GregroxMun has graciously granted me permission to maintain Alien Space Programs until he's ready to take it back.

Originally inspired by Little Green Men from Mars for Realism Overhaul, and by Alternis Kerbol Rejiggered, Alien Space Programs was originally three separately packaged add-ons that changed the home world to Duna, Laythe, or Eve. These offered unique challenges for our plucky kerbals. I've personally taken a shine to Eve, but these add-ons needed updating badly and I learned enough of Kopernicus to update them for KSP 1.2 to fix biomes, and later 1.3 to introduce localization. GregroxMun went a step much further, by re-packaging all of these into a single add-on with a selectable home world setting, including the original Kerbin, and provided three (four if you count Restored Duna) additional home world choices.

This release is up to date for KSP 1.12.3 and a matching version of Kopernicus.

Installation Instructions:

1. Use a clean, stock KSP installation to start. You can copy your current installation and delete all folders inside GameData, except for the Squad folder. Make sure it starts. Exit KSP.
2. Install Kopernicus and its included pre-requisites into GameData, and make sure KSP still starts. The main menu will open to a different view of Kerbin if successful. Exit KSP.
3. Install AlienSpacePrograms into GameData, and make sure KSP still starts. It should default to Kerbin as the home world. Exit KSP.
4. Edit HomeWorldSetting.cfg to choose your home world and, optionally, atmospheric settings. Start KSP, and your chosen home world should be on the main menu screen. Enjoy.