The US Long Range Strike Bomber: Future Roles, Capabilities and Challenges

The US Air Force (USAF) strategic bomber force – comprised of B-2, B-1B and B-52 heavy bombers – serves two purposes. The first is to project conventional striking power and extend deterrence over intercontinental distances. The round-trip of over 11,000 miles made by B-2s operating out of Whiteman Air Force Base in Missouri to hit targets in Libya in 2011 is just one example of this unique capability. Supported by aerial refuelling, the USAF’s strategic bomber force can strike targets anywhere in the world from their bases in the continental United States.

The range of the B-2, as well as the ability to forward deploy nuclear-capable B-52s, enables the second purpose of the bomber force, which is to engage in nuclear signalling. The US’ 2010 Nuclear Posture Review reiterated the importance of this role, noting that ‘bombers can be visibly deployed ... in [a] crisis to strengthen deterrence of potential adversaries and assurance of allies and partners’. Indeed, at a time of heightened tensions with North Korea in 2013, pre-planned exercises involving B-2s served as a way to reassure South Korea of the credibility of US nuclear guarantees. (The B-1B was stripped of its nuclear role in 1995 and now fulfils a purely conventional role in the USAF.)

Due to the strategic bomber force’s unique and flexible conventional and nuclear role, ensuring that it remains effective is one of the Pentagon's highest defence-capability priorities. In that context, the announcement in October that a contract for a next-generation Long Range Strike Bomber (LRS-B) had been awarded to Northrop Grumman was significant. With the country’s extended-deterrence posture being tested in both Europe and Asia, the US may well rely heavily upon the system in coming decades.

Whilst the B-2 likely remains capable of penetrating all known threat environments for the foreseeable future, USAF’s fleet of only twenty aircraft is not large enough to ensure long-range deterrence at sufficient scale. The unit cost of $1.4 billion per B-2 prevented the aircraft from replacing the B-52 and B-1B as had originally been intended.

The venerable B-52 carries stand-off cruise missiles as its nuclear armament and relies on its formidable jamming and electronic-warfare capabilities for survivability. It has been vulnerable in high-threat environments since the mid-Cold War so while it will remain useful, it cannot be relied on as a peer deterrent now, let alone for the next fifty years.

Accordingly, the LRS-B is being designed to complement, rather than surpass, the B-2’s formidable capabilities and to eventually replace the B-52. In order to keep costs under control, the new bomber is likely to be marginally smaller than the B-2, with a comparable level of stealth technology, superior network integration and electronic-warfare capabilities, and range and payload in a similar class but certainly not superior to the B-2.

The USAF appears to have learnt an important lesson from the incredibly expensive F-35, F-22 and B-2 stealth-aircraft development programmes. The stated $550-million unit price is a core part of the requirement if the bomber is to be affordable at scale, and in the name of affordability, the new aircraft is intended to rely on proven and mature technologies rather than being hostage to anticipated progress at the cutting edge of materials, software and aeronautical science.

One reported possibility, however, flies in the face of this approach – that the new bomber be ‘optionally manned’ for the conventional role. Due to its intended nuclear role, the LRS-B must be a manned aircraft. However, the USAF is reportedly interested in the bomber being operable without crew on board for conventional strike or deep penetration missions. Whilst such a capability would increase the maximum sortie length, which is currently limited by a bomber crew’s endurance, it would also require either datalinks to remotely pilot the bomber (as with the MQ-9 Reaper UAV, for instance) or for it to be capable of autonomous operations.

Both present drawbacks, in terms of cyber-vulnerability, increased software complexity, ethical issues around autonomous weapons release, and the vulnerability of remote satellite datalink to detection and interruption. Equally, the main benefit of an unmanned solution from an aeronautical-design point of view is the substantial savings in weight, space and complexity by eliminating the need for the cockpit, life-support and basic amenities. However, these will still need to be included in the LRS-B due to the requirement for any nuclear missions to be manned. ‘Optionally manned’ appears to be a way of incorporating the costs and weaknesses of both the manned and unmanned design philosophies without the benefits of either.

Beyond such potential technological rabbit holes, the biggest challenge the LRS-B will face may not be its operating environment, but getting off the ground in the first place. While the notional price cap of $550 million per aircraft has been agreed with Northrop Grumman, that figure is vulnerable to increases if extra capability requirements are added during the development process.

On Capitol Hill, and in the Pentagon, the completion for nuclear modernisation funding is likely to be cut-throat. The decisions taken during the last decade to invest in life-extension programmes for the Ohio-class submarine fleet and the Minuteman intercontinental ballistic missiles now means that all three legs of the nuclear Triad will be renewed simultaneously. Accordingly, the LRS-B will not only have to compete for funding against other USAF priorities, but across all three branches of the military. In relation to conventional capabilities, the LRS-B will have to compete against the USAF’s preference in the last three decades for short-ranged tactical fighters, and specifically the colossal funding requirements to procure and operate the roughly 2,500 F-35 Joint Strike Fighters which the USAF, US Marine Corps and US Navy are currently expected to obtain during the LRS-B development and procurement cycle.

As if that were not enough, the contract placed with Northrop is already subject to a review by the Government Accountability Office, which is considering a joint protest from Boeing and Lockheed, which submitted a rival bid. Given the political clout wielded by those manufacturers, a significant delay or even overturning of the contract is not out of the question.

If the programme is successful, the LRS-B should give the US global – and survivable – conventional strike and nuclear deterrence capabilities which are far less vulnerable to anti-access/area denial (A2/AD) threats than shorter-ranged aircraft or ship-based systems. However, as has been outlined here, there are many hurdles to overcome before the USAF gets its new stealth bomber.

Justin Bronk
Research Analyst in the Military Sciences research group at RUSI

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Timothy Stafford
Research Analyst in the Proliferation and Nuclear Policy research group at RUSI.