Directory of U.S. Military Rockets and Missiles
Appendix 5: Guided Bombs
Copyright © 2024 Andreas Parsch

Boeing GBU-57/B MOP

After the use of so-called bunker-buster bombs in Operation Iraqi Freedom in 2003 showed insufficient penetration and destructive power of existing weapons, the Defense Threat Reduction Agency initiated the MOP (Massive Ordnance Penetrator) program to develop a more capable penetrator. The development effort was led by the AFRL (Air Force Research Lab) with Boeing as industry partner. The result was the GBU-57/B, a GPS-guided very heavy penetration bomb, which was first tested in 2007. Several production contracts were subsequently awarded to Boeing, while Northrop Grumman modified the USAF's B-2A bombers to be able to carry two of the bombs. At least 20 GBU-57/B bombs have been delivered to the USAF, most likely more.

The GBU-57/B consists of a BLU-127( )/B bomb body, fitted with airfoils and the GPS guidance system. When dropped from high altitude, it can reportedly penetrate at least 60 m (200 ft) of ground, quite likely more. No reliable figures about its penetratiom capability in reinforced concrete are available. One potential mission target for MOP are the Iranian nuclear facilities, which are buried very deeply underground.

Photo: USAF
GBU-57( )/B (exact version unknown)

The GBU-57/B has gone through several upgrades. The initial operational version was the GBU-57A/B with a BLU-127A/B warhead. Later versions were designated GBU-57B/B (with a BLU-127B/B), GBU-57C/B, GBU-57D/B, GBU-57E/B and GBU-57F/B. The two latest versions' warhead is designated BLU-127C/B, but it's unclear since which GBU-57 iteration the -127C/B is used. Neither is there reliable information available about the nature of the upgrades. It is assumed that the penetration depth and destructive capability (possibly by improved fuzing and warhead shaping) has been successively improved.


Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!

Data for GBU-57( )/B:

Length6.2 m (20.5 ft)
Diameter80 cm (31.5 in)
Weight12300 kg (27125 lb)
Warhead2423 kg (5342 lb) AFX-757/PBXN-114 high-explosive

Main Sources

[1] Wikipedia: GBU-57A/B MOP
[2] The War Zone, Joseph Trevithick: Air Force Updates Massive Ordnance Penetrator Bombs Amid New Iranian Nuclear Posturing
[3] The War Zone, Oliver Parken: Our Best Look Yet At The Massive Ordnance Penetrator Bunker Buster Bomb

Back to Directory of U.S. Military Rockets and Missiles, Appendix 5

Last Updated: 4 February 2024