Lunar Evolution Mission The lunar evolution strategy places emphasis on development of an early human- tended outpost which is expanded to a self-sufficient facility. Key sizing groundrules include initial crew size of 4 growing to 8, maximum reusability of system elements, aerobraking at Earth return, and baseline chemical propulsion for all stages. Key costing groundrules include in-situ propellant production as a Block I reference, and limiting the operational phase of the exploration and evolution of lunar facilities so it can be accomplished for constant annual investment. This means the life-cycle development of major components (both spacecraft and surface systems) will be phased with their first use date to minimize yearly funding profiles. The lunar facility evolution is carried out through a series of unmanned cargo flights and manned sorties. The first series of missions establishes the human-tended basecamp and early science outpost. This facility would be assembled in advance of the manned landing using teleoperated equipment or must be capable of rapid deployment/assembly by a small unassisted crew. A combination of the two assembly strategies is most likely. The initial basecamp should be capable of housing a crew of at least four, who will remain at the base for as long as the system will allow, given early lunar lander delivery capability, with an initial goal of two plus lunar days (60 Earth days). Following inital manned operations and systems checkout, an oxygen production facility will be delivered, assembled, checked out, and operations initiated by a second crew of four. Early emphasis during this stage will be on deploying science instrumentation in the vicinity of the base, on gaining operating experience with the production facility, and on demonstrating use of in situ materials to support closure of the Life Support System (LSS). When operational, the oxygen facility should produce enough LOX to support one lunar lander round-trip to orbit per year (roughly 2 tons/month). Eventually, replication of facility elements should bring this capability up to 10 tons of LOX per month to support a permanent lunar base. At the end of this human-tended phase, the first crew of 4-6 will be delivered to begin permanent occupancy with six month tours of duty. The objective during the early permanently manned phase is to establish and test the systems required to support additional crew for extended durations. This involves expansion of habitat and laboratory facilities, plus increases in the degree of closure of the LSS using in situ materials to decrease the dependance on earth resupply. During this period, the permanent crew will increase to 8 or 12 serving 1 year tours of duty, and the lunar oxygen facility will be increased in capability to provide LOX for all lunar lander traffic (10 tons/month). During lulls between resupply/construction missions, substantial scientific exploration and establishment of a lunar observatory will be undertaken. At the end of this phase, the capability to support a crew of 30 will exist, and the first crew to serve a 2-year tour of duty will arrive. The lunar base would now be fully operational and be used to exploit lunar resources for all mankind. First, the production of in situ propellants would be enhanced to include liquid hydrogen (LH2) in quantities necessary to fuel all lunar based transportation systems. Then, the quantity of LOX produced could be increased to allow LOX to be ‘exported' to LEO in aerobraked tankers, allowing more useful materials to be launched into LEO and trans-shipped to low lunar orbit (LLO). During this phase, advanced propulsion systems such as NTRs and NEPs could provide very large benefits in reducing the cost of LEO to LLO transportation, allowing more rapid expansion of lunar capabilities for the same system operating
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