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hello it's scott medley here spacex's starship is currently the largest launch vehicle ever built and while it has not flown yet it is still an impressively huge piece of hardware with some of the construction photos intentionally evoking historic images of skyscraper construction from the early 20th century it's going to be taller than the saturn v and without that tapering profile of that historic vehicle that means the total mass of starship is about four and a half thousand tons at launch and of course this is actually a lot smaller and less ambitious than the original interplanetary transport ship concept which would have clocked in at just over ten thousand tonnes spacex has understandably attracted a lot of attention for this ambitious project and that means lots of news stories highlighting the magnitude of this launch vehicle compared to those regular rockets spacex fans out there are embracing the massive scale of things and of course there are a whole host of spacex skeptics who suggest that it's impossible and only an amateur like elon musk would imagine such a large rocket could ever work the thing is the super heavy design as it is is actually smaller than many concepts and designs from decades past which were studied but never built so i thought it would be fun to highlight a bunch of these larger than starship designs and the reasons why the designers needed to think big to solve the problems they had and to be clear the rockets in this list have all received you know serious analysis it's more than just sketching out something on a napkin and saying that this is the biggest rocket ever building a rocket is an engineering problem and engineering it's some is something which is done with numbers if you don't have the numbers it's just an opinion and we start all the way back in the 1950s with fun fun brown's massive rocket designs which were intended to launch space stations and construct a fleet of ships to go to mars von braun began writing a science fiction book about a mars mission in 1948 and it would be published in german in 1952 and later translated to english the uh in 1953 and along the way von braun's ideas about space flight would be featured in collier's magazine accompanied by some amazing space art by the likes of chesley bonestall and of course this was given the disney treatment with models and animations and everything else and of course von braun talking to the camera so von braun's 1950s designs were about 20 meters wide and 100 meters tall they would taper towards the top they would have fins and wings for aerodynamics and some of the images we see are partly a product of the artist wanting to make it look cooler rather than good engineering design but ultimately the rockets were big they had a mass of about 6 400 tons with three stages they would be able to launch 25 tons into a 1700 kilometer orbit now this is actually within the capabilities of the falcon heavy and new glen but those manage this with a fraction of the launch mass von braun's early designs had to be huge because the engine performance was a long way from modern capabilities the engines he designed used nitric acid and hydrazine propellant and those had a specific impulse of about 257 seconds and that's about 85 of what a titan using hypergolics would manage only a decade later so this was designed to be highly reusable the first stage and second stage would descend under parachutes and use breaking rockets to slow splash down to a manageable velocity and the third stage was a space plane that could glide back to earth it needed to be reusable because von braun's mars expedition would take about a thousand launches to deliver the stuff and assemble it in space moving onwards to the 60s in 1962 robert truax proposed possibly the most famous gargantuan rocket but not the largest ever studied you've probably seen the sea dragon in some form or another it features in the tv show for all mankind as a heavy lift vehicle the story about sea dragon is that after working on many important rockets including the thar viking and polaris missile robert truax concluded that a significant contribution to the cost of rockets was the resources putting into making them smaller and lighter with structures made using the latest in early 60s technology he imagined that this cost equation could be inverted and instead scale the rocket up make it heavier and dumber and skipping all that high-tech stuff to make a big dumb booster and that would bring the cost per mass to orbit down so sea dragon was certainly big the design would mass a whopping 18 000 tons and on paper it would be able to put 550 tonnes into orbit the rocket was 150 meters tall 23 meters in diameter and consisted of two stages with simple pressure fed engines which have the biggest rocket nozzles i have seen on any rocket design the first stage is kerosene and liquid oxygen and would generate 36 000 tons of thrust while the second stage is hydrogen and oxygen and only generated 6 000 tons of thrust now i'm kind of skeptical that this could ever work as designed because combustion instability was causing problems with the f1 engines on the saturn v which this was the result of your standing waves which would build up inside those massive combustion chambers and with sea dragon's engines being so much larger it's easy to imagine that this could be even worse but i've expressed this on the internet before and tom miller tweeted that the guy i mean he's the guy that basically designed the merlin engine uh he said that the pintle injector design is actually solves a lot of instability problems and he thinks that sea dragon could have worked i mean probably i'm not going to argue even if it didn't explode it would be the most spectacular rocket engine ever built finally the reason it was called sea dragon was because it was designed to be launched at sea and i don't mean from a platform in the middle of the ocean i mean it would lift off directly from the water with a vehicle held submerged and upright by ballast chambers on at the bottom the engine would ignite underwater and it would lift the whole thing upwards and skywards now i said that sea dragon wasn't the biggest uh and that honor actually goes to something called nexus that was designed around the same time by craft eric an engineer who had worked alongside von braun at pina munda and would go on to design the centaur upper stage nexus was pitched as a post-saturn launch vehicle and a smaller version was only 11 000 tons but who cares about that the larger version was 22 000 tons and the design was short and fat it was 61 meters in diameter 200 feet basically with massive tanks of hydrogen and oxygen and most importantly designed to be a single stage to orbit capable of delivering about 900 tons and then being fully recovered the aft engine structure of nexus would include a massive plug nozzle which is like an aerospike but it's been truncated it would then have four clusters of smaller engines for steering by differential thrust combined this would generate 29 million tons of thrust so technically the sea dragon would still rule in terms of total thrust at liftoff the re-entry landing and recovery of nexus is worth talking about so the front of the booster was basically a heat shield and after delivering the payload to space it would perform its deorbit burn and then turn nose first into the atmosphere and begin decelerating to keep it stable it would have these massive air blade air brake panels that would deploy from the side and that would keep it pointing forwards once it slowed down to like subsonic speeds it would deploy a parachute which was massive i mean the parachute was like 160 tons more massive than some rockets that parachute would still only slow the vehicle to about 80 kilometers per hour so the final touchdown in the water would actually require solid rockets to break it and place it gently in the ocean they would then deploy flotation devices and that would keep it pointed nose down so that the engines wouldn't go anywhere near the salt water moving onwards philip bono was responsible for a number of massively ambitious designs he actually really liked the concept of point-to-point rocket travel around the world and the us army was really interested in the possibility of rapidly deploying battalions of troops using this method ithacas was one of his designs a concept studied by bono and it would have been about 6 400 tons which is quite small compared to the previous ones and although it wasn't planned as an orbital launch vehicle it would have been capable of putting 450 tonnes into you know orbital speeds he also studied the nova the rhombus and the roost heavy lift designs which were similarly massive there were actually a whole lot of wildly optimistic post-saturn launch vehicles all thinking in terms of moon bases or boots on mars but we all know that post-saturn became the far less massive but still highly ambitious space shuttle but before the space shuttle launched there was one other flurry of future launch vehicle concepts researched which were still looking at putting hundreds of tonnes into low earth orbit using vehicles worth thousands of tons in the mid 1970s there was serious thought given to powering the us using space-based solar power and such ambitions would require launch vehicles which were vastly more capable than what the space shuttle could do so out of these the one that i find most interesting is boeing's space freighter because if you look at it it's almost exactly like something elon musk would have designed only 50 years ago it's a two-stage fully recoverable rocket with methane oxygen fueled boosters and a payload capability of 420 tons it kind of looks like a pair of massive space shuttle orbiters mating the reference vehicle was 11 000 tons 18.5 meters in diameter under 160 meters tall on the pad the wingspan on the first stage was 80 meters that's about the same as the airbus a380 it also included jet engines to help it return to the launch site the second stage was a bit smaller it used hydrogen propellant and it had a payload bay and support equipment capable of supporting the massive orbital construction plans that solar power stations would have needed i mean these power stations are the size of cities and would have to be constructed over a long period on orbit and to finish off uh this i know this has been very us-centric so let's skip over to the soviet union to look at the ur 900 ur stands for universal rocket which meant reusing lots of common tank and engine designs to build different rocket capabilities from the same parts it's a bit like kerbal space program but more communist and with a lot of toxic propellant and no actual funding the ur 100 was an icbm which actually evolved into the strela and rocot launchers the ur 500 became the proton rocket and the ur 700 was a proposal for the soviet moon program which lost out to the n1 but the ur 900 that was supposed to take people to mars and it was 8 000 tons with 15 cores powered by rd270a engines those by the way are the first full-flow staged combustion engines ever designed and fired it was able to place 240 tonnes into orbit it would be 28 meters wide 90 meters tall and it looked like a proton that had just kept on adding new stages and tanks after it should have stopped but then there was the ur 700 m which was bigger still the m was from mars and this would have been 16 000 tons at launch this design appears slightly later than the other uar design proposals and after a very messy proton accident in front of a lot of vips that showed just how dangerous hypergolic propellants where where so unlike its brothers and sisters the ur-700m used kerosene and liquid oxygen with hydrogen for the upper stages and unlike most of the us mega launch vehicle concepts there was no thought in either of these given to reusability so that's a selection of the biggest rockets from history there are still several others i've not talked about like boeing's leo vertical landing design which launched and landed from an artificial lake and then there was the advanced multi-purpose launch vehicle concept there's a whole bunch of philip bono designs i barely mentioned and of course craft eric was also involved in the orion nuclear pulse rocket concept which radically changed the scale of launch vehicles yet again in all of these cases it wasn't just a case of being big to put big numbers on display those good engineering reasons that favored really big launch vehicles like the surface area to volume ratio means that uh the larger you make a rocket the lighter the overall structure becomes for the same mass to orbit yeah and then the larger objects scale up better to re-entry conditions where your your boundary layer gets pushed further and further out when the object gets larger so this is the same kind of reasoning that ultimately makes starship as big as it is i'm scott manley fly safe [Music] you