Air Force Wants To Use External Pylons To Arm The B-1B Bomber With 31 Hypersonic Missiles

U.S. Air Force General Timothy Ray, head of Air Force Global Strike Command, which oversees all of America's bomber fleets, gave an update on future B-1B loadouts in a recent interview with Air Force Magazine. Last year, the service highlighted work to expand the bomber's ability to carry hypersonic weapons and other new stores, both internally and externally. This all also comes amid already controversial plans to retire 17 of its 60 remaining Bones in the 2021 Fiscal Year and has severely scaled back the activities of the fleet as a whole, prohibiting crews from flying at low altitudes and restricting total annual flight hours, which you can read about more in this past War Zone exclusive.

"My goal would be to bring on at least a squadron’s worth of airplanes modified with external pylons on the B-1, to carry the ARRW [Air-launched Rapid Response Weapon] hypersonic cruise missile," General Ray told Air Force Magazine. He added that the service had contemplated several options for integrating the AGM-183A onto the bombers, "but we believe the easiest, fastest, and probably most effective in the short term will be to go with the external pylons."

At present, B-1 squadron typically has 18 aircraft, according to Air Force Magazine. Ray appears to have misspoken in describing ARRW, which is pronounced "arrow," as a "cruise missile." The AGM-183A has an unpowered hypersonic boost-glide vehicle as its warhead. The weapon's rocket booster lofts that vehicle to an appropriate speed and altitude, after which it then glides down along a level trajectory within the Earth's atmosphere to its target. The weapon's high speed and unpredictable flight path make it difficult for opponents to detect and track, which makes it hard to move critical assets out of the target area, if at all possible, or otherwise take shelter before the strike hits, or even attempt an intercept. 

Rockwell had designed the Bones to carry external stores on up to eight external hardpoints. The Air Force had also developed special pylons that would have allowed the bombers to carry two nuclear-tipped AGM-86B Air-Launched Cruise Missiles (ALCM) on each one. Following the end of the Cold War, the B-1Bs lost their nuclear mission and, as a result, the external pylons fell into disuse. Today, the bombers use just one of the hardpoints to carry the AN/AAQ-33 Sniper Advanced Targeting Pod (ATP).

It's not clear what other modifications or upgrades the B-1Bs might need to be able to physically carry the AGM-183As or how many of these missiles the bombers might be able to carry at once. While we don't know how much the ARRW weighs, we do know that a B-52H Stratofortress bomber carried a prototype during a test last year using one of its heavyweight underwing pylons, which are rated to carry stores in the 5,000 pound class or lighter. The AGM-86B weighs around 3,200 pounds and the B-1B's original pylons were each supposed to carry two of them at once.

It's also worth noting that the Air Force's is looking to halt work on the Hypersonic Conventional Strike Weapon (HCSW) program in its latest budget proposal for the 2021 Fiscal Year in favor of the AGM-183A, specifically because the latter is smaller. The HCSW missile, which the service planned to designate AGM-182A Hacksaw, has a different hypersonic boost-glide vehicle warhead, which is a common design also found on ground and submarine-launched weapons that the U.S. Army and U.S. Navy are working on, respectively.

"The reason we went with ARRW was not that HCSW was bad, but ARRW is smaller," Will Roper, the Assistant Secretary of the Air Force for Acquisition, Technology, and Logistics, explained in March 2020. "We can carry twice as many on the B-52, and it’s possible it could be on the F-15[E Strike Eagle] … It’s in the class to be able to fit on the centerline."

General Ray did tell Air Force Magazine that some of the B-1s will need significant structural work," but it's unclear if this is directly related to plans to integrate the AGM-183A. The bombers have been flown hard in recent years and their airframes have seen greater than expected wear and tear as a result, which is part of the reason for the halt to low-altitude flight operations, which put additional physical stress on the aircraft.

The Air Force is also looking at the B-1B as a potential platform to carry the Hypersonic Air-Breathing Weapon Concept, or HAWC. The Defense Advanced Research Projects Agency (DARPA) has been leading the development of this powered hypersonic cruise missile, though the Air Force Research Laboratory has also been involved. Air Force Magazine says that the Bones, using external pylons and common rotary launchers in their internal bomb bays, could potentially carry a mix of up to 31 hypersonic missiles in total.

Interestingly, General Ray also raised the possibility of adding a conventionally-armed variant of the Long Range Stand Off (LRSO) stealthy cruise missile, which is presently in development, to the B-1B's arsenal in the future. “Right now, we’re not asking for that, based on the prioritization of the nuclear piece, … but there’s things that could change in the future,” he told Air Force Magazine.

This is curious because Congress specifically eliminated its requirement for a conventional version of the LRSO in the annual defense policy bill, or National Defense Authorization Act (NDAA), for the 2020 Fiscal Year, which President Donald Trump signed into law in December 2019. The law's language did not expressly prohibit the Air Force from pursuing this capability on its own, but removed an immediate legal demand for the service to do so.

Ray said that there could be a demand for this weapon based on a desire for "an even longer-ranged cruise missile with conventional capability" and because the AGM-86 series is "aging out on us." However, the Air Force has already retired the conventional AGM-86C/D variants and has initiated the development of an "extreme range" variant of the Joint Air-to-Surface Standoff Missile cruise missile, also known as the AGM-158D or JASSM-XR. 

The exact range capability the Air Force is seeking from JASSM-XR is unknown, but it is said to be in excess of 1,000 miles, which would already give it a substantially greater range than the AGM-86C/D. In addition, the service is hoping to have this missile, which will leverage existing work on the JASSM, including the AGM-158B JASSM-Extended Range (JASSM-ER) version, out of development by 2023, with the first examples hopefully entering service relatively soon thereafter. The nuclear-armed LSRO is not supposed to reach initial operational capability until at least 2030. 

It's possible that Ray's comments may be informed in some way by his knowledge of what the Air Force, as well as other services, might be doing in the classified realm. The LRSO program itself has been shrouded in secrecy and there are few hard details about the weapon's overall design or capabilities. 

In March, U.S. Air Force Chief of Staff General David Goldfein alluded to the development of at least one classified air-launched anti-ship munition, as well. He told senators at a hearing that the AGM-158C Long-Range Anti-Ship Missile, or LRASM, which is a derivative of the JASSM, was the only such weapon he could discuss in an unclassified setting. The Air Force has already integrated LRASM onto the B-1B.

Regardless, General Ray's comments do make clear that the Air Force is still very interested in expanding the B-1B's arsenal and what roles and missions the fleet might be able to perform in the backend of the aircraft's career. The head of Air Force Global Strike Command noted that integrating new weapons onto the Bones could also help ease the test and evaluation burden on the B-52 fleet, which are presently set to be the primary platform for testing any new hypersonic missiles, as well as other advanced air-launched munitions, in addition to employing them operationally.

The new capabilities look set to help the remaining B-1Bs remain relevant to Air Force operations for years to come.

Contact the author: joe@thedrive.com