Loitering munitions were pioneered by Israeli firm IAI (Picture: IAI).
By David Hambling, technology expert
Loitering munitions, which combine the precision effect of a missile with the long endurance of a drone, can find and destroy their own targets at extended ranges.
They are likely to have a significant effect on the future battlefield, but the UK’s latest effort seems to have crashed and burned in entirely the wrong way.
The concept of loitering munitions was pioneered by Israeli firm IAI with their Harop, introduced in 2005.
This has a 2.5 metre wingspan and weighs 135 kilos and can cruise over the battlefield for six hours before striking with a 15 kg warhead.
A version called Harpy NG is designed specifically to knock out air defence radars. These are normally turned off until the last second to avoid detection.
A Harpy loitering over in the area can take out any radar as soon as it is turned on, forcing defences to stay shut down.
In 2005, the same year the Harop took off, the MoD embarked on its own Loitering Munition Capability Demonstration.
This explored various options, including a modified Harop called White Hawk. Ultimately the decision was made to acquire a new weapon, known as Fire Shadow, from a consortium led by MBDA.
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Fire Shadow is similar in size and capability to Harop and is launched into the air with a rocket booster, after which a propeller takes over.
This provides an endurance of six hours and a range of over 100 km.
When a target is spotted, either by Fire Shadow’s own sensors or by other assets, the operator sends it into a lethal dive, striking the target with metre-accurate precision.
A series of test firings took place from 2008 onwards, with Fire Shadow smashing into moving SUVs and other targets.
Fire Shadow should have been deployed to Afghanistan in 2012, but according to the National Audit Office the technology was not sufficiently mature and the success rate was "lower than desired".
This was an ominous sign, and little has been heard of Fire Shadow in recent years. In July the MoD’s accounts showed the project had been finally written off, at a cost of some £95m.
Meanwhile, the Israeli Harop has been exported to several nations, including Azerbaijan, who have used it in action.
In 2016 an Azeri Harop reportedly hit a bus full of Armenian volunteers, killing seven of them. Bizarrely enough, Harop has also featured in a pop music video celebrating Azerbaijan’s military.
Israel now produces and exports many other such systems; one of the most unusual is the ROTEM-L, which resembles a large consumer quadcopter loaded with explosives.
Other nations produce their own loitering munitions.
China’s come in several sizes, from the ASN-301 which looks like a virtual clone of the Harop, to the miniature CH-901.
The US has fielded the portable SwitchBlade, a tube-launched killer drone weighing less than two kilos used by special forces in Afghanistan and Syria.
The ready availability of drone electronics means more countries are able to manufacture a small loitering munition.
This includes not only large nations like Iran, Turkey and Poland but smaller players such as Belarus, Slovakia and Ukraine who produce munitions for use against targeting personnel or light armoured vehicles.
Insurgent groups like Islamic State have even been producing their own garage-built versions, based on consumer drones like the Skywalker X-8.
The drone-carried bombs used in a recent assassination attempt against president Maduro of Venezuela suggest that such improvised weapons may become common.
While the larger versions can be as pricey as guided missiles, small tactical loitering munitions such as the Polish Warmate are intended as a low-cost option.
These may be fielded in large numbers to locate and attack opponents at extended ranges. Loitering munitions have considerable military potential, but it looks like UK forces will not be using them just yet.