The southern expedition proved uniquely bizarre. They had basically no intel about Antarctica's state after the Last War.
Prior to the Apocalypse, Antarctica accommodated billions of humans who had relocated there centuries ago.
Before space exploration became the norm, Earth suffered from serious overpopulation, but as the southern icecaps melted, a solution arose.
Each continent sent millions of 'undesired' humans, and they built cheap cities which could support themselves.
Large corporations owned these cities and used their population as slave labour.
The Antarcticans tried rising up against their oppressors, but each attempt failed miserably. Their slavery continued until the space exploration began.
Slowly, year-by-year, decade-by-decade, people forgot about the Antarctican population. The automated defenses continued keeping them in line until eventually those failed too.
