Power module control moment gyro

The directed design modifications to the Skylab/ATM CMG for application to the Power Module include new rotors of a different material with high resistance to stress corrosion cracking. The spin bearing retainer fix which was determined during the post Skylab mission was incorporated, and the speed pickoff was improved through the use of pickoff thermal cycling screening tests. The unlimited gimbal freedom on box axes was incorporated using slip ring assemblies. The on-orbit replacement capability was also incorporated for the CMG assembly and the inverter assembly.