The first generation of GLSDB used the standard GBU-39/B Small Diameter Bomb, which couldn’t stand the trial by modern warfare, but the new version aims to patch the critical vulnerability to jamming
American defense industry giant Raytheon, part of RTX Corporation, is developing a ground-launched version of its miniature precision-guided long-range GBU-53/B Small Diameter Bomb II, also known as StormBreaker. While the company is withholding details, it plans to begin testing the weapon this summer, as announced by Jon Norman, Raytheon’s Vice President of Air & Space Defense Systems Requirements & Capability, during the Fighter Pilot Podcast.
At this stage, Raytheon is only evaluating different propulsion options, considering either a classic solution on solid propellant or an air-breathing jet engine. The first approach suggests accelerating the GBU-53/B with a booster to a high altitude, from where it will glide towards the target. The second would incorporate a miniature turbojet engine, effectively transforming the bomb into a cruise missile.
Whichever option is chosen, it will be used not only for the ground launch version but also for the air-to-air extended range variant, enabling launches from much greater distances to the target. The current StormBreaker can already travel approximately 110 km on its own when released from high altitudes.
These announcements bring to mind a previous attempt to adapt a Small Diameter Bomb for ground launch. Boeing’s GBU-39/B was modified with a solid booster for this purpose, resulting in the GLSDB, developed jointly by Raytheon and Saab. However, in real combat use in Ukraine, the system proved vulnerable to Russian electronic warfare countermeasures.
The GBU-53/B, however, differs significantly from its predecessor GBU-39/B, particularly in its guidance systems. The original SDB relies solely on satellite and inertial navigation, with only a specific subvariant featuring a semi-active homing system. Given that this relatively lightweight 100-kg bomb depends entirely on accuracy, disrupting its guidance with electronic warfare severely reduces its effectiveness.
On the other hand, the GBU-53/B Small Diameter Bomb II has multiple terminal guidance methods at once: active radar, semi-active laser homing, and a thermal imaging seeker. Only during the midcourse flight does it use satellite and inertial navigation. In other words, even if the satellite connection is jammed, the StormBreaker will reach the target area and acquire the target independently, without relying on its precise coordinates.
Raytheon’s consideration of a jet engine over a rocket booster likely stems from lessons learned in Ukraine, too, where modern electronic warfare and air defense systems pose significant challenges. Technically, propelling the weapon to high altitudes with a booster gives a lot of time for the enemy to react and intercept it. In contrast, flying at low altitudes to evade detection may offer a greater chance of success.