Okay.... since Im not at home, I cant make any feasiblity checks on these ideas, so take it with that under condieration
Some stuff first:
Boarding operations are one of the most dangerous and tactcially most difficult operations, taking a hostile ship by force requires to fight an enemy which has the knowledge and control of the terrain, superior positioning and often superior numbes (that's why boarding is usually left to specially trained units). Pulling it off requires the boarding team to circumvent some of the advantages the defender might but will still proove to be exausting.
As such the terran position on the captured vasudan outpost will be weak; the base has been taken, damage done during the boarding (breached decks, disabled envoirmental systems etc) might not be repaired yet, the wounded not yet being treated and POW might still be on site.
With the response from the Vasudan defender imminent the Terrans might have some avenues of action left to tip the upcoming counter-offensive to their balance:
- Although the Vasudans have the layout of the outpost, they don't have a acurate image of it's current status; location of possible firedlies (remaining pre-takeover personell), unrepaired damaged and security weakpoints that are result of the previous takeover. That's why they may need an AWACs to coordinate the operation of boarding team and to provide them with accurate intelligence.
The mission now could be to compromise the AWACs ship while it is not with the main Vasudan task force (because it was stationed elsewhere or always on the move); this could be accomplished either by an electronic warfare mission, a subsystem strike or the through an agent aboard. The last one I think works best - the subsystem strike is too brute force and the electronic warfare angle you have used before.
What you now have to decide is if the fighter mission is a cover from the infiltration or the extraction of the on-board agent. As such you could make the player fight the escort, perform ruses (like faking an electronic warfare attack) or attack a nearby target as distraction. If you want the mission can take a turn for the worse and the player has to directly intervene into the infiltration/exfiltrstion although that was not planned.
- The Vasudans might be gathering supplies to build an alternative means of entry into the outpost other ships landing in the hangar or docking; mining equipment would make good impromptu breaching tools (so they can circunvent obvious chockepoints like docking ports). The pkay might be tasked to make sure the Vasudans don't gather a required set if items from different mining outposts in Dubhe.
The player woule have to jump to a mining facility and then by a set means have to deny the Vasudans the gear they want to acquire. Some of that can be achived through diplomacy, bribery, search-and-destroy of cargo or fighting the Vasudan teams that were send to procure the items.
- You could trun scenario one or two around; tasking the player to procure resources for the repairs of the outpost from a third party (with all the pitfalls that come from dealing with people who might be playing both sides for the middle; which has the player having to re-negoiate the deal in a timeframe before Vasudans appear while also preventing to be scammed) or a strategic asset for your side that will help hinder the progress of the capture attempt, e.g. procure communication codes (by scanning and "eavesdropping" - stay within X meters of a ship for Y minutes without detection) so your side can falsify orders (so ships will arrive later or earier in the counter offensive)
- Another possible scenario would be a prisoner transfer from the captured outpost back to Alphad; since both sides have limited ressiureces this could ammount to a stand-off between both sides in which the player's role would be to check if the Vasudans are bluffing and/or to call their supposed bluff. This could give the opportunity to show how ruthless either or both sides are as they willing to use bargain with the lives of the prisoners (insert a high-value prisoner in the situation which the Terrans don't know about yet and you have another point for a player objective - noticing and investigating the Vasudans special interest in a certain prisoner transport for example - and another way to resolve the situation without combat)
EDIT: you can also reverse the scenarío by replacing the prisoner convoy with a medical ship for the Terrans (which in a further modification of the scenario wouod be arriving from Alphad instead of depaeting there)