Vehicle configurations representative of several alternative uprating methods were specified by the Marshall Space Flight Center for initial studies.
The Saturn IC first stage would have been stretched 240 inches (610 cm) with 2,500,000 kg (5,600,000 lb) of propellant and five new F-1A engines; the S-II second stage would have been stretched 41 inches (100 cm) with 450,000 kg (1,000,000 lb) of propellant and five J-2 engines; the S-IVB third stage would have been strengthened, but with a standard 100,000 kg (230,000 lb) of propellant, and one J-2 engine.
[12] The propellant pressurization system would have had 15% higher flow rates to account for the differences between the F-1 and F-1A engines.
Manufacturing would remain largely similar, while testing and vehicle assembly equipment would see major changes.
[17] The MS-II-1 variant would have been almost unchanged from the S-II stage, except for it being strengthened to handle increased flight loads.
[20] Propellant load would be increased up to a maximum of 540,000 kg (1,200,000 lb) and stage length would have been extended less than or equal to 470 cm (187 in), without major facility changes.
Besides the 30 inch turbine, the 1650K config would have required improved pump impellers, and a stronger gas generator at a lower mixture ratio.
The 1800K configuration would have required an increased pump impeller diameter, increasing gas generator volume to solve temperature control issues, and reducing turbine exhaust back-pressure.
Uprating past the 1800K configuration would have been limited by turbopump torque and critical speed.
Uprating to the 1,000,000 N (225,000 lbf) variant would have required changes to the turbopumps, gas generator control valve, thrust chamber bypass system, and the injector.
To uprate to the 1,100,000 N (250,000 lbf) variant from the 1,000,000 N (225,000 lbf) variant would have required changes to the oxidizer turbopump assembly, concentric gas generator control valve, fuel turbopump, and high-pressure ducts added with the uprating.
In the MS-IVB stages, the use of nuclear propulsion could have been used to achieve higher Trans-lunar injection performance.
This would have caused higher structural loads and sometimes would have exceeded facility height limitations.
This could have been solved by: Crawler-related changes and issues are road load limits, and location of service arms and checkout equipment.