Credit goes to 85clarion
Just go in infinite mode on normal and DO NOT touch the screen every time, let your ship die from the enemies. when your game over just do the same go in infinite mode on normal rinse and repeat.
Do this 30- 45 min. Then you come into the game 1 or 2 enemies come and then the game is empty no more enemies spawn you flight alone with your ship in the space, leave it alone for the remaining of time that is left until achievement unlocks.
This achievement crashed the game when I got it, so I couldn't even enjoy the Achievement Unlocked pop-up and sound effect. Just play Infinite Mode on normal for 3 hours and it should pop and/or crash the game.