Killed all inhabitants of HELIOS ONE, yet quest still active

You should find Lt. Haggerty in HELIOS One to get information on the supplies you are tracking. If you have killed her, the quest is still solvable by finding the supplies without the tracer. They are directly north of the northeast corner of the Southern Nevada Wind Farm. The quest should update then to your next goal.

If that doesn't work, check where the quest marker on your compass is pointing to. Perhaps you've forgotten to do something in the quest.