Terra Firma

At its calmest, a human political activist group that advocates for the resettlement of Earth.

At it's most volatile, and usual state of being, it's a violent terrorist organization that regularly attempts to seize ships and weapons and then run the blockade around Humanities home, and thus resettle it by force.

In the modern parlance, they're regarded with the same seriousness as the now ancient 'Flat Earth' adherents, if they had armed themselves and promised violence.