The Guided Bomb Unit‐72 (GBU‐72), also known as the Advanced 5K (A5K) Penetrator, is a bunker busting bomb developed in the United States.
Description.
The GBU-72 is described as a class precision-guided bunker busting bomb which uses a JDAM guidance kit.
The GBU-72 is said to resemble an enlarged GBU-31/B JDAM fitted with a bunker busting BLU-109 or BLU-137/B warhead. It is fitted with the GBU-31/B JDAM’s GPS and INS tail-mounted guidance kit and two long fins fitted to either side of the bomb's underside.
No official data is available for how deep the GBU-72 can penetrate before exploding, although the weapon's program manager has been quoted as saying "lethality [of the GBU-72] is expected to be substantially higher compared to similar legacy weapons like the GBU-28". The capabilities of the later versions of the GBU-28 remain classified, but the earliest versions could reportedly penetrate of earth and over of reinforced concrete.
The US Air Force's B-1Bs and F-15Es are capable of deploying the GBU-72, along with the Israeli Air Force's F-15Is.
History.
The GBU-72 underwent a series of tests at Eglin Air Force Base. These included a number of ground based tests which included detonating the bomb’s warhead within an array of barriers to measure its blast and other effects, and airborne tests between July and October 2021 which included confirming "the weapon could safely release from the aircraft and validate a modified 2,000-pound joint-direct-attack-munition tail kit’s ability to control and navigate a 5,000-pound weapon."
On 23 July 2021, the test series consisting of three flights started, planned by the 780th Test Squadron and carried out by the 40th Flight Test Squadron; it aimed to "validate a modified Joint Direct Attack Munition tail kit’s ability to control and navigate a weapon."
On 7 October 2021, an 96th Test Wing McDonnell Douglas F-15E Strike Eagle released the GBU-72 (known as the GBU-72 Advanced 5K Penetrator), over the Eglin Air Force Base range, which ended the initial testing phase. The program moved on to additional JDAM integration test flights and developmental and operational testing in 2022.
In May 2024 it was reported that as part of joint American-British strikes during the Red Sea crisis, the US Air Force used a GBU-72 to destroy an underground Houthi facility in Yemen.
In September 2024 it was reported that the Israeli Air Force deployed up to ten GBU-72s on 27 September 2024 to kill Hezbollah's Secretary-General, Hassan Nasrallah, in his underground headquarters complex in Beirut. Subsequent reporting stated class JDAM-equipped BLU-109 bunker busting bombs were likely used.