USAF Want's To Dodge Latest Air Defences.

Maintaining the shroud of secrecy surrounding the US Air Force's (USAF's) new Long-Range Strike Bomber (LRS-B), the general in charge of the USAF's nuclear forces would only tell reporters that advances in air defence technology drove the development of the Long-Range Standoff (LRSO) cruise missile being designed to arm the US bomber fleet.

USAF Want's To Dodge Latest Air Defences.

"As we look around the world, air defences are getting more and more sophisticated as technology improves," said Lieutenant General Stephen Wilson. "We'll need a missile that can penetrate more sophisticated air defences."

He added that a conventional variant of the LRSO would be built after a nuclear-tipped missile is first developed.

The general said the USAF has completed its analysis of alternatives (AoA) and is now waiting on senior Pentagon leadership to allow the acquisition effort to proceed.

"We've finished the analysis of alternatives except for the Office of the Secretary of Defense coming forward, but we are proceeding on track," he said. "We're proceeding with an LRSO, working on the phasing and the timing and the funding for that going forward."

The USAF studied "a variety of options - different capabilities, different speeds, lots of different options", he added. "We narrowed our focus to what we currently have. Beyond that, I can't get into specifics."

In December 2012, the Pentagon announced plans to issue separate contracts to Boeing, Raytheon, Lockheed Martin, and Northrop Grumman for the technology development (TD) phase of the LRSO programme. A request for information released just ahead of that announcement contained no details about whether the USAF was seeking a subsonic, a supersonic, or even a hypersonic weapon.

Only a small amount of information about what the USAF is seeking in an LRSO missile is in the public domain.

Testifying before the Senate Armed Services strategic forces subcommittee in 2012, Lt Gen Wilson's predecessor described the LRSO as a stealth cruise missile. He was earlier on the record as saying that the weapon's range would be longer than the 500 n mile (c.900 km) range of the Joint Air-to-Surface Standoff Missile Extended-Range (JASSM-ER) and "closer to the current air-launched cruise missile [ALCM] range". The maximum range of the legacy nuclear-armed AGM-86B ALCM is 2,500 km. The maximum range of the conventionally armed AGM-86C and D models is 1,200 km.

The warhead for the nuclear-tipped LRSO is also unknown.

The US National Nuclear Security Administration (NNSA) and the USAF have asked Sandia National Laboratories and the Los Alamos and Lawrence Livermore National Laboratories to examine three existing nuclear warheads for possible use in the LRSO missile: the B61-12 (a nuclear bomb intended to replace four current but ageing B61 variants), the W84 (originally used on the now-retired BGM-109G Ground Launched Cruise Missile), and the W80 (currently used on the nuclear-armed version of the AGM-86).