Here is the full list of all 19 Into the Void achievements.
Research any tech
Craft any item
Return home alive
Upgrade any item
Extract any resources from planet or star.
Construct a new ship
Complete act I.
Complete Act II.
Complete Act III.
Complete Act IV.
Complete a battle against an ultimate BOA fleet.
Complete a battle against an ultimate En Eire fleet.
Complete a battle against an ultimate Kalthem fleet.
Complete a battle against an ultimate Auslia fleet.
Fully research any branch
Complete a game on easy
Complete a game on normal difficulty
Complete a game on hard difficulty
Complete a game on extreme difficulty