What is US 'bunker-busters' that could hit Iranian nuclear sites?

The US Air Force's B-2 Spirit stealth bomber represents one of America's most advanced strategic weapons platforms, capable of entering sophisticated air defences and delivering precision strikes against hardened targets such as Iran's buried network of nuclear research facilities.

The US military is ready to carry out any decision that President Donald Trump may make on Iran, Defence Secretary Pete Hegseth said on Wednesday (18 June), adding that Tehran should have heeded the president's calls for it to make a deal on its nuclear program prior to the start of Israel's strikes last Friday (13 June).

Iranian Supreme Leader Ayatollah Ali Khamenei rejected Trump's demand for unconditional surrender on Wednesday, and the US president said his patience had run out, though he gave no clue as to what his next step would be.

B-2 SPIRIT SPECIFICATIONS:

The US B-2 costs about $2.1 billion each, making it the most expensive military aircraft ever built. Made by Northrop Grumman, the bomber with its cutting-edge stealth technology began its production run in the late 1980s but was curbed by the fall of the Soviet Union. Only 21 were made after the Pentagon's planned acquisition program was truncated.

The bomber's range of over 6,000 nautical miles without refuelling enables global strike capabilities from continental US bases. With aerial refuelling, the B-2 can reach virtually any target worldwide, as demonstrated in missions from Missouri to Afghanistan and Libya.

Its payload capacity of more than 40,000 pounds allows the aircraft to carry a diverse array of conventional and nuclear weapons. The bomber's internal weapons bays are specifically designed to maintain stealth characteristics while accommodating large ordnance loads, which could include two GBU-57A/B MOP (Massive Ordnance Penetrator), a 30,000-pound precision-guided "bunker buster" bomb.

The two-pilot crew configuration reduces personnel requirements while maintaining operational effectiveness through advanced automation systems.

The B-2's stealth technology incorporates radar-absorbing materials and angular design features that minimise detection by enemy air defence systems. Its radar cross-section is reportedly comparable to that of a small bird, making it nearly invisible to conventional radar.

MASSIVE ORDNANCE PENETRATOR (MOP):

The 30,000-pound MOP represents the largest conventional bomb in the US arsenal, specifically engineered to defeat hardened underground bunkers. Its massive size requires the B-2 to carry only one or two MOPs per mission, but provides unmatched bunker-penetration capability.

The weapon's 20.5-foot length and GPS-guided precision targeting system enable accurate strikes against specific underground facilities. Its penetration capability of over 200 feet through hardened concrete makes it effective against the world's most protected underground installations.

CONVENTIONAL PAYLOADS:

Joint Direct Attack Munitions (JDAM) provide the B-2 with precision conventional strike capability against fixed targets. These GPS-guided weapons can be deployed in large numbers, with the bomber capable of simultaneously engaging multiple targets with high accuracy.

Joint Standoff Weapons (JSOW) extend the aircraft's engagement range while maintaining stealth characteristics during approach. These glide bombs allow the B-2 to strike targets from outside heavily defended airspace perimeters.

Joint Air-to-Surface Standoff Missiles (JASSM) offer long-range precision strike capability with their own stealth features. The extended-range JASSM-ER variant provides strike options against targets over 500 miles (805 km) away.

NUCLEAR PAYLOAD CAPABILITIES:

The B-2 Spirit serves as a key component of America's nuclear triad, capable of delivering strategic nuclear weapons with stealth and precision. The aircraft can carry up to 16 B83 nuclear bombs.