12 ms·

How to start a rocket engine

357 points by Jarlakxen 4y ago

ragebol 4y ago
I could watch stuff like this all day. Tim's stuff is so great. Easy to be jealous of, since being YouTuber seems easy, but to make quality content, it really can't be. And then he's going around the moon, it's really mind blowing to see the success he's had. His interviews with Musk are a treasure trove as well, whatever you think of Musk.
- adolph 4y ago
  To pile on the Tim Dodd praise, be sure to check out his music too (which is used in the videos). Solid stuff that reminds me of Tycho. So glad he got picked for the Dear Moon mission.
- samwillis 4y ago
  > His interviews with Musk are a treasure trove as well, whatever you think of Musk. My main take away from those interviews is just how knowledgable Tim is, he's able to engage in low level and in depth conversations about how these engines work. It's not just superficial high level knowledge from making videos, he is thinking himself how to optimise and improve these things, and leading that conversation. The passion for it is electric. In another life Tim would have been an incredible engineer, but that value he brings as an educator is immeasurable. Thats how he has earnt his way to a space flight. (They also show that the common argument that Elon doest know his stuff is wrong (at least for rockets), but I really don't what to derail this conversation into that.)
  - oger 4y ago
    It's absolutely worth to go on a tangent here - Tim did a great job in explaining Elon (or showing him to the public in a probably not too filtered way).
  - ragebol 4y ago
    Absolutely. Imagine if all journalists had this level of depth in all of the topic they covered? I don't think that's possible though.
    - prox 4y ago
      I agree. You need that intersection of interest, presentable qualities (listening, digesting,responding, speaking) and quest for accuracy. Hard to get those all in one person.
    - nordsieck 4y ago
      > Imagine if all journalists had this level of depth in all of the topic they covered? I don't think that's possible though. It helps a lot that Youtube seems to have become the home of long form video. Not really something that fits into traditional media. But for the people that really want to dive deep into a topic, it's great that there are now often high quality creators that cater to those tastes.
      - ragebol 4y ago
        Does not fit in traditional media indeed. When I was a kid/teen, Discovery Channel, at least in my native Netherlands, had some interesting content. I could also gobble up something like How it's Made all day. Content like Tim's could definitely fit in there too. YouTube enabled everyone to publish this type of content, for good and bad...
        kitsunesoba 4y ago
        When I was younger I loved shows like Modern Marvels on History Channel that presented the engineering behind the various amazing everyday things that we take for granted in a format accessible to the layman. It's depressing that good shows like that were killed off in favor of the "reality" TV and conspiracy/aliens/etc show junk food that took over Discovery and History from the mid-00s onward.
  - LargeTomato 4y ago
    To be honest he's regurgitating a lot of information. He has large gaps in his knowledge but presents himself as extremely knowledgeable. Understanding a rocket engine as a layman is easier than understanding a diesel engine. EDA acts like he's a genius but he is not. I work in space. Some of my coworkers have met EDA. He is insufferable and extremely arrogant. A very difficult person to be around.
    - peterfirefly 4y ago
      > He has large gaps in his knowledge Yes. > but presents himself as extremely knowledgeable. No.
      - LargeTomato 4y ago
        Yeah he has an extreme level of confidence. Tweeting Elon about how to architect the landing fins to use "fish scale biomimickry"? That's ridiculous.
        LawTalkingGuy 4y ago
        He didn't. He tweeted that he's surprised the tiles don't need to be overlapped to avoid blowing off but didn't suggest that Elon change them. https://mobile.twitter.com/Erdayastronaut/status/1442631530224959488 https://mobile.twitter.com/Erdayastronaut/status/14426315302...
      - JshWright 4y ago
        Perhaps he has gotten better at that in recent years. I got put off his early content for the very that very reason and haven't bothered to go back.
    - sho_hn 4y ago
      > but presents himself as extremely knowledgeable I don't get this sense at all. I've been watching his channel for a couple of years, and I've consistently found him to portray himself as a fan/enthusiast trying his best to understand and summarize complex information he doesn't have first-hand knowledge of. He's never pretended to be an engineer. I think the value is in getting inspired to dig deeper when he shows you something interesting.
- localplume 4y ago
  He, like most big Youtubers, probably have a large crew of people working with them. The article was written by Trevor Sesnic, the video was likely edited by others, I don't know if he did the graphics, but Tim still did a lot (and arguably did the most fun stuff). Smaller Youtubers need to do all of that, and from what I've heard editing is the absolute worst given how time consuming it is. Many Youtubers struggle with burnout centered around how time consuming editing becomes. Tim's content is really great though, and he does a fantastic job of explaining complex topics in a welcoming way. Very similar to smartereveryday IMO, where it is just really engaging and informative content presented in a great way.
  - MichaelZuo 4y ago
    From the about page: > In 2019 the team grew from just Tim to a small army of incredible helpers who make this website amazing, the videos higher quality, and help foster a fun and positive online community. So the 2017-2019 period where the channel took off was all done by him solo, apparently.
    - somenameforme 4y ago
      I'd also add this standard. Another amazing YouTuber is Veritasium. He went from [1] to [2]. The production quality is more than slightly improved, but the "spirit" remains identical. And I think that spirit is what drives success or failure. The production quality is just icing. [1] - https://www.youtube.com/watch?v=JUJPyQtoB5E https://www.youtube.com/watch?v=JUJPyQtoB5E [2] - https://www.youtube.com/watch?v=5eW6Eagr9XA https://www.youtube.com/watch?v=5eW6Eagr9XA
      - Retric 4y ago
        Veritasium videos are often subtly misleading which really annoys me. It’s great for views, but terrible for science education.
        jaywalk 4y ago
        Whenever he drops a new video, I just look for the "Here's how Veritasium was wrong" videos to get the real story.
- deleted 4y ago
  [deleted]
- lhoff 4y ago
  He recently was a guest in Lex Fridmans podcast. https://lexfridman.com/tim-dodd/ https://lexfridman.com/tim-dodd/
- dotnet00 4y ago
  Tim's stuff certainly has the information content nailed down better than most typical "science" youtubers, but he comes off as slightly overexcited at times, which brings up negative associations with typical misleading pop science rags for me.
- speed_spread 4y ago
  > whatever you think of Musk Musk is a clown but I'll give him one thing: he cares about technology. That's something that very few modern CEO in big tech have and probably gives him the edge in making his project successful.
  - sangnoir 4y ago
    > Musk is a clown but I'll give him one thing: he cares about technology. His hot takes on software / software architecture have been disappointing[1], and made me question the validity of his assertions in domains I have no expertise in (rocketry, computer vision and manufacturing). 1. Also, he wants to remain in charge of "Servers and Software" at Twitter even after (if?) He steps down as CEO.
    - speed_spread 4y ago
      I was thinking of pre-Twitter Musk. I'm not sure what game the clown is playing now or even if it's a game at all anymore. It's so bad that it's almost like a trash artistic performance. GG Allin billionaire.
- hoot 4y ago
  Did anybody else feel like the musk interview got really awkward towards the end? It seemed like he became really bored of it and just shut down.
  - raylad 4y ago
    Tim was trying to be too knowledgeable and not letting Musk shine enough. I would be surprised if Musk gives him another interview any time soon.
oger 4y ago
Definitely among one of the great pieces he has produced. Highly informative and educational. He really finds the right tone and this long piece never gets boring for a second. Also from a production perspective his animated engine charts are top and visualise the point he is making. BTW his interviews with Elon Musk at Starbase are also a must see (some clips included in this video as well). You really start to see and understand how Musk works - and it's not as bad as media is trying to make him. His engineering principles are really interesting and can be applied to many scenarios. It's this level of abstraction that makes the difference and gives him a competitive edge.
mackevers 4y ago
[flagged]
- dale_glass 4y ago
  Is that ChatGPT? Edit: Yup, I got something very close to that: https://imgur.com/PX0MmCR https://imgur.com/PX0MmCR
mannykannot 4y ago
There's lots of information here on the sequence of operations followed in starting the F1 motors of the Saturn V first stage: https://home.kpn.nl/panhu001/Saturn_V/Saturn_V_info/F-1_engine/F-1_engine_ignition_sequence.html https://home.kpn.nl/panhu001/Saturn_V/Saturn_V_info/F-1_engi...
- mtlebe 4y ago
  Related video: How To Start The Massive F-1 Rocket Engine from Scott Manley: https://www.youtube.com/watch?v=2cldgl9IIyY https://www.youtube.com/watch?v=2cldgl9IIyY
HPsquared 4y ago
Space shuttle main engines (RS-25) had a very complicated startup process, deviations from this could cause all sorts of different things to fail catastrophically. http://large.stanford.edu/courses/2011/ph240/nguyen1/docs/SSME_PRESENTATION.pdf http://large.stanford.edu/courses/2011/ph240/nguyen1/docs/SS... Slide 94 (pdf page 100)
- EvanAnderson 4y ago
  All the imperial units in this PDF hurt my head. I'm an American, so I'm used to them, but seeing them in the context of precision aerospace hardware is so jarring. As a student it seemed like math re: chemistry and physics was so much easier (read: less error-prone) with metric units than with imperial. Mars Climate Orbiter indeed.
  - Koshkin 4y ago
    I mean, sure, converting grams to kilograms is easier (for a human) than converting ounces to pounds, but how often do we have to do that in our heads? Computers, on the other hand, do not care (and they "prefer" the binary system anyway).
    - perilunar 4y ago
      Converting grams to kilograms not so much, but mm to m, mL to L, even g to mL and L to kg (of water) — all the time, and of course in our heads — it's so easy you barely need to think about it.
      - chriswarbo 4y ago
        I don't even consider those to be "conversions" at all; in the same way that "two dozen metres" and "twenty four metres" and are both just some number of metres (not a conversion from a separate "dozen-metre" unit). Technically, the SI standard does consider millimetres, centimentres, kilometres, etc. to be separate ("derived") units from the base unit of "metre". That matters when we have multiple interacting multiples, e.g. "one cubic centimetre" is not the same as "one centi cubic metre"; but of course, that's avoided if we stick to base units like cubic metre. (see http://www.chriswarbo.net/projects/units/improving_our_units.html#problems-with-si http://www.chriswarbo.net/projects/units/improving_our_units... )
Koshkin 4y ago
Starting the engine(s) even in a propeller-driven airplane used to be a big deal, too. Hell, I'm sure that even starting a car engine back in the day was a much more complex affair (than simply pushing a button like it is today).
- MS90 4y ago
  Yes, early cars had to be started with a crank handle that stuck out of the front of the grill, similar to how early propeller engines had to be hand-spun to get going. Apparently if you didn't crank it quite hard enough the handle could snap back at you rather violently, one of my great-grandmothers had her arm broken this way.
  - h2odragon 4y ago
    > the handle could snap back at you rather violently If it backfired. I got thrown over a Studebaker that way when I was like 8; I wasn't big enough to turn the handle by hand so I was jumping on it. It usually worked tho.
  - WalterBright 4y ago
    With the piston engines they had to be turned over by hand first to let the oil drain out of the cylinders before starting them by pulling on the propeller.
- jackmott42 4y ago
  Those things really are fundamentally easier, which is why it became routine and something every day people could operate day in day out pretty quickly. Rocket engines are still very hard to do 70 years later.
  - bryanlarsen 4y ago
    Starting a modern car engine is not easy. They've got high compression ratios and are other wise tuned for high performance and fuel economy making a sustained ignition difficult. It's the computers and other timing components that make it seem easy and everyday.
fnordpiglet 4y ago
This is great. My rocket starting experiences extend to hitting space in KSP and mashing the red button on an Estes launcher. To be fair in KSP they often wiggle to death on the pad and I’ve spent more time with bored 6 year olds wandering off as I figure out why the Estes motor didn’t ignite, but that’s nothing compared to this.
chasd00 4y ago
I think there was a russian engine that literally had 2x4's on fire stuck in the combustion chamber in place of torch ignitors or TEAB. If anyone's interested the experimental high-power rocketry hobby is pretty fun, there's a lot to learn and hack on. A lot of people focus on propulsion and formulating, profiling, and flying various solid fuels they develop themselves. This guy is highly regarded https://www.nakka-rocketry.net/ https://www.nakka-rocketry.net/ Others focus on flight controllers, GPS trackers, and other electronics. https://altusmetrum.org/ https://altusmetrum.org/ (i think one of the two owners of altusmetrum is a pretty famous Debian Linux guy from back in the day) There's also "hybrid" engines that use a solid fuel and a liquid oxidizer ( nitrous oxide ). Ex, this guy is probably the most well known in the hybrids side of the hobby https://contrailrockets.com/ https://contrailrockets.com/ Finally, there's the halfcat guys https://www.halfcatrocketry.com/ https://www.halfcatrocketry.com/ who do amateur liquid bi-prop engines in an approachable way. I've working on a design of my own based on their designs and plan to do a static fire in the Fall and hopefully a flight before end of year. The downside with liquid engines in the hobby is governing bodies Tripoli and NAR don't allow these engines at sanctioned launches. You either have to launch privately (including coordinating/paperwork with the FAA on your own ) or at FAR https://friendsofamateurrocketry.org/ https://friendsofamateurrocketry.org/
- pasiaj 4y ago
  > literally had 2x4's on fire stuck in the combustion chamber I REALLY wouldn't want to be the person tasked with starting that fire.
- skazazes 4y ago
  You probably already know of him, but you should check out BPS Space on youtube if you enjoy long-form video edutainment. Much like Tim Dodd, Joe makes videos full of detail and information about topics he is clearly passionate about. In the case of BPS Space that is pushing the limits of amateur rocketry in a uniquely hacker/programmer friendly manor.
  - polishdude20 4y ago
    BPS Space is what got me into building my own thrust vectoring rocket during COVID lockdowns. https://github.com/AdamMarciniak/CygnusX1 https://github.com/AdamMarciniak/CygnusX1 It was super fun to bring together lots of different disciplines and skills. 3D printing, software, soldering, circuit design, simulation etc. Ultimately, I got so obsessed with it I got burned out and had to take a break for a bit but came back fresh and finished it. Did a few flights over the year with more and more interesting things culminating in a dual stage flight. I've still got the rocket ready to go anytime. Just gotta wait for the weather to clear up.
ivankirigin 4y ago
This makes me want to go back to school and major in aero/astro engineering.
- martythemaniak 4y ago
  Yeah, I think atoms are just so cool. After almost two decades of many different kinds of software, it all starts to looks the same and kinda boring. Even LLMs, which are super exciting, can barely hold my interested. All my startup and side-project ideas are now robot or machine based. Feels like the combo of LLMs (or rather large multi-modal models) and cheap robots will yield tons of interesting results over the next decade.
- deleted 4y ago
  [deleted]
hoorayimhelping 4y ago
Tangential but related: "Toxic Propellant Hazards"[1] a video made in the mid/late 60s and published by the US National Archives Youtube channel. In addition to having some great information about hypergolic propellants, and having some interesting footage showing what they're like to use, it also has that mid-century production quality, the kind that the Fallout games love to simultaneously lampoon and pay homage to 1) https://www.youtube.com/watch?v=Zha9DyS-PPA https://www.youtube.com/watch?v=Zha9DyS-PPA
LargeTomato 4y ago
I'm surprised at the amount of people who enjoy EDA. I find him very irritating. Most people at my small space company find him extremely irritating. He is not a rocket scientist. He parrots silly buzzwords like "biomimickry" like a fanboy, not an engineer. He suggests things to Elon for how to do rockets that are just pants-on-head dumb. His blind fanboyism and arrogance irritate so many people who work in space. I'm very surprised HN loves this guy.
- ghostpepper 4y ago
  Didn't he suggest something to Elon that Elon immediately decided to alter on an upcoming rocket? Doesn't sound like he knows nothing..
  - LargeTomato 4y ago
    I forget exactly what he suggested but I remember is being like kind of dumb. Elon was humoring him. This guy is absolutely not a rocket scientist. He's not even an engineer.
    - sho_hn 4y ago
      If I recall, Musk was explaining that on the Starship booster they had recently begun to use directed venting of ullage gases for control authority to save a seperate hot or cold gas thruster system and Dodd asked if this also applies to the ship. Musk then went "now that you mention it, we should look into that". During a visit a year or so later he then confirmed they had begun doing it on the ship too and that it had occurred to him as he was explaining it to Dodd. It's of course unlikely that the engineering team wasn't already considering this, but it's also not like Dodd was suggesting anything, he was just asking a follow-up question. The way the conversations played out was Musk remembering to ask someone about it later to check the status of the plan or drive a decision, and later recalling that conversation when Dodd came by again.
      - ghostpepper 4y ago
MarkusWandel 4y ago
You can watch the whole thing from the very genesis of the turbopump powered liquid fueled rocket. The British did a very thorough documentation project on the German A4 / V2 rocket after WW2 and it's all accessible to the public. http://www.v2rocket.com/start/chapters/backfire.html http://www.v2rocket.com/start/chapters/backfire.html In particular, the pyrotechnic igniter that is mentioned in the article as still in use by the Russians was copied directly from there. Here's a direct link to the spot in the video where it is assembled for use. https://youtu.be/V_fPdXLx48c?t=2097 https://youtu.be/V_fPdXLx48c?t=2097
punnerud 4y ago
The more I learn about different types of rockets and all the engineering behind SpaceX, the more I am impressed by what they have accomplished. Huge thanks to ‘Every Day Astronaut‘ for this YouTube channel, so many good videos.
rwmj 4y ago
> [Ignition chemical TEA-TEB] is quite expensive, costing roughly the same as the cost of RP-1 for the Falcon 9. Is it true that the ignition chemical costs as much as the fuel? That sounds incredible.
- dtgriscom 4y ago
  But you'd need far less of the ignition chemical.
ofrzeta 4y ago
Related: John D. Clark "Ignition!: An Informal History of Liquid Rocket Propellants"
- bryanlarsen 4y ago
  “It is, of course, extremely toxic, but that’s the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water-with which it reacts explosively. It can be kept in some of the ordinary structural metals-steel, copper, aluminium, etc.-because of the formation of a thin film of insoluble metal fluoride which protects the bulk of the metal, just as the invisible coat of oxide on aluminium keeps it from burning up in the atmosphere. If, however, this coat is melted or scrubbed off, and has no chance to reform, the operator is confronted with the problem of coping with a metal-fluorine fire. For dealing with this situation, I have always recommended a good pair of running shoes.”
- ravedave5 4y ago
  This is such a great book. Even if your chemistry knowledge is minimal read it for the anecdotes.
0cVlTeIATBs 4y ago
I was hoping this would be an explanation of the second stage failure to ignite three days ago on Japan's H3 rocket.

357 points by Jarlakxen 4y ago

I could watch stuff like this all day. Tim's stuff is so great. Easy to be jealous of, since being YouTuber seems easy, but to make quality content, it really can't be. And then he's going around the moon, it's really mind blowing to see the success he's had. His interviews with Musk are a treasure trove as well, whatever you think of Musk.

adolph 4y ago
To pile on the Tim Dodd praise, be sure to check out his music too (which is used in the videos). Solid stuff that reminds me of Tycho. So glad he got picked for the Dear Moon mission.
samwillis 4y ago
> His interviews with Musk are a treasure trove as well, whatever you think of Musk. My main take away from those interviews is just how knowledgable Tim is, he's able to engage in low level and in depth conversations about how these engines work. It's not just superficial high level knowledge from making videos, he is thinking himself how to optimise and improve these things, and leading that conversation. The passion for it is electric. In another life Tim would have been an incredible engineer, but that value he brings as an educator is immeasurable. Thats how he has earnt his way to a space flight. (They also show that the common argument that Elon doest know his stuff is wrong (at least for rockets), but I really don't what to derail this conversation into that.)
- oger 4y ago
  It's absolutely worth to go on a tangent here - Tim did a great job in explaining Elon (or showing him to the public in a probably not too filtered way).
- ragebol 4y ago
  Absolutely. Imagine if all journalists had this level of depth in all of the topic they covered? I don't think that's possible though.
  - prox 4y ago
    I agree. You need that intersection of interest, presentable qualities (listening, digesting,responding, speaking) and quest for accuracy. Hard to get those all in one person.
  - nordsieck 4y ago
    > Imagine if all journalists had this level of depth in all of the topic they covered? I don't think that's possible though. It helps a lot that Youtube seems to have become the home of long form video. Not really something that fits into traditional media. But for the people that really want to dive deep into a topic, it's great that there are now often high quality creators that cater to those tastes.
    - ragebol 4y ago
      Does not fit in traditional media indeed. When I was a kid/teen, Discovery Channel, at least in my native Netherlands, had some interesting content. I could also gobble up something like How it's Made all day. Content like Tim's could definitely fit in there too. YouTube enabled everyone to publish this type of content, for good and bad...
      - kitsunesoba 4y ago
        When I was younger I loved shows like Modern Marvels on History Channel that presented the engineering behind the various amazing everyday things that we take for granted in a format accessible to the layman. It's depressing that good shows like that were killed off in favor of the "reality" TV and conspiracy/aliens/etc show junk food that took over Discovery and History from the mid-00s onward.
- LargeTomato 4y ago
  To be honest he's regurgitating a lot of information. He has large gaps in his knowledge but presents himself as extremely knowledgeable. Understanding a rocket engine as a layman is easier than understanding a diesel engine. EDA acts like he's a genius but he is not. I work in space. Some of my coworkers have met EDA. He is insufferable and extremely arrogant. A very difficult person to be around.
  - peterfirefly 4y ago
    > He has large gaps in his knowledge Yes. > but presents himself as extremely knowledgeable. No.
    - LargeTomato 4y ago
      Yeah he has an extreme level of confidence. Tweeting Elon about how to architect the landing fins to use "fish scale biomimickry"? That's ridiculous.
      - LawTalkingGuy 4y ago
        He didn't. He tweeted that he's surprised the tiles don't need to be overlapped to avoid blowing off but didn't suggest that Elon change them. https://mobile.twitter.com/Erdayastronaut/status/1442631530224959488 https://mobile.twitter.com/Erdayastronaut/status/14426315302...
    - JshWright 4y ago
      Perhaps he has gotten better at that in recent years. I got put off his early content for the very that very reason and haven't bothered to go back.
  - sho_hn 4y ago
    > but presents himself as extremely knowledgeable I don't get this sense at all. I've been watching his channel for a couple of years, and I've consistently found him to portray himself as a fan/enthusiast trying his best to understand and summarize complex information he doesn't have first-hand knowledge of. He's never pretended to be an engineer. I think the value is in getting inspired to dig deeper when he shows you something interesting.
localplume 4y ago
He, like most big Youtubers, probably have a large crew of people working with them. The article was written by Trevor Sesnic, the video was likely edited by others, I don't know if he did the graphics, but Tim still did a lot (and arguably did the most fun stuff). Smaller Youtubers need to do all of that, and from what I've heard editing is the absolute worst given how time consuming it is. Many Youtubers struggle with burnout centered around how time consuming editing becomes. Tim's content is really great though, and he does a fantastic job of explaining complex topics in a welcoming way. Very similar to smartereveryday IMO, where it is just really engaging and informative content presented in a great way.
- MichaelZuo 4y ago
  From the about page: > In 2019 the team grew from just Tim to a small army of incredible helpers who make this website amazing, the videos higher quality, and help foster a fun and positive online community. So the 2017-2019 period where the channel took off was all done by him solo, apparently.
  - somenameforme 4y ago
    I'd also add this standard. Another amazing YouTuber is Veritasium. He went from [1] to [2]. The production quality is more than slightly improved, but the "spirit" remains identical. And I think that spirit is what drives success or failure. The production quality is just icing. [1] - https://www.youtube.com/watch?v=JUJPyQtoB5E https://www.youtube.com/watch?v=JUJPyQtoB5E [2] - https://www.youtube.com/watch?v=5eW6Eagr9XA https://www.youtube.com/watch?v=5eW6Eagr9XA
    - Retric 4y ago
      Veritasium videos are often subtly misleading which really annoys me. It’s great for views, but terrible for science education.
      - jaywalk 4y ago
        Whenever he drops a new video, I just look for the "Here's how Veritasium was wrong" videos to get the real story.
deleted 4y ago
[deleted]
lhoff 4y ago
He recently was a guest in Lex Fridmans podcast. https://lexfridman.com/tim-dodd/ https://lexfridman.com/tim-dodd/
dotnet00 4y ago
Tim's stuff certainly has the information content nailed down better than most typical "science" youtubers, but he comes off as slightly overexcited at times, which brings up negative associations with typical misleading pop science rags for me.
speed_spread 4y ago
> whatever you think of Musk Musk is a clown but I'll give him one thing: he cares about technology. That's something that very few modern CEO in big tech have and probably gives him the edge in making his project successful.
- sangnoir 4y ago
  > Musk is a clown but I'll give him one thing: he cares about technology. His hot takes on software / software architecture have been disappointing[1], and made me question the validity of his assertions in domains I have no expertise in (rocketry, computer vision and manufacturing). 1. Also, he wants to remain in charge of "Servers and Software" at Twitter even after (if?) He steps down as CEO.
  - speed_spread 4y ago
    I was thinking of pre-Twitter Musk. I'm not sure what game the clown is playing now or even if it's a game at all anymore. It's so bad that it's almost like a trash artistic performance. GG Allin billionaire.
hoot 4y ago
Did anybody else feel like the musk interview got really awkward towards the end? It seemed like he became really bored of it and just shut down.
- raylad 4y ago
  Tim was trying to be too knowledgeable and not letting Musk shine enough. I would be surprised if Musk gives him another interview any time soon.

oger 4y ago

Definitely among one of the great pieces he has produced. Highly informative and educational. He really finds the right tone and this long piece never gets boring for a second. Also from a production perspective his animated engine charts are top and visualise the point he is making. BTW his interviews with Elon Musk at Starbase are also a must see (some clips included in this video as well). You really start to see and understand how Musk works - and it's not as bad as media is trying to make him. His engineering principles are really interesting and can be applied to many scenarios. It's this level of abstraction that makes the difference and gives him a competitive edge.

mackevers 4y ago

[flagged]

dale_glass 4y ago
Is that ChatGPT? Edit: Yup, I got something very close to that: https://imgur.com/PX0MmCR https://imgur.com/PX0MmCR

mannykannot 4y ago

There's lots of information here on the sequence of operations followed in starting the F1 motors of the Saturn V first stage: https://home.kpn.nl/panhu001/Saturn_V/Saturn_V_info/F-1_engine/F-1_engine_ignition_sequence.html https://home.kpn.nl/panhu001/Saturn_V/Saturn_V_info/F-1_engi...

mtlebe 4y ago
Related video: How To Start The Massive F-1 Rocket Engine from Scott Manley: https://www.youtube.com/watch?v=2cldgl9IIyY https://www.youtube.com/watch?v=2cldgl9IIyY

HPsquared 4y ago

Space shuttle main engines (RS-25) had a very complicated startup process, deviations from this could cause all sorts of different things to fail catastrophically. http://large.stanford.edu/courses/2011/ph240/nguyen1/docs/SSME_PRESENTATION.pdf http://large.stanford.edu/courses/2011/ph240/nguyen1/docs/SS... Slide 94 (pdf page 100)

EvanAnderson 4y ago
All the imperial units in this PDF hurt my head. I'm an American, so I'm used to them, but seeing them in the context of precision aerospace hardware is so jarring. As a student it seemed like math re: chemistry and physics was so much easier (read: less error-prone) with metric units than with imperial. Mars Climate Orbiter indeed.
- Koshkin 4y ago
  I mean, sure, converting grams to kilograms is easier (for a human) than converting ounces to pounds, but how often do we have to do that in our heads? Computers, on the other hand, do not care (and they "prefer" the binary system anyway).
  - perilunar 4y ago
    Converting grams to kilograms not so much, but mm to m, mL to L, even g to mL and L to kg (of water) — all the time, and of course in our heads — it's so easy you barely need to think about it.
    - chriswarbo 4y ago
      I don't even consider those to be "conversions" at all; in the same way that "two dozen metres" and "twenty four metres" and are both just some number of metres (not a conversion from a separate "dozen-metre" unit). Technically, the SI standard does consider millimetres, centimentres, kilometres, etc. to be separate ("derived") units from the base unit of "metre". That matters when we have multiple interacting multiples, e.g. "one cubic centimetre" is not the same as "one centi cubic metre"; but of course, that's avoided if we stick to base units like cubic metre. (see http://www.chriswarbo.net/projects/units/improving_our_units.html#problems-with-si http://www.chriswarbo.net/projects/units/improving_our_units... )

Koshkin 4y ago

Starting the engine(s) even in a propeller-driven airplane used to be a big deal, too. Hell, I'm sure that even starting a car engine back in the day was a much more complex affair (than simply pushing a button like it is today).

MS90 4y ago
Yes, early cars had to be started with a crank handle that stuck out of the front of the grill, similar to how early propeller engines had to be hand-spun to get going. Apparently if you didn't crank it quite hard enough the handle could snap back at you rather violently, one of my great-grandmothers had her arm broken this way.
- h2odragon 4y ago
  > the handle could snap back at you rather violently If it backfired. I got thrown over a Studebaker that way when I was like 8; I wasn't big enough to turn the handle by hand so I was jumping on it. It usually worked tho.
- WalterBright 4y ago
  With the piston engines they had to be turned over by hand first to let the oil drain out of the cylinders before starting them by pulling on the propeller.
jackmott42 4y ago
Those things really are fundamentally easier, which is why it became routine and something every day people could operate day in day out pretty quickly. Rocket engines are still very hard to do 70 years later.
- bryanlarsen 4y ago
  Starting a modern car engine is not easy. They've got high compression ratios and are other wise tuned for high performance and fuel economy making a sustained ignition difficult. It's the computers and other timing components that make it seem easy and everyday.

fnordpiglet 4y ago

This is great. My rocket starting experiences extend to hitting space in KSP and mashing the red button on an Estes launcher. To be fair in KSP they often wiggle to death on the pad and I’ve spent more time with bored 6 year olds wandering off as I figure out why the Estes motor didn’t ignite, but that’s nothing compared to this.

chasd00 4y ago

I think there was a russian engine that literally had 2x4's on fire stuck in the combustion chamber in place of torch ignitors or TEAB. If anyone's interested the experimental high-power rocketry hobby is pretty fun, there's a lot to learn and hack on. A lot of people focus on propulsion and formulating, profiling, and flying various solid fuels they develop themselves. This guy is highly regarded https://www.nakka-rocketry.net/ https://www.nakka-rocketry.net/ Others focus on flight controllers, GPS trackers, and other electronics. https://altusmetrum.org/ https://altusmetrum.org/ (i think one of the two owners of altusmetrum is a pretty famous Debian Linux guy from back in the day) There's also "hybrid" engines that use a solid fuel and a liquid oxidizer ( nitrous oxide ). Ex, this guy is probably the most well known in the hybrids side of the hobby https://contrailrockets.com/ https://contrailrockets.com/ Finally, there's the halfcat guys https://www.halfcatrocketry.com/ https://www.halfcatrocketry.com/ who do amateur liquid bi-prop engines in an approachable way. I've working on a design of my own based on their designs and plan to do a static fire in the Fall and hopefully a flight before end of year. The downside with liquid engines in the hobby is governing bodies Tripoli and NAR don't allow these engines at sanctioned launches. You either have to launch privately (including coordinating/paperwork with the FAA on your own ) or at FAR https://friendsofamateurrocketry.org/ https://friendsofamateurrocketry.org/

pasiaj 4y ago
> literally had 2x4's on fire stuck in the combustion chamber I REALLY wouldn't want to be the person tasked with starting that fire.
skazazes 4y ago
You probably already know of him, but you should check out BPS Space on youtube if you enjoy long-form video edutainment. Much like Tim Dodd, Joe makes videos full of detail and information about topics he is clearly passionate about. In the case of BPS Space that is pushing the limits of amateur rocketry in a uniquely hacker/programmer friendly manor.
- polishdude20 4y ago
  BPS Space is what got me into building my own thrust vectoring rocket during COVID lockdowns. https://github.com/AdamMarciniak/CygnusX1 https://github.com/AdamMarciniak/CygnusX1 It was super fun to bring together lots of different disciplines and skills. 3D printing, software, soldering, circuit design, simulation etc. Ultimately, I got so obsessed with it I got burned out and had to take a break for a bit but came back fresh and finished it. Did a few flights over the year with more and more interesting things culminating in a dual stage flight. I've still got the rocket ready to go anytime. Just gotta wait for the weather to clear up.

ivankirigin 4y ago

This makes me want to go back to school and major in aero/astro engineering.

martythemaniak 4y ago
Yeah, I think atoms are just so cool. After almost two decades of many different kinds of software, it all starts to looks the same and kinda boring. Even LLMs, which are super exciting, can barely hold my interested. All my startup and side-project ideas are now robot or machine based. Feels like the combo of LLMs (or rather large multi-modal models) and cheap robots will yield tons of interesting results over the next decade.
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hoorayimhelping 4y ago

Tangential but related: "Toxic Propellant Hazards"[1] a video made in the mid/late 60s and published by the US National Archives Youtube channel. In addition to having some great information about hypergolic propellants, and having some interesting footage showing what they're like to use, it also has that mid-century production quality, the kind that the Fallout games love to simultaneously lampoon and pay homage to 1) https://www.youtube.com/watch?v=Zha9DyS-PPA https://www.youtube.com/watch?v=Zha9DyS-PPA

LargeTomato 4y ago

I'm surprised at the amount of people who enjoy EDA. I find him very irritating. Most people at my small space company find him extremely irritating. He is not a rocket scientist. He parrots silly buzzwords like "biomimickry" like a fanboy, not an engineer. He suggests things to Elon for how to do rockets that are just pants-on-head dumb. His blind fanboyism and arrogance irritate so many people who work in space. I'm very surprised HN loves this guy.

ghostpepper 4y ago
Didn't he suggest something to Elon that Elon immediately decided to alter on an upcoming rocket? Doesn't sound like he knows nothing..
- LargeTomato 4y ago
  I forget exactly what he suggested but I remember is being like kind of dumb. Elon was humoring him. This guy is absolutely not a rocket scientist. He's not even an engineer.
  - sho_hn 4y ago
    If I recall, Musk was explaining that on the Starship booster they had recently begun to use directed venting of ullage gases for control authority to save a seperate hot or cold gas thruster system and Dodd asked if this also applies to the ship. Musk then went "now that you mention it, we should look into that". During a visit a year or so later he then confirmed they had begun doing it on the ship too and that it had occurred to him as he was explaining it to Dodd. It's of course unlikely that the engineering team wasn't already considering this, but it's also not like Dodd was suggesting anything, he was just asking a follow-up question. The way the conversations played out was Musk remembering to ask someone about it later to check the status of the plan or drive a decision, and later recalling that conversation when Dodd came by again.
    - ghostpepper 4y ago

MarkusWandel 4y ago

You can watch the whole thing from the very genesis of the turbopump powered liquid fueled rocket. The British did a very thorough documentation project on the German A4 / V2 rocket after WW2 and it's all accessible to the public. http://www.v2rocket.com/start/chapters/backfire.html http://www.v2rocket.com/start/chapters/backfire.html In particular, the pyrotechnic igniter that is mentioned in the article as still in use by the Russians was copied directly from there. Here's a direct link to the spot in the video where it is assembled for use. https://youtu.be/V_fPdXLx48c?t=2097 https://youtu.be/V_fPdXLx48c?t=2097

punnerud 4y ago

The more I learn about different types of rockets and all the engineering behind SpaceX, the more I am impressed by what they have accomplished. Huge thanks to ‘Every Day Astronaut‘ for this YouTube channel, so many good videos.

rwmj 4y ago

> [Ignition chemical TEA-TEB] is quite expensive, costing roughly the same as the cost of RP-1 for the Falcon 9. Is it true that the ignition chemical costs as much as the fuel? That sounds incredible.

dtgriscom 4y ago
But you'd need far less of the ignition chemical.

ofrzeta 4y ago

Related: John D. Clark "Ignition!: An Informal History of Liquid Rocket Propellants"

bryanlarsen 4y ago
“It is, of course, extremely toxic, but that’s the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water-with which it reacts explosively. It can be kept in some of the ordinary structural metals-steel, copper, aluminium, etc.-because of the formation of a thin film of insoluble metal fluoride which protects the bulk of the metal, just as the invisible coat of oxide on aluminium keeps it from burning up in the atmosphere. If, however, this coat is melted or scrubbed off, and has no chance to reform, the operator is confronted with the problem of coping with a metal-fluorine fire. For dealing with this situation, I have always recommended a good pair of running shoes.”
ravedave5 4y ago
This is such a great book. Even if your chemistry knowledge is minimal read it for the anecdotes.

0cVlTeIATBs 4y ago

I was hoping this would be an explanation of the second stage failure to ignite three days ago on Japan's H3 rocket.