The Twins

attack, although these ships will only be there for a short time (most likely destroyed very quickly). To complete this mission successfully all you have to do is destroy both of the Borg Spheres and make sure that Starbase 001 stays intact.
Here is a mission for QBR, where you have to stop two borg spheres from destroying Starbase 001 in orbit of Earth. This mission includes main Starfleet ships present at the time of the first sphere