This is a really good piece, I really love spacey- out of this world themes especially in a 60's propaganda style! Though this piece has a good composition, I think it could do with a little bit of effects, like the black space background with the blue spheres- perhaps the edges could have a blending effect? or have the spaceship near the light rays so that it looks as if its "shining" those rays? As at the minute it looks as if its just floating about.
However with the use of colour schemes i.e the pinks, creamy yellows and blue/turquoise hues this does make the piece stand out and quite unique. Good job!!