sentences:  In 1959, SOS became a separate Air University school reporting directly to the Air University commander.Originally established as a 12-week in-residence program at Maxwell AFB, SOS was shortened to an 8-week program in the early 1990s due, in part, to post-Cold War budgetary pressures.In 1997, in an effort to emulate The Basic School (TBS) program of the U.S. Marine Corps, the Air Force established the Air and Space Basic Course (ASBC) for all newly commissioned Second Lieutenants in the Regular Air Force, the Air Force Reserve and Air National Guard, regardless of commissioning source (e.g., USAFA, AFROTC, Air Force OTS, Academy of Military Science, direct commission, etc.