SMArt 155 is a Sensor Fuzed Munition (SFM), developed by Rheinmetall and Diehl BGT Defence in the late 1980s. It is a 155mm howitzer round which contains a pair of fire-and-forget top-attack submunitions. The submunitions use a ballute and parachute to slow their descent and allow the submunitions’ onboard infrared sensor and millimeter wave radar to locate its target and fire and explosively formed penetrator.
In a previous video/article we’ve looked at the 155 BONUS round which also carries two submunitions which are arrested by a pair of winglets which arrest the submunitions flight to enable their built-in sensors to detect targets within their search footprint before striking down on a target vehicle.
The round is manufactured by GIWS, a joint venture between Diehl Defence and Rheinmetall, and entered service in the late 1990s. It is capable of being launched by NATO standard 155mm howitzers but in Ukraine appears to primarily be used in conjunction with Panzerhaubitze 2000 self-propelled howitzers. The round is also in British service as the Ballistic Sensor Fused Munition fired from AS-90s, the UK has recently provided Ukraine with a number of AS-90s but it is unclear if they will deploy SMArt155 rounds.
The manufacturer describes SMArt 155 projectile as consisting of: “a thin-walled shell body, a base plate, an ejection unit, time fuse, and two functionally identical submunitions.” The SMArt155 round allows a 155mm projectile to deliver two submunitions capable of penetrating any tank’s top armour with considerable accuracy. SMArt155 has a listed maximum range of 22km (13.6 miles) when fired from 155mm/39-calibre systems and 27.5km when fired from 155mm/52-calibre systems such as the PzH2000. Adding a base bleed unit would extend the round’s range further. The submunitions carry a shaped charge of 9.7lbs (4.2kg) of high explosive which create explosively formed penetrators (EFP). The manufacturer states that extensive German Army trials found that the round has a very low failure rate.
Once the round is fired an onboard timer fuze, set before firing, ignites an ejection charge in the shell’s nose which pulls the submunitions out of the shell body. Once clear the submunitions’ ballute and then parachute deploys they begin to spiral down over the target area using their onboard sensors to detect the target vehicle before detonating their payload.
Though there is controversy surrounding SMArt, and BONUS, the shells do not fall into the category of weapons banned under the 2008 Convention on Cluster Munitions as they comprise of just two submunitions and both have onboard self-destruction mechanisms.
The summer of 2022 saw a flurry of drone videos which showed strikes of Russian vehicles and equipment many of these were attributed to either BONUS or SMArt 155, but with most of the videos it is difficult to definitively identify which top attack munition was in use.
On the 2 July, the first video believed to be a SMArt in action was shared online. In it a munition can be seen descening before detonating above. The framing and resolution of the video is too low to confirm if it is a parachute arrested submunition. Russian telegram channels shared a photograph of a ballute and parachute, said to have been seen near Kirovsky, in Donetsk in early August.
On the 13 September, another fairly low resolution video showed a top attack munition detonating above a Russian armoured vehicle. On 4 March 2023, photos of a ballute and parachute from a SMArt 155 were shared and said to have been found near Kreminna. Around the same time another video showing a potential SMArt 155 strike was shared. On 17 April, the 26th Artillery Brigade shared video showing what was claimed to be a SMArt munition striking two Russian vehicles. On 23 April, Ukrainian military journalist Andrii Tsaplienko shared a video from inside a PzH2000 showing some German DM702 SMArt 155 shells. The DM702 shells were again briefly seen in a video posted by the 43 Separate Artillery Brigade posted on the 16 May.
While the lack of easily verifiable videos of SMArt in use is frustrating it is impressive that we have any footage of top-attack munitions in use at all. Production of SMArt 155 paused in the late 2000s but even before the war in Ukraine began their had been plans to revive production. The war has, however, provided impetus for renewed production and in late 2022 the German government agreed to spend EUR 97.4 million to restart manufacture of the complex electronic components needed to manufacturer the round.
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Bibliography:
155mm SMArt, GD-OTS, (source)
Germany modernizes ammunition tested in Ukraine, Defence24, (source)
New serial production of SMArt 155 slated for 2024, Janes, (source)
The Armourers Bench 