defenses against ballistic missiles. In the mid-1980s, AFWL made important contributions to the SDI program through its studies of the laser vulnerability of solid and liquid-fueled ICBM boosters. AFWL used the mid-infrared advanced chemical laser (MIRACL) to demonstrate such vulnerabilities, and successful MIRACL tests destroyed both stationary and rotating reflective targets. By fiscal year 1986, Reagan's Strategic Defense Initiative (SDI) accounted for more than 60 percent of AFWL's budget. AFWL carried out tests of its Booster Vulnerability Test Program. In these tests scientists used MIRACL to destroy a decommissioned Titan I second stage booster under simulated flight loads at White Sands Missile Range, and the derived data were used to determine the vulnerabilities of representative solid motor cases and liquid boosters to lasers. In December 1990, the Air Force Space Technology Center and Weapons Laboratory consolidated to become Phillips Laboratory, and later, the Air Force Research Laboratory. On 1 October 1991, the 1606th Air Base Wing and 1550th Combat Crew Training Wing merged into one "super" wing called the 542d Crew Training Wing. Modern era In 1992, the Kirtland Underground Munitions Maintenance and Storage Complex (KUMMSC) was activated at Kirtland AFB. The facility provides storage, shipping and maintenance for the United States Air Force. It is operated by the 898th Munitions Squadron (898 MUNS) and the 377th Weapons Systems Security Squadron (377 WSSS). The facility is state of the art, with more than located entirely underground. KUMMSC is the largest storage facility for nuclear weapons in the world. Total number of deliverable nuclear warheads stored there is over 3,000. The majority of the munitions include the B83 and B61 gravity bombs, and W80, W78, and W87 warheads for the Air Launched Cruise Missile (ALCM), Minuteman III and Peacekeeper ICBMs. On 1 January 1993, the base again changed hands as the newly formed Air Force Materiel Command acquired Kirtland AFB from Air Mobility Command. The 377th Air Base Wing was reactivated to become the base's host organization. On 1 April 1994 the 1550th Combat Crew Training Wing was re-designated as the 58th Special Operations Wing under Air Education and Training Command (AETC). In addition to the helicopter training, it also trained crews in special operations aircraft, including helicopters and modified C-130 Hercules aircraft. It performed pararescue training and search and rescue missions as well. Additionally, the wing trained for missile site support and airlift for distinguished visitors. At the same time