I'm playing Godus on Android and I've reached Voyage of Discovery. There are several missions in that voyage, and the objective is to get 3 stars on all missions.
To receive 3 stars, I must reach a certain score. However, I have no idea how the score is calculated (and the game does not make it clear, that's a design fault).
How is the voyage mission score calculated? How can I get better scores, so that I can get all stars?