Direct from the Nightshade Books catalogue, here are the release dates.

Dark Space – October 2010

Chaos Space – April 2011

Mirror Space – August 2011

Transformation Space – December 2011

And here’s the Nightshade Blurb:

The Sentients of Orion is a wide screen, epic space opera. Deep Space chronicles of the intrigues and conflicts surrounding a seemingly omnipotent alien artifact, and a seemingly insignificant backwater star system and its ruling family.