There is an urgent requirement to deploy defences against theatre ballistic missiles (TBMs). The threat of theatre-range ballistic missiles is real and growing. More than 25 nations have, or are developing, nuclear, chemical and/or biological weapons and more than 20 nations have ballistic missiles capable of carrying them. In the near future, the US and its international allies will face missile strikes from terrorist and rogue regimes with ballistic missiles that may carry weapons of mass destruction. The 1988 Iran-Iraq war, the Gulf War and civil wars in Yemen have demonstrated the willingness of warring factions to use ballistic missiles to threaten military forces, strategic military installations and terrorise civilian population centres.
| Launch of a standard missile-2 BLK IVA |
While the majority of threat TBMs are of the short-range SCUD variety, several long-range missiles such as the CSS-2, Nodong, and Taepodong are in various stages of development and testing. Intelligence sources suggest that these long-range ballistic missiles may carry large payloads that could include nuclear, chemical and biological weapons as well as improved guidance capability for precise targeting and increased accuracy. The use of long-range ballistic missiles and improved guidance capability greatly increases the number of population centres that will be at risk to ballistic-missile attacks.
Today, the American TBM defence capability rests with the PATRIOT system and its evolving enhancements. PATRIOT has proven terminal defence capability against short-range TBMs that spend most of their time within the atmosphere. The army and the ballistic missile defense organization (BMDO) are developing a theater high-altitude, air-defense (THAAD) interceptor that will employ a powerful theater-missile defense ground-based radar (GBR) to improve area coverage. When combined with the PATRIOT advanced-capability (PAC-3) system, this land-based architecture will provide a two-tiered, layered-terminal defence capability. However, what is being done to prepare for future conflicts where there are no forward-deployed land-forces? And how can upper-tier coverage be expanded as the range of TBMs grows. The answer, navy theatre-missile defence.
Sea-based, theatre-missile defences provide tactical, strategic and financial leverage. Ship mobility allows quick reaction to changing threats and combat environments. Ships are self-sustaining and ready on arrival. In many theatres, forward positioning of sea-based assets will provide very large defended areas. Two Aegis ships placed in the middle of the Sea of Japan armed with standard missile LEAP interceptors could defend all of Japan from a North Korean ballistic-missile attack.
Sea-based, theatre-missile defence provides some unique political advantages. The insertion of naval TBMD is non-intrusive, and in most cases the intercepts would occur over international waters. Sea-based assets can be forward deployed on areas of potential conflict and represent a powerful peacetime message. Navy TBMD also may be required to insert forces into hostile regions. In the next conflict there may not be the luxury of a six-month build-up in a friendly nation.
Navy theatre-missile defence builds on existing ship assets that are deployed already or are in development. In the case of the US, the navy is building on a $40-billion investment in the AEGIS fleet. Navy TBMD will utilise existing AEGIS cruisers and destroyers, AEGIS weapon system, SPY radar, vertical launching system, and the standard missile-2. A standard-missile baseline capitalises on the navy's thirty-year investment that has continued to evolve with the threat. All the navy's depot facilities, trained personnel, support equipment, programme management and infrastructure would remain unchanged when employing a standard-missile baseline.
Other nations can take advantage of this major investment and some already have. Japan is procuring four AEGIS destroyers, the trilateral frigate programme is incorporating the standard missile-2, and Spain has signed on to purchase a frigate with a version of the AEGIS weapon system. Financial leverage also is provided by a common weapon platform. In addition to theatre-missile defence, AEGIS cruisers and destroyers will provide air defence, fleet self-defence, naval surface-fire support, long-range strike and submarine warfare.
The navy is utilising an evolutionary approach to theatre-missile defence. Along with the BMDO it has developed a synergistic two-tier defence based on the standard missile-2 BLK IV that has entered low-rate production. The standard missile-2 BLK IVA provides a lower-tier area defence against ballistic missiles in the atmosphere as well as against threat aircraft and cruise missiles. A side-mounted imaging infrared (IR) seeker provides the precise aimpoint accuracy required to intercept small, high-velocity ballistic missile warheads. The IR seeker also improves the missile's performance against aircraft and cruise missiles in the presence of electronic counter measures.
The SM-2 BLK IVA also has an improved, high- speed autopilot, an improved forward-looking fuse, and a highly lethal directional warhead. Although the SM-2 BLK IVA will get direct (skin-on-skin) hits in most cases, the warhead is being retained to ensure a kill in all scenarios, and maintain performance against manoeuvring aircraft and cruise missiles.
| Hughes Missile Systems Company's lethal exo-atmospheric projectile (LEAP) kinetic kill vehicle (KKV) |
The standard missile-LEAP (SM-LEAP) utilises the SM-2 BLK IV airframe, control fins, MK72 booster and MK104 sustainer motor. In place of the warhead and radar seeker, is a third- stage rocket motor (TSRM), a third-stage guidance unit, and a lethal exo-atmospheric projectile (LEAP) kinetic kill vehicle. The standard missile's first and second stages fly out on an intercept trajectory. After second-stage separation, the third stage ignites and propels the LEAP towards the predicted intercept point. All three stages provide the LEAP KKV with a velocity of over four kilometres per second. Prior to reaching the impact zone, the LEAP is ejected from the third stage and autonomously acquires and tracks the ballistic missile with its advanced long-wave imaging infrared seeker. Using a high-thrust, solid-propellant, divert-propulsion system the LEAP KKV manoeuvres itself directly into the path of the incoming warhead. This combination of accuracy, high velocity, and LEAP's 30-kilogramme mass translates into as much kinetic energy as a city bus travelling at over 600 miles per hour more than enough to destroy a ballistic missile's warhead.
The SM-LEAP interceptor provides an upper-tier, theatre-wide defence against ballistic missiles. SM-LEAP's high-velocity exo-atmospheric interceptor provides very large defended areas with multiple-shot opportunities and warheads often are destroyed prior to apogee, greatly reducing or eliminating chemical, biological or nuclear debris in the defended area. LEAP can operate down to an altitude of 70 kilometres, allowing it to intercept SCUD-class and longer-range theatre ballistic missiles. In fact SCUDs spend most of their flight time above 70 kilometres.
| Lethal exo-atmospheric projectile (LEAP) test launch conducted during the US Navy LEAP technical demonstration programme |
The two-tiered approach maximises the navy's potential firepower and minimises interceptor costs. Each interceptor is optimised for the region in which it operates. The SM-2 BLK IVA is designed to operate in the endo-atmospheric battle space, achieving high velocities and deep inland coverage while maintaining capability against low-apogee, short-to-medium range TBMs as well as AAW and Cruise missile defences. SM-LEAP takes full advantage of operating in the exo-atmosphere. Theatre-wide coverage can be achieved only by employing a very high velocity interceptor with a large aperture long-wave imaging infrared seeker for long acquisition ranges and increased interceptor margin.
| LEAP vehicle solid-propulsion hover test |
The navy's TBMD programme has been in place since 1992. The SM-2 BLK IVA has undergone a vast array of ground tests, including wind-tunnel tests sledge tests, and dome-ejection tests to verify the IR seeker operation in a harsh aerothermal environment, and the navy recently has completed its first successful flight test for the lower-tier programme. The environment tests round (ETR-1A) was launched successfully from White Sands missile range on August 2, 1966. All preliminary test data looks positive, including missile flyout, dome-cover eject and cooling gas flow.
The navy LEAP technology demonstration programme showed the feasibility of a sea-based upper-tier TBMD system. Although an intercept was not achieved, the programme achieved 42 of its 43 objectives and demonstrated all of the key components, including high-altitude flyout of a standard missile, first and second-stage separation, third-stage rocket motor burn, third-stage guidance to within 175m of the target, LEAP KKV ejection, and LEAP acquisition and tracking of a theatre-ballistic missile target at a range of over 130km. Exo-atmospheric intercepts have been demonstrated on previous programmes including the homing overlay experiment (HOE), the Delta 180 programme, and the exo-atmospheric re-entry-vehicle interceptor system (ERIS).
The navy is now moving forward with the SM-LEAP programme. The kill vehicle and third-stage technology demonstrated on the navy LEAP technical demonstration is being integrated with the SM-2 BLK IV missile, the MK41 VLS and the AEGIS weapon system. This programme is proceeding forward with rapid pace to deploy a user-operational evaluation system around the turn of the century.
The navy TBMD systems have become a high priority within the US government. The FY 1997 Congressional budget includes $311 million for the navy's area (lower-tier) TBMD programme, and $306 million for the navy's theatre-wide (upper-tier) TBMD programme.
Navy theatre-missile defence should be a critical element of US defensive capabilities. No other system can provide defence against TBMs during the initial stages of a crisis. The ability to make forcible entry must be maintained to defend critical ports and airfields early during force build up. As the ballistic missile threat continues to grow in range and accuracy, it will demand a sea-based, theatre- wide defensive capability to defend critical military targets and population centres. The US Navy has embarked upon an aggressive development programme to provide such a defence. Building on the AEGIS weapon system and the proven standard missile-2 BLK IV will yield a highly capable and cost-effective theatre-missile defence.
