Raytheon has revealed that it’s working on a ground-launched version of its StormBreaker glide bomb, previously available only in air-launched form. The new development of the weapon should provide a very versatile follow-on to the Ground-Launched Small Diameter Bomb (GLSDB), which made its combat debut in Ukraine but had reportedly performed poorly there, especially due to heavy Russian jamming. Meanwhile, the same motor that will be used on the ground-launched model is also planned to be added to the air-launched version, providing a considerably greater standoff range.
The existence of the ground-launched StormBreaker — the official name of the weapon was not revealed — was disclosed by Jon “Stormin” Norman, vice president of Raytheon’s Air & Space Defense Systems Requirements & Capability. He was speaking on the Fighter Pilot Podcast, the full episode of which you can find here.
“On company funding, we’re working with some of the service labs to do a ground launch variant of [StormBreaker],” Norman said. “We’ll be testing that to summer on company money, and that’ll give it a good range and a good point-defense capability.”
Norman added that the company was still looking at propulsion options for the ground-launched version, with either a rocket motor or an air-breathing engine under consideration. However, whatever option is chosen will likely also make its way onto the air-launched version, too. “We’re working on the engineering design to integrate that onto the weapon to greatly enhance the range of that StormBreaker so we can keep our pilots outside of threat rings. So we’re very excited about that. We think that this has a lot of growth capability.”
Before looking at the particular advantages offered by a ground-launched StormBreaker, it’s worth looking briefly at the development path that brought Raytheon here.
The story starts with the 250-pound GBU-39/B Small Diameter Bomb, or SDB I, a ‘fire and forget’ precision attack weapon that combines standoff with small size. This means more examples of the weapon can be carried by a single aircraft. Depending on the launch height and speed, the unpowered SDB I can reach targets as far as 60 miles away, thanks to its pop-out wing set. However, this is under optimal conditions, and a range in the region of 45-50 miles is more likely when launched from a tactical jet.
However, the original SDB I is not able to engage moving targets, a limitation addressed by the Small Diameter Bomb II, now better known as the GBU-53/B StormBreaker. This is able to hit moving targets in any weather, thanks to its tri-mode guidance system, which uses imaging infrared, millimeter-wave radar, or semi-active laser homing to hit a designated aimpoint. There is also a datalink, allowing the munition to communicate over the Link 16 network so pilots can send updated target information to the StormBreaker after the weapon has left its launch pylon. While it only weighs 204 pounds, this includes a surprisingly powerful penetrating warhead for its size.
Depending on the altitude and speed of the launching aircraft, the weapon can glide up to 69 miles on its own using a GPS-assisted inertial navigation system, after which it can strike a specific coordinate or begin searching for a target. For moving targets, the weapon’s range is reduced to 45 miles.
The air-launched StormBreaker is therefore well suited to tasks such as battlefield interdiction and destruction of enemy air defenses against ground-mobile targets and even anti-ship attacks. It’s also much more flexible when it comes to targeting and re-targeting overall.
The first effort to transform the series into a surface-launched long-range precision strike weapon was the Ground-Launched Small Diameter Bomb, or GLSDB, developed by Boeing, in partnership with Saab of Sweden, on the basis of the air-launched SDB.
Each GLSDB is comprised of two existing components, the air-launched GBU-39/B SDB and the rocket motor from the 227mm-caliber M26 artillery rocket. The M26 is among the rocket types that can be fired from the M270 Multiple Launch Rocket System (MLRS), and variants thereof, and the M142 High Mobility Artillery Rocket System (HIMARS).
The GLSDB relies on the M26 rocket motor to propel it for the initial boost/loft phase, after which the wings are deployed and the munition flies unpowered, as a glide bomb. It uses the GBU-39/B’s existing inertial navigation system and embedded GPS to guide it to its target. The GLSDB has a range of around 94 miles.
In its marketing literature, Saab claimed that the GLSDB’s guidance system not only ensures accuracy to within three feet but is also resilient to electronic warfare jamming, something that is of particular concern in the Ukrainian conflict.
However, once exposed to combat for the first time by Ukrainian forces, it seems the GLSDB was found wanting.
“One company, I won’t say who they are, they came up with a really cool idea of taking an air-to-ground weapon and doing a ground-launched version of it, and it would be a long-range fire weapon,” Bill LaPlante, under secretary of defense for Acquisition and Sustainment, said in April 2024. Although he didn’t mention the GLSDB by name, his meaning was clear, as no other weapons fit this description.
“They raced and did it as fast as they could,” LaPlante continued. He added that U.S. authorities relaxed their testing requirements to help speed the weapon system in question to Ukraine.
“We said, look, just test for safety. Otherwise, the operational testing will be non-cooperative with the Russians,” according to LaPlante. “And so then we sent it to Ukrainians. It didn’t work.”
LaPlante claimed the GLSDB’s performance was limited for “multiple reasons,” including the dense electronic warfare environment, as well as the tactics, techniques, and procedures.
“It just didn’t work,” LaPlante explained, before suggesting that the weapon had been more or less abandoned by the Ukrainians as a result.
While LaPlante didn’t provide any more details on the electronic warfare issue, it’s by now no secret that Russian GPS jamming, in particular, has reduced the efficiency of Ukraine’s use of Western precision-guided ground and air-launched munitions. As the war in Ukraine has continued, Russian forces have significantly expanded their use of various kinds of electronic warfare capabilities.
Clearly, weapons like GLSDB that rely on GPS are going to be especially vulnerable to Russian jamming of this kind.
The StormBreaker, however, should be much more resilient, thanks to its tri-mode guidance. Although Norman made no mention of the GLSDB’s performance or of its utilization in Ukraine, having a weapon that is better able to cope with Russian or any other hostile electronic warfare makes a good deal of sense.
A tri-mode seeker means that, unlike the GLSDB, the ground-launched StormBreaker will have the ability to find its way to a moving or static target and to cope with smoke, dust, and other poor weather conditions. Furthermore, the weapon’s onboard computer is able to classify and prioritize targets on its own, seeking out their especially vulnerable points, too.
Additionally, the StormBreaker features hardening against electromagnetic jamming and cyber attacks, providing a further level of reliability.
Aside from the propulsion choices, Norman didn’t provide details of how the ground-launched StormBreaker might work in comparison to the GLSDB. It’s unclear if the rocket motor he referred to would be the same as that used in the GLSDB, although the possibility of an air-breathing engine would tally with Raytheon’s goal of developing a weapon that will have a maximum range considerably greater than the roughly 94 miles of the GLSDB. This would be especially relevant for the air-launched version, in which the speed and altitude of the launch platform would combine with the motor to provide even greater standoff distance.
The war in Ukraine has also reinforced the importance of having munitions that put considerably more distance between the launch platform and the target area. Even the GLSDB, for all its apparent problems, provides significantly greater reach than the longest-range 227mm artillery rockets currently available for the M270 MLRS and the M142 HIMARS. These can fire precision-guided rockets out to around 50 miles. Meanwhile, the Ukrainian Air Force has had notable success with the air-launched SDB. A weapon that combines the versatility of the air-launched StormBreaker with even greater standoff range would be of huge interest to any number of air forces.
Clearly, depending on the eventual maximum range, a single ground-launched StormBreaker battery will be able to provide prompt precision strike option even against moving targets over a large geographical area. Just assuming the same range as the current GLSDB, it would be able to address targets over nearly 28,000 square miles. As such, it will offer even a small forward-based unit unprecedented capabilities. This could including striking numerous vehicles dozens of miles away with exacting precision, in any weather, without the use of air support — whether it be manned or unmanned aircraft. This capability would offer drastic efficiencies and a new level of organic precision fire support basically anywhere on the battlefield a launcher can survive.
When it comes to the powered air-launched SDB II, that would also offer a huge leap in capability, allowing aircraft to make greater use of ever more capable and farther-reaching kill webs that leverage advanced networking for targeting. Its extended range would also provide a larger margin of survivability for the launch platform, which face increasingly long-ranged air defenses.
TWZ has approached Raytheon for more details about the ground-launched version of the StormBreaker — and the powered air-launched model. With tests of the ground-launched version apparently now underway, we should learn more about the new weapon in due course. While it’s hard to determine the full scope of its capabilities at this early stage, the ground-launched StormBreaker would appear to offer a range of advantages over the GLSDB, not least its ability to hit moving targets in all weathers — and its better resilience to electronic warfare jamming.
Contact the author: thomas@thewarzone.com