you have to "earn points" by doing certain things like with the other companion quests. they all have a different value you'll need 2 points and have to be so far in the main quest .
1 point complete the white wash, either arrest anderson and keep the supplies and water, 2 points for framing the scorpion gang
1 point for visiting the repconn test site before complete the other quest there
1 point for finding the crashed vertibirs
1 point complete that lucky old sun direct the power to freeside
3 points enter the fort with arcade telling him you only want to see what the legion is up to then leave
1 point there stands the grass after talking to hildern about the OSI
after that he'll talk to you and give you the quest