The Death Star cake is really 2 separate cakes. The Death Star itself, plus a plain sheet cake (using the Wilton large paisley pan) upon which X-wings and TIE fighters wage a battle. The Death Star looked great, but before we could photograph it, the board got bumped and the ball rolled off the stand and hit the floor. Minutes before the party! I touched it up, but you can see the damage. C'est la vie.
In advance, make x-wing and TIE fighters out of fondant. I snagged some clear plastic skewers from the floral dept at my grocery store, and let the figures set in a block of Styrofoam. (These are the skewers that hold little cards in a bouquet of flowers or a plant, just break off the prongs at the top.) The TIE fighter wings are held on with toothpicks. Break off bits of toothpick to get the right size.
2. For the Death Star - frost smooth with gray buttercream. Add rolled fondant panels on the sides, leaving a space open for the weapons crater. When the icing is dry, depress the crater using a ping-pong size ball. I used the ball from my track-ball style mouse.) Use a Wilton No. 2 tip to add lines/detail to the crater.
Note: I covered a tall plastic drinking glass with black fondant to serve as the stand for the Death Star. I placed the Death Star on the stand, but did not "glue" it down with buttercream. 20-20 hindsight puts a big dollop of icing on that glass before I set the ball on it!
3. For the other cake, to make as pictured, cover the cake with high-quality rolled fondant, tinted dark gray. See my page on Rolled Fondant. Alternative, frost smooth with dark gray buttercream. Position the vehicles as shown (or as you like). Finish with a row of small fondant balls (or buttercream open stars) around the base.