The US Air Force maintains the most capable fleet of strategic bombers in the world, empowering the US military to deliver rapid, lethal force to adverse situations and to help allies in need.

The Air Force's bomber fleet -- now made up of B-1B Lancers, B-2 Spirits and B-52 Stratofortresses -- will look very different in the coming years following the unveiling of the new B-21 Raider, which is expected to start service in 2027.

The B-1B Lancer is the backbone of the United States' long-range bomber force and can carry the largest conventional payload of both guided and unguided weapons in the Air Force inventory. There are over 60 currently estimated in service.

The B-2 Spirit is a stealth bomber designed to penetrate dense anti-aircraft defences and capable of delivering both conventional and nuclear munitions. There are an estimated 20 currently in service.

The B-52 Stratofortress is a long-range, heavy bomber that can perform a variety of missions, including strategic attack, close-air support, air interdiction, and offensive counter-air and maritime operations. There are over 70 currently estimated in service.

The Stratofortress is expected to be in service through 2050, and the Air Force has several upgrades planned, including new engines, a new radar and a new nuclear weapon.

Although some of these older bombers will continue to be in service and receive upgrades, others will retire in the coming years as the B-21 Raider comes online.

Unveiled in early December, the B-21 Raider is expected to serve within a larger family of systems for conventional long-range strike, including intelligence, surveillance and reconnaissance; electronic attack; communication; and other capabilities. It is nuclear capable and designed to accommodate manned or unmanned operations.

"As the United States continues to innovate, this bomber will be able to defend our country with new weapons that haven't even been invented yet," US Secretary of Defence Lloyd Austin said December 2.

"And the B-21 is multi-functional. It can handle anything from gathering intel, to battle management, to integrating with our allies and partners. And it will work seamlessly across domains, and theaters, and across the joint force," he said.

The Air Force expects to acquire at least 100 B-21s.

Types of weaponry on US bombers

US strategic bombers are able to carry a variety of nuclear and non-nuclear precision guided munitions, such as the AGM-86 Air Launched Cruise Missile (ALCM), AGM-158 Joint Air-to-Surface Standoff Missile (JASSM), and the Joint Direct Attack Munition (JDAM).

The ALCM is a cruise missile that aims to dilute an enemy's forces and complicate defence of its territory. An enemy force would have to counterattack each of the missiles, making defence against them costly and complicated, according to the Air Force.

"The enemy's defences are further hampered by the missiles' smallness and low-altitude flight capability, which make them difficult to detect on radar," it said.

The JDAM is a guidance tail kit that converts existing unguided free-fall bombs into accurate, adverse weather "smart" munitions. JDAM enables multiple weapons to be directed against single or multiple targets on a single pass.

The JASSM is a low observable standoff air-launched cruise missile with a range of 370km, while the JASSM Extended Range (JASSM-ER) has a range of approximately 1,000km.

Equipped with 432kg warheads, the JASSM and JASSM-ER feature identical, low observable airframes designed to evade enemy air defence.

The missiles are also equipped with an inertial navigation system/global positioning system (INS/GPS) unit developed for the Joint Direct Attack Munition and Joint Standoff Weapon bombs, an infrared seeker for terminal guidance and a variety of special packages like electronic jamming.

The JASSM-ER when equipped with a weapon data link can correct course after launch, enabling it to hit moving targets on land or at sea.

Deliveries to the Air Force of another variant of the missile, the JASSM-XR (Extreme Range) with a range of approximately 1,800km, are expected to begin in January 2024.

Each Stratofortress can carry up to 12 JASSMs on its wing pylons and another eight inside its bomb bay.

With 20 B-52Hs, the US Air Force could deliver some 400 JASSM-ERs against targets from a maximum stand-off distance of 1,000km.

Recent missions

In 2022, US strategic bombers repeatedly reaffirmed Washington's commitment to its allies.

US Central Command (CENTCOM) conducted the latest of what is known as a Bomber Task Force (BTF) mission on November 10.

During the mission, two B-52H Stratofortresses flew from the US state of Louisiana to the CENTCOM region that includes the Middle East and Central Asia, and co-ordinated with 13 partner nation air forces along the way.

One such co-ordination was with Israel. Israeli Air Force F-35 Adir fighter jets escorted the bombers above Israeli airspace on their way back from the Arabian Gulf.

The type of high-level co-ordination during the mission showcased "the ability to rapidly deploy global airpower alongside coalition and regional partner forces and ensuring the security of this critical region", CENTCOM said.

In February, March and June, US bombers conducted three "presence patrols" in the Middle East.

In the June patrol, two US Air Force B-52 Stratofortresses, two KC-10 Extenders and three KC-135 Stratotankers flew over the Eastern Mediterranean, Arabian Peninsula and Red Sea, linking up in some places with regional and international coalition partners, military officials said.