▶▶ Pod 153 - Report:

The machine lifeforms not only infected the YoRHa soldier units on the ground, they also infected the <Bunker> with a viral attack, activating a self-destruct sequence.

With this, the 13th Orbital Satellite Base <Bunker> was destroyed. 

2B and 9S avoided infection from the virus and escaped the Bunker before it was destroyed. 
Proposal: Find the remaining surviving YoRHa Soldiers and start another descent-to-ground operation on Earth to fulfill the mission.
Well, if you want to call me Nines,
it's totally okay.
‫إن كنت تريدين مناداتي بناينز، فلا بأس بذلك.
Na, du kannst mich
auch ruhig Nines nennen!
Bah, que tu m’appelles 9, pardi !
De você me chamar de Nines, ora!
Por mim, eu topo!
Ну, если хочешь звать меня Девяткой,
я только за.