Once you have the base game and Knossos installed, look for these specific mods within the launcher to get the "Full HD" experience:
To legally play FreeSpace 2, you need the original data files. While it was occasionally offered for free in the past (notably on GOG ), it typically requires a small purchase today. freespace-2-free-download-pc-game-full-version
The preferred DRM-free version often found on GOG. Steam: Also available for purchase on Steam . 2. Install the "FreeSpace Open" Engine Once you have the base game and Knossos