Here is the full list of all 24 Star Hammer: The Vanguard Prophecy achievements worth 1,000 gamerscore.
Destroyed 25 Remnant ships.
Won a skirmish battle
Protected Novus on your own terms
Didn't lose a single escort objective during the war
Had a reinforcement join you in battle
Kept your crew friendly
Deployed a fleet group with maximum Command Points
Deployed thirty countermeasures
Killed a stunned enemy with the Destroyer's laser.
Destroyed 100 nautilids.
Killed an enemy with a laser beam
Stunned an enemy
Destroyed a nautlid
Destroyed an enemy with a missile
Destroyed a remnant ship in campaign mode
Recruit the pilot.
Recruit the comms officer.
Recruit the science officer
Recruit the intelligence officer
Uncover the Remnant conspiracy
Protect the shipbuilding yards.
Evacuate civilians from the Boardwalk.
Evacuate workers from DM3
Recruit the engineer