The Master Payload Control System (MPCS) controls power relay states for Airborne Payload and Control System on all NASA aircraft. As input the MPCS accepts an Iridium packet which contains a bit pattern describing all system relays as either open or closed. The MPCS outputs eight (8) sets of DC relay coil drivers, one set per EIP. The MPCS also provides GPS IRIG-B, and EIP monitor power. The MPCS also integrates the functionality of the systemís AC Power Distribution Unit (PDU), providing two circuits of switched AC power per Experimenter Interface Panel.