When in explore mode. If u call up your ghost. Each mission type, ( same reward dif quest) has a unique icon. In the alpha amd beta there was 5 unique icons for missions during explore. One was a ghost. I forget the others. But when u call your ghost up and look at the mission beacon (blinking green thing) it will have the icon related to its reward. 1 of them will give more marks then the others. I just forget.