Building a rocket engine from scratch
blog.ablspacesystems.com
blog.ablspacesystems.com
At least you don't have to retype the whole sentence. ;)
Recently I had to write in Russian (my native language) a tech doc of many pages. That is after 26 years of tech writing only in English (my 2nd language). That experience resulted in an epiphany for me on why Russia is so technically behind as I suddenly understood what Zadornov was talking about :) In comparison to English, Russian sucks, to say the least, as a technical language. All the things which make Russian great for literature and poetry make it terribly inefficient for tech writing, miles and miles behind English. If anything, I think English is the secret sauce of the success of the Western technical civilization.
(For older Russian speakers - if you remember another Zadornov's "dolbani pljuhalkoj po kuvykalke, prikin'sja vetosh'ju i ne otsvechivaj" - now I think it really comes from the same weakness of Russian for technical communication)
Check it out, the things for which a western scientist or engineer is given credit, were discovered/invented much earlier by soviet counterparts! What do you think about Kotelnikov?
But it is a common and easy trap for a lot of nationalities to fall into, because there are innumerable discoveries that happen before (and/or independent of) the canonical "inventor" (and you're automatically more likely to know the independent inventors if they come from your country!).
Regarding Kotelnikov specifically: You could make the same argument (re: discovery of sampling theorem) for Whittaker, who published in 1915; ultimately, though, the whole debate is mostly pointless.
I strongly believe that no single inventor so far was truly "significant", in that his nonexistence would have delayed science as a whole by more than a decade or two (consider Newton/Leibniz for calculus, Einstein/Poincaré/Hilbert for relativity, etc.).
People should not focus so much on WHO discovered a particular fact, because the cold truth is that it's mostly a personality cult and that any single scientist that ever existed, no matter how brilliant, was still replaceable (from a "human progress" kind of view). Which does not stop me from being a Fermi-fanboy.
But I completely agree with you that language did not really hinder USSR science.
I found the MBA.
Nope, thats a false positive.
Also cutting the quote there heavily twists the meaning: I'm not saying those scientists were replaceable as persons, just that their effect on all of humanities scientific progress was.
Many persons have a strong notion that we owe certain discoveries to a specific person, but this does not even hold up to cursory examination in my view (those discoveries would have been made in short order by someone else).
I'm very curious though if you have counterexamples, or think the premise is otherwise flawed.
I suspect we can find counterexamples if look enough, though to truly present some a serious knowledge of science history is needed.
What do you think of contributions of Srinivasa Ramanujan and George Cantor?
For Cantor, I think the maximum delay in results would've been even less, but maybe the impact (=> set theory) bigger during that time?
I will concede that there is a lot of value that any specific scientist provides just from correspondence/communication alone which is very hard to quantify.
I also think if you took away whole institutions from a hypothetical timeline, like, e.g. the University of Göttingen, then the impact could be quite clear (more than just a decade of lost progress in some field). So maybe you could argue that some founders of prodigious institutions helped human science more than any single scientist? But this is highly hypothetical (if the people AT those institutions would have existed regardless). Also a distasteful thought (to me).
If Sergei Korolev didn’t die suddenly and unexpectedly, the Soviets may have actually won the race to the moon. Their space program atrophied afterwards and struggled to succeed.
I really wonder at the modern obsession with associating people with cattle.
Computer servers can be divided into two roles in modern technical architectures… they are either “cattle” or “pets”. Pets are computer servers that have names and are always up. Cattle are servers that are transient, spun up and down as needed and do not necessarily have any long running identity/name as a component of a larger system.
http://cloudscaling.com/blog/cloud-computing/the-history-of-...
The poster is making a critiques of how by treating historical persons contributors as cattle, we are considering them a dispensable, unnamed, a commodity that is easily replaced and interchangeable and missing their very real contribution, value, and humanity.
I do find the Great Person theory and its critiques fascinating. I think of how Kennedy navigated the Cuban Missile Crisis and avoided nuclear war, then I think of how the sheer consensus of the US military after WW2 was to build a huge nuclear arsenal and use it any possible chance.
Beautifully said.
- Yellow is bad
- The 60s were awesome
Out of context of the thread, your second point was amusingly interpreted to be about LSD.
I have an incomplete set of the radlab textbooks. They're still useful even today, and have a really careful pace to them because they were written for a generation for whom electricity was still relatively new.
One of the things that is a real shame is just how artfully bound those old books are. Leather, thick but smooth paper, etc.
Once again people learn the hard way that it's valuable to have tight feedback cycles and embedded knowledge on your team.
Of course, not everything can ever be anticipated, so tight feedback loops are fantastic when you can get them.
I've been tinkering with 3D printers long enough that I've trivially halved print times after seeing long print time predictions. Lots of my brackets and parts fits together on first try and needs no supports. Rapid turnaround did help in _acquiring_ those skills, but now I could just waterfall little projects and tight looping is not that important.
I interact with a lot of people like the author in the article from this industry. And while yes, their worklife balance skews "work", they all have interesting hobbies and find time to hang out with friends, go on adventures, and live a pretty full life.
Unless you're on the Starship team at SpaceX. Truly, hats off to y'all at Boca Chica some intense hours you are pulling there.
But such employees will sometimes leave and build their own stuff. Which they'll very likely succeed at, exactly because of the approach they have.
Ultimately, I think these are a bit different fields/markets, and a bit different kind of jobs. Engineers creating real unique new stuff, vs more "bland" engineers just being a hand to accelerate someone's efforts. I worked in both roles and can clearly see pros and cons of both. Largely depends also on life phase one's at, which one would a person prefer.
Microsoft was known at some time to provide good environment for their engineers so they could focus on making the product, instead of learning the business side of things, which both removed distractions and reduced the incentives to leave and do things without well-learned habits.
Also, a rocket engine is a core feature of a rocket (literally cannot fly without it). If they started development of this engine in 2018, that's *six years* of work to get to their current state. Imagine spending 6 years on a core feature of an app that you'd consider "min-viable", and everytime you had a bug the computer you compiled the code on spontaneously combusted?
Eventually though, it became just a job, as it always does. And then the gaze turned elsewhere, looking for more enjoyment and satisfaction.
Far from a hard lesson, it was one they designed the company around.
At the same time I hate to be that business guy, but both this blog post and the abl site are missing a good answer to my first question: Why? Given that SpaceX exists and is quickly approaching feasibility of Starship on top of Falcon, what is the primary goal of this rocket system? How will it compete? Who will its customers be? Is it getting its metric ton payload to orbit faster/cheaper/easier? Is this "from scratch" engine design superior to existing designs in some way? What is its current ISP? Is Jet-A + LOX a better fuel choice given expected mission parameters?
I'd love to see a blog post that tackles these kinds of questions.
From the investor: SpaceX might fail. Even if there Falcons are pretty much unbeatable now, you don't know what's going to happen with Starship. And even the Falcons could conceivably be grounded for years after some hypothetical flaw is found. More likely: With the price reductions made by SpaceX, the market will grow and there will be more than enough clients.
From the inside: Because it's a fun challenge and literally rocket science, of course.
Always look for other ways to compete besides price. (not intended to be as preachy as it sounds :-)
Elon before the first Dragon worked was talking about reducing launch costs by a factor of ten.
However, a bunch of places rent out time on those machines. Draw up your rocket, and get a quote. Price is generally cc^2 volume
Metal is not cheap. Make a few out of plastic to verify dimensions.
But don't forget that the laser sintering of metal powders might result in design constraints not present in plastic printing!
3d printed titanium goes for 300-400 USD/kg, steel is a bit cheaper at ~150 USD/kg for most inconel grades.
PCB mounting outlines can be exported from above 3D CAD and imported to EDA tools such as Altium and KiCAD; KiCAD is fine unless you're doing DRAM or PCIe. Same PCBWay and JLCPCB takes your design, and optionally assemble PCB with parts for you.
That should take you to first 2-3 working units at ~$500 and up to few dozen beta units with zero initial cost and much inflated unit costs, and I guess beyond that involves significant human resourcing and networking problems outside of PoC hardware scope.
For the electrical side, there are plenty of schematics online that you can try to copy or use as a starting point. And the CAD side can be a simple box with snap fits. I'd recommend OnShape if you're just starting out since it's the lowest barrier of entry, but Fusion 360 is also good. All in, it should be <$150 for the PCBs + Components + 3D Prints.
After you get the satisfaction of seeing your device charge from something you made, then you'll start getting the itch and find more excuses to make things.
Meaning that instead of thinking "how do I 3D print this?" you should be thinking "how do I manufacture this?"
Something as simple as making a drawing, specifying the material and quantity needed and then going on reddit/r/manufacturing and asking "how would I build 50 of these" can provide very useful answers, even if you have to do a bit of research later to understand what you've been told.
Inconel powder is also Not That Great for your health and at the particle-size the printers rocket companies use, you need full PPE to safely handle the loose powder floating about.
The machines themselves are also expensive. Think in the millions of USD. EOS, SLM, and Velo3D are key players in this market. They require a fair bit of space, and training to use correctly.
You probably need a mechanical engineer who is well-versed in materials science and has a tolerance for finicky machines that constantly breakdown.
Then you have the metal powders. Which, also potential million or two.
And then you have all the associated infrastructure needed. High voltage power. Gas (Nitrogen, Helium, Argon, etc etc) in the thousands of liters per month. Waste disposal. Safety (some alloys are flammable in their powder form). Climate control (the powders are sensitive to the environment. Humidity will quickly destroy your powder supply). Tooling (the base-plates metal printers used are machined from solid blocks of steel).
And last but not least, any of the post-printing work. Heat treat. Coatings. Analysis. CNC Machining.
3D Printing metal on industrial scales is a CAPEX intensive endeavor, and not for the faint of heart.
And also the other engine mentioned isn't an aluminum one.
After the printing itself, one will have to remove to loose powder, which for small cooling channels in the walls of the combustion chamber is very challenging and time consuming.
After that, some post-processing may also be necessary. One process for achieving the greatest strength is hot isostatic pressing, when the part is baked in a furnace in a retort filled with a very high pressure inert gas.
Specifically for rocket engines, it is also desirable to have a layer with the high heat conductivity on the inside, typically made of a copper-based alloy, and the external structure from a higher strength material. This means either bi-metallic printing, which is a rather niche process, or some metal deposition process over the printed part.
In addition to this, there is usually quality control, for example, high resolution industrial computed tomography, to make sure that the invisible internal features have been fabricated and cleaned out correctly.
In addition to the additive steps, it will also be necessary to machine the features which are impractical or impossible to build sufficiently accurately.
Together, these steps add to a significant cost.
Some of the above processes can be seen in this video: https://www.youtube.com/watch?v=7pXEf0wHU1Y
I don't mean this as an insult, but why did they hire you? It's obvious now that you were a great choice, but from your background story I wouldn't have guessed that to be true.
The writer probably was referring to the fact that he was just a regular mechanical engineer and not a Propulsion Engineer.
We work for a lot of launcher companies, but ABL is the most interesting for me (even though we do relatively little for them). The containerised approach to the entire system is a really clever adaptation of existing methods to create a rapid launch system.
It seems the design choices are rather conservative, which is entirely justified by the "from scratch" part for the first engine. I'm sure subsequent designs will be more bold and adventurous.
Keep up great work!
Also, pressure fed rockets have always been a fairly terrible design. Pressure feeding requires heavy tanks, and incurs a big mass fraction (dry mass / wet mass) penalty. Outside of rare cases, it's only used for ground testing.
There is also a lot of control that goes into flying a rocket, and pressure-fed rockets are kind of hard to control.
On the site you can see: launch on demand, simple system that can go anywere, tactical launchs.
This is for nukes or similar stuff.
It's the Astra business model, hopefully without the Astra failure model.
(And practically speaking it's because you can't bootstrap a heavy lift launch company on VC funding or even a SPAC - the small sat launcher is a proof-of-concept for your medium/large launch vehicle).
The SDR world is incredible
edit: looks like they took down all the passive radar doppler videos : https://othernet.is/products/kerberossdr-4x-coherent-rtlsdr
lol, engineering humor