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Building a rocket engine from scratch

blog.ablspacesystems.com

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Re: Building a rocket engine from scratch

#41

Post by avmich »

mdorazio wrote: post #40

Great post on building extremely complex hardware from scratch. 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 metri…

SpaceX is certainly giving a hard time to its competitors, but it doesn't mean they shouldn't exist. Some of them may actually follow the same route, designing reusable hardware and reducing launch costs. SpaceX took 20 years to become relying on robustly reusable system; maybe some other companies reach a similar state sooner.

Re: Building a rocket engine from scratch

#43

Post by z3t4 »

The science of pressure chambers have also advanced, we could just pump whatever material, like liquid air into a pressure tank and then load it into the rocket. No mixing or pumping needed just open the valve and let the pressure out and you will have a very cheap and simple rocket.

Re: Building a rocket engine from scratch

#44

Post by sr-latch »

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...

and if you're ever writing 1DoF codes yourself, NASA's CEA for propellant chemistry calculations is freely available https://cearun.grc.nasa.gov/

Re: Building a rocket engine from scratch

#46

Post by choeger »

mdorazio wrote: post #40

Great post on building extremely complex hardware from scratch. 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 metri…

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 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.

Re: Building a rocket engine from scratch

#47

Post by trhway »

adrianN wrote: post #38
Horffupolde wrote: post #25

Earlier quoted context omitted.

English is great for technical writing.

I think English has too many ambiguities to be well suited for technical writing. There are efforts like https://en.wikipedia.org/wiki/Simplified_Technical_English but they don't have a lot of adoption.

In USSR/Russia we had a stand-up comedian (Zadornov) who in one of his jokes was explaining how the conciseness of the language is advantageous on the battlefiled.

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)

Re: Building a rocket engine from scratch

#48

Post by sr-latch »

z3t4 wrote: post #43

The science of pressure chambers have also advanced, we could just pump whatever material, like liquid air into a pressure tank and then load it into the rocket. No mixing or pumping needed just open the valve and let the pressure out and you will have a very cheap and simple rocket.

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 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.

Re: Building a rocket engine from scratch

#49

Post by z3t4 »

sr-latch wrote: post #48
z3t4 wrote: post #43

The science of pressure chambers have also advanced, we could just pump whatever material, like liquid air into a pressure tank and then load it into the rocket. No mixing or pumping needed just open the valve and let the pressure out and you will have a very cheap and simple rocket.

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)

Re: Building a rocket engine from scratch

#50

Post by dotancohen »

duped wrote: post #29
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...

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.

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