Sea Dragon (rocket)
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 engine |
| Maximum thrust | 355.8 MN (80,000,000 lbf) at sea level |
| Specific impulse | 242 s |
| Burn time | 81 seconds |
| Propellant | RP-1 / LOX |
| Second stage | |
| Powered by | 1 engine |
| Maximum thrust | 62.80 MN (14,120,000 lbf) vacuum |
| Specific impulse | 409 s |
| Burn time | 260 seconds |
| Propellant | LH2 / LOX |
| Vernier stage | |
| Powered by | 4 engines |
| Maximum thrust | 236.6 kN (53,200 lbf) each |
| Burn time | 1340 seconds |
| Propellant | LH2 / LOX |
The Sea Dragon was a 1962 conceptualized design study for a reusable 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 2026, Sea Dragon is generally regarded as the tallest launch vehicle ever formally proposed. With a payload of 550 tons, it has mistakenly been regarded as the largest and most powerful vehicle seriously considered. It is comparable to other unbuilt concepts such as Convair's Nexus and Super Nexus, Boeing's Large Multipurpose Launch Vehicle, Phillip Bono's series of reusable single stage launch vehicles, and various NOVA Post-Saturn launch vehicles.