Sea Dragon Rocket- the unborn beast

The Sea Dragon was the largest, most powerful rocket ever dreamed of. It was conceptualized in 1962 and was going to be a “sea-launched orbital super heavy launch vehicle”. The rocket would be 150 meters tall and 23 meters wide, making it the largest rocket ever. This monster would be able to carry 550 tons to LEO (Low Earth Orbit)! Saturn V, the largest rocket ever built was capable of carrying only 118 tons. Unfortunately, Sea Dragon never became reality.

Design and Technicals


The Sea Dragon project was led by Robert Truax. In one of his rocket designs, he conceptualized a rocket that would be launched by floating it on the ocean. There were several benefits to this. Launching the rocket from the ocean would lower the cost of operations- it did not require a launch pad and other support systems. In order to reduce cost even further, Robert Truax planned to use very cheap materials to reduce cost.

For the launch, the rocket would be attached to a ballast tank system- a system of metal compartments that hold water or release it to allow a ship/submarine or in this case, a rocket to change their depth or orientation in a water body- on shore. It would then be towed to the launch site with a ship. The ballast tanks would then fill with water, thus orienting the rocket vertically for launch.

Stages and Engines:

First Stage:

The first stage would be powered by a single 36 million kgf (kilogram force) engine that burned RP-1 (Rocket propellant 1) and LOX (liquid oxygen). To put that into perspective, the Saturn V’s 5 F1 engines together produced a combined thrust of 3.4 million kgf. The engine on the first stage would burn all of its fuel 81 seconds into the flight. At that point, the rocket would be travelling at 6400 km/h or 1.8 km/s and would be at an altitude of 40 km.

Second stage:

The second stage would also be powered by a single 6 million kgf engine that would burn liquid hydrogen and LOX.

Methods to recover the stages were also being planned

However, even though some interest was shown by NASA and Todd Shipyards for the project, this amazing beast never became reality.

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