Sierra Flight

 military, historical layer / disappeared object, intercontinental ballistic missile (ICBM)

An arrangement of 10 LGM-118A Peacekeeper Intercontinental Ballistic Missile Launch Facilities and a single Launch Control Facility, Sierra was one of five missile flights manned by airmen of the 400th Missile Squadron, 90th Missile Wing. The 90th MW was activated on February 21, 1963 at Francis E. Warren Air Force Base in Cheyenne, Wyoming and is presently stationed there today. Though the 400th MS originally operated the LGM-30 Minuteman ICBM series, these were replaced with the new Peacekeeper ICBM in December of 1986. The 400th has the distinction of being the sole operator of the only 50 Peacekeeper ICBMs to be operationally deployed. Under START II, that banned the use of MIRVs on ICBMs, the missiles were to be removed from operational status. Despite ratification, START II never went into effect due to various political complications in both countries. The missiles were eventually deactivated under SORT (which was signed between the U.S. and Russia on May 24, 2002), with the last Peacekeeper decommissioned in September of 2005. Their mission complete, the 400th MS was formally inactivated on October 4, 2005, ending 42 years of service.