Silent Space (a.k.a. Space Force / Space Wars) is a cancelled Sci-fi RTS that was in development in 2001 by Crytek, originally created as a prototype for PC, but later planned for Xbox and Playstation 2 too. This project was in the works along with Engalus (a cancelled FPS) and X-Isle (which evolved in Far Cry) in the early days of Crytek. When the game was announced, Faruk Yerli (president of the studio) told to GameSpot that:
Currently we are in negotiation with some publishers. We know that the game would be fantastic, but you surely know that without funding no game could be finished. We believe that Silent Space could break the limits of other space games, and we will soon announce the future of all of our projects.
It seems that they never found a publisher interested in Silent Space, and the project was soon canned.