Stardock announces that Forbidden Worlds, the first DLC for Sins of a Solar Empire: Rebellion is coming to Stardock's space strategy game on June 5th by way of digital distribution. The USD $4.99 pack will add new planet types, planet specialization, technologies, planetary bonuses and additional Steam achievements. Here's a feature list:

• Four new planet types to colonize and exploit (Barren, Ferrus, Greenhouse, Oceanic), each created with beautiful high-res textures.
• New Planet Specialization System: Dedicate your worlds to either social or industrial output. Devoting your planet to social improvements will increase its population and culture, at the cost of trade income and ship production. Choosing an industrial path will limit your growth and culture, but make your planet a trading and ship building powerhouse.
• 15 new research subjects allow the races to conquer and expand onto the forbidden worlds.
• Discover 40 new planet bonuses during your exploration of the galaxy, unlocking the dark past of the Sins’ universe.
• Unlock five new Steam Achievements and display your mastery of forbidden space!