Washington wants to double the range of Ukraine’s HIMARS rocket systems by supplying GLSDB ammunition, which are low-caliber glide bombs adapted for ground launch.
As reported by Reuters, the Pentagon is studying a proposal by Boeing to supply Ukraine with small, inexpensive precision-guided bombs fitted to widely available rockets, which would allow Kiev to strike far from Russian lines as the West struggles to meet demand for more weapons.
U.S. and allied military inventories are shrinking, and Ukraine faces a growing need for more sophisticated weapons as the war drags on. Boeing’s proposed system, called the Ground Launched Small Diameter Bomb (GLSDB), is one of a half-dozen plans to put new munitions into production for Ukraine and U.S. Eastern European allies, according to industry sources.
The GLSDBs could be delivered as early as spring 2023, according to a document reviewed by Reuters and confirmed by three people familiar with the plan. It combines the GBU-39 small-diameter bomb (SDB), originally designed for launch from fixed-wing aircraft, with the M26 rocket engine, which is used on the M270 (MLRS) and M142 (HIMARS) multiple rocket launchers successfully operated by Ukrainian forces.
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Ground-Launched Small Diameter Bomb
The GLSDB ammunition is the result of a co-development effort between Boeing and Saab to provide long-range, high-accuracy fire support at a low cost per shot by combining the GBU-39 Small Diameter Aviation Bomb (SDB I) and the Multiple Launch Rocket System.
The SDB is a 250-pound (113 kg approx.) weapon with an inertial navigation system assisted by an advanced satellite anti-jamming system, combined with a penetrating blast and fragmentation warhead and a programmable electronic fuze.
A HIMARS rocket launcher, such as those supplied to Ukraine by the U.S., when equipped with GLDSB ammunition, can engage targets at distances of up to 150 km, having also the ability to engage targets from different angles and with extremely high accuracy, being able to hit within a radius of 1 meter (CAP 1) around the target.
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According to the document – a proposal from Boeing to U.S. European Command (EUCOM), which oversees weapons destined for Ukraine – the main components of the GLSDB would come from existing U.S. stockpiles.
The M26 rocket motor is relatively abundant, and GBU-39 bombs cost about $40,000 each, making the complete GLSDB inexpensive and its major components readily available. The new weapons could start arriving in Ukraine in the spring of 2023, although at a low production rate, given the difficulties faced by arms manufacturers in meeting the war-triggered surge in demand.
Given that AGM-88 HARM missiles have already been fitted to Ukrainian MiG-29s to enable them to combat Russian air defenses, we may soon see them fitted with GBU-39 SDB glider bombs as well.
 Ukrainian HIMARS systems could hit targets accurately up to 150 km.){kind=link}