The W87 is an American thermonuclear missile warhead formerly deployed on the LGM-118A Peacekeeper ("MX") ICBM. Fifty MX missiles were built, each carrying up to 10 W87 warheads in multiple independently targetable reentry vehicles (MIRV), and were deployed from 1986 to 2005. Starting in 2007, 250 of the W87 warheads from retired Peacekeeper missiles were retrofitted onto much older Minuteman III missiles, with one warhead per missile. An upgraded version is planned for use on the forthcoming LGM-35A Sentinel ICBM.