Here is the full list of all 17 SPACECOM achievements.
Win a space battle with Siege fleets (any game mode)
Loose a fleet to attrition in any match (any game mode)
Destroy an enemy fleet within first 10 minutes of a multiplayer match
Build a Battlestation or a Shield within 10 minutes of a multiplayer match commencing
Capture 4 systems within 10 minutes of a multiplayer match commencing
Complete a multiplayer match on every map in the game
Control at least 80% of the systems on the map (Multiplayer or Skirmish)
Fight 4 battles at the same time in a match (any game mode)
Destroy at least 80% of systems on the map (Multiplayer or Skirmish)
Don’t loose a single fleet in a multiplayer match
Don't loose a single system in a multiplayer match
Write something on chat
Unlock all achievements, apart from this one
Complete all single player missions
Complete all optional objectives in single player missions
Win a match with only 3 or less fleets left alive (Multiplayer)
Loose a match with 10 or more fleets alive (Multiplayer)