Operation Monopole was an initiative sponsored by the Robotech Expeditionary Force during the Pioneer Expedition. Their original goal was to make peace with the Robotech Masters on Tirol and prevent a Second Robotech War. However, the SDF-3 arrived too late as the Masters had departed for Earth whilst their homeworld was besieged by the invading Invid.
The skirmish with the Regent's forces led to critical damage to the engine system of the SDF-3 thus stranding the entire Expeditionary Force in that part of the Local Group. In order to rebuild their fleet and repair their ship engines, it was decided that the Zentraedi contingent of the crew would return to their original size in order to mine Fantoma of the much needed Monopole Ore. Breetai personally volunteered to return his forces to their original purpose of mining the giant planet which only their large physique were capable of surviving.