Head to the Exodus Cluster and enter the Asgard System.
There will be an animation, afterward travel to and land on Asteroid X57.
You must first disable 3 Torches. They are huge, can't miss 'em.
Each torch is guarded by a number of heavy turrets that remain shielded until you get within their range. Drive by, or back approach is the way to go.
#1 - Right near where you land, enter the door at the bass, kill all the bad guys, turn off the switch upstairs.
#2 - to the E/SE of #1. Careful there are mines. the proximity is noted by blinky lights. Don't drive up to them. get out and walk. A gauge will pop up to tell you if you are to close. They show up on your radar, so just try to walk in-between them best you can. Once you get through there will be a little box you can use to turn them off. Again, go inside, kill the bad guys and turn off the torch.
#3 - head NW. Same as #1 except these bad guys are biotic. After wiping them, a henchman will have a conversation with you. You can talk your way out of the fight or just kill him.
Now, you'll have the info on the main base. head there (north). There is a huge battle and in the end you'll have to deal with a hostage situation. Either way you deal with it the achievement will pop.