The Sea Dragon was a 1962 conceptualized design study for a two-stage sea-launched orbital

super heavy-lift launch vehicle A super heavy-lift launch vehicle can lift to low Earth orbit more than by United States (NASA) classification or by Russian classification. It is the most capable launch vehicle classification by mass to orbit, exceeding that of the heavy-lif ...

. The project was led by

Robert Truax Captain Robert C. Truax (United States Navy, USN) (September 3, 1917 – September 17, 2010) was an American Aerospace engineering, rocket engineer in the United States Navy, and companies such as Aerojet and Truax Engineering, which he founded. T ...

while working at

Aerojet Aerojet was an American rocket and missile propulsion manufacturer based primarily in Rancho Cordova, California, with divisions in Redmond, Washington, Orange and Gainesville in Virginia, and Camden, Arkansas. Aerojet was owned by GenCorp. I ...

, one of a number of designs he created that were to be launched by floating the rocket in the ocean. Although there was some interest at both

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeedin ...

and

Todd Shipyards Todd or Todds may refer to: Places ;Australia: * Todd River, an ephemeral river ;United States: * Todd Valley, California, also known as Todd, an unincorporated community * Todd, Missouri, a ghost town * Todd, North Carolina, an unincorporated ...

, the project was not implemented. With dimensions of long and in diameter, Sea Dragon would have been the largest rocket ever built. , among rockets that have been fully conceived but not built, it is by far the largest ever and, in terms of payload into

low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never m ...

(LEO), equaled only by the

Interplanetary Transport System SpaceX Starship development began in 2012, when Elon Musk, CEO of American aerospace company SpaceX, first publicly described a high-level plan to build a reusable rocket system with substantially greater capabilities than the Falcon 9 and the ...

concept (the predecessor to

SpaceX Starship Starship is a fully reusable, super heavy-lift launch vehicle under development by SpaceX, an American aerospace company. With more than twice the thrust of the Saturn V, it is designed to be the most powerful launch vehicle ever built and the ...

) in the latter's expendable configuration with both designed for 550 tonnes.

Design

Truax's basic idea was to produce a low-cost heavy launcher, a concept now called "

big dumb booster Big Dumb Booster (BDB) is a general class of launch vehicle based on the premise that it is cheaper to operate large rockets of simple design than it is to operate smaller, more complex ones regardless of the lower payload efficiency.Schnitt, Arthu ...

." To lower the cost of operation, the rocket itself was launched from the ocean, requiring little in the way of support systems. A large ballast tank system attached to the bottom of the first-stage engine bell was used to "hoist" the rocket vertical for launch. In this orientation the payload at the top of the second stage was just above the waterline, making it easy to access. Truax had already experimented with this basic system in the Sea BeeSea Bee was a proof of principle program to validate the sea-launch concept. A surplus

Aerobee The Aerobee rocket was one of the United States' most produced and productive sounding rockets. Developed by the Aerojet Corporation, the Aerobee was designed to combine the altitude and launching capability of the V-2 with the cost effective ...

rocket was modified so that it could be fired underwater. The rocket worked properly the first time in restrained mode. Later tests of repeat firings proved so simple that the cost of turn-around was about 7% that of a new unit. and Sea Horse.Sea Horse demonstrated sea-launch at a larger scale and on a rocket with a complex set of guidance and control systems. It used a surplus pressure fed, acid/aniline

Corporal missile The MGM-5 Corporal missile was a nuclear-armed tactical surface-to-surface missile. It was the first guided weapon authorized by the United States to carry a nuclear warhead. A guided tactical ballistic missile, the Corporal could deliver eithe ...

on a barge in San Francisco Bay. This was first fired several metres above the water, then lowered and fired in successive steps until reaching a considerable depth. Firing from underwater posed no problems and there was substantial noise attenuation. To lower the cost of the rocket, he intended it to be built of inexpensive materials, specifically 8 mm steel sheeting. The rocket would be built at a sea-side shipbuilder and towed to sea for launch. It would use wide engineering margins with strong simple materials to further enhance reliability and reduce cost and complexity. The system would be at least partially reusable with passive reentry and recovery of rocket sections for refurbishment and relaunch. The first stage was to be powered by a single thrust engine burning

RP-1 RP-1 (alternatively, Rocket Propellant-1 or Refined Petroleum-1) is a highly refined form of kerosene outwardly similar to jet fuel, used as rocket fuel. RP-1 provides a lower specific impulse than liquid hydrogen (LH2), but is cheaper, is s ...

and LOX (

liquid oxygen Liquid oxygen—abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries—is the liquid form of molecular oxygen. It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an app ...

). The tank pressure was for the RP-1 and for the LOX, providing a chamber pressure of at liftoff. As the vehicle climbed the pressures dropped off, eventually burning out after 81 seconds. By this point the vehicle was up and downrange, traveling at a speed of . The normal mission profile expended the stage in a high-speed splashdown some downrange. Plans for stage recovery were studied as well. The second stage was also equipped with a single very large engine, in this case a thrust engine burning

liquid hydrogen Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form. To exist as a liquid, H2 must be cooled below its critical point of 33 K. However, for it to be in a fully l ...

and LOX. It was also pressure-fed, at a constant lower pressure of throughout the entire 260 second burn, at which point it was up and downrange. To improve performance, the engine featured an expanding engine bell, changing from 7:1 to 27:1 expansion as it climbed. The overall height of the rocket was shortened somewhat by making the "nose" of the first stage pointed, lying inside the second-stage engine bell. A typical launch sequence would start with the rocket being refurbished and mated to its cargo and ballast tanks on shore. The RP-1 would also be loaded at this point. The rocket would then be towed to a launch site, where the LOX and LH2 would be generated on-site using

electrolysis In chemistry and manufacturing, electrolysis is a technique that uses direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of elements from n ...

; Truax suggested using a nuclear-powered

aircraft carrier An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and facilities for carrying, arming, deploying, and recovering aircraft. Typically, it is the capital ship of a fleet, as it allows a ...

as a power supply during this phase. The ballast tanks, which also served as a cap and protection for the first-stage engine bell, would then be filled with water, sinking the rocket to vertical with the second stage above the waterline. Last minute checks could then be carried out and the rocket launched. The rocket would have been able to carry a payload of up to or into LEO. Payload costs, in 1963, were estimated to be between $59 to $600 per kg (roughly $500 to $5,060 per kg in 2020 dollars). TRW (Space Technology Laboratories, Inc.) conducted a program review and validated the design and its expected costs. However, budget pressures led to the closing of the Future Projects Branch, ending work on the super-heavy launchers they had proposed for a crewed mission to Mars. Sea-Dragon

Sea Dragon in fiction

The Sea Dragon appears in the first-season finale of the 2019

Apple TV+ Apple TV+ is an American subscription streaming service owned and operated by Apple Inc. Launched on November 1, 2019, it offers a selection of original production film and television series called Apple Originals. The service was announced ...

series ''For All Mankind''. The series is set in an

alternate history Alternate history (also alternative history, althist, AH) is a genre of speculative fiction of stories in which one or more historical events occur and are resolved differently than in real life. As conjecture based upon historical fact, alte ...

timeline in which the 1960s-era

space race The Space Race was a 20th-century competition between two Cold War rivals, the United States and the Soviet Union, to achieve superior spaceflight capability. It had its origins in the ballistic missile-based nuclear arms race between the t ...

did not end. In the post-credits scene, which takes place in 1983, a Sea Dragon is depicted launching from the Pacific Ocean to resupply the US lunar colony. An astronaut says in a voice-over that the ocean launch is being used as a safety measure because the payload includes plutonium. The Sea Dragon continues to play a role in season 2; its high payload capacity is used to resupply an expansive lunar base and is the subject of a lunar blockade by the Soviet Union.

Notes

References

External links

Truax Engineering Multimedia Archive

Sea Dragon Concept Volume 1 (Summary)
LRP 297 (NASA-CR-52817), 1963-01-28.
Sea Dragon Concept Volume 3 (Preliminary program plan)
LRP 297 (NASA-CR-51034), 1963-02-12. * YouTube Channel Link

* Encyclopedia Astronautica
Sea Dragon

* YouTube
Sea Dragon - 8.14
TMRO - Interview show about "Sea Dragon" * Search "Sea Dragon Concept" at th
NASA Technical Report Server
to read the unclassified design study: *
Sea Dragon Concept Volume 1 (Summary)
LRP 297 (NASA-CR-52817), 1963-01-28. *
Sea Dragon Concept Volume 3 (Preliminary program plan)
LRP 297 (NASA-CR-51034), 1963-02-12. {{DEFAULTSORT:Sea Dragon (Rocket) NASA space launch vehicles Hypothetical spacecraft Pressure-fed rockets Sea launch to orbit Cancelled space launch vehicles Proposed reusable launch systems

Design

Sea Dragon in fiction

See also

Notes

References

Further reading

External links