However, there was one significant change in procurement terms: instead of replenishing Kyiv’s dwindling stock of ATACMS ballistic missiles, the US now plans to supply Ukraine with ground-launched small diameter bombs (GLSDB). How do these weapons compare and in what ways are they different?

ATACMS no more 

Two sources told Reuters that the GLSDBs were purchased as part of a military aid package by the Biden administration. The Associated Press (AP) reported on Thursday that Ukraine had run out of ATACMS long-range ballistic missiles, as the US had provided Ukraine with fewer than 40, and their stocks were depleted by the end of January.

According to Reuters, the GLSDBs have been upgraded by their manufacturers to counteract interference from Russian electronic warfare systems. The bombs could be delivered within days, Reuters said, noting that there were already stocks of GLSDBs in European warehouses, though it didn’t indicate how large they were.

“Both weapons are launched from the ground by means of an M270 Multiple Launch Rocket System (MLRS) or an M142 HIMARS multiple rocket launcher,” Ivan Stupak, a military analyst and former Ukrainian secret service officer, told Novaya Gazeta Europe. “But whereas an ATACMS is a fully-fledged ballistic missile with a warhead weighing about 225kg, a GLSDB is a steerable glide bomb that carries under 100kg of explosives. It’s like comparing a Jeep with a Mini.”

“The ATACMS has a range of up to 300km, whereas the GLSDB can only fly 150km. Yes, the bomb has a satellite guidance system and can fly around obstacles in its path … but most of the ATACMS missiles supplied to Ukraine were modified to carry cluster munitions, which could target a large area, whereas GLSDBs carry high-explosive incendiary warheads with a narrower radius of destruction.”

“GLSDBs will be a poor stand-in for ATACMS,” military analyst Kirill Mikhailov told Novaya Europe. “The ballistic missiles supplied to Ukraine had a cluster warhead that carried hundreds of submunitions and could take out many enemy personnel at once. Now, the only long-range, high-precision weapons the AFU have are missiles compatible with the HIMARS MLRS, which can only hit Russian objects up to 60km to 70km away. GLSDBs will occupy that niche.”

Three instead of one 

“Ukraine received modified ATACMS M39 missiles with a range of 160km. The allies provided few 300km ATACMS,” military expert and reserve AFU colonel Roman Svitan told Novaya Europe. “The GLSDBs with a range of 150km will be able to replace them to a large extent, but they’ll have to fire three bombs instead of a single missile. But it will still be better value for money. A ballistic missile costs over $1 million [€920,000] while a small-diameter bomb costs $40,000 [€37,000]. And the US has manufactured thousands of the M26 launch modules they require.”

Svitan explains that when launched from an MLRS, the booster accelerates to ultrasonic speed and will send the small-diameter bomb to a height of 10km, at which point it will unfold its wings and begin to head towards its target.

Stupak says the AFU has already used GLSDBs, though they were shown to be fairly ineffective due to Russian electronic warfare systems. This was looked into by the manufacturers — Boeing and the Saab Group — and, Stupak says, the bombs have been modified to resist such interference, though he believes the Russians will have learnt how to deal with this type of bomb in a few months’ time, at which point they will require a further upgrade, or outright replacement. But for some time, at least, GLSDBs will be able to cause significant challenges for the Russian army.

“Ukraine has several dozen GLSDB launchers," says Svitan. “If the modified bombs are supplied in their thousands, as is entirely possible, they will play an important role at the front.”