The Galornden Core System Patrol in Tau Dewa Sector Block is bugged. After herding the Gekli pod all the way to the end of the path, and destroying all the Hirogen Ships in the area, the Gekli refuse to go through the fluidic space portal and finish the mission. They just sit around in front of the portal and don't do anything. There are no interaction options, and there isn't anything you can do to finish the mission.
This is really frustrating because this particular mission is much more time-consuming than other missions in Tau Dewa. You don't know until you reach the end whether or not it's going to give you credit, either.
I've had this happen a few times, too. I found sometimes if you fly back towards the start position, you can come across a stray Hirogen patrol, then the Gekli will go through, and mission completes properly (sometimes it will complete without even having to engage the patrol).