As far as I can see there are a few possibilities:
Superlight Drives: They are reminiscent of Star Treks' Warp Nacelles. This theory is dashed on the rocks as assault transports and engineer pods do not have Superlight Drives.
Shield Generators/Projectors: There are none visible in bigger ships becaus the pods leak radiaton and ontl larger ships have room for suitable insulation. Fighters do not have shields. Against this is that engineer pods are meant to be unmanned and therefore do not need protection from radiation. Against this is that the radiation interferes with the engineer pods' AI.
Gyroscopes: For manuverobility. Ships without the pods are (a) Large enough to be able to rely on their shielding/escots to keep them alive until the enemy is destroyed. (
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Sublight drives: NO the splash screen clearly shows an orange thing on the back of an Ishiman heavy cruiser.
Weapons pods: No the cruisers weapons are all shown in the briefing picture. The blue half-circle is the F-pulse reactor and the two orange bits at the side are the PK beams.
Does anyone else have any other ideas or can anyone read Ishiman script and decipher the 'labels' at the side.
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Grand Fleet Admiral Slathkill, Supreme Commander I.M.A. Fleet