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Building a rocket engine from scratch

blog.ablspacesystems.com

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Re: Building a rocket engine from scratch

#71

Post by myrmidon »

avmich wrote: post #65
myrmidon wrote: post #61

Earlier quoted context omitted.

> 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 b…

> 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?

I think some of Ramanujans results might have come significantly (more than a decade!) later without him, but I don't think that this would have held up mathematics as a field significantly.

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).

Re: Building a rocket engine from scratch

#72

Post by duped »

dotancohen wrote: post #50
duped wrote: post #29

Earlier quoted context omitted.

If there's two things I've learned about chemistry from ExplosionsAndFire in YouTube it's - Yellow is bad - The 60s were awesome

Just yesterday I pointed out a yellow flame to someone as evidence of incomplete combustion on the gas stove. Laughing I showed them your timely comment. Out of context of the thread, your second point was amusingly interpreted to be about LSD.

I'm sure a lot of the chemists making things go boom in the 60s were also on LSD, for what it's worth

Re: Building a rocket engine from scratch

#73

Post by spxneo »

sr-latch wrote: post #45
spxneo wrote: post #7

now all that is required is a github for passive radar...for educational purposes

https://github.com/krakenrf/krakensdr_docs/wiki/ The SDR world is incredible

Is this the codebase that they took down ???! Yes to all of the things you can do (minus the passive radar stuff beyond educational purposes that is ;)

edit: looks like they took down all the passive radar doppler videos : https://othernet.is/products/kerberossdr-4x-coherent-rtlsdr

Re: Building a rocket engine from scratch

#74

Post by quartesixte »

greenish_shores wrote: post #57
nothercastle wrote: post #35

Earlier quoted context omitted.

Employees who are married to their job are the best employees. Just like in a real relationship you can treat them like shit and they mostly stay married

Honestly I did read that as "Employers who are married to their job are the best employers". You probably won't treat them like shit, but they'll still remain married anyway. 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. E…

It's a lot harder to just spin-off and "build your own stuff" in hardware though, which is I think what keeps the "married employees" around longer. The startup costs are much higher and riskier. And you need a lot more people. Building that rocket engine from scratch probably required around 50 - 60 people to really get it all together.

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?

Re: Building a rocket engine from scratch

#75

Post by quartesixte »

z3t4 wrote: post #49
sr-latch wrote: post #48

Earlier quoted context omitted.

This is absolutely not true - injector design is the most important aspect of designing a thrust chamber. Poor mixing of propellants leads to severe combustion instability, which often leads to explosions. Even the earliest space programs did significant testing on propellant choices and injector designs (see Ignition! by John D. Clark) Also, pressure fed rockets have always been a fairly terrible design. Pressure fe…

just drop the tank when the weight/thrust ratio is too low. Thanks for the book suggestion! (have not read it yet)

The rocket equation would like to have a word with you. The wall thicknesses required to create rockets with enough thrust to get to orbit on pressure-fed would render the rocket physically impossible.

There is also a lot of control that goes into flying a rocket, and pressure-fed rockets are kind of hard to control.

Re: Building a rocket engine from scratch

#76

Post by quartesixte »

criddell wrote: post #58

> You might call me an unlikely candidate to lead an engine program from scratch, but I was hired by ABL in 2018 to do just that. My background was in commercial aircraft interiors, web development, semiconductor fab fluid components, and SpaceX Falcon 9 hydraulic systems. 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'…

Seems like from the blogpost that the writer and the founder were part of the same cohort at SpaceX. I would hazard a guess that they became friends, and had planned to do this together, and he joined ("hired") as soon as feasible for him (or the founder gained enough traction to pull him away from SpaceX).

Re: Building a rocket engine from scratch

#77

Post by consumer451 »

hinkley wrote: post #64
choeger wrote: post #46

Earlier quoted context omitted.

From the outside: Diversification is always great. Build a whole ecosystem of small-scale rocket manufacturers instead of one big monopoly. That will foster competition and innovation. 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…

SpaceX was looking to reduce prices to orbit by 10x, and they are currently sitting at around 6.7x.

Just curious, how did you calculate the 6.7x?

Re: Building a rocket engine from scratch

#78

Post by buescher »

mhh__ wrote: post #34
buescher wrote: post #24

NASA's report server is a national treasure, especially the material from the 50s and 60s that he references. Some of the most crisp and succinct technical writing you'll find, and you can infer a lot about how they ran projects. Declassified NRO reports are also very good - you can see the Lockheed Skunk Works principles in action. Example: https://www.nro.gov/Portals/135/documents/foia/declass/WS117...

Lots of academic and engineering things from back then are great. 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.

The rad lab series basically set the program for electrical engineering ever since. I have a couple too. They are also available on archive.org.
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