Not a flag, but the Mars constitution's 1st amendment should be the inalienable right to bear arms, SPECIFICALLY including all present and future weapons technology. If you can afford 100 kg of antimatter or a solar mass black-hole bomb, you can buy them. If any future advancements in physics allow for the creation of even more destructive weapons, you have a right to own them, too. No limits on the number of weapons, the total yield of a personal arsenal, and no right for the government to confiscate or invasively track any person's weapons. Oh, and biological and super-AI weapons are included, too.