oh i love this.. something about the model just makes it work so well in that dark enviroment... one thing that would look really cool is if you added some clouds below it and behind it.. almost like it is high up in the sky... but not exactly in space. Unless i missed something and this is a space balloon :O. Not even really physically possible.. but would be cool.. haha. But yea, some light clouds would be cool.

BTW, I really like what you did to the balloon itself.. the texture is nice .