SPECS 2004 Various ADCS Sizing Actuators: Based on the disturbance torques I’ve looked at so far, mainly in the vicinity of the Earth, I’m estimating the following, for the highly elliptic phasing orbits transfer option, with 3-axis control: • 4 Reaction wheels on CSC( recall MSC still attached), 3 nominal, 1 backup. Each has mass of 10 kg, so total of 40 kg (plus some extra for electronics, so say a total mass of 50 kg). It’s really hard to get numbers for power, so assume for now a power requirement of 100 W (average value from SMAD). • External thrusters for attitude control during orbit burns, halo orbit stationkeeping, formation repointing using precession, and occasional MSC position control. (in progress) Sensors: • Combination of Sun sensors, Star Trackers, and Rate Gryos (RGs), all of these can be used at L2 also, so no need for extra sensors. See the excel sheet for the actual numbers. Total mass of sensors for 3 MCS = 30 kg Total power of sensors for 3 MCS = 162 W Total mass of sensors for 1 CSC = 51 kg Total power of sensors for 1 CSC = 228 W