Moon & Mars Orbiting Spinning Tether Transport - Tethers Unlimited

Appendix L: Tether Boost Facility Design Final Report• Waste heat from power conversion for ED thrust — Drives thermal controldesign/mass which impacts station configuration and structural design ofED tether bayThe Control Station was assumed to follow the 41:20 Resonance Designmission profile provided by TUI and was assumed to be launched by a Delta IV-H ona due east launch to a 600 km circular orbit, 28° inclination.3.6.2 Mass Properties StatementThe mass properties, summarized in Table 3-1, show an operational Facility(Control Station, tether, Grapple) that can be launched with a single launch of a DeltaIV-Heavy is feasible. Mass margins between 25-30% at this level of conceptualdesign are desirable. Note the two overall mass margins labeled “Bottom-upCalculated Margin,” and “Available Margin,” in Table 3-1. The mass properties wereestimated using a bottom-up approach, starting from the component level of eachsubsystem. Mass margins were placed upon each subsystem component; the sumof these component-level margins expressed as a percentage of estimated ControlStation mass is the “Bottom-up Calculated Margin.” The “Available Margin” is theallowable mass growth for a single launch on a Delta IV-H. The lower “Bottom-upMargin” indicates the estimated Control Station mass may be low, but the fact thatthe “Available Margin” is higher indicates that there is reasonable margin for massgrowth. Table 3-2 shows a more detailed mass properties statement.3.6.3 New Issues and Requirements IdentifiedAs design development continues, the launch configuration is growing inimportance. A quick look at launch configurations showed that the current conceptlooks promising, but still is not geometrically sized to fit within the Delta IV-H dynamicP/L envelope. This was not unexpected, with the level of subsystem definition at thisphase. The only other new configuration requirements involve PV array and FEACpackaging requirements. The FEAC panels must be sealed prior to flight, with aminimum requirement of a GN2 environment. This leads to derived requirements forFEAC packaging: a vented housing with a removable cover to expose the FEACpanels to space. FEAC packaging is expected to be a beefed up box with amechanized cover release and panel deployment system. The packagingrequirements were taken into account for the FEAC mass estimate.L-67