Sins of a Solar Empire: Diplomacy pre-orders open By Patrick Garratt, Wednesday, 16 September 2009 14:47 GMT Share on: Facebook Twitter Reddit Google+ Stardock’s opened pre-orders for Sins of a Solar Empire micro-expansion, Diplomacy. See here. The add-on will bring a new tech tree, new ships and “deadlier pirates” to the space-based RTS. Yours for $10. It’s out February 9. Buy it here.