Old space computer game

hello.. i am looking for an old space game.. i think it's a dos kind of game.. i barely remember it though.. i think the game is about conquering planets. the planets could defend and it has resources like oxygen, fuel, nuclear weapons and it has population.. you have a spaceship and you need to go to your planet so that you can refuel and buy ammo's and nuclear weapons to shoot and nuke planets and be able to conquer them.. there were computers as well.. anyone remember this game? please tell me