Try counting the number of ships escorting the Colossus in the intro cutscene and Colossus cutscene. 
I reckon a destroyer, two to three corvettes, three to four cruisers and perhaps five to ten squadrons. The Aquitaine had about four or five squadrons, according to Their Finest Hour's briefing.
The Orion can hold up to 10 000 officers and crew (who are willing to die for Neo-Terra). A corvette should be able to hold 4000 to 6000. Cruisers...I don't know, 500? 
AWACS, freighters, transports and gas miners should hold about five to ten people. Medical frigates should be capable of about 1500.
...and of course, the Colossus has space for 30 000.
I think Vasudan large ships should be operated by more Vasudans, since their interiors are like...whoa. 
Hmmm, i see.
Well as I'm on a roll, what do you think's the possibility of the Shivans being a gasmining species, ill copy paste the command briefing from one of missions in my campaign
Shivan Theory?
After careful study of Shivan tactics, the Security Council has deduced some motive for the Shivans actions in the Capella System. Based on intelligence gathered by the Vasudans during their stint in the Nebula in which the first Sathanas was encountered, the Shivans appear to mine the Nebula Gas to power their ships, and possibly an economy. The Security Council believes that in order to power the large number of Sathani, the Shivans were running short of deposits within the nebula. In order to create more deposits, the Security Council believes that the Shivans destroyed the Capella Star, forcing it go supernova, and creating a large number of deposits. However skeptics argue that the creation of new deposits is not a reasonable cause to sacrifice a dozen Sathani. However we have reason to believe the Shivans populate a large number of systems, and during the GTVA's reconstruction period, the Shivans developed and mass produced the Sathanas. While this is not a very heartening piece of information for the GTVA, it explains the presence of many Sathani in the nebula. Unless the GTVA can counter this threat, we will be forced to sidestep the Shivans for the time being. However with the Economic Crisis in Vega, the Terran and Vasudan Economies will have to expand, and all eyes are on the GTVA to come up with a system ripe with resources. However, In Short, we believe Shivan Motives are to power a constantly thriving fleet and/or an economy. To do this, the Shivans rely on the creation of the deposits via the destruction of stars. However when this does not happen, the Shivans must make it. While doing this, they have become the protectors and destroyers of life. The Shivans have shown a quality many species before it have not. Discretion. By using discretion, the Shivans were able to drastically rebuild and expand their fleet, but were also wary of disturbing ill-developed life, or species that were not capable of space travel. When the Lucifer was destroyed, all Shivan ships quickly dissappeared from contested systems. The Shivan retreat allowed the Shivans to expand and multiply in a fashion that has not been observed since. It is also quite possible that the Shivans had arrived in the Sol system many centuries before Terrans acquired space travel, and simply bypassed the system because of its lack of nebula deposits. However had the Ancients stumbled upon the Sol system, they would've surely eliminated Terrans as a species long before GTA was formed, as they showed no intention of making Alliances with other species. While it is not clear wether the Shivans have made alliances with other species or in contact with any other species, it seems clear that their paramount objective is to acquire nebula deposits, however it may not be clear wether the extermination of species is part of their overall objectives. It may be so, or it may be that the Shivans suspect us to be mining their deposits, or that we are a reincarnation of the Ancients.
