[HN Gopher] Engine cooling - why rocket engines don't melt
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       Engine cooling - why rocket engines don't melt
        
       Author : wolfram74
       Score  : 295 points
       Date   : 2022-01-13 15:49 UTC (7 hours ago)
        
 (HTM) web link (everydayastronaut.com)
 (TXT) w3m dump (everydayastronaut.com)
        
       | Animats wrote:
       | Making rocket engines by metal 3D printing has become popular. A
       | rocket engine bell and combustion chamber has one big rigid part
       | with lots of channels and voids inside. That's the ideal case for
       | 3D printing. Much simpler than building the thing up by machining
       | and welding together many individual parts.
        
         | avmich wrote:
         | There are different problems with 3D printing than with
         | classical subtractive manufacturing. E.g. you need to get the
         | supporting powder out of long thin passages in the cooling
         | chamber - you don't have such problem with milling machine
         | approach.
        
         | m4rtink wrote:
         | I remember reading in an article that without 3D printing they
         | could simply not get the cooling channel geometry they needed
         | on the Super Dracos on Dragon 2.
         | 
         | Without 3D printing the combustion chamber they would need to
         | use other cooling channel geometry, makin ghr engine heavier,
         | bigger and less efficient.
        
       | ortusdux wrote:
       | One of my favorite bits from Tim's videos was during a tour of
       | Firefly Aerospace's facility when they talk about engine cooling.
       | They discuss EDM machining small holes into the coolant channels
       | just before the throat, which lets a small amount of cryogenic
       | coolant out to cool the interior. The funny part is that you can
       | purposefully undersize the holes and they will melt larger until
       | they are big enough to adequately cool the engine. You basically
       | pre-season the engine with a test-fire and let it choose how much
       | internal cooling it needs.
       | 
       | https://youtu.be/ac-V8mO0lWo?t=2203
        
       | jamesmunns wrote:
       | This is just a really clearly written introduction of a lot of
       | rocket engine concepts.
       | 
       | It was a super good read.
        
       | mountainwalker wrote:
       | Tim's videos are always so well done! Even if you're not a rocket
       | enthusiast there's tons to get out of this video.
        
         | throwaway894345 wrote:
         | Agreed. Tim was an old friend of mine in university, but we
         | lost touch over the years. He was always a good, quirky,
         | creative, and talented guy. He bought an old cosmonaut suit on
         | ebay on a lark and started doing funny/silly photo shoots with
         | it and then photo shoots at rocket launches and then real
         | educational stuff. It's been wild to see it take off (pun
         | intended).
        
       | bernulli wrote:
       | Minor nitpick: fluids are not either liquids or gases, this is
       | particularly true for rocket engines where many of the discussed
       | processes (injection, compression, regenerative coolant flow)
       | actually occur at super- or transcritical conditions.
       | 
       | Also, I don't think you can say the faceplate is heat sink-
       | cooled. Remember that just behind it is the propellant manifold,
       | so it's rather some form of regenerative cooling.
        
       | jpm_sd wrote:
       | Ignorant question: are solid-fueled rockets at all interesting,
       | anymore? Do they have any advantages (e.g. simplicity of design)
       | over the fancy throttle-able liquid-fueled engines?
        
         | anarazel wrote:
         | Depends on the purpose. E.g. for military uses like ICBMs
         | they're quite important...
        
         | evo wrote:
         | I suspect their primary advantage remains shelf-stability at
         | room temperatures, which will make them stay relevant for
         | military applications, e.g. you don't want a cryogenics
         | facility in your submarine or cruise missile launch platform.
         | 
         | Historically, I think they're cheaper than an equivalent
         | disposable liquid fueled engine but don't hold up to the fully
         | reusable designs of today, and from a reliability perspective
         | there's not a lot of room between working-as-intended and
         | "activate the flight termination system" at a total loss.
        
           | Terr_ wrote:
           | > I suspect their primary advantage remains shelf-stability
           | at room temperatures, which will make them stay relevant for
           | military applications
           | 
           | I while ago I read--but barely understood--a book that went
           | into a lot of this: "Ignition! An Informal History of Liquid
           | Rocket Propellants" by John D. Clark.
           | 
           | _____________________
           | 
           | IIRC there were some cases where a fuel was not militarily-
           | acceptable because you would need to warm/thaw the mobile
           | missile prior to firing in a Russian winter, or other cases
           | where a permanent missile-silo meant it was cost-effective to
           | run heating/refrigeration all the time, etc.
           | 
           | > [I]n applications which do not require a low freezing
           | point, hydrazine itself is fused, either straight or mixed
           | with one of its derivatives. The fuel of the Titan II ICBM
           | doesn't have to have a low freezing point, since Titan II
           | lives in a steam-heated hole in the ground, but it does need
           | the highest possible performance, and hydrazine was the first
           | candidate for the job.
           | 
           | _____________________
           | 
           | Another fuel-choice issue involves how badly it might self-
           | destruct if anything unusual happened:
           | 
           | > [I]n the summer of 1960, we tried to fire a 10,000-pound
           | thrust Cavea B motor. [...] Well, through a combination of
           | this and that, the motor blew on startup. We never discovered
           | whether or not the [detonation] traps worked--we couldn't
           | find enough fragments to find out.
           | 
           | > The fragments from the injector just short-circuited the
           | traps, smashed into the tank, and set off the 200 pounds of
           | propellant in that. (Each pound of propellant had more
           | available energy than two pounds of TNT.) I never saw such a
           | mess. The walls of the test cell--two feet of concrete--went
           | out, and the roof came in. The motor itself--a heavy,
           | workhorse job of solid copper-- went about 600 feet down
           | range. And a six-foot square of armor plate sailed into the
           | woods, cutting off a few trees at the root, smashing a
           | granite boulder, bouncing into the air and slicing off a few
           | treetops, and finally coming to rest some 1400 feet from
           | where it started. The woods looked as though a stampeding
           | herd of wild elephants had been through.
           | 
           | > As may be imagined, this incident tended to give
           | monopropellants something of a bad name. Even if you could
           | fire them safely--and we soon saw what had gone wrong with
           | the ignition process--how could you use them in the field?
           | 
           | > Here you have a rocket set up on the launching stand, under
           | battlefield conditions; and what happens if it gets hit by a
           | piece of shrapnel? LRPL came up with the answer to that. You
           | keep your monoprop in the missile in two compartments: one
           | full of fuel-rich propellant made up to A. = 2.2 or 2.4, and
           | the other containing enough acid to dilute it to X = 1.2.
           | Just before you fire, a can-opener arrangement inside the
           | missile slits open the barrier separating the two liquids,
           | you allow a few seconds for them to mix, and then push the
           | button.
        
         | j8asic wrote:
         | Not really. Gel propellants are a new direction.
        
         | jandrese wrote:
         | They are useful when you need a rocket that can take off at a
         | moments notice but sit idle for decades at a time. For typical
         | rocket launches they don't make much sense.
         | 
         | I suspect the Space Shuttle SRBs were chosen because they were
         | a handout to ICBM manufacturers.
        
         | dylan604 wrote:
         | Depends on your definition of "interesting". If you mean do
         | people still use them for practical purposes, then yes they
         | are. If you mean are people still researching them for use in
         | exploring space, then probably not.
        
         | Robotbeat wrote:
         | Extremely simple (basically just one big rocket combustion
         | chamber with the propellant already inside, no pumps or
         | plumbing) and shelf storable and potentially extremely high
         | thrust to weight ratio.
         | 
         | Useful for munitions and for one-time-use. I'd like to think
         | we're going to reusable rockets and not as much war, so I'd
         | LIKE to think they have fewer uses, but...
        
       | opwieurposiu wrote:
       | This thing I can not comprehend about rocket engines is how the
       | turbopump manages to hold together.
       | 
       | A turbine blade in the SSME about the size of your thumb makes
       | 600 horsepower.
       | 
       | https://www.enginehistory.org/Rockets/SSME/SSME6.pdf
        
         | VBprogrammer wrote:
         | If that interests you then this series of videos is definitely
         | worth watching. It details several parts of the German V2
         | missile, the grand father of all modern liquid propellant
         | rockets. This one is about the turbopump which is one of the
         | most interesting parts.
         | 
         | https://youtu.be/EgiMu8A3pi0
        
         | kunai wrote:
         | It is pretty mind-boggling. Makes the average turbofan's
         | turbine assembly look like child's play, and those are also
         | pretty ridiculous in terms of power-to-weight ratio.
        
           | HPsquared wrote:
           | It's mostly because the working fluid is at very high
           | pressure (much denser than the air coming through an aero
           | engine). The turbine side works with hot gas at 100+ bar, and
           | the pump side is dealing with liquid. Therefore small parts
           | can exert a lot of force (large pressure differences) and do
           | a lot of work (high speeds).
           | 
           | The most similar technology is a boiler feed pump (used to
           | feed the boilers in a steam turbine system, e.g. in a ship or
           | power station) - these work in a similar way, high pressure
           | steam is bled off from the system to drive a small turbine,
           | which drives a high pressure pump to feed the boiler, which
           | feeds the 'main' steam turbine. Similar pressure (>100 bar),
           | but the turbine on the rocket engine needs to handle much
           | higher temperatures (hot gas rather than steam).
        
         | bernulli wrote:
         | Also try to imagine the thermal stresses when you have
         | cryogenic propellants on the pump side and hot exhaust gases
         | (gas generator or staged combustion) on the turbine side!
        
         | jaywalk wrote:
         | Well, 63 blades together make 600 horsepower. But as that paper
         | notes, each blade is subject to 50,000 psi which is wild.
        
           | jhgb wrote:
           | 600 horsepower _each_. The whole turbine has tens of
           | megawatts of mechanical power output.
        
             | jaywalk wrote:
             | Yep, you are correct. I misread.
        
           | TylerE wrote:
           | It is wild, but not as wild as you might think.
           | 
           | The fuel rail in a modern diesel engine is operating at
           | 25-30,000 psi all the time.
        
         | HPsquared wrote:
         | I the power level of these engines is difficult to comprehend.
         | The _fuel pump_ has thousands of horsepower. Compare this to
         | the fuel pump on a car engine, which is a tiny little electric
         | thing. The combustion power must be in the gigawatt range.
         | 
         | Edit: the SSME high pressure fuel pump turbine produces 63000
         | hp (46 MW). There's also one for the oxygen, and a pair of low
         | pressure pumps as well. Crazy...
         | 
         | Edit edit: the fuel pump transfers 155 lb/sec of liquid
         | hydrogen. If fully combusted (142 MJ/kg), that would release
         | 10.0 GW of heat per engine.
        
           | skykooler wrote:
           | This is why electric turbopumps (like those used on
           | RocketLab's Electron rocket) don't scale up to larger rockets
           | well - the power draw is just infeasible to support with
           | current battery technology.
        
             | Robotbeat wrote:
             | Not quite. Electric pumps scale just fine (that is,
             | linearly), but turbopumps scale better. It's hard to build
             | a very small turbopump but not much harder to build a
             | larger one, and turbopumps improve in efficiency as they
             | get larger. BTW, the largest electropump (4 times that of
             | RocketLab's Rutherford electropump engine) for a rocket
             | engine is the electropump for the 100kN (10 ton) thrust
             | rocket engine for the reusable crewed suborbital Spica
             | space rocket by the volunteer-run Copenhagen Suborbitals
             | group, which more people ought to know about:
             | 
             | https://twitter.com/CopSub/status/1468280164404666373?s=20
        
               | sephamorr wrote:
               | The major issue is the energy storage, not the power
               | plant itself. The penalty of the battery mass scales far
               | worse than a tank holding very energy dense rocket
               | propellant.
        
               | Robotbeat wrote:
               | Again, the energy storage scales just fine: linearly.
               | Rocket propellant tends to scale better than linear, but
               | it is not in every case better than lithium ion
               | batteries! For example, the R7/Soyuz rocket family is the
               | most-launched orbital rocket ever, and it uses a hydrogen
               | peroxide gas generator to drive the turbopump. That has a
               | concentration of 82.5% peroxide. Pure peroxide has a heat
               | of decomposition of 2.84MJ/kg, and turbine that is
               | typically 30% efficient (actually, it might be much less
               | than that... I think the V-2 turbine was only like 10%
               | efficient, maybe worse... so 30% is optimistic) gives you
               | a usable energy density of only 700kJ/kg, or about
               | 194Wh/kg. The best lithium batteries available are about
               | twice that, up to 400-500Wh/kg (with those in the lab
               | even better still), and electric motors can have 90-95%
               | efficiency.
               | 
               | And gas generators using main propellants are better,
               | certainly, but less than you might think because they
               | have to haul all their oxidizer with them (unlike
               | aircraft) and are also usually run very far from
               | stoichiometric (maybe just 0.3 O:F ratio compared to a
               | stoichiometric 3.4) to keep the temperature down. So
               | unless you have a pretty high temperature turbine, you
               | might not beat peroxide by much!
               | 
               | So the easiest gas generators have worse energy density
               | (keep in mind RocketLab does stage off batteries if
               | necessary...), and the next easiest, while better, aren't
               | MASSIVELY better without careful efficiency improvements.
               | The real efficiencies come when you use like an expander
               | cycle or a staged combustion cycle or you feed the gas
               | generator exhaust back into the nozzle like Merlin Vacuum
               | or F-1. And those are all much more complicated. A level
               | of complication that is not worth it for small rockets
               | but is for larger.
               | 
               | So it's really not about electric scaling poorly
               | (electric scales just fine) but about the greater
               | complexity of better engine cycles being worth it at
               | larger scales.
        
           | kragen wrote:
           | Yeah, it's pretty amazing. Doing this in a controlled fashion
           | is the hard part; a largish wooden building on fire can also
           | dissipate 10 GW.
           | 
           | A .22 LR rifle bullet might acquire 200 J in 2 ms, which
           | means the firing gun is producing 100 kW mechanical, plus
           | probably another 300 kW thermal. So another way of thinking
           | of this is that an engine dissipating 10 GW is equivalent to
           | something like 25000 handguns firing at once, without ever
           | stopping.
        
           | 7952 wrote:
           | Saturn V at take off had an equivalent power of 166GW. If
           | that was electricity it would be around 2x the total capacity
           | of all the power stations in the UK.
        
           | beerandt wrote:
           | And then on top of it all, throttling ability.
           | 
           | People don't grasp what an unbelievably complex engineering
           | problem that is. It's at least an addition of difficulty at
           | the same magnitude as building a steady-state 63000 hp
           | turbine pump in the first place.
           | 
           | Mechanically implementing it in the inherently steady-state
           | design rocket of most rocket cycles. Having variable controls
           | able to work at those pressures. Testing structural dynamics
           | for a range of harmonic conditions instead of one. And do all
           | of that with materials that need to tolerate temperatures
           | going from cryogenic to white hot, without allowing thermal
           | expansion to affect the mechanical tolerances of parts
           | running at thousands of RPMs. And now you have varying flow
           | rates and negative pressures in the lines coming from the
           | external tanks, so have to design such that cryogenic liquids
           | (that normally would require immense positive pressure to
           | keep liquid) don't spontaneously boil or cavitate or cause a
           | shock-like wave (think water hammer turning off your bath
           | faucet) under changing negative pressures.
           | 
           | It's really difficult even for seasoned engineers to grasp
           | the scale of difficulty involved.
        
             | LeifCarrotson wrote:
             | Appreciation of engineers for the difficulty of an
             | assignment like this seems bimodal.
             | 
             | On the one hand, you have https://xkcd.com/793/ responses:
             | 
             | > _You 're trying to predict the behavior of <complicated
             | system>? Just model it as a <simple object>, and then add
             | some secondary terms to account for <complications I just
             | thought of>. Easy, right? So, why does <your field> need a
             | whole journal, anyway?_
             | 
             | Just pressurize the tanks, and meter the flow with some
             | valves. Easy, right?
             | 
             | They move to the other side of the distribution after a
             | little more thought, when they they realize it's simply
             | infeasible to put thousands of horsepower in a pump that
             | size, and declare the whole endeavor completely nonsensical
             | and impossible.
             | 
             | Ran through this on a recent project involving an automated
             | sewing machine. At first, it seems ludicrous that you could
             | tie knots thousands of times per second. Oh wait, it's a
             | single motor and old cam-driven tech from the 1800s,
             | available off the shelf for a couple hundred dollars?
        
               | avmich wrote:
               | They also move to the "simple" side as well. The phrase
               | "the rocket science is not a rocket science" has reasons
               | to exist.
        
             | codeulike wrote:
             | _It 's really difficult even for seasoned engineers to
             | grasp the scale of difficulty involved._
             | 
             | Its rocket science
        
               | InitialLastName wrote:
               | A joke you hear unceasingly when you take tours of
               | engineering schools with a heavy aerospace focus.
        
           | post_break wrote:
           | Reminds me of fuel injectors of funny cars. Watch it go from
           | just idling, to full throttle. Then remember there's 8 of
           | them on the engine.
           | https://www.youtube.com/watch?v=xGTbQuhhluY
        
             | jcims wrote:
             | Top Fuel copypasta -
             | https://wediditforlove.com/techtalk21.html
        
         | dekhn wrote:
         | It sounded incomprehensible to me too but as I did some more
         | learning about the process of building rocket engines I learned
         | some interesting details. First, remember that people have been
         | making high strength metals through careful processing for
         | thousands of years. Second, the parts of engines are not made
         | as part of large-scale industrialized manufacturing. Almost all
         | the parts are made as few-offs, with far more energy, time, and
         | effort put into making sure that a single instance of something
         | is extremely reliable. Third, we got damn good at materials
         | science in the past 100 year, and metals can be absurdly
         | resistant to deformation under heat.
        
           | [deleted]
        
           | dokem wrote:
           | They also only run for a few minutes.
        
             | beerandt wrote:
             | SSMEs are reusable.
             | 
             | Designing for thermal cycles and serviceability[0] is at
             | least as difficult a problem as running a hypothetical
             | rocket engine an equal amount of time in one longer, hotter
             | burn.
             | 
             | (Such a design isn't needed and wouldn't be practical, but
             | then again multiple aspects of SSMEs being reusable turned
             | out not very practical either, depending on what version of
             | design criterea you evaluate and how the expected vs actual
             | usage changed over the lifetime of the program.)
             | 
             | [0]In both the engineering sense, as durability of the
             | various loading cycles (ie lifetime turbine rotations or
             | number of thermal cycles before eol or failure), _and_ as
             | being constructed as able to undergo maintenance and
             | refurbishment between launches.
        
               | avmich wrote:
               | > SSMEs are reusable.
               | 
               | Not as much as RL-10s. SSME you can disassemble - because
               | you should do that, as thermal stresses on turbine blades
               | are too dangerous, so you have to periodically replace
               | the parts which nearing the fault.
        
             | yetihehe wrote:
             | Engines in dragsters are also know to have very high power
             | comparing to engine size, but they also make less than 10k
             | rotations at full power before they fail. That is enough to
             | last one drag race which is several seconds.
        
         | throwaway0a5e wrote:
         | Don't think of it as "making horsepower", think of it as
         | "resisting the forces upon it".
         | 
         | A gear tooth the size of your thumb pulls a semi truck up a
         | mountain.
        
       | Dig1t wrote:
       | Everyday Astronaut is such an impressive dude, I don't understand
       | why he doesn't just work for SpaceX at this point. He knows more
       | about rocket engineering and can explain it 10x better than most
       | aerospace new grads.
        
         | guynamedloren wrote:
         | Small pedantic note: this article is authored by Claire
         | Percival, not Tim Dodd.
         | 
         | I'm not familiar with the working dynamic - Tim very well could
         | been involved in authoring this piece - but, credit where
         | credit is due.
         | 
         | Edit: I partially recant this. The article includes a video by
         | Tim.
        
           | philipwhiuk wrote:
           | As I understand (as a Patreon), in general, Tim writes the
           | video and then one of his team write an article that covers
           | what the video says only with more text to substitute for the
           | lack of visuals.
           | 
           | For Pre-Launch Previews they are written first by a team
           | member.
        
         | colordrops wrote:
         | He's probably making more money with his media that he would
         | working there.
        
         | paxys wrote:
         | Having a YouTube channel with 1M+ subscribers and videos that
         | get 5M+ views each is a _much_ more profitable and generally
         | better gig than SpaceX employee #10,000+ working 60-80 hours a
         | week in a high pressure culture.
        
         | philipwhiuk wrote:
         | There's a big difference between researching a topic to a
         | standard good enough for 'popular rocket science' and
         | 'understanding the maths well enough to work in the field'.
        
           | kragen wrote:
           | Has he built prototype rocket engines like Integza, Ben
           | Krasnow, or Tech Ingredients? They're still primarily
           | _divulgadores_ (there isn 't a good word for this in English)
           | but they have a certain amount of practical experience
           | getting things to work.
           | 
           | OTOH at the point that you're EDM-drilling thousands of
           | micron-scale holes in your combustion chamber for film
           | cooling, you may start to need practical experience with
           | different things.
        
             | patrickyeon wrote:
             | I've never heard the term _divulgadores_ (I don't speak
             | Spanish, so that's no surprise), but it sounds maybe like
             | "science communicator" in this context? There's something a
             | bit more to the people you've listed in that they are also
             | entertainers, not straight educators, I don't know if
             | that's wrapped up in divulgadores as well?
        
         | mlindner wrote:
         | I don't actually think he's that impressive and I don't get
         | people's praise for him. His videos have a lot of mistakes in
         | them and while they're written in a way that dumbs down a topic
         | well for an audience who doesn't understand the subject very
         | well, that's his only major skill that's involved here. He's
         | not especially smart or ingenious, he's just a good
         | communicator. If he was to work somewhere it would be in a
         | communications department, but he probably makes more from
         | Youtube than such a job would provide.
         | 
         | That's why he doesn't work for somewhere in the industry,
         | youtube makes him more. (He makes enough money to hire other
         | people to write for him, as we can see in the linked article.)
        
           | HectorRamos wrote:
           | Tim spends countless amount of time going through the
           | scripts, read throughs, first recordings, and so on, with
           | Patreons. I've been on many of these read throughs, usually
           | with several engineers in the aerospace industry present, and
           | it's meticulous how Tim makes sure any possible mistake is
           | identified and rectified. Even then, once you upload, there's
           | no editing of a video.
           | 
           | The goal is to bring the subject down to a level where
           | everyday people can still follow. It's not meant to be a
           | college course, so of course there will be some dumbing down.
        
         | criley2 wrote:
         | SpaceX sounds pretty nasty to work for. Long hours,
         | machismo/sexist culture, aggressive management, and certainly
         | not the best pay you can find.
         | 
         | He's probably happy where he is.
        
           | sgtnoodle wrote:
           | I worked there for a few years, on flight software. The
           | culture depends quite a bit on what department you're in. I
           | learned how to push back on schedule pressure and was able to
           | strike a reasonable work-life balance, and the head of my
           | department was very good at buffering us from management. My
           | departure was uncommon in that I left on good terms while I
           | was happy. There were other departments, though, that seemed
           | to operate more like a fraternity, and plenty of burnt-out
           | people.
        
         | geocrasher wrote:
         | He is definitely knowledgeable, but strikes me as too much of a
         | fanboy to be taken seriously. I have a hard time taking his
         | videos all that seriously. And it's not about his knowledge,
         | it's about his presentation.
        
           | texasbigdata wrote:
           | Take seriously? Ok let's use his last Russian rocket program
           | history piece....what exactly did you feel was factually
           | inaccurate about it?
        
             | ceejayoz wrote:
             | > And it's not about his knowledge, it's about his
             | presentation.
             | 
             | They're not quibbling with the factual content.
        
             | geocrasher wrote:
             | I never said anything about his accuracy.
        
             | wolfram74 wrote:
             | Weren't you aware? learning is #SeriousBusiness, no fun
             | allowed.
        
               | geocrasher wrote:
               | It's not about _fun_ it 's about getting past the "ZOMG
               | SPACEX!!!!!" stage.
        
               | [deleted]
        
               | Bellend wrote:
               | I know you are getting a lot of snarky comments, but
               | honestly I know what you are saying. I can't watch his
               | channel for whatever that gushiness thing is.
        
               | geocrasher wrote:
               | I appreciate that. Thanks.
        
               | m_mueller wrote:
               | Worth checking it out again, he toned it down a lot
               | recently IMO. Still prefer Scott Manley, but only
               | astronaut gets the level of access like that. I mean Elon
               | showed him basically everything in front of a camera.
        
               | geocrasher wrote:
               | There's definitely reason to watch his channel, and that
               | particular two part series was one I consumed in whole.
               | Loved it. HUGE takeaways from it.
        
           | lilyball wrote:
           | > _too much of a fanboy to be taken seriously_
           | 
           | I would be really interested to know why "caring too much" is
           | a disqualification.
        
           | Dig1t wrote:
           | I guess some people's exuberance can turn people off, but
           | honestly its great in my opinion. Why should someone's joyful
           | exuberance for something make his educational content not
           | worth watching? The guy is obviously just very passionate
           | about spaceflight and people who are pushing the boundaries
           | of science/technology. I think 99% percent of the people I
           | talk to approach this kind of stuff with mundane indifference
           | and cynicism, so I think seeing someone genuinely passionate
           | and excited by it is a breath of fresh air.
        
             | geocrasher wrote:
             | I sincerely appreciate his passion. It just goes over the
             | top _for my personality_ and keeps me from really getting
             | into it.
        
           | sebzim4500 wrote:
           | Classic SpaceX fanboys, always making 90 minute documentaries
           | about the history of every Russian rocket engine.
        
             | geocrasher wrote:
             | If you can pick your video to base your assessment of my
             | comment on, then so can I:
             | 
             | https://www.youtube.com/watch?v=7STa-tiQajQ
             | 
             | And by the way, I never mentioned SpaceX
        
           | thamer wrote:
           | I've seen this kind of comment before about his presentation,
           | and I don't really understand it. It's true that he's a
           | fanboy and that's especially visible in his video
           | interviews/visits with Elon Musk, but the style of those
           | videos is markedly different from the more educational ones
           | which are often trying to cover a topic with a lot of detail
           | while remaining relatively accessible.
           | 
           | I watched the video version of the article linked here this
           | morning, and don't recall any part that was fawning over
           | anyone or anything in particular.
           | 
           | What is it about his presentation that puts you off?
        
             | geocrasher wrote:
             | I don't know what the right word is for it. I used "fanboy"
             | but maybe there's some other better word. Somebody else
             | above used "gushiness" I think and that sounds about right.
             | 
             | It's like having a friend who won't shut up about a new
             | sushi place they found. Yes, the sushi is amazing. Yes, the
             | staff is nice. Yes, the atmosphere is great. And I could
             | enjoy it more if my friend would stop making a big deal
             | about every little thing about it.
             | 
             | Edit: Just skipped through the video this thread is about
             | and that vibe just won't go away. I don't feel like I'm
             | being informed, I feel like I'm being _sold_. The
             | information itself is very, very good!
             | 
             | For what it's worth, the Professor of Rock on YT has the
             | same vibe for me.
        
           | mlindner wrote:
           | I completely agree, but the fanboy aspect isn't really my
           | main sticking point, it's his tone that feels like he's
           | teaching elementary schoolers something.
        
             | dvtrn wrote:
             | Isn't that the point of the channel? Making astronomy
             | accessible to "Everyday" people?
        
             | piyh wrote:
             | He's teaching literal rocket science to the masses.
        
           | GuB-42 wrote:
           | I find he toned down the fanboy aspect a bit. A few years
           | ago, he could have been part of SpaceX marketing department.
           | 
           | He still loves SpaceX, and to be fair, who doesn't. You may
           | not like Elon Musk, his fanboys, the outrageous claims, and
           | the way the company is run, but most of the exciting news in
           | rocketry for the last decade are about SpaceX. But for the
           | last few years, it is clear that he makes some efforts to be
           | impartial and focus on the technical aspects.
           | 
           | And you should watch the videos he made with Elon Musk when
           | he visited SpaceX. I expected little more than an ad for
           | SpaceX, and it turned out surprisingly technical and hype-
           | free.
        
             | geocrasher wrote:
             | I did watch both those videos, and they were excellent!
             | Well, Elon's parts were excellent. I still found the
             | questions to be more on the fanboi side than the
             | engineering side, and that's okay. It's his brand, he can
             | do what he likes.
             | 
             | I prefer Scott Manley's approach to things, and so I watch
             | him instead. And when he says that EverydayAstronaut has a
             | great video, I go watch it :)
        
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