Arrow ATBM: Lethal Evolution
Israel faces the grim prospect of potential Tactical Ballistic Missile (TBM) strikes with Nuclear, Biological or Chemical (NBC) warheads not only from its adversary nations but also from ‘ sub- states’ ( read terrorist groups). To tackle such threats, the Israeli Defence Force (IDF) deploys combination of Ballistic Missile Defences (BMD) systems with IAI/Boeing Arrow 2 Anti-Tactical Ballistic Missiles (ATBM) developed by MLM Division of Israel Aerospace Industries (IAI) presently forming the centre piece of Israel’s layered system of strategic missile defence called Homa. The first battery at Palmachim airbase, near Tel Aviv became operational in 2000 followed by one at Ein Shemer airbase to the south of Haifa in 2002. They are deployed in such a manner that coverage of the systems overlaps vital military, commercial installations and concentrated civilian population. The system practically forming National Missile Defence ( NMD) in Israeli context, is stand alone yet integrated with national command & control, and has the capability to provide early warning for itself and of dealing with multiple threats. In Israel, Arrow 2 Block 4 and Arrow 3 function as the upper-tier of the multi-tier combined air defence/ATBM network. The middle tier comprises of United States-origin and Israeli Patriot PAC-2/PAC-3 and United States Navy ( USN) ship- borne AEGIS systems in addition to the IDF David’s Sling Weapon System (DSWS) providing the mid-tier and lower tiers, defending against tactical missiles, long range rockets, cruise missiles and attack aircraft. The low-level is protected by Rafael’s Iron Dome countering short-range rockets (C-RAM) and 155 mm artillery shells.
The refined and leaner ( 1,300- kg) Arrow 2, was first tested in 1995 being derived from the Chetz (Arrow) 1, a project initiated by the United States Strategic Defence Initiative (SDI) to be developed by IAI. The Arrow 2 is meant to intercept tactical ballistic missiles just as they begin re-entering atmosphere after reaching the highest point in their flight trajectory.
In February 2003, IAI signed an agreement with Boeing to establish the production infrastructure to manufacture components of the Arrow missile in the United States with Boeing responsible for the production and co- ordination of approximately 50% of the missile components in United States while IAI undertook integration and final assembly of the missile in Israel. Under the Arrow System Improvement Programme (ASIP), being carried out jointly by Israel and United States Ballistic Missile Defence Organisation (BMDO), a real (as against simulated) Scud-B Short-Range Ballistic Missile (SRBM) was successfully intercepted and destroyed at an altitude of 40-km at Point Mugu naval test range in California in July 2004. In December 2005, an Arrow 2 Block 3 missile successfully intercepted a target at an unspecified but reported record low altitude. In February 2007, the system
successfully intercepted and destroyed a Rafael Black Sparrow target missile, simulating a ballistic missile, at high altitude.
An Arrow battery is typically equipped with four or eight launch trailers, each with six launch tubes and ready-to-fire missiles, a truck-mounted Hazelnut Tree Launch Control Centre (LCC), a truck-mounted communications centre, a trailer mounted Elisra Citron Tree Fire Control Centre (FCC) and the units of a mobile Green Pine early warning radar system. There are microwave and radio data and voice communications (Link-16) between the LCC and the radar command & control centre with the launch system deployable up to 300 km from the site selected for the radar command & control centre offering unparalleled protection and flexibility to the Arrow Weapon System (AWS).
The two- stage Arrow 2 ATBM is equipped with solid propellant booster and sustainer rocket motors. The Arrow 2 is launched vertically, separately or in salvos, giving 360-degrees coverage to each battery. The Green Pine L-band, phased array, dualmode (detection and fire control) radar determines the intercept point and thereby up-linking very accurate data to the Arrow 2 guiding the intercepting missile to within 4 m of the target. The missile uses an initial burn to carry out a vertical hot launch from the container and a secondary burn to sustain the missile›s trajectory towards the target at a maximum speed of Mach 9, or 2.5 km per second. Thrust Vector Control (TVC) is used in the boost and sustained phases of flight. At the ignition of the second stage sustainer motor, the first stage assembly separates. The Kill Vehicle (KV) section of the missile, containing the warhead, fusing and the terminal ElectroOptical (EO) seeker is equipped with four aerodynamically controlled moving fins to give low altitude interception capability. The dual mode missile seeker has a passive infrared seeker ( Raytheon- developed indium antimonite focal plane array) for the acquisition and tracking of TBM and an active radar seeker used to home on air breathing targets at low altitudes. After the Arrow 2 is brought to the best engagement point on the TBM, its EO sensor acquires the target to allow very near pass and then activates the Rafael Advanced Defense System developed high explosive directed blast fragmentation warhead which is capable of destroying the target within a 50 m radius or sufficiently deflecting it beyond the confines of defended territory. The current Arrow 2 Block 4 version with improved target identification and discrimination capability remains an extremely lethal interceptor.
The ELTA Electronics subsidiary of IAI developed the EL/ M- 2080 Green Pine Early Warning & Fire Control (EW & FC) radar for the Arrow system. The Green Pine radar has a proven track record demonstrated in over twenty successful ballistic missile intercepts. The radar includes the trailer mounted antenna array, the power generator, a cooling system and a control centre. Developed from the ELTA Music phased array radar, Green Pine is an dual mode, electronically scanned, solid state, phased-array radar operating at L-band in the range 500 MHz to 1,000 MHz, weighs 60 tonnes and comprises of 2,000 transmit-receive modules. Green Pine is said to be capable of tracking ballistic missiles from a range of up to 500 km and is able to track targets up to speeds over 3 km/s while intercept of the attacking missile may occur 90 km away at an altitude of 10 to 50km. The long range of Green Pine radar system ensures that a second shot can be taken at the incoming ballistic missile if the first shot fails to secure the “kill”. The ballistic missiles are again intercepted at a much higher altitude (exo-atmospheric or endo- atmospheric) to prevent them from disintegrating as they approach lower altitude, thus faking multiple targets on radar screens. Israel also receives data from the United States Defence Space Programme (DSP) early warning satellites and Boeing RC-135S Cobra Ball intelligence aircraft capable of picking up rapid movement or a rocket launch flash.
Interestingly, India had placed an order and received its first Green Pine EW & FC radar in 2001 and has since been integrated with the country’s indigenous missile defence
system as the Swordfish radar system. The Super Green Pine also operated by India, has a tracking range of 800 to 900 km.
Tadiran Electronics Limited Golden Citron Tree Battle Management/ Fire Control Centre ( BM/ FCC) capable of conducting multiple, simultaneous ( up to 14) interceptions and includes ten battle stations. Launches are controlled by Hazelnut Tree launcher control centre. Citron Tree, which is trailer mounted, downloads the radar data along with data from other sources and uses powerful signal processing tools to manage the threat interceptions along with man-in-the-loop intervention capability at every stage.
Meanwhile, the United States and Israel have developed the upper-tier component (including an exo-atmospheric interceptor) to the Israeli Missile Defence architecture, commonly known as Arrow 3, based on an architecture definition study conducted in 2006-2007, determining the need for the upper-tier component to be integrated into Israel›s Ballistic Missile Defence system in addition to the Arrow 2 Block 4 ATBM, which was declared operational on 18 January 2017. The KV of two-stage Arrow 3 is propelled by rocket motor and equipped with flexible nozzles to offer exceptionally large divert capability, while the gimballed seeker obtains substantial hemispheric coverage to facilitate exo- atmospheric interception. By measuring the seeker’s line of sight relative to the vehicle’s motion, the KV would employ ‘proportional navigation’ deflecting the KV to divert its course and align exactly at target’s fight path, hence achieving an accurate Hit-to-Kill (HTK) even at very high closing speeds and over long distances. The Arrow 3 in addition is reported to be a formidable Anti-Satellite (ASAT) weapon.