Boeing has been awarded a $70 million contract for the procurement of GBU-57 Massive Ordnance Penetrator precision-guided “bunker buster” bombs for the U.S. Air Force, a U.S. Department of Defense press release said.

Work under the indefinite-delivery/indefinite-quantity sole source acquisition contract (FA8681-19-D-0008) issued by the U.S. Air Force Life Cycle Management Center is expected to be complete by December 31, 2022, the Monday, September 30 release said.

The GBU-57 Massive Ordnance Penetrator (MOP) is a 30,000-pound (14,000 kg) class GPS-guided “bunker buster” bomb employed only by the iconic B-2 Spirit stealth bomber.

The 20-feet (6m) long weapon is designed to attack deeply-buried and hardened bunkers and tunnels. It carries 5,300 pounds of explosive cased in a special high‑performance steel alloy. The Air Force says it can penetrate up to 200 feet (60m) of concrete before exploding.

Monday’s contract announcement marks a significant dollar increase over previous Massive Ordnance Penetrator orders. The last GBU-57 procurement contract issued was for just under $21 million in February 2018.

Neither Monday’s nor the 2018 contract specified the number of bombs to be procured, but in 2011 the U.S. Air Force ordered eight of the weapons plus supporting equipment for $28 million.

In April, Boeing was awarded a $21.6 million GBU-57 Massive Ordnance Penetrator sustainment contract expected to be completed by July 18, 2023.

The GBU-57 is reportedly the world’s largest in-service non-nuclear bomb, significantly heavier than two other well-known massive bombs – America’s 21,000-lb GBU-43/B “Mother of All Bombs” or MOAB that was dropped in Afghanistan in 2017, and Russia’s 22,000-lb ATBIP “Father of All Bombs” rumoured to have been used in Syria the same year. Both the MOAB and FOAB are thermobaric bombs, designed for huge explosive power rather than penetration.