An Overview of OASuW and the LRASM


A Long-Range Anti-Ship Missile (LRASM) on a pallet. The aircraft in the background is an F/A-18E Super Hornet.

In light of recent tensions with Russia and China, the US military is looking to improve its high-end combat capabilities. Long focused on fighting two wars in the Middle East against terrorist groups, the US military now finds its near-peer competitors able to challenge its supremacy. Whether it’s AIP submarines, cruise missile proliferation, or the potential deployment of anti-ship ballistic missiles such as the DF-21, there are many domains in which the US Navy finds its preeminence challenged.

Offensive Anti-Surface Warfare (OASuW)

As time passes, the US Navy increasingly lags in the anti-ship cruise missile (ASCM) department. ASCMs are the primary weapon used by navies worldwide to engage surface combatants. Surface warships use ASCMs to strike from long range, while the employment of strike aircraft with ASCMs allows for even further reach. Some submarines also use ASCMs, which have a much longer range than torpedoes but tend to inflict less damage.

Countries such as Russia and China already field ASCMs which travel at supersonic speeds over hundreds of miles, and have been incrementally improving such weapons for decades. The US Navy, on the other hand, has essentially decided to ignore the development of anti-ship missiles in recent years, offloading the anti-shipping role to its nuclear attack submarines (SSNs). The US still fields the dated Harpoon ASCM — even the most advanced Harpoon variants have a lackluster range of around 130 nmi, compared to hundreds of nmi for many Russian and Chinese ASCMs. The abandonment of US ASCM development was acceptable when the Russian fleet was rusting away and the Chinese PLAN was still an assortment of largely-obsolete vessels. That time, however, has come to pass, and the US Navy finds itself with the startling realization that its adversaries have a substantial edge when it comes to ASCMs.

Increment I: LRASM

In fact, the US ASCM deficiency is so acute that naval leadership decided to skirt the normal procurement process and attempt to rapidly field a stopgap solution. LRASM, or Long-Range Anti-Ship Missile, was chosen for integration with the F/A-18E/F and B-1B to fill the gap. LRASM is a subsonic cruise missile which relies on stealth and long range to defeat enemy surface vessels. The airframe is a based on the stealthy, air-launched Joint Air-to-Surface Standoff Weapon-Extended Range (JASSM-ER). With a range of around 500 nmi and a 1000 lb penetrator, LRASM is a massive improvement over the newest Harpoon variants, which have a range of about 130 nmi and a warhead of only 488 lbs. In addition, the LRASM boasts advanced guidance capabilities including Electronic Counter-Measures (ECM)-resistant GPS, datalink capabilities, and a multi-modal sensor suite. While exact details are not available, LRASM will feature some sort of autonomous targeting capabilities, which allow the missile to be fired without a lock and acquire targets of opportunity once aloft. This autonomous functionality should allow the LRASM to be employed even when datalinks and satellites are being actively jammed or destroyed, a growing US Navy concern. The subsonic velocity of LRASM allows targets more time to detect and intercept compared to a supersonic missile, but subsonic sea-skimming missiles like LRASM are notoriously tricky to distinguish from sea clutter. Combined with LRASM’s emphasis on ECM hardening as well as signature reduction, LRASM should be a difficult missile to intercept.

LRASM is slated for deployment starting in FY17 on the F/A-18E/F and B-1B, which will give carrier strike groups and land-based strike elements a significant ASuW boost. LRASM is quite impressive on paper, and its utilization of the JASSM-ER’s relatively mature technologies is a plus. Thus, initial indicators are positive for the program.

A B-1B strike aircraft deploys a LRASM during testing.

A B-1B strike aircraft deploys an LRASM during testing.

Increment II

As stated, the rapid procurement of LRASM is designed to fill a short-term capability gap. A long-term ASCM solution will be chosen during OASuW Increment II, a competition for the next-generation anti-surface missile. OASuW Increment II will pit LRASM against competitors, likely a modified Tomahawk Land Attack Missile (TLAM), an upgraded version of the Harpoon, and Kongsberg’s Naval Strike Missile (NSM). A modified TLAM would have exceptional range but lower survivability than the stealthy LRASM. TLAM is not a new or innovative weapon, but it is highly mature and tests have been conducted to evaluate its use as an anti-shipping weapon. NSM and Harpoon are inferior to the LRASM in the range department but are at a high level of technological maturity.

The OASuW Increment II missile will need to be compatible with the Mk 41 VLS cells used on US Navy surface combatants, and deployment of the system on submarines is a possibility.

The successful development of OASuW is critical to the US Navy’s power projection abilities going forward. As discussed previously, the US military as a whole has fallen behind in ASCM development. While Navy nuclear attack submarines currently fill this gap in the anti-shipping role, their numbers are limited and submarines have inherent limitations as well.

As of now, the SSN fleet relies on heavyweight torpedoes. While highly lethal, they require the sub to be in close proximity to its target. On the other hand, a sub, ship, and air-deployed OASuW can be employed from hundreds of miles away, a relatively safe distance. Considering the shock involved with losing a large combatant, it is highly preferable that the US Navy be able to strike from beyond the range of IADS systems such as the S-400 and ASCMs such as the YJ-12. As such, the successful execution of the OASuW program is critical to preserving the US Navy’s influence and combat capability, especially in increasingly-contested regions where advances in anti-access/area denial technologies may limit the ability of the US Navy to maneuver.

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