are the same as for the LEO base modules described previously. Figure B-35 shows a summary of crew requirements for the LEO and GEO construction base operations. Component Packaging for Launch - Component packaging for launch is a very significant factor in construction as well as space transportation. Packages must not only meet dimensional and weight constraints of the launch vehicle, but must have appropriate mass density to far cost effective transportation. Figure B-36 illustrates the dimensions, density, and part count of various SPS components. As indicated, densities vary from a low of 12 kg/m ^3 for antenna subarray elements to about 2500 kg/m^3 for power conductor. To obtain desired densities, components must be packaged in appropriate mixes as indicated in figure B-37. Such packaging minimizes the number of launches, thereby reducing transportation costs. Crew Considerations - Figure B-28 illustrates the integrated space operations. The satellite construction phase requires 580 days as indicated on the construction timeline shown in figure B-29. During construction, a crewman will be located in geosynchronous orbit. The reference crew scheduling concept is summarized below. o 90 day staytime o 6 days on/1 day off per week o 10 hours work shift per day o 2 shifts per day (2 crews) o 0.75 operator productivity factor Radiation protection is provided to limit crewmen to 35 REM/year exposure. Shielding of 2 to 3 gm/cm^2 in LEO and 20 to 25 gm/cm^2 in GEO will provide this protection. Habitat walls will provide the 2 to 3 gm/cm shielding, however, special "storm shelter" facilities must be provided to obtain 20 to 25 gm/cm shielding. This type of facility would be needed during solar flares only.
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