General Atomics Orbit-to-Orbit Lunar Shuttle System Part four of my Project Orion Series, previous installments at the links below. Part One: Project Orion: A Design Overview. Part Two: Right Before Part Three: Project Orion Historical Context Chart Lunar operations support vehicle designs include options for an earth-orbit-to-lunar-orbit re-usable nuclear propulsion system with a separate re-usable chemical-descent/ascent-stage cargo-Lander vehicle in both manned and unmanned versions. In protracted Lunar base support operations Cargo Landing vehicles would be transported one-way to a manned lunar base where they would serve on a serial basis, individually tanked for launch to lunar orbit for additional cargo retrieval missions. Surface to orbit vehicles carry only fuel for a single ascent or descent – arriving orbit-to-orbit cargo shuttles would need to carry a descent fuel load to be transferred to the Cargo-Lander in an orbital tanking operation. The system incorporates the basic nuclear 10-m (33 Ft) diameter propulsion module, includes a propulsion magazine section, cargo modules, a two-deck shielded command module with adaptor connections for up to two passenger modules. A base-line of three crew members was assumed for operation of the Orbit-to-Orbit Cargo Shuttle with a two man operational crew required for Cargo-Lander operations. The Command module is intended to separate from the cargo load and fly on station-keeping orbit with the propulsion module during cargo-transfer and tanking operations. The Command module is equipped with an independent orbital maneuvering hydrazine-fueled propulsion system Passenger modules can accommodate up to twenty passengers, and are serviced by independent life-support systems but carry no independent propulsion or maneuvering systems. A separate Passenger-Shuttle was designed to accommodate up to twenty passengers and two crew members within a single large cabin fed by an open-cycle life support system. The passenger Shuttle is equipped with a surface-excursion ladder while Cargo-Landers would require a roll-up gantry for crew egress and module systems access and maintenance. Credits: Diagram figure 3.8 and figure 3.9 from GA-5009, Vol. 1; Nuclear Pulse Space Vehicle Study. Note: It is only rarely that I elect use a model or model-element from an on-line source in these vehicle reproductions – and in that rare case it is because the model (or element) represents the best or most accurate resource – as in the case of the NASA EVA suits – NASA is the best source of this item. In this case I’ve chosen to use this G.V.C.S (Generic Vehicle Construction Set) module (with slight flattening and re-scaling) for the piloted command module element of the General Atomics landing craft – all other modeling is my own. Note: Update 3/1/2011 Due to a slight scaling error. As always, thank you all for your thoughtful comments, interest, and encouragement.