Here is the full list of all 25 Interplanetary achievements.
Hit your own planet with a railgun.
Grow five cities to their maximum populations.
Unlock all technologies.
Win an online multiplayer match with at least two players.
Win an online multiplayer match.
Win 5 online multiplayer matches.
Win 10 online multiplayer matches.
Win 50 online multiplayer matches.
Win 100 online multiplayer matches.
Win 10 single player games.
Win 100 single player games.
Beat the Impossible AI.
Win an online multiplayer match with at least four players.
Win an online multiplayer match with eight players.
Fire Solar Laser superweapon.
Fire Asteroid Diversion superweapon.
Destroy 100 cities over any number of games.
Defeat an enemy planet.
Defeat two enemy planets in one turn.
Build 200 buildings on your planet.
Win a match with barely any population left.
Fire all the superweapons during the same turn.
Have your planet run out of material.
Have 25,000 material in stock.
Produce 7,000 Energy in one turn.