From FreeSpace Wiki
Black Horizon - Episode 1
Description: The jump nodes to Sol have reopened after 100 years and the Shivans have returned to try and finish what they started, but the Shivans are the least of the GTA's worries as the human race approaches its own destruction... 10 Missions, includes 3 multiplayer missions
Black Horizon - Episode 2:The Birth of a Nightmare Description: The story of Black Horizon continues in episode 2 of the Black Horizon campaign. As the GTVA declares an official state of war on the Black Horizon, they discover that their greatest fears have become a reality. Includes new models and pics. Uses modified ships, weapons and AI tables.
Note : The links won't probably work for long