Completing the Survival Directive contract comes immediately after you finish Introducing: NuCaloric and unlock the foodie faction in Marathon. This is the first contract that you actually do for them and it'll give you a decent chunk of faction rep so you can start unlocking some of their best upgrades—I recommend the ones that give you free daily Patch Kits and Shield Rechargers.
Before that, though, you'll have to head to Perimeter and interact with two terminals, one in Station and another in Overflow. In case you're struggling to find either, here's how to complete Survival Directive in Marathon.
