NSM - a scenario

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edit years later: I've been informed that it's not that clear a problem as I described it here. The RAM missile may approach from the side (not being launched at the target bearing), which allows for a larger target silhouette in the terminal approach anyway. The problem is that this requires a somewhat earlier launch for intercept than a direct shot. IR and UV Missile detection sensors of the ship itself would still be blind towards the sun. That in turn could cost the few seconds warning time that one would need for an indirect launch profile with RAM.

Imagine the following:

A destroyer with an armament of SM-2, ESSM, RAM missiles and one or two 76-127 mm guns is engaged by a strike aircraft carrying something like a NSM (Naval Strike Missile). The pilot times the terminal engagement for dawn time.* He also avoids the SM-2 missiles by flying high only as much as necessary and staying low (behind the horizon and thus quite invulnerable to semi active radar homing missiles such as SM-2**).

The NSM is programmed to follow waypoints on its approach to its target and approaches the target at dawn from the direction of the sun - exactly from the direction of the sun. This takes the frigates' non-radar sensors (especially infrared sensors such as Mirador) out of the fight, since they cannot detect the missile on the background of the sun. The same applies to the infrared/UV sensor of the Rolling Airframe Missile. Its passive radar homing ability is devalued by the fact that NSM itself uses no radar seeker.

The only organic defences of the frigate would thus be its radar technology and the munitions which can make do with radar support only (ESSM, guns, decoys).

The problem with this is that there are good reasons for why modern warships get non-radar sensors: Radar physics are tricky. At times they can detect a missile at 5 m altitude, but wouldn't detect it if it only flew at 10 m altitude. Radar physics are much more complicated than mere line of sight - and this is very troublesome against sea skimmers. That's why warship developers have agreed that sensor fusion - especially between radar and infrared horizon scanners - is the way to go.

Unlike radar-guided anti-ship missiles, NSM could devalue the sensor fusion of even modern warships, could neutralise the short range anti-missile defence system reputed to be the most surefire one in the world and on top of this it makes do without any treacherous radar seeker emissions.

And on top of this it's usable as a cruise missile against structures on land.

Count me as a NSM fan. I suppose it's one of the military hardware things which would have become standard or at least a famous benchmark real quick if the world was bad enough to offer it real combat opportunities to shine.

S O

defence_and_freedom@gmx.de

*: This should not be much of a challenge for a modern strike aircraft pilot. German torpedo bombers of 1942 did this already, with a five minute window. The ship targets were easily visible, the torpedo bombers weren't.

**: Another reason for why at least some of the more expensive active radar seeker missiles should be embarked (also see this blog post).

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edit 2016: I think I published this late in 2015, not in 2014. Something may have gone wrong with this blog post.