The U.S. Armed Forces are one of the largest militaries in terms of the number of personnel. It draws its personnel from a large pool of paid volunteers. Although conscription has been used in the past in various times of both war and peace, it has not been used since 1972, but the Selective Service System retains the power to conscript males, and requires that all male citizens and residents residing in the U.S. between the ages of 18–25 register with the service.
High school and postsecondary students can also take the ASVAB test as part of the Department of Defense’s Career Exploration Program. This paper-and-pencil version of the test is the same as the paper-and-pencil enlistment version but excludes the Assembling Objects section. It is intended to help those students considering a career in the military to discover their strengths in both military and civilian jobs. If the student scores high enough in the AFQT section of the test, he may use the score to enlist within the two-year expiration window.
In the 2000s, women can serve on U.S. combat ships, including in command roles. They are permitted to serve on submarines. Women can fly military aircraft and make up 2% of all pilots in the U.S. Military. In 2003, Major Kim Campbell was awarded the Distinguished Flying Cross for landing her combat damaged A-10 Thunderbolt II with no hydraulic control and only one functional engine after being struck by hostile fire over Baghdad.