Why do cylindrical rockets roll?

[@albertbatfinder5240]

We live in a wonderful age. I am not talking about space exploration, but the fact that such a quality science video can be produced by enthusiastic individuals and published for free. 30 years ago it would have taken a full production team and the commitment of an entire broadcast network. Great stuff, sir. (And your helpers)

[@lifter1000]

Yep, today every semi-talented kid can lecture on rocket science

[@awuma]

@@lifter1000 Actually, they have to actually get it right! The fact that Elon and other to people have granted interviews to Tim shows that he is a respected journalist and commentator on space matters. This is a wonderful development, that journalists can win a following and even earn a living without being hired by someboy else and being beholden to an employer (though it's not an ideal situation when the platform owners can decide what videos are worthy of earning money).

[@mrbrianbrush]

@@lifter1000 you upset gil?

[@lifter1000]

Always

[@lifter1000]

The whole article you wrote is related somehow to the subject of this video?

[@higgydufrane]

The man loves talking about rockets. It makes it so much easier to listen when the speaker is enthusiastic about the topic. Well Done.

[@BenSullinsOfficial]

I'm sticking with they roll for fun

[@hmm396]

No

[@prohz9129]

Edvin Tabakovic: no you can’t just do it for fun *haha roll go brrrrrr*

[@lucky5853]

Yeah, but first they rock and then they roll.

[@markushahn9123]

Because loopings are not so a good idea, exept the orbital ones.

[@hamburgerhamburger4064]

That must hurt

[@ioresult]

KSP really comes to life when used as an educative tool. I love it.

[@cjax469]

2:52 engines are in the front, not the back. This bothers me lol.

[@alanmaclaren4118]

Hey give some credit to sfs

[@felsfat4734]

Alan MacLaren SFS is ridiculously unrealistic

[@alanmaclaren4118]

@felsfat because the developers are trying to make the game as simple as possible for players to understand it, plus the game has realistic orbital mechanics

[@beats007]

How to download ksp?

[@SpecialEDy]

Yup, In Kerbal Space Program, I learned that separatrons and flea boosters arent enough to separate some larger asparagus boosters. You need to constantly roll to keep the next pair of separating boosters parallel with the horizon

[@SpecialEDy]

@Addison Brendtro the plumbing is very difficult. As far as I know, only the space shuttle and Buran Energia have a retractable fuel coupling like this to an external tank, but they detatch after Main Engine Cutoff

[@solomanwill1]

"Why do cylindrical rockets roll?" Because they rock!!!

[@eliethdiez964]

@Addison Brendtro falcon heavy uses asparagus staging

[@CarlosAM1]

@@eliethdiez964 it doesnt. It was going to but it was decided it would not

[@Thor_the_Doge]

Oh, so I'm not the only one who keeps my rockets stable in ksp by rolling?

[@liesdamnlies3372]

I kinda love how KSP can be used as a tool to demonstrate so many of the basics of spaceflight.

[@theswagman1263]

So glad I took the time to get vaguely competent at ksp. Gives you a way better understanding of spaceflight. Furthest I've had a manned (kerballed?) landing is only Duna tho

[@martinincze1911]

@@theswagman1263 Build a refueling station on minmus mate. I launch all my craft to minmus where i have a permanent mining operation going with massive fuel tanks. I fuel up there and then on.

[@baflabies]

@@martinincze1911 Thx ama try that:)

[@dongurudebro4579]

Another great video. At first it seems like a no problem, but you really did a good job explaining why its necessary and how it works. Moreover i really have to thank you for your ever increasing quality standard; nowadays you live up to your name, cause it is literally out of this world! ;-)

[@arghya426]

Agreed😊

[@falafeldurum2095]

great video, but I disagree with Everyday Astronaut that it especially would make sense that asymmetrical rockets roll..

[@micahrandall1344]

he does good job every time

[@chemiegamerpeter]

Bist du nen bot oder was? Ich sehe dich echt überall

[@dongurudebro4579]

@@chemiegamerpeter Ich bin Bot Don Versionsnummer 1.55.97.3 beep beep Ich bin gegen Artikel 11 & 13 beepi bup. ;-)

[@nettlesoup]

I skipped watching this video the first time it came up in my recommendations because I guessed it wouldn't be that interesting. Boy, was I wrong! This was fascinating from start to finish, and I really enjoyed the way you put it all together and summarized at the end. 🙏🙏

[@BillPickle]

Man that 20 minutes flew by so fast, and was still incredibly informative and entertaining. Great video Tim!

[@FlyGuy2000]

Totally! I was like, "Well maybe I'll just watch a few minutes of this" and then it was over.

[@bluered3228]

Thanks. We all really appreciate the obvious time and effort you put into your videos.

[@zymosan99]

i cant tell if this is sarcastic or not

[@bluered3228]

@@zymosan99 it's not. Perhaps if it was about his live streams, we'd have something to be sarcastic about...

[@zymosan99]

@@bluered3228 ok

[@PeterArnold1969]

Another amazing explanation of what can be a complicated subject. Always remember, going to space is HARD! Thanks for putting the time in to make this.

[@pilsnrimgaard2507]

Wow, the scary part is I actually comprehended almost half of what you just covered. So much to know. I will have to watch all of your videos now that I'm hooked. Great stuff to know! And always remember, Rockets don't fly, they roast the air into submission.

[@Trev0r98]

"Why do cylindrical rockets roll?" *Because they rock!!!*

[@74wf]

It's backward innit

[@theEWDSDS]

Ha

[@myrobotfish]

Most dads: "Okay are we ready to rock-and-roll?" Tim as a dad: "Okay are we ready to rocket-roll?"

[@panda3d180]

I saw this from the phinese and ferb show thing

[@edmund3504]

ready to rock pitch yaw and roll dad

[@hazgebu]

Are you ready for Rick & Roll? kzbin.info/www/bejne/mYSkoWypd9-DmMU

[@steve1978ger]

It's only rocket roll, but I like it.

[@myrobotfish]

@@steve1978ger Rock-and-roll. Rock-et-roll

[@AmxCsifier]

First time I see a thumbnail arrow which is actually useful and not spammy

[@mr.boomguy]

And it's not even that eyecatching 😉

[@AmxCsifier]

@@mr.boomguy It doesn't have to be eye catching because I actively look for them in thumbnails 😅

[@AmxCsifier]

@C S English is neither my first nor my second language so my English may not be perfect but I'm always learning and I thank you for providing a correct example. 🤗

[@bfunkt4313]

@C S You couldn't even take the time to write a complete sentence when complaining about someone else's English?

[@roderickwhitehead]

🎯

[@Davide_sd]

Another great video, thanks Everyday Astronaut. One thing I'm not entirely sure about is the 20% increase of payload capacity of the Space Shuttle (that would be insane!!!!). A few months back I followed the entire open course "Engineering the Space Shuttle" at EdX, and the question "why the SS perfomed the roll maneuver" came up a few times. The engineers doing the talks gave 2 reasons: 1. They were re-using old Apollo launch pad, therefore they were subjected to their limitation and needed to be able to place the vehicle at the right attitude (with the roll maneuver). 2. The aerodynamic engineers figured it out that there was less stress on the orbiter when it was sitting underneath the main tank during the max Q phase (maximum areodynamic pressure), this was because (as you mentioned) the thrust was directed throught the center of the mass of the entire system, therefore the orbiter was somewhat skewed with respect to the flight path. Funny story (I don't know if it's actually true, but it was stated on the aformentioned course): when Soviet launched their first and only Buran, they too did the roll maneuver. They didn't have to, because their launch pad was capable of giving the right attitude to the vehicles. So american engineers (after the collapse of the soviet union) asked russian engineers: why did you do that roll maneuver??? They replied: "Because you did it" :)

[@eigenvalue9358]

I'm no rocket engineer by any means, but the payload increase seems quite logical to me. As stated in the video the engines of the space shuttle had to gimble outward in order to compensate for the far stronger thrust of the booster. If now the space shuttle is aligned so the booster is "outside" of the flight curve and the shuttle "inside" of that curve there is less need for compensation. I can just guess that this way less gimble has to be used on the engines, which would sound more efficient to me. In case I'm wrong please someone smarter correct me.

[@kindlin]

There are a number of reasons that make having the the heavy, lopsided thing orient earthwards makes sense, not least of which what Eigen Value discussed. With less stress on the vehicle, the vehicle can now handle more weight within. With this being the case, the critical limit state must have been the structural integrity of the shuttle/booster at max-Q. I would have thought it would have to do with how much fuel you can fit into the tanks, but maybe the tanks aren't always full, and, actually, they only have as much as they need?

[@matejlieskovsky9625]

If the improved aerodynamic saved a few percent of fuel and the decreased engine gimbal saved a few percent of fuel and the reduced stress allowed for a little more fuel on board and a little lighter shuttle... Yeah, I can imagine that made a 20% payload difference. Don't forget, that would be a change of roughly 5 tonnes to LEO on a 2000 tonne system.

[@kpatelPub]

Tim mentions that the increase was from the shuttle being in the wake of the tank, presumably indicating aerodynamic benefits. I also wonder if it might have benefited from the fact that, with engines always gimbaled outward, situating the shuttle underneath automatically orients its engines' thrust vectors so as to have a stronger upward component to them throughout the fight path than they would in the opposite position. Apologies if this idea is foolishness. I, neither, am a rocket engineer. :D

[@matejlieskovsky9625]

@@kpatelPub Rockets don't care about upward thrust - most of their energy goes into moving sideways. You really just want forward thrust and the rocket mostly just pitches over to point where it needs to. The whole SSME gimbal vs SRB offset and gimbal thing is getting more complicated the longer I look at it. :-(

[@dukecity7688]

Finding this at my late age is just thrilling. Let me be clear. I played this three times and i am years away from understanding but i don't care because i love watching and you are a great teacher - You are great and i feel lucky to have found your site. First go up really fast - then sideways really,really fast. Funny Thank You

[@nathanwahl9224]

You got it! Just add "And point it in the right direction, too." Methinks you understand a lot more than you let on to, and a LOT more than most folks in the general population do!!! I'm "at that age," do understand most of it; now, that is anyway. And have wondered about these whys for six decades! It IS rocket science: If you liked it, you're doing great! Cool!

[@lawrencequave8691]

I absolutely LOVE your presentation technique. Young good looking guy with a nice smile, a bit of a beard wearing a t-shirt and baseball cap (at least it's not on backwards), rattling off "rocket science" stuff as if even a second-grader could understand it, with the point being that if one really wants to learn all this stuff it can be done because other's before have. I suspect there's a lot of young folks who watch your presentations (all very interesting), shake their heads in awe, and then turn and say, "Mom, I've decided I'm gonna be a rocket scientist." You wanna call me a nerd, then call me a nerd, because being a nerd is fun and I'm proud of it. Your enthusiasm makes your shows fun to watch. Keep up the good work.

[@jacobsteinebronn2966]

IMU stands for Inertial Measurement Unit not Instrument unit Please upvote so he can see this

[@mattsi-eb4bo]

Hello fellow redditor

[@nicholasboccio]

came to comments to say this as well

[@bennylofgren3208]

@@nicholasboccio Me too.

[@joevignolor4u949]

Correct. The IU is the entire Instrumentation Unit. The Inertial Measurement Unit (IMU) is a major component of the IU that is located inside it.

[@jocax188723]

It's okay Tory Bruno beat us to it twitter.com/torybruno/status/1141298274491613184

[@AthanImmortal]

Tim, I really appreciate that you asked a question on twitter that turned into a whole video. You're one of the best examples of not being afraid to ask what you don't know, especially with some of the idiotic replies you got. The video is fantastic, well produced, great narrated. Thanks again!

[@shehulsuratwala2684]

This is what a quality video should look like. Amazing explanation and knowledge rich content. Seriously man, Hats off to your work. You have improved your videos quite a lot.

[@esecallum]

DONT YOU FIND IT BORING?

[@fruitella196]

Ese Callum no?

[@shehulsuratwala2684]

@@esecallum It is definitely more interesting than reading your useless comment and replying to it. From which angle you think it is boring? I am an engineer and I know how much time they have invested in development of these rockets and the math behind it. For me it is very interesting. You please enjoy your cats and dogs videos.

[@shehulsuratwala2684]

@@fruitella196 English please.

[@fruitella196]

Shehul Suratwala what are you on about? It was English

[@keithbrown2458]

This is probably my third or fourth time to watch this film because I forgot all the reasons why the rotation you’re the first one to actually explain most all of them if not all of them indeed, Thank you sir for keeping me well educated, love your stuff man!

[@joncapps3338]

Just wanted to say thanks, I've always been a space nerd but don't have the math skills to understand engineering speak. You hit the perfect balance of common sense layman terminology but still giving a really precise and comprehensive explanation. Great job and I've learned so much.

[@facuigua12]

The quality of this channel is simply breathtaking.

[@Gibson99]

Tim: Hey Elon, why was there a big roll in the launch from Vandenberg today? Elon: That's how I roll...

[@MrJaiimez]

Although like others have said, it's highly unlikely they didnt have a reason, but I would be crying with laughter if he did it just to mess with Tim, it would be beautiful. Let's face it his speed in responding to the raptor video I wouldn't be surprised if he was a patreon and was able to see bits of the video before release.

[@drpeejay54]

Robert Slackware That’s what I’ve been saying all along😏

[@zhongxina9420]

@Robert Slackware *insert angry essay here* Just kidding you don't desrve attention

[@borgman151]

Wow Tim! Even an idiot like me can now understand azimuth, pitch, yaw and roll in rockets. You are brilliant sir.

[@thunderbird1921]

Remarkable so, why did the space shuttle not roll after a few moments? Did the wings stabilize the whole launch stack during flight?

[@oliverdots]

Not only is this well explained, it's answered a question I have asked myself for many years. Great Video

[@craigdeandean4036]

Great job Tim I really enjoy your episodes I grew up in the time of Apollo and ever since have been mesmerized by space! Thank you

[@Airguardian]

Wonderful, WONDERFUL video! Well done! :D

[@KonstaKokC]

In Soviet Яussia launch pad rolls you 🚀

[@kindlin]

This is great, had me lol'ing.

[@mattc.8839]

Nice 👍

[@Ivan_Chesnokov]

В точку!

[@calumaguer0]

Soviet Yahssia

[@NelsonBrown]

lofr - laughing on the floor rolling!

[@faceplants2]

Out of clever comments for the day but gotta show love and keep the engagement up for Tim's channel!

[@ericcsuf]

This could have been a terminally boring video esp. for someone who never even considered why rockets roll. It wasn't...boring, that is. I didn't even realize I had just watched a 20 minute video until someone in the comments mentioned it. Very entertaining and informative. You're a talented teacher.

[@tracycapilot2002]

Hey Tim, I grew up watching the Apollo flights and always heard that 'roger roll' callout and just figured that it (the reason) was too technical for us space fans to comprehend. THANK YOU for the explanation! Others might have 'fire hosed' us with too much info but you keep it simple. Your 'friend' Elon just toys with us simpletons (fun) but it's helpful to know why a thing does what it does. My 3 year old granddaughter is at that stage where she asks "but why?" and it occurs to me that we all ask "but why?" all our lifetimes and it's great to be taught and understand. Thank you again Sir!

[@marco_plebani]

I've developed a mild addiction to your videos recently. They make me marvel at the many unexpected challenges of space exploration and at the spectacular engineering ingenuity that overcome them.

[@jebediahkerman3826]

Other world: *turns a rocket to its flight asimuth* Soviets: *turn a launchpad to rocket's flight asimuth*

[@oremooremo5075]

Jedediah Kerman Other world pours millions of litres of water to reduce sound levels during launch. Soviets build a deeper trench

[@TarsoFranchis]

Another world: build rockets horizontally, like a production line, USA: They build the most difficult, vertically, needs a costly VAB and large tugs for the pad. xD

[@nikolatasev4948]

In Soviet Russia launchpad rotates you.

[@notmenotme614]

@@TarsoFranchis How fragile the payload is determines is it can be fitted horizontally or vertically. Because the payload is designed for less gravitational forces and can’t withstand the weight bearing on Earth in certain directions

[@obsidianop9802]

The soviets were pretty genius in terms of spaceflight Yes, more genius that the US

[@frisk151]

Excellent video! My brother and my kids (and both of us too!) watch all of your content. My uncle retired from NASA (in Clear Lake, TX = Houston) a decade and a half ago but we got entrance to Mission Control (guest viewing area) a few times in the 80's to watch Shuttle launches, but he only talked "rocket science" to us, which to kids is essentially static... The way you explain things is easy for even the layman to understand! Thanks!!!

[@prjndigo]

You forgot centripetal distribution of fuel / slosh dampening.

[@integralmath]

Plus there's moisture in the air that gets it wet. 'Roll program' and 'rolling about its x-axis' is just a highfalutin way of talking about putting it on spin cycle.

[@kvltizt]

It helps prevent resonant waves forming in fuel, I suppose?

[@KRGruner]

Man, you are killing it once again. Excellent in all respect. Keep the videos coming!

[@jacksagrafsky4936]

"Stick the pointy end" in the direction you want to go?? I have to go now this highly technical talk is way over my head.

[@a64738]

That actually work if you have enough fuel and power... I successfully managed to go to the moon in Kerbal Space Program using that method but it is ineffective.

[@small_SHOT]

in ksp my abominations usually commit explosion

[@fancy4663]

This conversation is too high iq for me

[@achtsekundenfurz7876]

[@theEWDSDS]

Ha ha very funny

[@RaitisGrandovskis]

@9:48 IMU stands for Inertial measurement unit- basicly combination of multiaxial Gyro/Accel/Magnetometer , every modern phone has IMU chip inside.

[@stevee8884]

MEMS-IMU : en.wikipedia.org/wiki/Vibrating_structure_gyroscope#MEMS_gyroscopes

[@stevee8884]

All flying drones have a MEMS IMU

[@AbsoluteDespotism]

en.wikipedia.org/wiki/Saturn_V_instrument_unit

[@kindlin]

I always wondered how our phones could do so many marvelous things, it's all because of that one chip.

[@JesseMcCall]

Came here to clarify. Thanks for beating me to it!

[@rickskrovan2477]

I don't know how you don't have more subscribers on this channel. Your videos are always so informational! Soon as my kids are old enough to comprehend what you are talking about, they will be watching your channel. Keep up the awesome work!

[@bryandraughn9830]

Excellent work man! You and your team are going places! Far away places! Wink wink;) Congrats on your trip and I can't think of a more deserving recipient. Peace

[@laurin4405]

😉Indeed💌🌛

[@rowde8203]

10:50 "It's nice to keep it simple" while literally talking about ROCKET SCIENCE

[@TheGreatDrAsian]

That's the best part! :D

[@TheBrandoGR]

It's actually exactly why they need to keep it simple. Any added complexity can increase the risk of failure by a substantial amount.

[@AdrianoCasemiro]

Simpler will do.

[@Sciguy95]

I have a shirt that says, Aerospace engineering: It's not rocket science, Oh wait, yes it is.

[@Theraot]

@@Sciguy95 So, you like to signal that you think engineering and science are the same thing

[@djdm2603]

When you forgot to add sepatrons to your SRBs and dont wanna blow up when staging.

[@MrFlarespeed]

When u added sepatrons but they don't work well enough to not boom your kerbals

[@valorkaizen]

@@MrFlarespeed when you use those small solid thrusters to launch your Rocket

[@tylisirn]

You don't need sepatrons 99% of the time if you attach your SRBs correctly. Instead of putting the decoupler in the middle, put the decoupler high, and then use the translate tool to move the SRB down, so that the decoupler attaches to the nose of the SRB. (Optionally, attach a strut on the bottom of the SRB to keep it rigidly connected to the rocket). This way when you decouple, the decoupler kicks the SRB such that it starts to rotate *away* from your rocket, rather than towards it like it does when the decoupler is in the "default" middle position.

[@franklinz8098]

separate them one second early so the shoot out instead of hitting the rocket

[@ebigunso]

@@franklinz8098 And by chance they shoot into your rocket instead of outwards. If you ensure that doesn't happen, you now don't have to separate early.

[@windmillstudio]

Speaking of rocket azimuths... In 2017 Russian "Fregat" booster has failed to deliver some communication sats to the orbit. The launch was happening on the new "Vostochny" cosmodrome, which has a starting azimuth of 168°. Target azimuth for lower stage was 354°. So the lower stage has decided prior to launch: "I need to rotate from 168 to 354, the fastest way is to rotate left by 174 degrees". Target azimuth after separation for upper stage, however, was 344°. So the upper stage has decided before launch: "I'm gonna rotate right by 170 degrees, it's the fastest way". Then after launch when the first stage completed the roll succesfully to the left, the upper stage calculated correctly that it is only 10° to the right from it's target direction, but it already decided on the ground that the fastest way to roll is to roll right... So it started to roll full 350° to the right, but didn't make it before second stage ignition and has gone to the wrong unstable orbit, ditching to the Atlantic Ocean shortly after. The problem was in the code of booster's navigation system, but it always worked just fine before, because there was never such an unfortunate combination of azimuths.

[@chmeee9562]

thanks for sharing that!

[@janiss2926]

yikes! - that's an oopsie! :)

[@kvltizt]

That is a painful way to figure that out.

[@yodaandthebike5839]

This was an awesome video. I watched someone else trying to explain roll a few days ago and came away with more questions than when I started. Brilliantly explained and the summary at the end was perfect.

[@nathanwahl9224]

Absolutely answers questions I've had for six decades!!!! Thank you!!!

[@mikekocziban]

I love rocket-roll, so put another dime in the soyuz baby!

[@kenfreeman8888]

You helped clarify a lot for me. Thank you.

[@LordOstrik]

As someone from that area of Iowa... I feel special lol.

[@grlldfsh123]

I ALSO am from Iowa, felt good to be youtube recognized on a quality video

[@JeremiahCecil]

Hear, hear!

[@Duckeasily]

It’s weird hearing someone online talking about a town I’m am used to.

[@curtislowe4577]

Oddly Rocket Man overlooked that the streets in the downtown Houston are also oriented 45° to the compass points.

[@tpstrat14]

that Chris Hadfield masterclass ad is the only ad I have ever watched all the way through on youtube. And I've watched it 3 times now!

[@wallymcguire2033]

Timothy Stratton Lol, I took a screenshot of it and made a Facebook post that I actually watched a KZbin ad to the end for the first time ever 😂 Good job Chris, you kept me interested!

[@thomasdillon7761]

Thank you for answering a question that I have had since the 1960s,

[@theanonymous393]

Great Video, really appreciate your work. :)

[@bobcousins4810]

I always wondered about this too. The V2 was literally pointed in the desired direction by rotating the launch platform, I guess before the days of electronics it only had a primitive pitch control.

[@allangibson8494]

The V-2 had a rather complex programmed pitch routine hard coded into the guidance system. The gyro’s have pitch limits due to the gyro gimbals which can lockup if over rotated. All the rockets until the shuttle had mechanical gyro’s and thus gimbal lock was a problem.

[@johndododoe1411]

@@allangibson8494 Modern gyros are still mechanical, Just smaller.

[@johndododoe1411]

The turned launch mount makes a lot of sense once you know that the USSR classified it's rocket program as part of the artillery. Artillery officers are used to rotating their cannon on the ground to point towards the target. Same with the V1 and V2.

[@allangibson8494]

@@johndododoe1411 The Russian R-11 Scud was a direct A-4 (V-2) descendant with a duplicate of the A-4 guidance system and engine just like the American Redstone but with even fewer changes.

[@allangibson8494]

@@johndododoe1411 Modern guidance systems are solid state using silicon accelerometers (like what’s in your phone) and laser ring “gyroscopes”. No spinning masses at all. That has been state of the art since the 1980’s. Reaction wheel gyroscopes are actually much larger than traditional guidance gyroscopes - because they actually move the entire flight vehicle on their own.

[@AndrewTheiss]

In case you don't want to sit around for 22 minutes to get an answer it's at 5:30. The rocket rolls to align itself with its flight azimuth so that the rest of the launch is reduced to only pitch adjustments.

[@SpydersByte]

you see a question like this and can't even wait around 6 minutes for the full answer?

[@ImaSpacePotato]

@@SpydersByte That is the answer. Anything else is added context or fluff.

[@SpydersByte]

@@ImaSpacePotato added context or fluff? At the end of the video he lists multiple answers to the title question that were explained throughout. If you think everything but "it rolls to align it's flight azimuth" is just added context or fluff you must've had terrible grades in school. Why do you even bother to watch videos like this with such a meager sense of curiosity?

[@ThetaDyne]

Most it is super super basic. The real answer to why symmetrical rockets roll is that the rockets aren't symmetrical.

[@chrisneale7453]

The best space channel at the best time in human space history. Thank you for your hard work

[@davidsymalla]

I was really impressed with your knowledge!. I am so happy I stumbled onto your page. I absolutely enjoyed this video. Thank you. You just filled my head with knowledge. I had no idea. I knew that rockets rolled and now, I know why.You don’t know what you don’t know.

[@maglax]

Great video as always. I did want to point out that IMU typically stands for inertial measurement unit, and consists of Accelerometers and Gyroscopes. You'll find em in a whole lot of thing (including in a good percentage of boards in any modern car). They can be pretty small too. But yeah a little nit-picky.

[@MrJdsenior]

TIM, you could most likely NEVER figure out all the reasons for the roll program, and CERTAINLY not all the decisions that went into augmenting it. As an engineer, I can tell you that many decisions that are made are never voiced, not even in "lowly" (functionally) design reviews, and certainly never committed to "paper", and most all of them stem from a plethora of competing, often directly contrary, requirements. Payload wants the rocket to weigh nothing, structural want some "factor of safety", aero wants NOTHING anyone else wants, etc. and all with good reasons. I like that the SpaceX guys were "griefing" you on some of it, shows they are interested. With a bit of research, you could find plenty to playfully pick back, I can guarantee you....but with your little "stunt" in the space suit...maybe NOT. Keep up the good work, nice to have someone explaining this stuff to the interested layman with due diligence toward accuracy and reasonable completeness. Here's a fun one for you. My boss and I were walking out of the building one day, and the group in front of us was trying to figure out where their cars were parked, and started one way, then turned around and went the other. I made a snarky comment, and one of them said something to the effect of "the worst of it is we are the G&C (guidance and control) group". We got a great laugh out of that one. Back to the original point, I can GUARANTEE you I've made many design choices, hopefully the right ones for good reason at the time, that I will never remember again. ;-) As I often say, old age sucks

[@jamesbarisitz4794]

Loving the dig deep you do on all things rocket. The animations were outstanding. Super clear and beautifully presented. Oh , and top notch editing. 👍

[@reda.woodcock]

Amazing video, man. So much info and so clear (nice gfx, they really help) and answered a head-scratcher for me. Thanks!

[@QRSTUVWXYZ123ify]

Hats off, wonderful presentation!!! Thx to anyone helping produce these and to your patrons.

[@secularmonk5176]

10:47 Stannis Baratheon has entered the chat: "Fewer"

[@DerKiesch]

15:30 - I think flying parallel to the horizon should give you an additional small amount of lift allowing for a less fuel consuming ascent profile. Since the drag should be roughly the same in perpendicular or parallel configuration, this might be the main reason. From KSP (with ferram) I personally noticed that the rocket seems to also be more stable if you fly parallel.

[@forloop7713]

Good point

[@xnandox]

watched the video 4 times... still haven't got it yet... gonna re watch it 5 more times... i'll keep you post.

[@xnandox]

I just kind of got it. For real I watched 12 times. I'm a huge nerd, and an all time weirdo, but this video clarified me a bunch of my weird theories. for instance: 1.- That "Boring Company" doing high speed tunnels... that might be 1st stage development for: Rail gun orbital objects, and so forth. 2.- within that cannon you can test all the "early life theories" 3.- I'm kind of high and Iost my point

[@rhijermem9300]

ok

[@aoiattentiononinvention8031]

First time watching your videos! Don't think I've ever subscribed to a channel without watching more than one video, but I did here. It's obvious you put a lot of effort in your research. Love it!! While rocket science is fascinating I just never put much energy towards it because of the other things I am interested. I'm making "space" in my free time for this channel. Thank you, for the spark of Interest. 👍👍👌

[@Enemji]

With the amount of reasearch you do, you could and should be awarded a honorary degree in Rocket Science.

[@jimmyb998]

20:40 You forgot one: sometimes, they just roll for fun ;)

[@Avida-l7s-instrumental]

🚀 they see me rollin' They hatin'...

[@edwardmunye]

lol, good one

[@nethascotx24]

Patrolling and tryna catch me ridin dirty

[@spaceguy9025]

Lmao

[@janstankiewicz9816]

Elon, why?! That's how I roll!

[@LibertyDankmeme]

africans don't go to space - let's keep the cow-hide drum banging outta space too plz

[@MrMattie725]

"A nice simple zero" you say, that is, until somewhere someone forgets an exeption and the computer tries to divide by zero :D

[@robertgift]

Well done! Nice, clear graphics. Many do not realize orbit isimply falling toward earth, butraveling fast enough that you continually fall beyond the horizon.

[@jefflindeman]

I love discovering a "new" channel; and by that I mean a mature one that: *rolls to align it's azimuth, rather than moving it's launch pad, easing the viewers guidance by considering topic structure and streamlining presentation (aerodynamics), orienting the viewer's vantage point for logically sequenced deployment, adding thrust to it's communication of complex data through a stable and understandable downlink.* ...takes a big breath and I think that covers it. New sub - was a physics and astronomy major (w/ art minor). Never worked in the field; spent 20yrs as a working saxman and then 20 more as an advertising photographer. Spirit name: Dances with Squirrels. Cheers~

[@Mr.Ramirez95]

8:15 Yea can we stay out of the weed, I'm already having a hard time following along 😂

[@edwardstrassberger2024]

Roll to azimuth could be 180 degrees around. Alignment was to make the astronauts sink into seat rather than fly up, restrained by safety belts. Other way would be like going over the top of a roller coaster or an outside loop. It also keeps the breakfast down!

[@BeechSportBill]

How Air Force Missileers understood the guidance system... The missile knows where it is at all times. It knows this because it knows where it isn't. By subtracting where it is from where it isn't, or where it isn't from where it is (whichever is greater), it obtains a difference, or deviation. The guidance subsystem uses deviations to generate corrective commands to drive the missile from a position where it is to a position where it isn't, and arriving at a position where it wasn't, it now is. Consequently, the position where it is, is now the position that it wasn't, and it follows that the position that it was, is now the position that it isn't. In the event that the position that it is in is not the position that it wasn't, the system has acquired a variation, the variation being the difference between where the missile is, and where it wasn't. If variation is considered to be a significant factor, it too may be corrected by the GEA. However, the missile must also know where it was. The missile guidance computer scenario works as follows. Because a variation has modified some of the information the missile has obtained, it is not sure just where it is. However, it is sure where it isn't, within reason, and it knows where it was. It now subtracts where it should be from where it wasn't, or vice-versa, and by differentiating this from the algebraic sum of where it shouldn't be, and where it was, it is able to obtain the deviation and its variation, which is called error.

[@TheNevawuz]

Like dribbling a ball with your eyes closed.

[@Migs3]

Excellent video. Thanks for taking the time to film and edit it and of course for positing it for our benefit. Keep up the good work! -Migs

[@davidkailer5522]

Really enjoy these deeper-dive, longer videos. Really cool and appreciated!

[@REDACT3D]

extra points for KSP custom flag - I learned somthin ^.^

[@A.Lifecraft]

5:00 most successfull accident in history of space flight :D That mission was to test emergency escape thrusters for the apollo program. While that rocket wasn't supposed to rip itself apart, it provided a perfect testing situation in doing so :D

[@marcusrauch4223]

Error: task failed successfully

[@sweeflyboy]

Literally the most hilarious fail ever

[@nathanwahl9224]

I can just imagine the voices in mission control. "Huh? Oh. OH. OHHHHHH!!! OhOhOhOhOh. (X50) Wow, you got all that, right? Alright, that worked out well; great job everyone!"

[@lyrimetacurl0]

"Actually, it is rocket science."

[@kevinolson9625]

Congrats on addressing questions that the avg person and enthusiast alike benefit from.

[@SirThreepio]

This is a very good introduction to aerospace students as an overview (first year). Good and pleasant

[@me4956]

Kurzgesagt and The everyday astronaut should team up, just imagine

[@svenkathememelord]

That would be a dream come true

[@night_aviation]

Gotta love how Tim explains it with KSP

[@DieSalami120]

How about a video why the N-1 failed? I think that would be interesting! Btw. it's a shame that the N1 didn't fly long enough xD As always great vid! Thanks

[@joevignolor4u949]

The N-1's main flaw was that it used 30 small rocket engines on the first stage that were required to generate enough combined thrust to lift the fully fueled rocket up off the launch pad. Getting 30 separate engines to start and operate reliably in a synchronized fashion turned out to be very difficult. In contrast the American Saturn V moon rocket only used 5 much larger F-1 engines to do the same job. While its true that designing a reliable large chamber engine as big and powerful as the F-1 was no easy task, once the F-1's were developed being able to use just 5 engines on the first stage instead of 30 made the defining difference.

[@epicbastard1]

@@joevignolor4u949 That was just one of the many reasons. The guidance system, aerodynamic effects caused by the massive plume of the first stage and the lack of stability that was later fixed with grid fins. There are probably more, those are just the ones off the top of my head. Problems however were being fixed after every test and every launch, but politicians eventually lost interest because they would be second to the moon anyway. Boris Chertok and others in the project were confident that the 5th launch would succeed. There were two N1s ready for launch when the project was cancelled.

[@stomsits]

Mo engines, mo problems!

[@waltermunday7585]

How GREAT! Thanks for this dive into why things are Rocket Science and not simple. We have a good friend who works at Goddard on programming and communications with analytical instrument payloads at or going to Mars, Jupiter and Saturn. Your information helps me communicate with him.

[@ruediix]

Your one line explanation at 5:25 was enough for me. Of course on Kerbal Space Program, I go and completely align my rocket on the launch pad, including an inclination to start the the gravity turn. Hence the program is to shoot for prograde. Adjusting the time of retaining the initial launch angle, and adjusting the delay between the booster and ascent stage give me two time periods to easily adjust pitch. Holding initial launch vector for longer raises the gravity turn, while waiting longer for activation of ascent stage lowers it. I can do the same as the ascent stage with my maintainer stage if I have one in my rocket.

[@ashishganguli4660]

i still didn't understand, i am so dumb

[@frankv7068]

You’re smarter than you think if you click on rocket science content 😉👍🏽

[@emmgeevideo]

Me either... But I love listening to a smart guy.

[@Concavenator_corcovatus]

Idk, but I can try to help. The rocket is never perfectly balanced, so one side will always be a little heavier then the other, so when the heavier side starts to tip the rocket down so we spin the rocket, this means now the OTHER side is heavier, so it starts to tip back that way, and it keeps turning like that to keep the heavier side keep chasing itself

[@jasonzhang3540]

@@Concavenator_corcovatusdid you watch the video?

[@Concavenator_corcovatus]

@@jasonzhang3540 yeah…?

[@jackglossop4859]

“Surely the reason for this cant be something you do naturally in KSP to make it easier for yourself” - “oh my god it can!”

[@TaeSunWoo]

I just figured the rockets like the dance

[@ricardiagnostics]

Hello Tim started to go by all the videos again and giving thumbs up that I normally forgot to… Once more thanks for all your videos

[@zeeraboom]

Hey mate all of your videos are complete course in rocket science ,loved it

[@ge3346]

Was that the primary buffer panel? Did the primary buffer panel just fall off my gorram ship for no apparent reason?

[@dartmaster501]

It did seem to resemble…

[@topiastanhuala5146]

🎵They see me rolling, they hatin'...🎵

[@BaconBitsGamer1907]

🎵 Patrolling and tryna catch me gravity turning 🎵

[@sumdumbmick]

I kept waiting for you to mention onboard computer complexity, and finally you did give a little nod to it. but I felt it was understated in the vid, and really, it is what it all boils down to. controlling rotation along one axis makes the calculations easier, but if a computer's doing the calculations then just write a program and be done with it right? I mean, that's how the modern world works, I don't need to understand how a cellphone works to operate one, because somebody did all that work already and now it's just a tidy little package that does the things. so, the easier calculations are important not because of a person's ability to perform them, but because of the computer's capacity to perform them in real time. the Soviet solution of aligning the pad basically eliminates the need for any onboard calculations at all, and the SpaceX tactic of doing everything onboard is a luxury specifically afforded by modern computers. so really this is underlyingly a story of the development of computing technology and strategic use or non-use of it. if my computer can only handle a tiny amount of memory, and perform a few hundred or thousand operations per second, then I want to lighten the computational load as much as possible by doing some things outside of the dynamic computational environment. the Soviet solution was essentially to do everything outside of a dynamic computational environment. and SpaceX operates in a world where multicore GHz procs are cheap, so they can basically do whatever the hell they want in the onboard computer.

[@klaus-udokloppstedt6257]

I still don't understand why one has to physically align the rocket's coordinate system to the world's one to turn a general 2 parameter calculation into an easier 1 parameter specialized case one. instead you could use a virtual coordinate system that is aligned to the world one to have the only 1 parameter calculation. the difference between rocket's physical and virtual coordinate system is constant and the conversion to and from is a simple affine transformation, isn't it?

[@waymanharris1284]

Thanks for sharing! I didn't learn this until playing the SpaceX docking simulation!

[@philmoore71]

i better watch this a few times again to comprehend this intriguing topic - really good. tks

[@YukonK9]

Just like Joe's Falcon Heavy, we roll the rocket just because it can

[@lalithchandramusipatla1480]

another BPSSPACE fan

[@YukonK9]

@@lalithchandramusipatla1480 Actually run my own Bps like program. Called Canine Rocket Technologies

[@billsixx]

They roll because it is much harder to flip.......

[@deephorizon1365]

Thanks for the super quick TL:DR

[@AlmostBipedal]

Lost interest. Googled "Why do cylindrical rockets roll?" and found the answer in a couple of minutes!

[@erenozcilingir5918]

AlmostBipedal Omg thank you for coming down into the comments and flexing on us with your ability to do basic google searches.

[@AlmostBipedal]

@@erenozcilingir5918 It was a pleasure. Consider yourself flexed upon.