Sea Dragon (rocket)

Sea Dragon

Sea Dragon internal and external views. Both show the ballast tank attached to the first-stage engine bell. An Apollo CSM-like spacecraft is mounted on top.
Function	Orbital super heavy-lift launch vehicle
Country of origin	United States
Size
Height	150 m (490 ft)
Diameter	23 m (75 ft)
Mass	18,143 t (39,998,000 lb)
Stages	2
Capacity
Payload to LEO
Altitude	229 km (124 nmi)
Mass	550 t (1,210,000 lb)
First stage
Powered by	1
Maximum thrust	350 MN (79,000,000 lbf) sea level
Burn time	81 seconds
Propellant	RP-1 / LOX
Second stage
Powered by	1
Maximum thrust	59 MN (13,000,000 lbf) vacuum
Burn time	260 seconds
Propellant	LH2 / LOX
[edit on Wikidata]

The Sea Dragon was a 1962 conceptualized design study for a two-stage sea-launched orbital super heavy-lift launch vehicle. The project was led by Robert Truax while working at Aerojet, 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 and Todd Shipyards, the project was not implemented.

With dimensions of 150 m (490 ft) long and 23 m (75 ft) in diameter, Sea Dragon would have been the largest rocket ever built. As of 2024^[update], 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 (LEO), equaled only by the Interplanetary Transport System concept (the predecessor to SpaceX Starship) in the latter's expendable configuration with both designed for 550 tonnes.