costs. As a byproduct of the intensive mining effort, large quantities of iron and titanium would be produced which could be used to enlarge pressurized living and working volumes. Finally, serious mining of the lunar regolith to produce 3He could be started in an effort to make the moon economically independent. If demand for clean fusion power materialized on Earth then the crew of the lunar base could expand a thousandfold in order to operate and maintain thousands of automated 3He mining machines. Mars Evolution Mission Definition The Mars evolutionary strategy grows from an initial exploration of Mars to establishment of propellant facilities and ultimately a permanent manned base on Mars. Key sizing groundrules include: initial crew size of 4 growing to 8, reusability of selected vehicle elements, aerobraking at Mars and at Earth, baseline chemical propulsion for all stages, and accomplishment of program objectives with constant annual investment during the operational phase. The evolutionary program is carried out through a series of unmanned cargo flights and manned exploration missions described in Craig [3] and summarized briefly here. FY89 NASA strategy also imposed an annual limit on the allowable mass to LEO in support of the Mars evolution mission. The design groundrule was to use Block I technologies (chemical propulsion) until the exploration objectives, especially schedules, could no longer be met within the yearly mass-to-LEO constraint. At that point, advanced propulsion technologies would be introduced as a Block II update. Evolutionary strategy determines the mission characteristics for the Mars case. The initial manned mission would be to explore the Martian moons with no manned landing on Mars. This would be followed by development of a Martian moon gateway on Phobos which functions as a transportation node, a propellant source, and a propellant depot to reduce the cost of establishing an outpost and eventually a base on Mars. Both manned and unmanned missions are planned, with the cargo often ‘sent ahead' using minimum fuel Hohmann type trajectories and the crew using faster opposition class 600+ day trajectories. The first manned mission to Mars will aerobrake in the Martian atmosphere and then rendezvous with Phobos. The Mars Piloted Vehicle (MPV) can remain at Phobos and explore Diemos either robotically or with a small chemical Orbit Transfer Vehicle (OTV). Use of this exploration option allows the reusable MPV to be sized for its primary mission, which is to ferry humans to the Mars gateway station at Phobos. If it must rendezvous with both Phobos and Diemos in its maiden flight, the MPV design will be compromised with oversized tankage and heat shield, and therefore be nonoptimum for later flights. The second Mars mission departs earth in September 2007 in the refurbished MPV with a cargo of a Mars Crew Sortie Vehicle (MCSV) and a Mars Cargo Lander (MCL) containing a surface habitat and 1 year's supplies. All three vehicle aerobrake in the Martian atmosphere in August 2008 with the MCL landing on Mars while the MPV and the MCSV perform rendezvous with Phobos. The crew secures the MPV at Phobos, transfers into the MCSV, and descends to the Martian surface. They assemble the habitat facility and spend 1 year collecting extensive geophysical and environmental data and performing selected science experiments. In July 2009, the crew secures the habitat facility and ascends from Mars using the MCSV. They rendezvous with Phobos and transfer to the MPV for the trip back to earth. In May 2010, the MPV aerobrakes at Earth and rendezvous with the space station.
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