The Robotech Relief Expedition was a fleet from the Pioneer mission that had been sent into deep-space to find the homeworld of the Robotech Masters. However, their mission was ultimately a failure as the Tirolian armada had departed for Earth and begun the Second Robotech War.
During the conflict, the Reflief Expedition arrived back in Earthspace where they were commanded by Major John Carpenter and ambushed by the massive Tirolian Motherships. Amongst these ships was Recon One that was destroyed but not before Carpenter and much of his crew escaped to Earth's surface in escape pods. These survivors were taken to United Earth Command where they informed Supreme Commander Anatole Leonard that there would be no reinforcements from the Robotech Expeditionary Force.