Moon & Mars Orbiting Spinning Tether Transport - Tethers Unlimited

Appendix L: Tether Boost Facility Design Final ReportThough we do not have answers to these questions, our design of the firstfacility includes a large open area at the end of the CS to accommodate docking of amodule.2.2 Zero or Low ConsumablesWe set a design goal of zero consumables for the MMOSTT tether facility. Ifmet, this goal avoids the need for resupply operations and thereby reduces risk andoperations cost. The key design impact of this goal is the use of electrodynamicpropulsion for reboost of the facility and CMGs for orientation control of the facility.Electrodynamic (ED) propulsion imposes a number of challenges on the designand on technology development. ED thrust varies in magnitude and directionaccording to variations in the geomagnetic field and the ionospheric plasma density.This drives the flight control system to use new methods. ED thrust also requiresquite high voltage - tens of thousands of volts. This is beyond current practice forhigh-power space electrical systems.2.3 High Power For ThrustTo achieve 30-day reboost using electric propulsion requires quite high powerlevels, primarily near perigee. This means the CS must provide hundreds of kilowattsof average power from solar arrays and much higher peak power from batteries forthrust during near-perigee passes in the Earth's shadow. The size of the solar arraysand the mass of the batteries dominate the CS design.L-54