| The pace of ballistic missile development and proliferation among third world countries has continued to increase over the past five years. In 1998 North Korea provided a wake up call to the world with their flight testing of the Taepo Dong missile over the islands of Japan. China continues to rattle its ballistic missile sabre at Taiwan over re-unification. China has completed one missile base at Yongan, and is in the process of completing another at Xianyou, well within range of Taiwan. The Pentagon estimates that each base will have an arsenal of 97 advanced missiles known as the CSS-7 Mod 2. This is a mobile missile with a range of about 300 miles. Likewise Iran continues to modernise its ballistic missile inventory and Iraq refuses to allow UN inspectors access to suspected weapon locations. In short, the world is still a dangerous place.
The solution
The United States has embarked upon an aggressive theatre ballistic missile defence programme led by the Ballistic Missile Defence Organisation. The US is pursuing several major defence acquisition programmes in both the navy and the army. This isn’t a fractured approach, but rather a complementary approach to bring the best that each service has to offer. In addition, the TBMD mission has been divided into lower and upper tier segments. Just as we have a multitude of weapons designed to destroy tanks, we will require more than one weapon to destroy ballistic missiles. It would be foolish to assume that one silver bullet will perform all the functions required. This would lead to a Majinow line of defence that could be out-manoeuvred by our enemies. Therefore the clear solution is a multi-layered defence in-depth.
Each service has its own unique capabilities and requirements that will drive the weapon system of choice. The army requires highly mobile weapon systems that can be transported easily by existing military aircraft. Size and weight were a major limitation in making the THAAD system C-130 transportable. This capability will allow the army to operate well inland in support of mobile forces.
The navy on the other hand is inherently mobile. US Navy ships are deployed around the world and can be re-positioned as tensions arise. The size and weight of the interceptor is limited only by the vertical launching system on board the Navy’s AEGIS cruisers and destroyers – well over 3,000 pounds. The navy operates only from the sea, however over 90 per cent of the world’s population lives within 100 miles of a coastline. This puts most areas of interest well within the navy’s reach. The navy may in fact provide the only available TBM defence in certain situations that preclude the operation of land forces.
The navy chose to attack the TBMD problem by leveraging its existing investment in the AEGIS cruisers and destroyers deployed around the world today, and the AEGIS weapon system, the vertical launching system, and standard missile. By leveraging these existing systems, the navy will be able to achieve a TBMD capability at a significantly reduced cost. There is also a significant operational saving because each AEGIS ship will be performing multiple functions in addition to its TBM defence role.
The navy is developing two interceptors to meet the two-tiered defensive strategy, and each is based on the Standard Missile-2 Block IV. This is the latest standard missile to enter production and operational service, it recently completed several production qualification flights at White Sands Missile Range and several production rounds have been successfully fired at sea.
Primary modifications
The interceptor for the Navy Area (lower tier) mission is the SM-2 Block IVA. This missile is a modification of the SM-2 Block IV. The primary modifications involve the addition of a side-mounted imaging infrared seeker and a forward- looking RF fuse. The IR seeker provides extremely accurate target position allowing the interceptor to home in on the warhead, the most lethal part of a ballistic missile. The forward-looking fuse is required to perform fusing of the warhead for the extremely fast closing velocities encountered. In addition to its TBMD mission, the SM-2 Block IVA will retain all of the anti-aircraft and Cruise missile defence capabilities of its predecessor. The SM-2 Block IVA operates in the Earth’s atmosphere as a lower tier to the theatre-wide systems. It also provides a stand-alone capability to defend coastal airfields, ports of debarkation, amphibious operations and forces further inland.
The interceptor for the Navy Theatre Wide (Upper Tier) mission is the standard missile-3 (SM-3). This retains the SM-2 Block IV airframe, rocket motor, booster, and steering control section. However, the upper portion of the missile is replaced with a third stage rocket motor (TSRM), a new GPS-based guidance section, and a kinetic warhead. The SM-3 is designed solely for TBM defence and operates above the Earth’s atmosphere to intercept medium and long-range tactical ballistic missiles.
Navy area TBMD programme status
Prior to beginning engineering and manufacturing development the navy was required to complete a series of flight tests as part of a risk reduction flight demonstration (RRFD). The RRFD programme culminated in a successful intercept of a ballistic missile target on 17 January 1997. An SM-2 Block IV modified with a side-mounted imaging infrared seeker intercepted a Lance target at White Sands Missile Range. Although standard missile retained its warhead the intercept resulted in a direct skin-on-skin hit. Following this test, the programme entered EMD and the SM-2 Block IVA design was matured to meet the out year threat.
Although the SM-2 Block IVA will achieve a direct hit in many cases, the missile has retained the MK125 warhead. This is necessitated by the highly manoeuvrable targets. As TBMs enter the atmosphere, they slow down dramatically, often exhibiting large G manoeuvres, and may break-up. This presents a very difficult target for lower tier intercepts. Thus the warhead is retained to ensure a lethal kill in the event of a near miss. The navy implemented an intensive test programme to validate the lethality of the MK 125 warhead. Several static warhead tests were performed at Dahlgren VA to validate the performance of the warhead. This was further validated with dynamic sled testing of the warhead at Holloman AFB. In each case a variety of different target types were arrayed around the warhead detonation point to measure lethal effects.
Navy theatre-wide TBMD program status
The navy completed a series of flight tests as part of the Navy LEAP technology demonstration programme back in 1995. Although an intercept was not achieved, the navy was successful in demonstrating all of the key elements, including the high-altitude flight of the standard missile, 3rd stage separation, 3rd stage rocket motor, 3rd stage guidance in space, nose cone separation, KW separation, KW divert and attitude control system, and KW IR seeker target acquisition and tracking. On one test, the 3rd stage delivered the LEAP kinetic warhead within 170 metres of the target. On a second test, the kinetic warhead was able to acquire and track the target at a range of over 130 kilometres. The results of this testing was enough to convince the navy and congress to move on with the NTW programme.
The focus of the next phase of the program has been to integrate the LEAP kinetic warhead and 3rd stage technologies into the SM-2 Block IV airframe and integrate them with the AEGIS weapon system. This phase of the programme is called the AEGIS LEAP intercept (ALI). The navy conducted the first flight test (CTV-1A) in September 1999. The SM-3 FTR-0 round was fired from USS Shiloh (CG 67) off the coast of Barking Sands, Kauai. The MK 72 first stage separated after burnout, and the MK 104 second stage successfully ignited, propelling the missile into the upper atmosphere. The inert 3rd stage separated shortly after the 2nd stage burned out. All the events occurred as planned and the test was termed a total success. |
