I think the Vajra have either captured or destroyed the main Galaxy colony ship.
In the Gattai sub of episode # 6 at 09.20, you see the recording of the transmission from the Galaxy captain(?) and in the Gattai sub he says:
"The damn bugs have taken Mainland! Please! Someone!"
At first I thought this was a translation error by Gattai, as they are AFAIK, the only fansub group to use the word "Mainland" in this scene, but then I listened closely, just concentrating on what the character is saying and he clearly says "Mainland" in English.
I'm guessing that Mainland is the name of the main colny ship in the Galaxy fleet.
Graham