On October 11, 1967, the Israeli destroyer Eilat was sunk by three P15 cruise missiles
fired by two dinky sixty-one-ton patrol boats of the Egyptian Navy firing from nearly twenty
miles away.
The realization dawned on navies across the world that long-range “over-the-horizon”
missiles had replaced the gun, torpedo and aerial bomb as the preeminent antiship weapon
in naval warfare.
German air-launched antiship missiles had already scored some notable successes during
World War II, but now it was clear that even small surface combatants could be capable
launch platforms.
A decade later, the U.S. Navy debuted the AGM-84 Harpoon missile, a subsonic sea-skimming
weapon with a 488-pound warhead that came in variants that could fire from a ship, a
submarine or an airplane.
The Harpoon still serves with dozens of countries on platforms including Type 209 submarines
of the Turkish Navy, modified Fokker 50 airliners of the Singaporean Air Force and early-model
Arleigh Burke–class destroyers of the U.S. Navy.
The land-attack SLAM-ER variant remains an important standoff weapon for Navy fighters.
The antiship Harpoon has also seen action in a number of naval skirmishes, sinking several
missile boats.
However, the Harpoon’s striking range of seventy to 150 miles (depending on type) has
fallen far behind competing antiship missiles.
Quite simply, after the end of the Cold War, Russian and Chinese surface-warfare capabilities
appeared modest, so the U.S. Navy became preoccupied with planning for littoral operations.
Even harpoon-launch capabilities were removed from Oliver Hazard Perry–class frigates
and U.S. attack submarines, and not built into later Arleigh Burke–class destroyers.
Navy surface warships did eventually gain the capability to use longer-range SM-6 missiles
against both air and sea targets, but these employ a small 140-pound warhead, less optimized
against large ships.
Meanwhile, Russia and China developed antiship missiles that outranged their U.S. equivalents,
many of them specially designed to overcome anti-missile defenses using supersonic speed
and evasive maneuvers.
Notable examples include the Russian ramjet-powered P-800 Oniks cruise missiles (capable of streaking
at naval targets up to 370 miles away while flying two-and-a-half times the speed of sound);
the Russian-Indian BrahMos, which weighs six thousand pounds and performs an S-shaped evasive
maneuver before impact; and the Chinese YJ-18, derived from the Kalibr cruise missile, which
accelerates to Mach 3 on its terminal approach.
Enter the LRASM
The Navy has finally pushed into production a next generation surface-to-surface missile
under its “Offensive Anti-Surface Weapon” program—by adapting a weapon already in
use with the Air Force.
The AGM-158 Joint Air-to-Surface Standoff Missile is a stealthy and highly precise surface-skimming
cruise missile with a range of 230 miles, or 620 for the Extended Range AGM-158B.
The shorter-range AGM-158A model saw its combat debut on April 4, 2018, when two B-1B bombers
launched nineteen of the stealth missiles at a Syrian research center in Barzeh.
Lockheed Martin went ahead and developed the antiship AGM-158C model, designated rather
plainly by the Navy as the “Long Range Anti-Ship Missile.”
Rather than a Russian-style supersonic missile that’s too fast for a ship’s defenses
to intercept, the LRASM is the missile an enemy vessel simply won’t see coming until
too late.
The missile retains the basic model’s inertial and jam-resistant GPS navigation system, its
high-efficiency F107 turbofan engine and its thousand-pound penetrator/fragmentation warhead—more
than twice the weight of the Harpoon’s.
However, unlike the ground targets the JASSM was designed to destroy, ships are mobile.
Therefore, the LRASM carries multiple sensors allowing it to autonomously search for and
identify adversary warships, while sorting out civilian, friendly or low-priority enemy
vessels, by matching their radar profile to data in an onboard database.
The missile also transmits data, including day/night camera feed, back to its launch
platform via a two-way data link, which allows the launcher in turn to feed it during course
corrections.
An LRASM is first fired using targeting data from the firing platform towards its target,
which it approaches at medium altitude.
However, if the data link is disrupted the missile’s guidance algorithm allows it to
acquire and home in on a target without external direction, or to maneuver around neutral or
hostile ships that interpose themselves in its path.
Guidance of the missile is handed over to a radio-frequency sensor (or Electronic Support
Measure) as soon as an appropriate target enters range.
Rather than exposing itself by using its own radar to search for a target, the missile
stealthily homes in on an enemy adversary’s radar signals—the very radar intended to
warn the target of a missile attack.
In the terminal stage, the missile descends to skim low over the ocean’s surface, and
the RFS seekers hands over guidance to an infrared sensor which has sufficient fidelity
to target specific locations of an enemy vessel to maximize damage.
If multiple LRASMs are inbound on the same target, their networked software allows them
to time their terminal approach for a simultaneous swarming attack, helping them oversaturate
enemy defensive fire.
The LRASM also dispose of electronic counter-countermeasures (ECCM) to overcome enemy defense systems.
All these systems do add a few hundred pounds to the missile, leaving it with a decreased
range of at least 230 miles, though some sources suggest it may actually reach up to 350 miles.
The AGM-158C is entering service in 2018 with the Air Force’s B-1B bombers.
The Navy’s carrier-based FA-18E or F Super Hornet jets will follow in 2019, and a few
years later it will enter service with cruisers and destroyers equipped with the ubiquitous
Mark 41 Vertical Launch System, which can pack a wide variety of munitions in its launch
“cells.”
The surface-to-surface LR-ASM variants would be fitted with Mark 114 rocket boosters which
hare jettisoned after launch.
For smaller frigate-sized vessels that don’t use the Mark 41 VLS (in U.S. service, Littoral
Combat Ships or some future FFG(X) design), Lockheed Martin is developing a deck-mounted
canister-launched version—though the U.S. Navy has chosen the cheaper, shorter-range
Norwegian Naval Strike Missile to fulfill this role for now.
LRASM and Naval Strategy
All in all, the LR-ASM could significantly improve the striking power and reach of U.S.
surface warships, and fits well with a new doctrine of “Distributed Firepower,” which
emphasizes networking sensor data and spreading firepower over multiple launch platforms.
Furthermore, the missile’s redundant guidance systems would remain effective even in a heavy
electronic-warfare environment against a tech-savvy opponent.
There are a few caveats to consider, however.
Long-range missiles can only be used to their fullest potential when combined with equally
long-range sensors feeding targeting data to the launch platform—not something that
can be taken for granted.
Fortunately, between drones and aircraft capable of networking their sensor data, such as the
F-35C stealth fighter and new Cooperative Engagement technology under development, the
U.S. Navy has prospects for executing such a strategy.
A second consideration is that while the stealthy LRASM may evade radar direction and delay
response of antiaircraft defenses until too late, its subsonic speed may leave it a comparatively
easy target for shorter-range close-defense autocannons and heat-seeking missiles—though
the LRASM supposedly has a reduced infrared signature.
A final issue is price: the LRASM appear to cost roughly $3 million per missile, making
it a premium asset at over twice the cost of newer-model Harpoon missiles.
This could limit the number fielded.
Currently, the Navy seeks to acquire 467 LRASMs, though in the near term only twenty-three
are on order.
Down the line, Lockheed Martin has explored creating a submarine-launched version of the
LRASM, though that would require substantial modifications to enable underwater firing.
Another concept is a supersonic, ramjet-powered LRASM-B similar along the lines of the BrahMos
missile, which could prove difficult for short-range defenses to intercept.
Like the Air Force, the Navy might also be interested in a longer-range variant of the
LR-ASM, perhaps by lengthening the fuselage so it can carry extra fuel, or by lightening
the warhead.
Longer striking range would make it the LRASM practical as a land-attack weapon, though
one that comes at a steeper price than the Tomahawk.
Currently, however, efforts are focused on bringing into service the air-launched AGM-158C,
which has been successfully test-fired from B-1 bombers six times—most recently on March
20.
The first full test launch from a Super Hornet is scheduled for later this year.
A 2017 annual report from the Department of Testing & Evaluation is relatively satisfactory,
though it does register concerns over cybersecurity and notes that there are difficulties modeling
performance of the LRASM’s RFS sensor.
Large-scale naval warfare has been relatively rare since the end of World War II.
Hopefully that won’t change in the twenty-first century.
However, as China rapidly enlarges its navy with cost-efficient, hard-hitting and far-reaching
warships, the U.S. Navy will be compelled to upgrade its neglected surface-warfare capabilities
to defend its primacy.