A trio of NASA-Marshall heavy lift launch vehicle concepts, circa 1985. The first two configurations used a clustered booster stage; the third configuration used series staging, with a unique feature than the booster stage had no LOX tank, only a kerosene tank. The LOX for the first stage was contained within the second stage. This would make the vehicle more complex, but it would also make the first stage more recoverable.
The three designs were designed for the same mission, launching 300,000 pounds to LEO (specifically a 100X540 nautical mile transfer orbit, with circularization at 540 n. mi. to be performed by a kick stage). All three used an all-new LOX/kerosene booster engine, the Space Transportation Booster Engine, slightly more powerful than the F-1. All three used a new LOX/LH2 upper stage engine, the Space Transportation Main Engine, on the core vehicle. The STME used an extendable nozzle for good performance at both low and high altitude.
The selected configuration was #2:
The boosters for Configuration 2 were independently recoverable. The five STMEs for the core stage were contained in a recoverable propulsion & avionics module, which would splash down for recovery, refurbishment and reuse.
