It is my understanding that cadets apply for CULP and are chosen from a national pool (in other words, battalions are not guaranteed a certain number of spots). Like most things ROTC, they are looking at an overall profile: good grades, good pt scores, other leadership roles, etc. One of my sons went to Liberia last summer. Their mission was teaching English, providing some humanitarian support, training the Liberian army, and reaching out to the community. It was an amazing experience.