Thrawn's Revenge is a large-scale mod for Empire at War: Forces of Corruption. It includes the events of the Galactic Civil War after Palpatine's death at Endor, up until the signing of the Pellaeon-Gavrisom treaty. If you own the Steam version of EaW, you will have to complete extra steps to run the mod after installation. Please see the manual for these steps.
A lot of the environment art has been changing for 2.2, and asteroids are no exception. Slevered has updated the standard asteroid and asteroid field assets in the mod to match the rest of the art style in the mod more. We haven't touched the pirate base or the mines yet, as you can see in the picture- those will likely not change, at least for 2.2.