MOPping Up: The USA’s 30,000 Pound Bomb

Defense Industry Daily

MOP in B-2 WLT

Grand Slam Bomb

“Grand Slam”
(click to view full)

More low-rate production contracts. (Aug 2/11)

During the Second World War, attacking heavily protected targets like U-boat pens and protected “V-weapon” facilities was a key challenge. Enter a brilliant British engineer named Barnes Wallis, fresh off the dam-busting “Upkeep” bouncing bomb. His next trick was a 12,000 pound weapon called the “Tallboy,” a streamlined, spin-stabilized bomb with a claimed terminal velocity of Mach 1 when dropped from 20,000 feet. That mass, carrying 5,200 pounds of Torpex D1 explosive, made a crater 80 feet deep x 100 feet across when it hit. By 1945, Wallis’ next “Earthquake bomb” was in production – the 22,000 pound “Grand Slam.” His creations made short work of U-boat pens.

These bombs went out of fashion with the advent of nuclear weapons, but if you wait long enough, fashion comes around again. Enter the USA’s new Massive Ordnance Penetrator (MOP). Despite additional funding, and October promises of accelerated deployment, the MOP did not arrive by mid-2010, as planned.

The MOP Program

Massive Ordnance Penetrator Boeing Load

Boeing MOP
(click to view full)

With the FY 2006 demise of the RNEP nuclear bunker-buster program, the US Defense Threat Reduction Agency stepped out of its usual verification and WMD detection/ destruction programs to fund a project called the Massive Ordnance Penetrator (MOP). This 30,000 pound weapon is approximately 31.5 inches in diameter and 20.5 feet long, with about the same amount of explosives inside as Wallis’ Tallboy (5,300 pounds). It isn’t the biggest bomb the USA has ever built – the 44,000 pound T12 has that distinction – but it could well become the biggest conventional bomb ever used. Even the famous GBU-43 MOAB (Mother Of All Bombs) fuel-air explosive weighs in at only 21,000 pounds.

Unlike the MOAB, however, this project’s goal is a GPS-guided, penetrating weapon that can be carried aboard B-52 Stratofortress or B-2 Spirit bombers to defeat “a specialized set of hard and deeply buried targets” like bunkers and tunnel facilities. Some graphics show expectations of over 60 feet of concrete destroyed, and a USAF article stated that the bomb was meant to penetrate 200 feet underground before exploding.

The reasons for developing those capabilities include advancing trends. Pentagon spokesman Bryan Whitman:

“The threats have been developing over the years… There are, without getting into any intelligence, there are countries that have used technologies to go further under ground and to take those facilities and make them hardened. This is not a new phenomenon, but it is a growing one.”

Pentagon Press Secretary Geoff Morrell:

“The reality is that the world we live in is one in which there are people who seek to build weapons of mass destruction, and they seek to do so in a clandestine fashion,” he said. “And this has been a capability that we have long believed was missing from our quiver, our arsenal, and we wanted to make sure we filled in that gap.”

MOP mockup

MOP Mockup, Whiteman AFB
(click to view full)

The B-2 will be able to carry 2 MOPs: one in each bay, mounted to the existing forward and aft mounting hardware.

According to GlobalSecurity.org the MOP, also called or “Big BLU” or “Direct Hard Target Strike Weapon” program in some documents, required a total of $11.4 million for development. That’s a very frugal program. Their figure may be wrong, or it could be interpreted to exclude testing and integration contracts – which are already several times that amount, at about $74.5 million.

Northrop Grumman is the B-2A prime contractor, and leads the MOP integration effort. Boeing Company is the prime contractor to produce the MOP, and will also be the B-52 fleet integrator. They serve as a subcontractor to Northrop Grumman for the B-2 integration effort.

November 22, 2011 | 1 Comment »

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  1. Dropping two 15-ton bombs from an 80-ton aircraft. Those sound like ship dimensions, not flying machines! Very impressive.