The basic progression is:
L1 Mission --> Frigate/Destroyer
L2 Mission --> Cruiser
L3 Mission --> Battlecruiser
L4 Mission --> Battleship
L5 Mission --> A Fleet

Minimum skills for pve:
Frigates skill level 2,
Cruiser skill level 3,
Bc skill level 4.
BS tanking skills 5, be able to fit all t2 tanking mods . Comp skills may be 4.
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Cosmic anomalies are ranked in difficulty by 10 levels, these are:

* (Faction) Burrow / Drone Collection (easiest)
* (Faction) Hideaway / Drone Cluster
* (Faction) Refuge / Drone Gathering
* (Faction) Den / Drone Gathering
* (Faction) Yard / Drone Surveillance
* (Faction) Rally Point / Drone Menagerie
* (Faction) Port / Drone Herd
* (Faction) Hub / Drone Squad
* (Faction) Haven / Drone Patrol
* (Faction) Sanctum / Drone Horde (hardest)

A particular anomaly may be further sub-divided into 3 more categories:

* Blood Raider Hidden Hub (easiest)
* Blood Raider Forsaken Hub
* Blood Raider Forlorn Hub (hardest)