@CuriousGeorge, if you're past this stage ignore this: I just started building ships today. Anything that wasn't a single booster with a capcom on top exploded. I've learned 3 things that stopped the exploding: 1. Before launching, make sure the stages are in the right order, and that the icons in each stage are where they belong. When you hover over them their 3D counterparts are slightly hilighted. 2. I discovered the yellow symmetry button in the top left of your building window, I clicked it until I had triple symmetry and then I could add 3 boosters symmetrically. 3. Don't detach boosters while they're burning.