The MRASM differed from the strategic cruise missile in three ways: requiring much less range, a terminal guidance system, and a different munition. The demands of range and accuracy appear to be well in hand. The technology to get a cruise missile hundreds of miles within hundreds of feet of a target, with TERCOM, and then within tens of feet of the target, with terminal guidance (DSMAC or SMAC), is both available and demonstrated. The developer's biggest problem centers on the munition, which according to the aviation press is the reason for the conservative schedule. The concept is to crater the runway and taxiway at 2,000-foot intervals. The MRASM can carry 50 to 80 submunitions totaling up to 1,000 pounds of payload.
Beginning in 1976, the United States and Great Britain jointly developed such a munition, the JP-233 runway buster. "Was" is the key word, because in early 1981 Congress decided the United States should withdraw from the program, primarily because of cost, much to the chagrin of the Air Force. The JP-233 contains cratering and delayed action mines as well as antipersonnel devices. The RAF used it in the 1982 Falkland Islands campaign. [NOTE: This is incorrect; JP.233 was not employed in the Falklands.]
Other runway-busting munitions under development included the Lawrence Livermore Laboratory's tactical airfield attack munition (TAAM). It is a 3.35-inch diameter, 13-pound, two-charge munition fitted into mortar tubes. The cruise missile discharges 60 to 80 of these devices, each retarded by a parachute before detonation. But the US military cancelled TAAM because of technical problems in July 1982. The Germans demonstrated the same type of weapon, the STABO, to American authorities at Eglin AFB in September 1982. The German STABO also uses a two-charge system, as does a similar munition - the boosted kinetic energy penetrator (BKEP) - under development by the Air Force Armament Division. After release from MRASM, a rocket charge in the BKEP drives a steel spike through the runway concrete where it explodes and creates a large crater. The Air Force MRASM can carry 28 BKEPs or 30 STABOs. Other munitions considered for this role include the 70-pound BLU-81 Grasshopper, the 16-pound Martin Dual Charge, and the 45-pound cluster airfield denial munition (CADM). But to knock out a 240-foot-wide runway may require multiple sorties (the kill probability of a 15-shot load of BLU-81s is .5, a 40-shot load of Martin Dual Charge is .6, and a 20-shot load of CADM is .3). The Air Force narrowed its attention to the STABO and BKEP, and conducted a direct competition in September 1982 to choose between the two. In February 1983, the JCMPO recommended purchase of the BKEP.