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In 1963, the Aerojet corporation presented a report detailing a rocket that was


400 feet long and was designed to launch out of the ocean vertically and could put a payload totaling 1.1 million pounds into low-earth orbit. Let's meet the unrealized Sea Dragon. Before we get into the details of Sea Dragon let's put it into context against a few of its contemporaries, namely what the Soviet Union and the United States were launching at the time. Aerojet's report was published in 1963. At the time the US was using the Atlas V version of the Atlas ballistic missiles to launch mercury missions into orbit in the Soviet Union variations of the r7 rocket were launching the Voskhod missions into space both of these rockets stirred about 100 feet and could put no more than about 3,000 pounds into low-earth orbit then comes along the sea dragon not only is it four times taller than either of these Rockets it can put so much more payload into low-earth orbit three thousand pounds versus 1.1 million pounds and then there's the fact that sea dragon launches vertically out of the water as opposed to off a launch pad on the ground and the final thing that makes sea dragon an incredible rocket of the early 1960s it was designed to be almost entirely reusable whereas Allison r7 were both expendable the sea dragon was a two-stage rocket and each stage only had one engine this would an attempt to make it simpler the simpler the rocket but fewer fail points and the more likely it is to work beautifully there was an inter stage between the first and second stage as well as one between the second stage and the payload stage at the very top of the rocket would be an Apollo style spacecraft either an Apollo command/service module or if the mission was simple enough a mercury or Gemini style spacecraft the guidance and navigation and control for the entire mission would come from that spacecraft the NASA heritage one that's because it already existed so why not make use of what NASA was already developing it was also a way to have the sea dragon potentially double as a manned launch vehicle not just for unmanned car the sea dragon was designed to be built using classic shipbuilding methods after all for Aerojet if submarines could exist underwater for months at a time with complex electronics and even life-support systems on board why could the same methods not apply to a giant rocket so the sea dragon would be constructed either especially designed facilities for things that didn't yet exist or in existing dry docks so the parts that were a little bit easier to build like a fuselage then the rocket would be constructed in the specially dredged Lagoon near Cape Canaveral this would allow technicians to actually make the rocket vertically instead of horizontally like we've done in the VAB for the Saturn 5 it was a simple matter of keeping all exposed components above the waterline rotating the rocket as need be to access certain components the lagoon was also designed to give technicians calm waters in which to work which meant that most of the pre-launch checkouts could be done in this Lagoon with the rocket horizontal it could also be fueled while floating at sea in these controlled waters once the rocket was completely mated the portions were checked out and everything was ready to go it would be towed out to its launch location some 40 miles off the coast of Florida at that point the ballast unit would come into play to help upright the rocket the ballast unit would be filled with fluid to kill its buoyancy and by virtue of sinking because it would weigh some million pounds on its own it would move the rocket from a horizontal position into an upright position this would be the point of highest stress on the rocket not only would it be dealing with mild waves the force of moving it upright would put so much stress on the body of the rocket that it risked buckling but the sea dragons own construction was designed to counteract that both the first and second stages of the Rockets used pressure fed engines that meant that the fuel and oxidizer tanks in both stages will be pressurized with a third gas to force the propellant and the oxidizer into the combustion chamber for a stronger reaction it also meant that because the tanks are pressurized they were more rigid that meant that not only while the rocket was being towed and popped up right the sheer structure of the rocket helped with its rigidity but the internal pressurization helped keep it that much more rigid so that it could resist any kind of buckling from being uprighted once the final checks were done the K would sign off on launch and the actual launch sequence would be ordered by a tugboat standing nearby or floating near by the launch location the ballast unit surrounding the first stage engine would create a sort of casing now of course the engine was still exposed to water it was going to start launching underwater regardless but the bowels unit sort of protected it from heavy flows of either currents or waves or anything that might hit it and jostle the engine at the moment of ignition such that it would destroy the launch for auxilary engines on the second stage would fire just a fraction of a second before the main engine started then the rocket was sliced smoothly out of the water separating from the ballast unit which would start to sink and from there the launch was fairly standard after 81 seconds of flight the rocket would be at an altitude of about 125,000 feet at that stage the first engine would cut out and the second stage would ignite almost immediately such that there was very little coasting the second stage main engine as well as those four auxiliary engines would burn for an additional two hundred and sixty seconds once the second stage main engine cut off at about nine hundred and eleven thousand feet or 150 nautical miles it all came down to those four auxiliary engines they would fire from an additional twenty two point four minutes this was a low thrust period but when sufficient enough to give the rocket payload just that little bit of extra velocity needed to get into orbit the final orbit would be about 300 nautical miles the payload that would reach orbit was initially conceived as being a giant tank of liquid hydrogen something that could refuel deep-space missions before leaving the earth as for recovery the ballast unit would sink initially but inflatable floatation bags would bring it back up to the surface then it could be towed back to the assembly Lagoon where it could be mated to another rocket the first and second stages were both covered at first using just simple aerodynamic braking as they fell through the upper atmosphere but the active stage of recovery would be using an aerodynamic deceleration device this decelerator was a reliable and very easy system it was a large conical flare 300 feet in diameter that could be pressurized with the same pressurizing gas as we've used in the pressure fed engines for each stage this also ensured that both stages would hit the water at the correct down orientation a way that would minimize the forces and stresses on the body such that it could be refurbished easily and reused as opposed to building a new one after the first and second stages both splashed down they would be recovered and towed back to the assembly Lagoon there they would be refurbished and any parts that need replacing could be replaced but at the end of the day most of the rocket could be just refurbished mated together again in that Lagoon and used again on another sea dragon launch as arrogant noted in its 1963 reports the sea dragon definitely represented a massive leap in technology but it wasn't one that was completely impossible every challenge with the sea dragon was actually just an engineering challenge and engineering challenges could be solved and it wasn't even that expensive Aerojet predicted the cost would be about 2.8 billion dollars over about six years to have the system operational it all came down to the cost saved in reusing most of the rocket parts but as we know the sea dragon never flew it was just not something NASA could work into its Apollo decade getting to the moon was just more important than building a 400 foot long rocket that would just put fuel into orbit but it's a pretty compelling idea so it might be something that we could see pop up one of these days that is the absolute cold notes version of the sea dragon there is so much more of the story including the intricacies of how it was built the things like fuels that would use and pressurizing gases and all the decisions that led to the aerodynamic celebrator all of that is in my companion blog post over at Discoverer so be sure to check that out if you want an even deeper dive into the sea dragon but in the meantime are there other early rocket concepts you've heard of that you'd like to see a video about because I love digging into these things for you guys let me know all of those things in the comment section below and of course questions you might have about the seed right and the other big rockets or anything old-timey space be sure to follow me on Twitter and on Instagram for daily vintage space content and if you guys want weekly videos detailing things you didn't even know you were curious about about the early Space Age definitely subscribe right here so you never miss an episode