UPDATE - Now Available for purchase:
Price is set to $50 for a very limited introductory time - will increase to around $100-$150 shortly.
Over the past few months, instead of sleeping, I've been spending my nights on creating an asset package for Unity 3D =) If you are making a space themed game in Unity this may be something of interest to you.
Here is the official promo video that takes you through all the features:
Basically, it's a space scene construction kit allowing you to create unique space scenes for your game(s). It comes with hundreds of textures (up to 4096x4096, but you decide what resolution you need) and scenes with stars, nebulas, galaxies, planets, moons, and asteroids are automatically generated.
Official web site: http://www.spaceunity.com
Here are a few screenshots as well: