiring. It's like the speaker connections on my home stereo - the connectors corrode over time, and the sound cuts in an out randomly.
The MCAS behavior absolutely presents as runaway trim behavior. Remember I worked for 3 years on the 757 stab trim system. I know what runaway trim is.
> deactivating the electrical trim system would make it all too easy to enter a regime where the pilots couldn't physically recover the plane.
That's why the instructions provided to the pilots said to use the thumb switches first to restore normal trim. All three crews had managed to do just that to restore normal trim. The second instance the pilots restored it ELEVEN TIMES and it never occurred to them to then turn off the trim system.
You might want to review the first incident. The MCAS system came on 2 or 3 times, and each time the crew used the thumb switches to restore normal trim. Then they turned off the trim system. The flight continued and they landed safely. They knew nothing about MCAS - they just followed the runaway stab trim procedure.
> I expect this kind of self-contradictory "logic" from narcissists and sociopaths
Being nasty doesn't lend credibility to your arguments.
This is exactly correct in the context of the decision as it played out, but stretches and re-engines are very common in commercial airlines. Changing that decision without reinforcing the safety culture probably would have ended in the same place.
Wasn't the whole point of the MAX that they had reached the limit of what their existing design had, but due to the demands of the airlines, as well as their current position in the market, they felt it was an easier idea to extend the lifespan of their already tired design by using software to overcome the physical limitations of the aircraft? I do understand that the airplane would have flown fine without the MCAS system, but then it would not have satisfied all their requirements.
Taking a step back, I think it's more than that. It's just the company structure. It remains to be seen if SpaceX and Tesla survive long term. But if they do, a lot will be attributed to the company structure that Elon designed. When you have a company that does stuff like this: https://www.youtube.com/shorts/1InUlHXv718
Compared to Airbus: https://www.youtube.com/shorts/KS9Xt6hmbTU
You just think to yourself, even if the airplane was completely safe, and they are incredibly safe, this is just not a great look. Both doors accomplish the task but little thought was put into the operator of the door. The little things matter and I notice them more and more everywhere I go with a lot of legacy American companies.
My point was more too highlight his approach to problems, not make the argument that this would have been successful or profitable for Boeing.
In fact, I would say there's probably a very narrow set of circumstances where his back to the drawing board approach can be deployed successfuly.
That said, the 787 Dreamliner remains statistically one of the safest widebody long-haul aircraft in commercial aviation history, which I think is a Counterpoint. It achieves this despite any more globally diverse supply chain, and moving production out of unionized Boeing manufacturing plants.
Safety by Design and design for manufacturability can help eliminate the possibility of quality issues during production.
> very narrow
He applied it to Tesla and SpaceX, which are very very different.
Sure, that is no accident. Elon seeks out markets ripe for disruptive engineering innovation.
His approach probably wouldn't work as well if you threw him in as CEO of a random company like JC penny or Pizza Hut. Other CEO's are good at different things - like squeezing the extra 0.1% out of a 40 year old brand or product line
Now I'm thinking about him firing the pizza cooks and bringing in a crack team of engineers to redesign the concept of Pizza from first principles.
> Elon seeks out markets ripe for disruptive engineering innovation.
I.e. products that everyone else dismisses as impractical/impossible. And then people complain when he's late delivering the impossible products.
Yes
That's basically what happened at DOGE, there was a hilarious quote from one of the software engineers he brought in that they thought the government would be full of useless and overpaid people, like silicon valley.
I mean, they're not wrong, but it's a harder problem for real reasons. A lot of over constrained problems leaning to bizarre Solutions
The decision to re-engine the 737 rather than design a new airframe saved the airlines a vast amount of money.
Slight aside, he also has driven capability that was challenging to justify existence for, and was later removed re: Dragon 2 propulsive landing via SuperDracos, landing legs, and the ballast sled. I'm sure the Dragonfly programs matured their abort programs, but surely, that was a ton of time and effort wasted.
You win some, you lose some.
If you aren't failing now and then, you aren't really trying.
I've been inspired by that to refactor my code so that function parameters are minimized (many pass TMI).
I find it mind boggling that you can 3d print rocket engines. I thought that the standard line is that 3d printing metal wasn't developed enough for anything serious. Not a mechanical/materials engineer, but if you can 3d print rockets what's off the table? Jet Engines and that's about it I think?
From the article links, I am amused that SpaceX uses cybertrucks to tow their rocket engines around the grounds and not a normal cheaper truck. They also do it in a totally uncovered trailer, which must be good for the guys taking pictures for forums. But isn't that also good for guys taking pictures for competitors / Russians/ China?
> I thought that the standard line is that 3d printing metal wasn't developed enough for anything serious.
This hasn't been true for over a decade. High value relative to weight, highly complicated internal geometry, or repeated need for one off parts are all reasons to choose 3d printing today for production parts.
> I am amused that SpaceX uses cybertrucks to tow their rocket engines around the grounds and not a normal cheaper truck
If they buy $131M worth of Cybertrucks[1], they might as well use it for something...
[1] https://www.businessinsider.com/spacex-bought-tesla-cybertru...
3D printed metal components are also in Hyper cars, Bugatti and Koenigsegg have implemented them for different components
https://newsroom.bugatti.com/en/press-releases/bugatti-refin...
Apple uses some 3d printed components at volume, i.e. the ultra 3 and 4 watch cases.
Beehive is 3D printing jet engines today, albeit small and potentially only going one way.
Why would you want a yet engine to go backwards?
I think by one way they are referring to cruise missiles i.e. the engine is only used once or twice. Once during test fire, and once in production environment.
3d printing metal has some strength downsides, I'm not sure what it is for the raptor engines, but I've heard other space companies claim ~5% less strength that traditional methods for aluminum structures, but that can be worth it in cases where you are able to make shapes that wouldn't be possible with traditional methods, or if you save enough money by printing it. Rocket engines often can benefit from intricate internal channels and shapes that you can 3d print as once piece with no way to do it via subtractive manufacturing.
It has mild strength downsides, but very severe fatigue and damage tolerance downsides. Knowing this, it makes sense that 3d printing tech would make headway in space industry but not (yet) in aviation
What's the current theory for why this is?
crack growth in metals is driven by microscopic flaws that cause high-intensity but very localized stress concentrations. Over time even low stress levels cause these flaws to grow to the point where they start causing strength problems. Even in traditional aluminum machined parts, increased surface roughness can have a large impact on fatigue life.
3D printed parts are chock-full of these microscopic flaws, porosity, and have horrible surface roughness (most parts you see in production are post-machined to improve the finish). Additionally, the repeated heating-cooling of the layers as they are deposited builds up residual stress in the part. All just due to the nature of how they are manufactured.
Is there a known source of internal flaws/porosity in an otherwise solid part? Presumably laser melting produces a puddle which shouldn't allow for internal pores, as long as it isn't printed too fast (or solidifies too fast, which is why I think most chambers are internally heated to near melting temp).
Re: surface roughness, I can understand that the powder grain size creates a sort of minimal structure size, and can in principle be the start of a crack if a surface grain gets knocked loose. Is that the sort of thing you mean? I can see that for any internal or external surfaces, and a rocket engine combustion is certainly applying a lot of heat and pressure on surface grains. Can this be alleviated by smaller grain sizes, or is there some limit there?
Re: repeated heating/cooling and internal stresses, this strikes me as just requiring standard post-printing stages like tempering to alleviate internal stresses.
I can't speak to the proximal cause of the roughness and porosity, but if you've ever held a raw printed aluminum part in your hand it is immediately apparent. That said there are processes to deal with porosity like Hot Isostatic Pressure (HIP) treatment that basically crushes all the voids with immense pressure. This does come at the cost of dimensional accuracy though (HIP will compress the part somewhat).
Similarly, annealing a 3D-print to relieve residual stress does work, but it also will cause warping as those stresses are relieved. Again, sacrificing dimensional accuracy. Frontier AM companies have ways to compensate for all of these effects but it's a trial and error process for each part essentially.
At this point you're now stacking multiple processes on each other just to try to get to near-billet properties. Calibration Trials > Print > HIP > Anneal > Machine. The cost adds up quickly. It can be justified especially in non-fatigue-critical applications but it's no free lunch
I'm not sure if it make sense but... is it possible to put the printer inside a vacuum chamber so there is no air to fill the internal bubbles?
Cooling would be an interesting problem. Atmosphere takes away the heat pretty readily.
You could have a cooling plate the work is on. But the higher temperature difference is apt to cause warping.
Vacuum filled pores would also be an issue.
I expect them to collapse due to surface tension or something.
[Slightly related https://en.wikipedia.org/wiki/Cavitation The problem is that the bubbles are filled with vapor instead of CO2 like in sparkling water.]
SLS printers lay a layer height worth of powdered metal and fuse it with a laser engraver. Thee bed lowers one layer and the process is repeated. They don't bring materials used like inconel to full melting temperature, only do what it takes for the metal sand to clump together. That's one source of pores.
I assume you can just anneal or print then recast in sand or whatever, maybe even lostwax with Al as wax, but the point is that porosity in a print itself is inevitable with current powder based tech.
3D printed metal is now as strong as machined metal, assuming an identical alloy. The process has been pretty well perfected.
The strength loss comes from the fact that not all alloys are 3d-printing friendly, so you often have to compromise and you end up with a less than ideal alloy for your application.
Sure, but I mean what's the technical reason a material isn't it 3D printing friendly? Are we talking grain structure here? Is it something that can be at least partly mitigated by some post-printing heat treatments, like tempering?
Some alloys don’t like to be melted. If an alloy has a large solidification range, certain areas can partially solidify without the liquid part keeping up to fill in the gaps so to speak. This leads to solidification cracking / hot tearing. This is a simplification and only one possible cause, but there are literal books written about this kind of thing (I like Solidification by Dantzig and Rappaz). This is also why you see things like friction stir welding for rocket bodies. No melting means no solidification means no solidification issues.
Eh. A lot of materials get their strength from being worked, which 3d printing doesn't do at all.
Try machining some printed 316 stainless! It’s basically pre work hardened from the thermal stresses!
Don't get good crystal/grain structure from 3d printing.
One of the things that 3-D printing allows is a fine honeycomb structure. This comes with a somewhat bigger strength reduction, but a dramatic weight reduction. Less materials is cheaper.
Also subtractive manufacturing requires paying to melt away a lot of metal. 3D printing saves.
I don't know all of the ways in which SpaceX is using
What makes jet engines less printable than rocket engines?
GE9X aircraft engines have 3D printed low pressure turbine blades, so I think the view that jets are somehow exceptional is already disproven. There are real benefits to using additive processes for turbojet/fan applications: many jet components have intricate passages and bizarre shapes to conduct gasses, and they are hideously expensive to manufacture with conventional tools.
The thrust vector control (TVC) subsystem is usually considered a part of the engine. The major change the Soviet NK-33 underwent for a USA model was the addition of TVC, and the engine was named differently, so there are two engines, named differently, which mostly differ by the presence of TVC.
Raptors can be used without TVC. Be that by using differential thrust, or just not needing that - because rocket is controlled using other means, or other engines - it's possible. Tory Bruno specifically explained that he meant - among other things - that absence.
A picture of the engine working on the test stand can be that for the engine - or for the chamber, a significant component of the engine, with or without turbopumps involved.
Tony Bruno, when referring to the partially assembled engine, was complaining about the lack of engine controllers, fluid management, and TVCs [1].
In addition, SpaceX isn’t cheating by not including TVCs. They purposely designed their rocket to need a minimum of them and fully take advantage of the space savings the lack of TVCs affords them.
[1] “So, there is no need to exaggerate this by showing a partially assembled engine without controllers, fluid management, or TVC systems, then comparing it to fully assembled engines that do.”
https://x.com/SawyerMerritt/status/1821679540973765026?s=20
Oh yeah, Tory Bruno made that gaffe of a comment publicly, and completely unprompted, before he abruptly quit. I had forgotten, but you’re right of course.
https://www.spacex.com/content/starship/holy-grail-of-rocket... at 13:35 has a good view of a raptor 3 with TVC, do you think that adds substantially to what is pictured at the top of the article?
TLDW but TVC for rocket engines is usually achieved by like one hydraulic suspension rod each for X and Y axes(Y and Z in rocketry? idk) serving as parts of the engine mounting frame. It shouldn't add a lot to the system.
I didn't have a particularly good view from 13:35 frames. TVC is a relatively simple subsystem, but it's there.
Yes, that's the usual way. With SpaceX, however, Raptor engines are gimbled with electric actuators.
And yes, the TVC adds very little to the complexity of Raptor 3's appearance: it still looks like science fiction, even when operating in Starship. Had TVC been present in the original SP1 image that had Tory accusing SpaceX of misleading everyone, it would have made no difference.
> TLDW
That video has beautiful shots of Raptor 3 firing and gimbling. It's worth watching.
> And the problems haven’t been completely ironed out: the first launch attempt of Starship’s flight test 13 was aborted automatically by the vehicle’s flight software at T-0 (right before liftoff) this past July when several Raptor 3 engines failed to start
And several engines failed to relight on the booster for flight 13. I believe ice in feed lines is viewed as the most likely cause.
I'm pretty sure that the heat exchanger is going to end up being one part they have to put back in. Pushing CO2 and H2O (both ices at prop temp) into the tanks just seems so ill-advised to me. The amounts of contamination are small, but there are just so many different ways that can go wrong.
> A full-flow staged combustion engine is very complex, and prior to the Raptor only two had been built, neither of which successfully flew on a rocket.
Isn't the Space shuttle main engine / SLS engine a full-flow staged combustion engine?
In SSME, most of the LOX never goes through a preburner.
The SSME uses the same kind of fuel-rich combustion chambers for both preburners. This presents a problem for the oxidizer side because any leaking along the shaft between ox pump and turbine in either direction would be catastrophic. This is resolved by an extremely expensive and complex multi-stage helium-purged rotating seal.
One of the cool parts about most FFSC designs, and the raptor in particular, is that they can afford slight leaking from high pressure to low pressure through any seal in the system and it's broadly safe, and only marginally reduces performance. This allows them to be made much more cheaply.
No, it's a fuel rich staged combustion cycle: https://en.wikipedia.org/wiki/RS-25
As it said raptor was the first and the SLS engines are way older.
I think China has made a full flow engine too.
3d printing metal has come a long way!
It’s extremely premature to celebrate something which hasn’t been shown to work in its intended application, nor at the original specs.
Given the original specs are the kinds of numbers Musk pulls out of his behind, I wouldn’t expect it to anytime soon.
It’s certainly an achievement of SpaceX engineering what they can do despite his constant meddling.
> There turned out to be less detail available here than I hoped.
I'm surprised the author was surprised that a component of a multi-billion dollar company which is vital to it's future success in the industry and is covered by US regulations governing information export wasn't available as a cut-away diagram.
Someone was reverse engineering the engine in public on a spacex owned website.
It got taken down.
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