This is a custom LEGO Starship Discovery I built, using only one set of legos (specifically, I used only pieces from the LEGO Star Wars set "The Phantom", and I even have leftover pieces!). This is one of my proudest LEGO custom achievements, although there are a couple things I wish I could fix. First, I wish the saucer was more round and had a wider diameter. Second, and this is thankfully hard to tell in the picture, but the underbelly is very fat, much moreso than in the show. Now to the details! The pale greenish blue pieces on the aft end of the nacelle pylons are the impulse engines, and the macaroni colored pieces are RCS thrusters (I don't know if the Discovery has visible RCS thrusters or not but mine does). The most fun aspect is a side effect of the set I bought to build this ship: she comes with two forward facing photon torpedo launchers on each nacelle pylon! The torpedoes themselves are not shown in the pic below, but I do have them, and yes, they do fire when you press down on them. 
I appreciate all feedback! Thanks!

I appreciate all feedback! Thanks!
