The mission where you are attacked by like 15 wings of Thul drones seems to have a bug, at least for me. I have beaten this mission 7 times and each time I finish killing all of the drones and am given permission to land, at some point before I can land I get the cutscene showing the cruiser being destroyed (the lady says "there they go on a long journey") and mission failed?!? And most times the cruiser still has shields and full hull...has anyone else had this issue? Quite frustrating...

I know the exact mission which you're talking about, but I've not run into this issue before. There is a few things you can do to check that everything is fine. Firstly make sure you set the difficulty level to its lowest setting, and also when you finish killing the drones, radio the cruiser and ask for permission to land. If you're not even managing to get to the cruiser it might be that you're taking too long to complete the mission somehow.
Give that a go and tell me what happens. :)

Looks like it was a 48-hour virus. I retried the mission several more times, gave up frustratingly, and left the silly thing alone for a couple days, then went back into it and it worked.
Now that I have beat the game there really seems to be no replayability or reason to keep playing except for the last side mission, but I cant get to the Ascarong system because I cant get the last artifact to get the Zero Point drive since the 1 remaining artifact is in the Bailebeag system in the Thul cluster Communa. Does anyone know how I can unlock this system? I have done the side mission for that cluster which unlocked a different system and flown to all the other systems to see if I would get the new Nav data, but to no avail.

Check this map out
It will give you the information as to how to unlock each system. If you really get stuck, just ask and I'll guide you through it.

Excellent map...unfortunately it doesn't show what systems unlock others. But I went back to the cluster and jumped through every system again and finally got Bailebaeg unlocked.
Thanks again...now gonna go play Freelancer to remove the bad taste of DSO, or maybe I should give X3 a try...

Freelancer is better than DSO, but I still hold that DSO has a certain level of charm to it.