This mod adds a new generic mission which involves delivering a bunch of wares to an npc construction vessel. After the mission is over, you can also continue helping to build extensions. Basically, you can use these missions to make a lot of money through trading while slowly expanding the universe.
This mission is not the same as the one recently added in the 3.5 patch. The 3.5 patch mission asks you to build a station for yourself where as this mission involves helping an npc faction build their own station.