Limitations breed innovation. Japan needed unguided stages, so they designed advanced passive stabilization. The soviets had limitations imposed by rail travel, so they designed rockets that look like bundles of straws. Innovative ideas to get around seemingly arbitrary problems is my favourite part of engineering.

"It took them 5 times to make this work" That's genuinely impressive

This is a KSP challenge. Mad respect to those who made it happen.

I think it’s funny how the Japanese rocket was designed to not be a weapon, yet it look most missile like of any orbital rocket I’ve seen.

Thank you for allowing everyone to look at rocket launches from a different angle.

Seems pretty logical; Europe is in the center, so it's launching straight up, Japan is all the way to the edge so they have to launch tilted.. and Australia is on the other side so they launch their rockets with the nose pointed towards the ground.

Absurdly high stage count? Insane twr? Spin stabilization? Sounds like my early rp1 career. That the Japanese made this work in real life gets my utmost respect.

"Anybody can build a bridge that stands. It takes an engineer to build a bridge that barely stands." - IDK where I heard that

As a child I watched in the middle of the 80's a documentary about the exploration of Halleys Comet. They showed as well the launch of the Japanese spacecraft and I remember that I asked my father: "Why are the Japanese launching their rockets sideways?" ... My fathers answer was: "Because it is a small rocket." 🤣 Thank you for helping me understanding my (or rather my fathers) misconception after such a long time! Fly safe!✌

When you think of the restrictions the Japanese had, they had to work harder and think more critically than other nations to get into orbit. That really is impressive.

"The (M-4S) second stage lacks those fins. I believe it must have been spin-stabilized?" [9:40] That too, but the M-20 second stage's stabilization was actually unique among space boosters. There were six things which happened at one-second intervals following first-stage burnout: Upper (cone) payload fairing jettison; Lower (cylinder) payload fairing jettison; First stage separation; Second stage spinup (six internal motors just below the transition section having exposed 90-deg nozzles); Split flares open; Second stage ignition. It was the "split flares" (often called simply "flares") which were unique. These were six panels which comprised the bottom of the second stage's exterior and were hinged at their tops. After staging, a piston behind each one pushed it out to a 38-deg angle, approximating a cone-like geometry and thus providing additional stability. In typical ISAS fashion, the concept was proven through a series of progressively larger/higher-fidelity tests: Wind tunnel 10%-scale models; The flares in their deployed geometry affixed to a 160 mm IIRC sounding rocket (presumably to determine basic aero coefficients); Operating split flares which appeared to be sized for flight on a Kappa rocket (if true, 420 mm and so about 1/3-scale); The real deal flown on the M-3D (M-4S minus live fourth stage) suborbital test flight which preceeded M-4S-1.

At 9:00 "It took them five attempts" *IRL attempts* I still can't do it in KSP after two dozen attempts.

The striking thing for me is just how good the photograph of every step along the way are. Very sharp and colorful. It really goes to show how much of an industrial and engineering powerhouse Japan was becoming post-WWII.

So Scott, you say it took them 5 attempts with that 4.5 stage launch vehicle to get that first satellite into orbit... I am properly impressed that they did it in only 5 attempts with that crazy, complicated launch profile! As you stated, first they had to set the launch vehicle at the exact angle to match the required orbital profile that would allow the satellite to get to LEO. If that went right, the next stages had to be spun up to remain stabilised & on target, then before the next stage sep, it had to be de-spun, then separated, then spun back up for stabilization and perfect LEO Insertion.

Nobody does this content as good as you do. Thanks for your work Scott.

Ooh I remember doing "unguided" SRB only challenges (no reaction wheels, rcs, or steerable fins -pure passive stability) in ksp. For timing consistency and telemetry modelling (for iterative development) I used kOS. The hardest part was probably adjusting the fuel/timing for seperatron rotation manoeuvres & tediously adjusting srb fuel in the last 2 stages for accurate orbital insertion. Having a motor you can't turn off is really impractical sometimes.

Reminds me of my early KSP rockets which I would let do gravity turns on their own.

5:49 I just want to take a moment to appreciate how crazy and cool looking that haul truck is with the driver barely above the ground

Rocket science is hard, but this adds a lot of extra hoops to jump through, I mean, ballistic guidance followed by spin stabilization, followed by stopping spin and reorienting before restarting spin. Thank goodness for thrust vectoring, but those engineers were top of their game.

I like the history of rockets so much !! Thank you for that. A lot of great, to me unknown, information. I really would like to see a video of the Diamant Rocket launched by France for example. Thank you Scott ! :)

When you are on holiday, but need to do an urgent video about rockets from 60 years ago...

I would love to see a video of all 5 attempts of the de-spin, orient, re-spin, ignition to orbit. We're so lucky to be seeing live video links of most major events during Falcon 9 launches. Must have been so satisfying to all involved on that 5th flight.

This story is truly amazing, as people ultimately involved in the Japanese war machine managed to reinvent themselves and carried out something extraordinary, given the complications.

I loved this background on the Japanese space program thank you Scott. As a child I sat there glued to the black and white TV programs on the Saturn 5 missions. James Burke, BBC2. I still have my A4 prints of the Saturn 5 launches, view from the moon and moon shots that were "free" with 50 tops of the Tyfoo tea packets. Filling in the gaps of space history we missed is so interesting.

I had the pleasure of seeing an epsilon launch a few years back at the uchinoura space center. Very impressive to watch, especially since it was a pre dawn launch and we got to see noctilucent clouds as a bonus!

A lot of modern sounding rockets still use the passive guidance technique, the Japanese experience helped them, no doubt. These small rockets are becoming very popular for launching very small nanosatellites at low cost and the same sort of angled launch rails are used today at Andøya and Svalbard to launch hundreds of these skinny pencils every year.

The Japanese space program is a very interesting and multifaceted subject. I had the chance to work with NASDA during a time where Japan had three separate space agencies, each focused on a different area of development and utilization. The activities of each, and their combination into JAXA, is an interesting story unto itself. Each of the Japanese engineering satellites is likewise an interesting story. I followed each closely during their flights to learn what I could apply to my own work at the time. Also, the Japanese are the masters of the "shoestring catch", recovering missions that otherwise would have failed.

And here I thought they chose Kappa in honour of that Japanese mythical troll like creature.

While all this was going on Japan was also developing liquid-fuel rocket technology, licensing tech from the US. A series of boosters derived from the Delta family followed, each version adding more and more Japanese components. Eventually a Japanese-designed and built liquid LV (with solid boosters), the H-II was developed. But that's another story...

Great video! love from Japan 🇯🇵

That’s one stark AirBnB. “Boutique property with an austere aesthetic. TV, bed, smoke alarm; nothing extraneous”.

I only had a passing interest in rocketry until finding your channel and AST’s little corner of the internet. Now I watch every video and find every one so interesting. Thanks and keep coming up with such interesting content as long as you can! Your work is appreciated!!

It's always great when a country can succeed at hard things without compromising on their political standards. The innovations they made to work within these restrictions are also a great bonus.

Thanks Scott. Can always count on you for an informative video without any hype or nonsense.

still posting videos when on the road, legend!

There’s one of these tilted rockets outside Ueno station, where I pass by frequently. I’d been wondering what’s up with it. And now I know, thanks Scott!

Great video. Thanks for covering the lesser known rocketry attempts.

This is a piece of space history I was unaware of. Thank you.

Mate. How the hell do you knock this stuff out from a random Hotel room with such amazing quality?. Its really spooky.

1950's Japanese rocket nerds deciding they aren't going to wait several decades to play KSP.

An Air BNB in new jersey. That sounds like the sort of place someone on the run would willingly go and few others.

Damn, Japanese fisherman just can't seem to catch a break can they?!

Scott, your videos are, one by one, answering every space question I've ever had (and some I didn't know I had)

The nissan skyline line about the sky.. line Was great 😁 thanks and fly safe

This was the first time I ever thought about the Japanese space program. Thanks Scott

Hey Scott... Fantastic content about Japan's march to space.

Absolutely Fascinating ! You learn something new EVERY day ! Thanks for these Vlogs ! More please ! Fly safe ! Stu.

That was great! It was nice to learn more about the developments that led to Japan's present status as a respectable and competent space-launch power. Scott's use of the angled launch profile to explain the sensitive path that Japan had to thread (for geopolitical reasons) really helped to make the subject matter more accessible. Thanks!

Thanks Scott. I live on an island across from Wallops flight facility and they still regularly launch sounding rockets like the Black Brant this way. They are great for inexpensive sub-orbital experiments. When not launching sub-orbital rockets we get to see the Antares payloads to ISS and soon the Rocket Lab Electron and Neutron.

I'm reminded of the days when I would spend hours assembling home made rockets from A, B, C, and D-cell solid rocket boosters. My favorite one was a rocket that would separate at apex, releasing small camera and parachute tied to the nose cone. When deployed, the wires to the parachutes and camera would tension as the chute deployed and that tensioning, in turn, would cause the camera shutter to activate. I got some pretty nifty pictures of the ground far below like this. Amateur rocketry was so much fun. Unfortunately, it has been banned almost everywhere now in the U.S. under the same restrictions as those imposed on personal drones, unmanned vehicles, etc.

Thank you for the joy I have when I see a new episode release!

I love the angled launch!! It's just cool, as are fins! Next some snazzy colours please!! (Great video, Scott!)

Not surprised the Japanese liked Kappa as a greek letter. 🐢

damn, all those japanese rockets and ground hardware give off massive thunderbirds vibes

This channel definitely picks the best topics out of all the space channels

"and if you're used to rockets then the first thing that stands out to you is likely the fact that it's not standing straight up and down like everybody else's rockets." Also that it looks like it's from a Gerry Anderson production.

So my angled launches in KSP are actually a thing in real life. Cool! They were my solution to being super early in career mode while doing contracts with the cheapest rockets possible...limitations kind of like those of Japan's early space program

What an amazing story. Thank you for the history lesson! Can’t wait for the next one :D

I love these historic videos with so many cool pictures.

Very interesting video love to watch your channel Scott. Good afternoon from the UK

Oh! I think I’m pretty early on this one. I’ve done this in KSP with very different outcomes. 🤣

OMG, I've just understood why Haruki Murakami called "Sakigake" to the cult in his novel 1Q84. Thank you Scott!

Thanks Scott. Love you stuff. Very educational and inspiring. We can be so much more without killing each other!

Thank you for this fascinating history of Japan's early angled launch Rockets. Especially enjoyed the graphics of the Rockets themselves

Kept a stash of propellants! hahahah rocket prepper. I like it.

Incredible! I always thought this was something we only do in KSP!

Making boring stuff extremely interesting and entertaining... once again. Thanks, Scott!

Great video! Great japanese history and explanation for angled rockets.

I was designing a gimbal system for a turbopump fed liquid rocket engine,(it’s for an undergraduate student project) I was told that it’s prohibited since a gimbal system kinda implies the launch vehicle will have guidance which is a no-no even here in the US

Pointy end up-ish, flamey end down-ish (?)

Great video topic Scott

It's just like Scott to take on a subject that no-one else had thought of, and make another fascinating exposition. Thank you. My inner nerd is now satisfied. Here's one for you, though: fins. You made it clear here why the Kappa had fins for passive stabilisation, but there are many rockets which have thrust gimbaling and also have fins, and others that do not. I may be mistaken, but I understand that later iterations of the Saturn V, if they had been manufactured, would likely have done away with the fins on the first stage. There's no getting away from it, though: fins do look cool.

Great video! Extremely educational!

IJN: "So you want to join the war effort? What skills can you bring?" This Guy: "I make rockets at home in my spare time." IJN: "Perfect! Here's an 18" gun. Your job is to make it go boom!" This Guy: "Sweet." Later.... *Whistles walking past a guard carrying propellant in pockets*

Guy kept a stash of explosive propelant for personal use. Interesting guy. Worked out nicely so Yay him.

Nice video. Audio different but very good. Loved the topic.

With no steering? Sounds super hard...

In 1967, I wondered if a multistage sounding rocket could reach orbit using a simple guidance system. Launching at an angle was a critical parameter for success. After several months and visits to two aerospace conventions, I had all the equations and a supplier's list of the sensors and components required. I didn't have the money to assemble the project, but I knew it was possible.

Excellent stuff bro

Keep going Scott. GOOD JOB

Why couldn't they make more underwater aircraft carriers? Those things were brilliant.

Great video!!

welcome to NJ from Connecticut. Hope all is well, great content

seems like a classic case of "best part is no part" lol

Very interesting. On a somewhat related note and involving future tech. If Japan were to ever build a Space Elevator (assuming materials strong enough for this ever come into existance) it would also be at a noticeable angle. Though not for political reasons with their constitution. It would be scientifically required given their location on Earth in relation to the location of Eath's rotation and equator. Space elevators use the centrifugal force of the Earth to keep the object at the "end" of the space elevator's cable(s) in place and the force of the mass at the end of this cable wanting to pull away from the Earth is what keeps that cord tensioned. The mass at the end of the Space Elevator isn't necessarily in a stable orbit. That mass would either fall into a much higher orbit or leave Earth entirely if the cable lost it's connection to the ground/mass detaches from cable. (though if the cable broke from the ground instead, the mass at the end would likely not escape Earth and would either fall into some kind of orbit or get dragged down to earth due to drag involving the cable. only if just the mass came off would that mass fall into higher orbit or escape Earth) The mass has to have extra energy in it's motion to keep the cables tensioned and lifted up against gravity so a normal orbit wouldn't be enough. The mass at the end would have to be somewhere beyond the geostationary orbital plane and the further away from equator you base your Space Elevator, the longer the cable has to be to reach the area needed to provided the force required to keep all that mass suspended against gravity. Long story short only Space Elevators at the Equator would have the shortest possible cables and be vertically straight when seen from the ground. The mass at the end would migrate to a area close to or at the center of rotation of the Earth. This means the cables would be straight at the equator but would have a "lean" relative to the ground on the earth the further away you mount it from the Equator. I believe if Japan ever built one, it would have a signifcant lean because of this and would be very noticeable. There have been a few sci-fi media (mainly anime. :P ) that depicts Japan having a space elevator and it has kinda bothered me that they are depicted has going straight up into the sky. I think they would instead go into the sky at a angle. Not sure how noticeable the angle would be but the angle would exist! I have yet to see one realistically shown in this manner. :P

great explanation Scott! As we were listening, my wife said "That guy is really smart!" I agree and love your casts. Keep it up!

Thank you for making the video

Like we're supposed to be surprised that Japan does things just a bit different (or in many cases A LOT different). This is why I love Japan.

Hayabusa 2 was the coolest probe ever It was a little fleet carrier with an anti-tank round 🔥

Another great video! Thought I saw you this week in NY and I could hardly believe it! Hope you enjoy your time here and let us know next time! 😂

Thanks Scott! Can never get enough rocket history!

The Japanese pilots just kinda forgot where the controls were, alright?

One of these days, I want to make it down to Tanegashima to catch a launch…. I hear that plane tickets and lodging are hard to come by, though.

Wow, this video was so cool, I just wanted to say that. This is the kind of thing I'm subscribed for 🙂

Great video, Scott...👍

I love your videos! You never responded to my email about farting into orbit around small asteroids, but it's okay, I understand haha.

Actually, launching at the gravity turn angle is the optimal trajectory, that is why vertically launched rocket pitch over to the gravity turn angle after tower clearance. The list of advantages to launching large rockets vertically is long, and far out-ways the performances losses of the initial sub-optimal vertical trajectory. A long time ago, I initialized a Space Shuttle simulation wrong. It was sitting on the pad horizontally, it still made it to SRB separation, after having initially falling through the earth at liftoff then pitched up instead of down at tower clearance. Dynamic Pressure was about double and the Winds would have been ripped off, but it was a fun simulation to look at.

thanks for very detailed and impressive video about history of japanese rocket.

IIRC, Japan is the first country to put Sat on orbit with full solid engine. Impressive skill on prediction.

So, is the following correct? The disadvantage of launching at an angle is that the rocket has to fly a longer path through the thick part of the atmosphere? It would also have to deal with a higher Max Q (dynamic pressure).