Now, blowing up a planet with an asteroid has its perks, definitely. But if you want a better visual effect and more of a prophesied doomsday feel, you’re going to want a comet. Thus, I used this tutorial.
Now, of course, you don’t have to do a doomsday scenario. Perhaps your heroic sky pirates are have a base on the comet. Or your beleaguered space exiles have to mine the comet for water. In my upcoming story, the comet is being used to hide a secret research facility.