Tugboats. Guide cargoships, couriers, luxury liners and cruisers safely to their destinations. Build cargo and passenger docks, repair and refuel stations, and defence satellites. Create a solar infrastructure to wring profit from passing shipping. Sounds easy right? But when you also have to deal with politics, aliens, pirates, smugglers, travelling film stars, terrorists, floods of refugees, sunspot radiation, wormholes, meteors and nebulas, it can get complicated.