WBS 1.1.1.6: Maintenance The maintenance system is mostly annealing systems and the gantries and tracks to support them. Tracks are assumed to be structural aluminum, gantries are largely structure but include motors, and at least half of the annealer mass is assumed to be radiators, solar arrays, and power processors. Minor components of the maintenance system include cargo handling and docking systems, which were assumed to be non-lunar due to complexity. Thus, 90% lunar is probably a conservative estimate of the composition of this system. WBS 1.1.2.1: Microwave Power Transmission System (MPTS) Structure As mentioned above, the transmitting antenna must remain flat to high precision. Because of variations in the antenna’s thermal environment, this flatness can only be maintained by using structural materials with low CTE, or by using active structural adjustment. A passive structure made of foamed glass is assumed. WBS 1.1.2.2.1: RF Amplifiers Klystrons are assumed to be more than 99% lunar, as described in section 5.2. With any power conversion system but silicon planar, magnetrons would replace klystrons because the magnetrons’ higher efficiency would reduce non-lunar mass in the power conversion system. WBS 1.1.2.2.6: Control Circuits The mass of control circuit components is difficult to estimate. The most massive component of each control circuit is probably the radiator for the klystron circuit breaker, a semiconductor switch. The radiator is assumed to be 99.6% lunar and to constitute 90% of the control circuit’s mass. All other components are assumed to be made on Earth due to their electronic complexity. WBS 1.1.2.3.3 DC-DC Converters As described in section 4.3, an electronic voltage converter was assumed to replace the transformer used in previous designs. The primary components are inductors (iron, silicon, aluminum), capacitors (aluminum and silicon dioxide), and a non-lunar semiconductor switch. There must also be a control component, which is assumed to be non-lunar. Elimination of the transformer would reduce total mass, but replacement of non-lunar electrolytic capacitors with solid-state lunar capacitors would slightly increase mass. To be conservative, it is assumed that total mass is unchanged. WBS 1.1.2.3.4 Thermal Control The mass of the radiators which cool the DC-DC converters is assumed to decrease by 50% from its original value due to the increased efficiency of t^e electronic power converter, as compared to transformers. WBS 1.1.2.3.5 Energy storage In the reference SPS, nickel-hydrogen batteries provided energy storage. Flywheel storage technology (section 4.4) was assumed here to reduce non- lunar mass. WBS 1.1.2.5 Phase Distribution This component includes mostly electronics and fiber optics, which would be
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