After more than 30 years, the Harpoon missile is undeniably showing its age. It is not fast, nor manoeuvrable; it is a poor match for modern anti-missile countermeasures; and its lack of precision guidance is a serious limitation in today’s operating environment. There is no doubt that it is time for it to go, but no matter how technically near-obsolete it is, in the absence of a suitable replacement to fill the looming capacity gap, its loss will certainly be noticed.
When the Admiral Kuznetsov carrier group passed through UK waters on its way to Syria last year, Harpoon missile canisters were plain to be seen on the decks of HMS Duncan, Richmond and Sutherland tasked with escorting the Russian vessels. Although the Royal Navy has never fired a Harpoon in anger, the display was both a domestic reassurance and a clear deterrence to others. Roll on a year or two, replay the scenario, and the navy would be facing that foreign fleet armed with nothing heavier than a 4.5-inch gun.
However, all may not be entirely lost. In answer to a written question from Lord Campbell of Pittenweem in January, Earl Howe, Minister of State for Defence and Deputy Leader of the House of Lords, said that “the Royal Navy is working alongside other areas of the Ministry of Defence to consider options for a Harpoon replacement”.
So, if a successor system is to be found, what might be in the frame?
Harpoon Next Generation
Boeing’s Harpoon Next Generation – the latest Block II+ER version – is one obvious candidate. Unveiled in 2015 and expected to be ready during 2017, the Next Generation boasts a host of new features to improve performance. It will have an increased range of 134nm, a lighter but reportedly “more lethal” warhead weighing in at 140kg, a more efficient turbo-jet engine with state-of-the-art electronic fuel controls and an active radar-homing seeker to give enhanced all-weather operation.
One big factor in its favour is its compatibility with existing launchers, but at around $1.2m per missile, it is not a cheap option.
If the Royal Navy was to follow the US Navy’s lead in choosing a likely successor, then the Long-Range Anti-Ship Missile (LRASM) from Lockheed Martin would be the system of choice. Tipped as the leading contender to replace the Harpoons in US service, although the LRASM is not set to be the fastest weapon in the world, it will be one of the stealthiest and most intelligent, able to defeat jamming and detection, while autonomously seeking and engaging its own targets.
Described as the ‘gold standard’ for modern anti-ship missiles and developed as a DARPA project, LSASM will rely on on-board systems for target acquisition without the need for detailed prior intelligence, GPS navigation or external data-feeds.
Expected to be a little cheaper than the Harpoon Next Generation, it comes with both air and vertical canister launch capabilities, which might make it of interest to arm the navy’s new F-35s as well as its surface ships.
Naval Strike Missile
Developed by Norway’s Kongsberg Defence & Aerospace, the Naval Strike Missile (NSM) could be another serious contender. It is nowhere near as sophisticated as the LRSAM, nor does it have its range or warhead, but the NSM does offer a relatively low-cost, currently available replacement which could be quickly bolted on to maintain the Royal Navy’s anti-ship capability once Harpoon is retired.
A stealthy weapon flying at high-subsonic speeds, the NSM also has some capacity to detect and recognise targets independently using an imaging infrared seeker in combination with an onboard target database, and can navigate by GPS, inertial guidance and terrain referencing.
A new multi-role version of the system is now being jointly developed with Raytheon, which will bring lower costs and provide compatibility with the F-35, making it an even more attractive possible option for the UK to consider.
Arguably the most state-of-the-art missile system of its kind currently available in the West, Saab’s RBS15 Mk3 is the latest member of a highly successful missile family that first entered service in 1985.
Packed with a range of high-end features, including sophisticated electronic counter-countermeasures (ECCM) and an advanced graphical user interface, it has a low sea-skimming capability and manoeuvres in unpredictable attack profiles at increased thrust during the terminal phase of its approach to improve its ability to penetrate defences. It carries a heavy, high-explosive blast and pre-fragmented warhead over a range of around 134 nautical miles and at a speed of 0.9 mach.
Claimed to have low maintenance requirements and an extremely low life cycle cost, the RBS15 Mk3 is a possible contender today, and with a Mk5 under development, the family could remain on the Royal Navy’s inventory well into the future.
Exocet MM40 Block 3
The latest incarnation of the French-built Exocet MM40 missile has ditched its traditional single solid propellant rocket motor in favour of a solid-propellant booster, turbojet sustainer motor combination, which gives it an increased range in excess of 97 nautical miles, for less weight than its Block 2 predecessor. The Block 3 includes a number of other enhancements and upgrades, including changes to its navigational system which now accepts GPS waypoints to enable it to use different angles of attack against naval targets and also provide a limited land-attack capability.
Although notably finding itself on the wrong side of this missile during the Falklands War, the Royal Navy operated Exocets until 2002.
Rather than specifically designed anti-ship systems, the Royal Navy could also consider some of the other missile types that have been adapted to fulfil the role, notably by the US. The supersonic Standard SM-6 missile is one example, having been effectively repurposed away from its original anti-missile/anti-aircraft role to provide surface warfare capability. Despite its smaller warhead in relative terms, combined with its high velocity / high kinetic energy impact the SM-6 makes a potent weapon against most vessels. In addition, adopting one of the ‘Standard’ missile family with its common Mk41 vertical launch system would have the potential benefit of significantly opening up the range of munitions that Royal Navy vessels could field.
The Tomahawk cruise missile is another system that has been shown to be ripe for anti-ship adaption, hitting a moving target at sea in a recent US Navy demonstration. Although relatively slow, it boasts pin-point accuracy over a range of over 860 nautical miles, and seemingly the conversion of existing Tomahawk land attack missiles (TLAMs) for surface warfare purposes would be a low-cost and fairly straightforward process. For that long-distance punch alone, adapted TLAMs must be worthy of some serious consideration.
Looking further to the future, the Admiralty has already made it clear that directed energy weapons, electromagnetic rail-guns and hypersonic defensive missiles are high on the wish list, along with super-cavitating torpedoes capable of travelling at speeds of over 300 knots.
For the moment, the bristling array of high-tech weaponry envisaged aboard the likes of the Royal Navy’s Dreadnought 2050 (T2050) vision of its future warships remain rather more science fiction than science fact, but the boundaries on this kind of technology are undeniably being pushed back. Projects such as the £30m MoD funded Dragonfire demonstrator already underway could make laser weapons operationally mature by the mid-2020s and perhaps ultimately make anti-ship missiles themselves a thing of the past.