AGM - 129 ACM The AGM - 129 ACM ( Advanced Cruise Missile ) is a low observable , subsonic , turbofan - powered , air - launched cruise missile originally designed and built by General Dynamics and eventually acquired by Raytheon Missile Systems . The AGM - 129A is carried exclusively by the US Air Force ' s B - 52H Stratofortress bomber s . Early development . In 1982 the US Air Force began studies for a new cruise missile with low - observable characteristics after it became clear that the AGM - 86B cruise missile would have difficulty penetrating future air defense systems . The AGM - 86B relied on low - altitude flight to penetrate the Soviet air defense system centered on surface to air missile s . The deployment of the airborne early warning systems with " look down " radars reduced the likelihood that the low - altitude AGM - 86B would reach its target . The solution was to incorporate various " low - observable " ( ' stealth ' ) technologies into a new " Advanced Cruise Missile " system . Design , test and initial production . In 1983 General Dynamics Convair Division ( GD / C ) was awarded a development contract for the AGM - 129A . The AGM - 129A incorporated body shaping and forward swept wings to reduce the missile ' s radar cross section . The engine air intake was flush mounted on the bottom of the missile to further improve radar cross section . The jet engine exhaust was shielded by the tail and cooled by a diffuser to reduce the infra - red signature of the missile . To reduce electronic emissions from the missile , the radar used in the AGM - 86B was replaced with a combination of inertial navigation and terrain contour matching TERCOM enhanced with highly accurate speed updates provided by a laser Doppler velocimeter . These changes made the AGM - 129A more difficult to detect and allowed the missile to be flown at higher altitude . The newer Williams International F112 - WR - 100 turbofan engine increased range by about 50 % . The newer guidance system , increased accuracy to a quoted figure of between 30 m ( 100 ft ) and 90 m ( 300 ft ) . The AGM - 129A like the AGM - 86B is armed with a W80 - 1 variable yield nuclear warhead . The first test missile flew in July 1985 and the first production missiles were delivered to the US Air Force in 1987 . The development program experienced some hardware quality control problems and testing mishaps . The flight test program took place during a period of high tension between the machinist ' s union and GDC management , with a 3 1 / 2 week long strike occurring in 1987 . US Congressman Les Aspin called the ACM a procurement disaster with the worst problems of any of the eight strategic weapons programs his committee had reviewed . The US Congress zeroed out funding for the ACM program in 1989 . Manufacturing quality problems led the US Air Force to stop missile deliveries in 1989 and 1991 . McDonnell Douglas was invited to qualify as a second source for missile production . In early 1989 , the United States requested and received permission to test the AGM - 129A in Canada . Plans called for producing enough missiles to replace the approximately 1 , 461 AGM - 86B ' s at a rate of 200 missiles per year after full - rate production was achieved in 1993 . In January 1992 , the end of the Cold War led US President George H . W . Bush to announce a major cutback in total ACM procurement . The President determined that only 640 missiles were needed . The ACM program was later reduced still further to 460 missiles . In August 1992 General Dynamics sold its missile business to Hughes Aircraft Corporation . Five years later in 1997 , Hughes Aircraft Corporation sold its aerospace and defense business to the final production contractor Raytheon . The US Air Force pushed for production of a AGM - 129B variant for targets for which the AGM - 129A was considered ineffective . The US Air Force submitted this requirement in 1985 and proposed to modify 120 missiles into the AGM - 129B variant . In 1991 the US Congress denied the request and the US Air Force was forced to terminate the program . In 1992 , the US Air Force was directed by the US Department of Defense to restart the program , an effort which was opposed by the General Accounting Office of the US Congress . Confusion exists as to precisely how this weapon is different from the original . The Department of Defense document DoD 4120 . 15 - L " Model Designation of Military Aerospace Vehicles " states that the AGM - 129B was an AGM - 129A " modified with structural and software changes and an alternate nuclear warhead for accomplishing a classified cruise missile mission . " However , Ozu states the AGM - 129B was intended to be a non - nuclear version of the ACM , much as the nuclear AGM - 86B led to the conventional AGM - 86C . Operational history . The B - 52H bomber can carry up to six AGM - 129A missiles on each of two external pylons for a total of 12 per aircraft . Originally , an additional 8 ACMs could be carried internally in the B - 52 on Common Strategic Rotary Launchers , for a total of 20 per aircraft . The B - 1B bomber was also slated to carry the AGM - 129A , but that plan was ended after the cessation of the Cold War . The AGM - 129A provides the B - 52H bomber the ability to attack multiple targets without penetrating an air defense system . An AGM - 129A impacted and damaged two unoccupied trailers , part of a cosmic ray observatory operated by the University of Utah and Tokyo University , located in the " hazardous operations " area of the United States Army Dugway Proving Ground on December 10 , 1997 . The AGM - 129A was released over the Utah Test and Training Range from a B - 52H bomber assigned to Minot Air Force Base , North Dakota . The missile had flown for approximately 3 . 5 hours on its planned route and had fulfilled all test objectives prior to the mishap . The missile was carrying an inert test payload . Mission planners were unaware of the existence of the trailers . The Air Force in 2008 maintains an arsenal of 1 , 140 AGM - 86 ALCMs and 460 AGM - 129 ACMs . The B - 52 is the only platform for these missiles . The reductions also include all but 528 nuclear - armed ALCMs and are in part a result of the SORT / Moscow Treaty ( 2002 ) requirement to get below 2 , 200 deployed nuclear weapons by 2012 , with the ACM chosen because it has reliability issues and higher maintenance costs . In March 2007 , despite a Service Life Extension program ( SLEP ) intended to extend its operational usefulness to 2030 , the USAF made the final decision to decommission its entire inventory of AGM - 129s with the last missile being destroyed in April 2012 . On August 30 , 2007 twelve ACMs loaded on a B - 52 were flown across the US from Minot Air Force Base in North Dakota to Barksdale Air Force Base , Louisiana for decommissioning . The nuclear warheads which should have been removed before the flight were mistakenly left installed on six of the ACMs . For 36 hours the nuclear weapons were unaccounted for , which led to an official investigation of the incident .