The U.S. Air Force and U.S. Navy have, for a number of years now, been developing the “Air-Sea Battle” (ASB) Concept. ASBC is designed to counter the proliferation of Anti-Access/Area Denial (A2/AD) systems and tactics being developed and deployed by nations like the People’s Republic of China (PRC), Russia, and Iran. These include everything from ballistic anti-shipping missiles (the PRC’s DF-21D), Cyber attacks, and Electronic Attack (EA) to disable enemy electronics.
One of the key concepts of ASB is the ability to conduct long-range, standoff maritime strikes with precision weapons able to pick out targets autonomously in crowded sea lanes and coastal areas. However, the U.S. presently lacks such weapons, having retired all but a small inventory of elderly and obsolete R/A/UGM-84 Harpoon anti-ship missiles. Once the finest such weapon in the world, Harpoon has been in fleet service since 1977, and is now outclassed by weapons like the Russian SS-N-26/P-800 3M55 Oniks (Onyx). Clearly, for the roles and missions envisioned in ASB, a new and much more capable system will be needed.
The test missile then detected all three MSTs via their R/F emitters, properly identified the desired target, and autonomously initiated an attack. The missile then locked onto the desired MST with its IIR seeker, and flew directly into the moving target within several feet of the programmed impact point, just under the simulated bridge.
To meet this challenge, in 2009 the Tactical Technology Office of the Defense Advanced Research Projects Agency (DARPA), along with the Office of Naval Research, Air Force, and Navy, have initiated the Long Range Anti-Ship Missile (LRASM) program. Designed to produce advanced maritime strike weapons suitable for ASB applications, LRASM was originally intended to culminate in a pair of missile designs. LRASM-A had the goal of producing an interim anti-ship missile utilizing an existing missile design the Lockheed-Martin AGM-158B Joint Standoff Strike Missile –Extended Range (JASSM-ER), with new navigation and guidance systems. LRASM-B would have created an entirely new design, capable of very long ranges and hypersonic speeds. Costs and technology risks resulted in the cancellation of LRASM-B, but the LRASM-A design/development effort has proceeded quite well, and is now in the testing phase.
Based upon the existing JASSM-ER, LRASM incorporates a new guidance and navigation system that emphasizes autonomous flight and search functions, along with an improved radar altimeter and a real-time datalink. What LRASM keeps from JASSM-ER is its stealthy shape, 1,000-pound (450 kg) WDU-42/B blast-fragmentation warhead, and a 620-mile (1,000-km) range. This gives LRASM a greater ability to penetrate enemy defenses, twice the warhead power, and nearly 10 times the range of the original Harpoon missile when it was fielded back in 1977. LRASM’s capabilities also vastly exceed those of the larger R/UGM-109B Tomahawk Anti-Ship Missile (TASM), which was withdrawn from service in the 1990s.
The key to LRASM’s capability is a new BAE Systems seeker/guidance system, which integrates jam-resistant GPS/INS and datalink data with an imaging infrared (IIR) seeker equipped with automatic scene/target matching recognition, along with passive Electronic Support Measure (ESM) sensors. Tied together by a state-of-the-art software package, this gives LRASM operators the ability to fire a missile into a potentially crowded area of ocean, including those containing neutral shipping, and reliably hit specific types of enemy shipping, potentially down to individual hull numbers.
This is a vast improvement over Harpoon and TASM, with their earlier radar-only seeker heads, programmed with what might be best described as a “Kill Fido” targeting logic. More than once during the Cold War, anti-ship missiles missed or were decoyed from their planned targets, and continued on to hit other vessels. LRASM attempts to overcome that problem through use of an advanced multi-sensor seeker, which fuses information from onboard sensors along with datalinked targeting updates and other information as required. The IIR terminal guidance seeker ensures that not only the correct target is attacked, but also where on the target vessel it hits. As an added bonus, LRASM can also be used in a land-attack mode, much like JASSM–ER.
The LRASM Development/Test (D/T) program has gone surprisingly well, with a total of five all up round (AUR) missile firings planned. The first D/T launch on Aug. 27, 2013, was conducted on Sea Range, Point Mugu, off the coast of California. Launched by a USAF B-1B Lancer bomber from the 337th Test and Evaluation Squadron at Dyess Air Force Base, Texas, the test LRASM was fired into a test area with three moving 260-foot Mobile Sea Targets (MSTs), with cargo containers stacked to visually simulate escort vessels and equipped with representative threat radio frequency (R/F) emitters. For the first half of the test flight, escorted by an F/A-18 from VX-31 at NAS China Lake as escort, the missile flew a point-to-point, pre-programmed course guided by its onboard GPS/INS system. The test missile then detected all three MSTs via their R/F emitters, properly identified the desired target, and autonomously initiated an attack. The missile then locked onto the desired MST with its IIR seeker, and flew directly into the moving target within several feet of the programmed impact point, just under the simulated bridge.
“We have taken a basic waypoint-following cruise missile and added brains to it,” said Dr. Arthur “Artie” Mabbett, the DARPA LRASM program manager. “It can autonomously detect, track and engage targets of interest without depending on lots of a priori knowledge, and with reduced dependence on ISR assets. The purpose of the test was to stress the sensor suite. It detected all the targets and only engaged to one we had told it to. This fully functional test is a significant step in providing the U.S. Navy and U.S. Air Force with a next-generation anti-ship missile capability. This test is the culmination of the five-year development and integration of advanced sensors in an AUR missile. It also represents the first time we’ve integrated advanced sensors and demonstrated the entire system, resulting in performance that substantially exceeds our current capabilities.”
Three weeks later, on Sept. 17 at the White Sands Missile Test Range in New Mexico, a LRASM test missile was successfully launched from a land-based Mk. 41 Vertical Launch System (VLS), similar to those used aboard U.S. Navy guided-missile cruisers and destroyers. Using a Mk. 114 booster rocket, the test was part of a Lockheed-Martin-funded effort to prove the LRASM’s compatibility with the Mk. 41 launcher and suitability for launch for surface ships. Current plans are for a pair of LRASM AUR test launches from surface ships in mid-2014.
“Two more flight tests are planned this year, involving different altitudes, ranges and geometries in the target area,” said Mabbett. “We will push the envelope, with more stressing tests, to get a good assessment of the maturity of the technology. We are working very closely with the Navy so they can assess LRASM’s capability along with other systems out there.”
Once the DARPA flight test program is completed, LRASM will be a likely candidate for the Navy’s Offensive Anti-Surface Warfare program (OASW). OASW is presently ramping up, and budgets allowing, is expected to become the program of record to replace the Harpoon as the Navy’s primary anti-ship missile.