GBU-57A/B MOP
| GBU-57A/B Massive Ordnance Penetrator | |
|---|---|
GBU-57 MOP prototype | |
| Type | Bunker buster |
| Place of origin | United States |
| Service history | |
| In service | 2011–present |
| Used by | United States Air Force |
| Wars | United States strikes on Iranian nuclear sites |
| Production history | |
| Manufacturer | Boeing |
| No. built | at least 20 |
| Specifications | |
| Mass | 27,125 lb (12,304 kg) |
| Length | 20.5 ft (6.2 m) |
| Diameter | 31.5 in (0.80 m) |
| Filling | AFX-757/PBXN-114 |
| Filling weight | 4,590 / 752 lb (2,082 / 341 kg) |
The GBU-57 series MOP—the initials stand for Guided Bomb Unit and Massive Ordnance Penetrator—is a 30,000-pound (14,000 kg) class, 20.5-foot-long (6.2 m) precision-guided munition "bunker buster" bomb developed by Boeing for the United States Air Force (USAF). Composed of a BLU-127 bomb body and an integrated GPS/INS guidance package, the GBU-57 has seven variants, the most recent being the GBU-57F/B. Due to its size and weight, the GBU-57 MOP can be carried only by the Northrop B-2 Spirit strategic bomber and the B-21 Raider, although initial tests were conducted with a modified Boeing B-52 Stratofortress.
The GBU-57 MOP was first used in combat on June 22, 2025, when seven Northrop B-2 Spirit stealth bombers dropped 14 GBU-57 bombs on Iran's Fordow Uranium Enrichment Plant and Natanz Nuclear Facility.
The bomb is much larger than earlier USAF bunker-busters such as the 5,000-pound (2,300 kg) GBU-28 and GBU-37.