Research is necessary on 0.14 of this mass, or 0.14 • 264 t = 37.0 t. The mass of equipment constructed on earth is that of the total of the above list of objects launched by the shuttle with mass of fuel deleted, or 685 t - 56 t = 629 t. Extended S.S.I. Plan with Pure Self-Reproduction and Construction in Low Earth Orbit Assumptions This plan follows the extended S.S.I. plan with pure self reproduction with the following modifications. 1. Only the space manufacturing facility is constructed on earth. 2. Fuel for the lunar transfer vehicle, the space manufacturing facility, and enough raw material for it to construct the remaining equipment are placed in low earth orbit by the space shuttle. 3. The cost of these raw materials is low enough in comparison to other costs used in this plan that it is assumed negligible, with the result that the construction cost of the equipment built in orbit becomes zero. 4. Two-thirds of the mass of equipment constructed in low earth orbit is aluminum, and this aluminum is provided free from shuttle external tanks. 5. 30 t of the 35 t of the mass of an external tank is aluminum. 6. Since the external tank powderer is required to convert the tanks into a form in which they can be used by the space manufacturing facility, it is constructed first.
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