From the colonization of the New World in days of old on Earth, to the colonization of the stars, the transportation of food, weapons, medical supplies, or people, be it civilian or military has always been a concern to both kings and generals.  Space transport ships come in all shapes and sizes.  From the huge bulk container ships with 100 crew, to the tiny 2-3 man tramp freighters. Be it for profit or just pressed into service, these ships keep supply lines between the stars or military actions moving along.