Last I checked, the Helios doesn't have "supercap" and thus cannot kill a Sathanas. Also, using game mechanics, especially "Alpha 1", in any discussion of actual physics or scenario building is stupid.
Keep in mind that in a real war, everyone is "Alpha 1". You, your wingmen, enemy fighters, and...the gunnery crew on the Sathanas. And they're all playing on Insane. One pilot trying to attack a Sathanas would be torn to pieces by flak turrets and several hundred Shivan fighters with pilots of similar skill to himself. Even one pilot against a cruiser would likely amount to little more than a clay pigeon for the AAA beams.
And you know that 10^12 GT figure I posted? That has to be delivered all at once. Try doing that in your puny bomber.
I could probably rant for hours in the incredibly trite, stupid, annoying direction that universe discussions always follow.
In general, no one seems to consider that real military people have brains. A freighter under attack by a pirate wing is probably going to jump away as quickly as possible unless it's right near a node that it needs to travel through. A Ravana attacked from behind is going to turn around. A fighter wing reduced to half strength is going to flee, either because of not wanting more casualties (GTVA) or not wanting to throw away units that could be used for something else (Shivans). Each side is going to do its damnedest to minimize its weaknesses and maximize its strengths. FreeSpace may be a game, but war is not a game, and a fighter pilot is just one tiny, tiny pawn in a war. Alpha 1's efforts mean very little in the grand scheme of things.