equipped with a single very large engine, in this case a thrust engine burning liquid hydrogen 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; Truax suggested using a nuclear-powered aircraft carrier 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 in fiction The Sea Dragon appears in the first-season finale of the 2019 Apple TV+ series For All Mankind. The series is set in an alternate history timeline in which the 1960s-era space race 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.