So...
I have a friend who has a problem with his colony on Mars. There about 1.5b colonists on Mars and they are protected by about 500k ton worth of ground troops. Yet they are still complaining about lack of military protection and unrest is rising.
What is a reasonable number for the amount of ground troops my friend needs to keep his colony happy? 500k tons of troops seems like a lot for only 1.5b (but maybe not?).