GBU-57 Massive Ordnance Penetrator
Built by Boeing under an initiative from the Defense Threat Reduction Agency (DTRA), the GBU-57 Massive Ordnance Penetrator is the largest hard target penetrator bomb in the United States Air Force inventory. Its total weight is 30,000 pounds/13,608 kg of which 5,300 lb/2,404 kg is explosive. The rest is principally a hard casing that can penetrate over 200 feet into concrete. It is the successor, in explosive yield, to the GBU-43 Massive Ordnance Air Blast, which was not a penetrating bomb.
While the GBU-43 could only be dropped from the C-130, the GBU-57 is being integrated with the B-2 and B-52 heavy bombers, which will be able to carry two, and drop them from high altitude. DTRA's involvement comes from an initiative to defeat deeply buried weapons of mass destruction (WMD) facilities, although it would also have a role against superhardened command posts.
The weapon uses GPS satellite guidance.
In March 2011, the Air Force issued an 18-month sole source contract to Boeing, for 18 months of logistic and technical support for the GBU-57.  The pre-award announcement suggested that between 12 and 20 bombs would be supported by the contractor.
- Air Armament Center (17 March 2011), Solicitation Number: FA8681-10-C-ICS, Interim Contract Support, General Services Administration