{"id":17214,"date":"2025-06-26T07:45:10","date_gmt":"2025-06-26T10:45:10","guid":{"rendered":"https:\/\/www.fie.undef.edu.ar\/ceptm\/?p=17214"},"modified":"2025-06-26T07:45:10","modified_gmt":"2025-06-26T10:45:10","slug":"el-sucesor-del-penetrador-de-municiones-masivas-gbu-57-ya-esta-en-desarrollo","status":"publish","type":"post","link":"https:\/\/www.fie.undef.edu.ar\/ceptm\/?p=17214","title":{"rendered":"El sucesor del penetrador de municiones masivas GBU-57 ya est\u00e1 en desarrollo"},"content":{"rendered":"

El primer uso en combate de las bombas rompeb\u00fankeres\u00a0GBU-57\/B Massive Ordnance Penetrator\u00a0(MOP) de 13.668 kg por parte de la Fuerza A\u00e9rea de EE. UU .\u00a0en recientes ataques contra instalaciones nucleares iran\u00edes\u00a0ha renovado la atenci\u00f3n sobre la b\u00fasqueda de un sucesor. Ya exist\u00eda un gran inter\u00e9s militar estadounidense en un nuevo Penetrador de Pr\u00f3xima Generaci\u00f3n (NGP) cuando el MOP entr\u00f3 en servicio a principios de la d\u00e9cada de 2010.<\/p>\n

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The U.S. Air Force\u2019s first combat employment of 30,000-pound\u00a0GBU-57\/B Massive Ordnance Penetrator<\/a>\u00a0(MOP) bunker buster bombs\u00a0in recent strikes on Iranian nuclear sites<\/a>\u00a0draws new attention to work toward a successor. There was already very active U.S. military interest in a new Next Generation Penetrator (NGP) when the MOP first began entering service in the early 2010s.<\/p>\n

B-2 Spirit stealth bombers<\/a>\u00a0dropped 14 GBU-57\/B on targets in Iran \u2013 12 on\u00a0the enrichment facility at Fordow<\/a>\u00a0and two more on the one at Natanz \u2013 during strikes this past weekend dubbed Operation Midnight Hammer, which you can read more about\u00a0here<\/a>. The B-2 is the only aircraft cleared to employ the MOP operationally, but the forthcoming\u00a0B-21 Raider<\/a>\u00a0stealth bomber is expected to be able to employ them, as well. B-52 bombers have also dropped the huge bunker busters during testing. The existing MOP stockpile is understood to be relatively small, but\u00a0Bloomberg\u00a0<\/em>reported last year<\/a>\u00a0that work was being done to help triple or even quadruple the annual production capacity of the munitions.<\/p>\n

The 20-and-a-half-feet-long GBU-57\/B is a precision-guided bomb that consists of a penetrating \u201cwarhead,\u201d which has its own designation (BLU-127\/B), along with a GPS-assisted inertial navigation system (INS) guidance package, specialized fuzes, and other components. The explosive content of the MOP, which also has a diameter of 31-and-a-half-inches, is only roughly 20 percent of its total weight.<\/p>\n

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A partially assembled GBU-57\/B MOP. USAF<\/figcaption><\/figure>\n

The most recent publicly stated requirements for the NGP come from a contracting notice the Air Force\u00a0put out in February 2024<\/a>. It called for a warhead weighing 22,000 pounds or less, and that would be \u201ccapable of blast \/ frag[mentation] \/ and penetration effects,\u201d but did not specify a desired gross weight for the entire munition. No prospective dimensions were provided, either.<\/p>\n

\u201cThe prototype penetrator warhead design effort should allow integration of technologies acquired and lessons learned under previous penetrator warhead developments to meet performance requirements for the HDBT target set,\u201d the contracting notice added. \u201cThe USAF will consider novel, demonstrated, or fielded Guidance, Navigation & Control (GNC) technologies with viability for integration into a warhead guidance system design that can achieve repeatable, high accuracy performance in GPS aided, degraded, and\/or denied environments.\u201d<\/p>\n

The notice also said that a \u201cterminal accuracy\u201d of \u201cCE90 w\/in 2.2m both in GPS aided, degraded, and denied environments\u201d was desired. What \u201cCE90 w\/in 2.2m\u201d means in layman\u2019s terms is a munition that can hit within 7.2 feet (2.2 meters) of a specified impact point at least 90 percent of the time. This is a very high degree of required accuracy, especially for employment in GPS-degraded or denied environments. For comparison, the Air Force says, on average, GPS-assisted INS-guided Joint Direct Attack Munition (JDAM) bombs\u00a0can hit within<\/a>\u00a016.4 feet (five meters) of designated target coordinates under optimal conditions, but that this can grow to nearly 100 feet (30 meters) if GPS connectivity is lost. While the exact terminal accuracy of the existing MOP is unknown,\u00a0post-strike imagery<\/a>\u00a0from Fordow and Natanz points to an extreme degree of precision.<\/p>\n

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A satellite image showing MOP impact points at Fordow after the U.S. strikes on the night of June 21-22, 2025. Satellite image \u00a92025 Maxar Technologies<\/figcaption><\/figure>\n
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Another satellite image showing Natanz in the aftermath of the Operation Midnight Hammer strikes. A large hole\/crater is seen at the center. Satellite image \u00a92025 Maxar Technologies<\/figcaption><\/figure>\n

The NGP contracting notice put out last February also mentions \u201cpossible integration of embedded fuze technology,\u201d but does not elaborate. Reliable fuzing, in general, is particularly important for bunker buster bombs, the components of which have to be able to withstand additional forces as the munition burrows through hard material.<\/p>\n

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An additional image showing a MOP about to hit a target during past testing. DOD<\/figcaption><\/figure>\n

Bombs like the MOP and any future NGP that are designed to penetrate very deeply have additional specialized fuzing needs, especially for employment against targets where pre-strike intelligence about the exact depth and\/or physical layout is limited. Work\u00a0on advanced void-sensing fuzes<\/a>\u00a0that can detect when a munition has breached into a sufficiently large space, such as a room in an underground facility, is an area of development that has already been of particular interest for the U.S. military for years now. A fuze that is able to just effectively \u2018count\u2019 floors to help determine depth to detonate the bomb at a certain level for maximum damage would also be a useful addition.<\/p>\n

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A graphic from the Hard Target Void Sensing Fuze (HTVSF) program, which focused on the development of advanced fuzes for bunker buster bombs smaller than MOP. USAF<\/figcaption><\/figure>\n

As already noted, the U.S. military was already looking ahead to a future NGP when MOP began entering service in the early 2010s. The February 2024 contracting notice specifically mentions \u201cthe 2012 Hard Target Munitions (HTM) Analysis of Alternatives (AoA) and HTM AoA Excursion from 2019\u201d as having contributed to the requirements for the next-generation bunker buster. The GBU-57\/B\u2019s own development, which the Pentagon\u2019s\u00a0Defense Threat Reduction Agency<\/a>\u00a0(DTRA) carried out in cooperation with the Air Force, dates back to at least 2002. Work on MOP also notably began as a so-called \u201cquick reaction capability\u201d effort to meet pressing operational needs, rather than a full program of record, and the design\u00a0has been upgraded several times<\/a>\u00a0in\u00a0the past 15 years or so<\/a>.<\/p>\n

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U.S. Air Force personnel and contractors pose in front of a Massive Ordnance Penetrator mock-up in 2007. USAF<\/figcaption><\/figure>\n
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A MOP mock-up sits inside a training device that simulates a B-2 bomb bay in 2007. U.S. Air Force<\/figcaption><\/figure>\n

In addition to the requirements laid out in the contracting notice last year, the Air Force has said in the past that one of its key areas of interest for NGP is the addition of a powered standoff capability. Notional renderings have shown a design with a rocket booster. MOPs are unpowered and have to be released close to the target, a key reason why the highly survivable B-2 is currently the only operational delivery platform.<\/p>\n

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A 2010 briefing slide discussing plans for a Next Generation Penetrator, which could have a powered standoff capability, and other future bunker busters. USAF<\/figcaption><\/figure>\n

The Air Force has also said it is interested in a future NGP with the ability to prosecute more hardened and\/or deeper targets, as well as enhanced and potentially scalable terminal effects. The current maximum depth that MOP can penetrate down to is unknown, but it is at least 200 feet (60 meters), according to\u00a0publicly available data<\/a>. Subsequent upgrades may have increased its penetrating capability substantially.<\/p>\n

The Air Force has also talked previously about the possibility of NGP being a family of systems, rather than a single munition, and has also tied it to the secretive Long Range Strike (LRS) family of systems. The best-known member of the LRS \u2018system of systems\u2019 is the B-21 bomber, but it includes the stealthy\u00a0AGM-181A Long Range Stand Off<\/a>\u00a0(LRSO) nuclear-tipped cruise missile and many other elements, as you can read more about\u00a0here<\/a>.<\/p>\n

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A 2011 briefing slide offering a graphic depiction of elements of the Long Range Strike family of systems, including a Next Generation Penetrator (NGP) with standoff capability and the Long Range Stand Off (LRSO) nuclear-armed cruise missile. USAF<\/figcaption><\/figure>\n

In 2020, the Air Force publicly disclosed interest in a separate next-generation\u00a0Global Precision Attack Weapon<\/a>\u00a0(GPAW) bunker buster bomb that would be small enough to be carried internally by a stealthy F-35 Joint Strike Fighter. The service also began fielding a new precision-guided 5,000-pound-class bunker buster,\u00a0the GBU-72\/B<\/a>, sometime in the past few years. What appears to be the first reported operational use of GBU-72\/Bs\u00a0came last year<\/a>\u00a0during strikes against Iranian-backed Houthi militants in Yemen.<\/p>\n

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A GBU-72\/B bunker buster bomb. USAF<\/figcaption><\/figure>\n

The B-21 presents its own specific considerations for both MOP and a future NGP. The B-2 can already only carry two MOPs at once, and the smaller Raider is expected to be able to lug just one. Taking the example of Operation Midnight Hammer, it would\u2019ve taken twice as many B-21s to carry out that mission. As such, a new bunker buster bomb that sits somewhere in the wide range between the GBU-72\/B and the GBU-57\/B could be a major boon for pairing with the Raider. It is also worth noting here that the Air Force does currently plan to acquire a\u00a0B-21 fleet that will be significantly larger<\/a>\u00a0than\u00a0its current B-2 force<\/a>.<\/p>\n

The assessed outcome of the GBU-57\/B strikes on Fordow and Natanz will now be another factor for the Air Force to consider when it comes to the future NGP. Though the U.S. military says the strikes successfully hit the intended targets,\u00a0significant questions remain<\/a>\u00a0about the actual damage caused to the underground Iranian facilities. Well before Operation Midnight Hammer was launched, a debate had emerged about whether Fordow, in particular,\u00a0could be beyond the reach<\/a>\u00a0even of the MOP.<\/p>\n

For the U.S. military, the value of having a\u00a0non-nuclear<\/a>\u00a0means to prosecute very deeply-buried targets from the air extends well beyond Iran. North Korea has also been\u00a0notably expanding its underground infrastructure<\/a>, a trend that has been driven in no small part by the threat of strikes from the United States.<\/p>\n

MOP, as well as any future NGP, could be called upon in any future conflict against a larger adversary like China or Russia, both of which have long histories of\u00a0building deep underground facilities<\/a>, including\u00a0mountain caverns for aircraft<\/a>\u00a0and\u00a0submarines<\/a>. In January,\u00a0the\u00a0Financial Times<\/em><\/a>\u00a0newspaper published a detailed piece on the Chinese People\u2019s Liberation Army\u2019s (PLA) construction of a new 1,500-acre command center complex in Beijing that includes a major subterranean component. Additional details that emerge about the MOP strikes on Iran might further fuel global trends regarding the construction of new underground facilities.<\/p>\n

The video below includes a clip of a B-2 bomber dropping a GBU-57\/B during a test.<\/strong><\/em><\/p>\n