On the left side of Condemned you can see a large UNSC ship that is half burned to slag and a standard frigate in the distance trading salvos with the corvette.
One of my disappointments in Reach was that you never got to see a UNSC ship larger than a frigate aside from the pillar of autumn.
My guess is that is is a carrier.
May it is part of the station but it looks to be a ship to me.