At the excellent #IAVEvent last week Adam Griffiths of @ElbitSystemsLtd gave a great overview of #IronFist. When you think hard kill APS you tend to think Trophy but Iron Fist is more widely adopted and looks to be leading global market with significant new developments presented 
A very capable system, but the exciting thing in the briefing was the information on the new version- Iron Fist Light Kinetic (IFLK), oriented at high performance HEAT/KE threats.
Traditionally hard kill were only effective against direct flight (ie not top attack) ATGM & RPG/rocket threats. High velocity attacks like APFSDS penetrators were not within capability range. Defeating these is v hard, they move extemely fast and present very small target
Broadly it will be unlikely an APS will destroy the rod in flight as it would with a rocket or missile. Instead it seeks to hit it with a blast or physical impact that knocks it off axis. Even a minor deflection has a huge effect, degrading penetration significantly.
Rotational movement results in vastly increased drag, reducing impact velocity. Also means force is not transferred on-axis when it impacts, which can break the penetrator apart as well as increase effective armour thickness. A 10 degree movement can reduce penetration by >50%.
IFLK adds capability to engage these stressing threats, videos were presented of successful intercepts against HEAT & APFSDS. In the latter case it appeared the penetrator was not destroyed, but as above, the intercept knocked it significantly off axis.
Worth noting even with a considerable effect on the threat penetrator, the defended vehicle will still need substantial passive armour to survive the resultant impact. It doesnt magically protect light vehicles from penetrators. but does offer potential for medium/heavy armour
As with most APS, IFLK/IFLD link into the users BMS to share data and allow mutual protection and so on. Users should ensure this integration is included in their APS acquisitions or they are missing a big benefit.
Another interesting add-on shown was the soft-kill module, providing layered flexible capability and a further level of protection when the hard kill is out of ammo or otherwise unable to engage, as well as a precursor to avoid unecessary hard kill ammunition expenditure
An interesting system to watch, and already getting good uptake globally - US/NL/AUS as well as native Israel. If nothing else it creates a good product to drive hard kill market developments by competitors and get the tech out there.
With integration work already being done for Australian Boxer, UK should take a look and make a quick win to radically enhance survivability of the vehicle in UK service. Regardless of a peer or insurgent-type opponent, this sort of protective capability is hugely relevant. /end
