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  • [♪ INTRO]

  • The early 1960s was an optimistic time for space engineering.

  • With the Space Race between the U.S. and the Soviet Union in full swing,

  • cameras, animals, and humans were being launched into orbit.

  • And the world seemed headed for a space-faring future,

  • where hundreds or even thousands of people would be living and working off-Earth.

  • Getting that civilization into orbit, though, would require a lot of power.

  • And, in 1963, a team led by engineer Bob Truax proposed a solution:

  • a supersized rocket capable of launching an entire space station in one go.

  • They called it the Sea Dragon.

  • And while it never launched, it was well ahead of its time

  • and it continues to inspire engineers today.

  • When the Sea Dragon was proposed, the Soviets were leading the charge

  • with rockets that were about 50 meters long and 3 meters wide.

  • They could carry maximum payloads of about 5 metric tons.

  • The Sea Dragon would have been an absolute monster by comparison.

  • It would have been more than 150 meters tall and more than 22 meters wide,

  • and it was designed to carry more than 500 metric tons into space.

  • And it would have been nearly 400 times more powerful than rockets of the time,

  • and 10 times more powerful than the future Saturn V,

  • the rocket that eventually took humans to the Moon.

  • And, as the name suggests, it was also intended to launch from the sea.

  • No, not on a floating platform or anything.

  • Likedirectly from the water.

  • As impractical as that might sound, there are actually a few

  • good reasons why a water launch was the best option.

  • For one, it would have made transporting and assembling the rocket's

  • huge components a lot easier, since a buoyant environment would

  • support the rocket safely as it was being constructed.

  • Then, there was all that thrust.

  • At ignition, the Sea Dragon's powerful engines would have caused

  • major damage to launch pads of the time, tearing apart concrete and melting metal.

  • Water, on the other hand, just boils off or flows away.

  • Finally, after launch, the Sea Dragon's huge and scalding exhaust plume

  • would be kept far away from populated areas.

  • Of course, while a water launch offered a ton of benefits,

  • it did create a few potential engineering challenges, too.

  • For example, salt water is really good at corroding metal and messing up

  • delicate electronic components.

  • To get around that, engineers hoped to borrow techniques from submarines,

  • which spend months at a time completely immersed in salt water.

  • Their idea was to build the rocket with thick steel plates, insulation,

  • or special paint to resist corrosion, and to place access panels

  • for waterproofed electrical components above the waterline.

  • But aside from water protection, the rocket's design was really simple,

  • a style that would become known as a “big dumb booster”.

  • Each of the Sea Dragon's two stages would store fuel

  • and liquid oxygen in pressurized tanks.

  • At liftoff, simple valves would open, and the chemicals would mix,

  • igniting on contact to produce a bunch of thrust that would

  • carry the payload into space.

  • This design is less efficient than those found on the sophisticated

  • Saturn V, but the Sea Dragon's huge size would have made up for that,

  • making it considerably cheaper per kilogram of payload.

  • The simple design would have also helped ease its assembly and launch.

  • The main components would be built in dry docks and onshore facilities,

  • then would be floated and assembled in a specially-made lagoon

  • in Cape Canaveral, Florida.

  • The rocket would then be filled with fuel and pressurized

  • before being towed out to the launch point about 60 kilometers from the shore.

  • When it was time to launch, ballast sacks attached to the bottom

  • would be filled with a heavy fluid, like muddy clay.

  • Then, they would sink, and would pull the Sea Dragon upright.

  • Once the engines were lit, water would be expelled from the first stage,

  • and everything would work pretty much like any other rocket.

  • Its massive payload would be in low Earth orbit in a few minutes.

  • All this is really cool, but the Sea Dragon had one more innovation

  • up its gigantic sleevesone that would put it way ahead of its time:

  • The rocket was designed to be almost entirely reusable.

  • After launch, bags on the ballast tanks could be inflated

  • with air to float the tank back to the surface.

  • And both the rocket's first and second stages would be fitted with inflatable drag skirts

  • to point them in the right direction and slow them down enough

  • to survive a water landing with no damage.

  • Each Sea Dragon would have been able to make more than 100 flights,

  • and that reuse would have massively reduced the cost of getting to space.

  • It really was a time of infectious optimism.

  • Although the Sea Dragon was many times bigger than anything that had come before it,

  • none of the engineering challenges seemed insurmountable.

  • The team even got as far as a couple of prototypes

  • to prove that a sea launch was possible.

  • Unfortunately, though, the whole program just kind of fizzled out after a while.

  • And while Truax was asked to develop other versions of his designs

  • over the next few decades, nothing ever really got off the ground.

  • Or out of the water, I guess.

  • What left the Sea Dragon adrift wasn't the engineering challenges,

  • or even the cost, but the motivation.

  • Although some of the public may have looked forward to a

  • space-faring future, NASA was more tightly focused on a single goal:

  • getting a man on the Moon.

  • The Sea Dragon was an incredible tool, but not one that the

  • space agency really needed at the time.

  • It was a workhorse for large scale settlement of space,

  • at a time when pioneers were still making tentative steps to explore space.

  • Even today, we're not launching anything that needs

  • the Sea Dragon's massive lifting power.

  • Still, the idea of a sea launch certainly isn't dead in the water.

  • Among the many private companies clamoring for space,

  • several are proposing sending their rockets from the sea.

  • One of the main benefits is that you don't need a designated launch pad

  • which could become really useful as we start to launch more rockets

  • and set our sights on a space-faring future once again.

  • And if the day ever comes where we do want to launch a city into space

  • well, we have a design worth dusting off.

  • Thanks for watching this episode of SciShow Space

  • and special thanks to Destin Sandlin over at Smarter Every Day

  • for first telling our team about this sweet old rocket.

  • If you want to check out Destin's channelwhich, you should, it's amazing

  • you can go to youtube.com/smartereveryday.

  • [♪ OUTRO]

[♪ INTRO]

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シードラゴンを紹介します。これまでに設計された最大のロケット (Meet the Sea Dragon: The Biggest Rocket Ever Designed)

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    林宜悉 に公開 2021 年 01 月 14 日
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