Just as the President, the Secretary of Defense, and the Secretary of Homeland Security, are in charge of the entire military establishment, maintaining civilian control of the military, so too are each of the Defense Department's constitutive military departments headed by civilians. The four DoD branches are organized into three departments, each with civilian heads. The Department of the Army is headed by the Secretary of the Army, the Department of the Navy is headed by the Secretary of the Navy and the Department of the Air Force is headed by the Secretary of the Air Force. The Marine Corps is organized under the Department of the Navy, however it is still considered a separate and equal service. The Coast Guard is under the Department of Homeland Security and receives its operational orders from the Secretary of Homeland Security. However, the Coast Guard may be transferred to the Department of the Navy by the President or Congress during a time of war, thereby placing it within the DoD.
The projected active duty end strength in the armed forces for fiscal year 2017 was 1,281,900 servicemembers, with an additional 801,200 people in the seven reserve components. It is an all-volunteer military, but conscription through the Selective Service System can be enacted at the President's request and Congress' approval. All males ages 18 through 25 who are living in the United States are required to register with the Selective Service for a potential future draft.
In the Navy, the rank of Admiral of the Navy theoretically corresponds to that of General of the Armies, though it was never held by active-duty officers at the same time as persons who held the rank of Fleet Admiral. George Dewey is the only person to have ever held this rank. After the establishment of the rank of Fleet Admiral in 1944, the Department of the Navy specified that the rank of Fleet Admiral was to be junior to the rank of Admiral of the Navy. However, since Dewey died in 1917 before the establishment of the rank of Fleet Admiral, the six-star rank has not been totally confirmed.
The Air Force ASVAB scores are frequently a subject of confusion and anxiety for the person planning a career in the Air Force. The real meaning of ASVAB scores as they apply to each person's future in this branch of the military is rarely explained fully . There are some unfortunate misapprehensions about what the scores mean and how they affect a person's occupational prospects in the Air Force.
Each service has a uniformed head who is considered the highest-ranking officer within their respective service, with the exception of the chairman and vice chairman of the Joint Chiefs of Staff, and the chief of the National Guard Bureau. They are responsible for ensuring personnel readiness, policy, planning and training and equipping their respective military services for the combatant commanders to utilize. They also serve as senior military advisors to the President, the Secretary of Defense, their respective service secretaries, as well as other councils they may be called to serve on. They are as follows:
Whereas recruits who join as officers tend to be upwardly-mobile, most enlisted personnel have a childhood background of relative socio-economic deprivation. For example, after the US suspended conscription in 1973, "the military disproportionately attracted African American men, men from lower-status socioeconomic backgrounds, men who had been in nonacademic high school programs, and men whose high school grades tended to be low".
Although concerned with research into military psychology, and particularly combat stress, and how it affect troop morale, often the bulk of military science activities is directed at military intelligence technology, military communications, and improving military capability through research. The design, development, and prototyping of weapons, military support equipment, and military technology in general, is also an area in which lots of effort is invested – it includes everything from global communication networks and aircraft carriers to paint and food.
When you are considered a career in the military you need to take the ASVAB test. But each branch of the military has different ASVAB requirements that you need to meet. They are different levels of education that you must reach to take the test. But you also need to score a certain amount of points on that ASVAB test to gain access into the branch you desire.