Ballistic missile defense is characterized by three pillars; offensive operations, passive defense and active defense all supported by command, control, communications, computers and intelligence (C4I). Individually, each has its own advantages, challenges and measured success in application. However, it is not until they are fully integrated with air and cruise missile defense that the full benefit of BMD is realized.
Offensive Operations. Actions undertaken to strike at ballistic missiles before they are launched -disabling or destroying their supporting production and launch infrastructure via offensive counterair (OCA)1 has been a traditional methodology to deal with this threat. The reality, however, is marked by disproportionate expenditure of attack assets for benefits realized. From Operation CROSSBOW in the latter stages of WWII to SCUD hunting during Desert Storm, significant portions of airpower has been diverted towards the effort to pre-empt ballistic missile use, all with desultory results. From Aug 1943 through May 1945, a significant portion of the British and US strategic bombing force was diverted from Operation POINTBLANK2 to the aerial campaign against the V-1 and V-2. Between December 1943 and June 1944 alone, more than 25,000 sorties were flown and 36,000 tons of bombs dropped in support of CROSSBOW – and this was before the first V-2 attack in Sept 1944. During that phase of the operation the USAAF (Eighth and Ninth Air Forces) lost 610 airmen, forty-nine heavy- and 30 medium bombers and other USAAF and RAF units lost 161 airmen and seventy-five aircraft of mixed type,3 none of which prevented the V-2 campaign which began with the strikes on Paris and London in Sept 1944.
Similarly, during Desert Storm, one third of the over 2,000 daily air sorties were diverted to SCUD hunting beginning 18 Jan 1992. As part of that effort, a dedicated A-10 was kept in each box for twenty-four hour coverage and a high-value asset, an E-8 J-Stars, was diverted from supporting Allied armor forces on the opening day of the ground offensive at Al Khafji, to instead to fly west to locate SCUD launchers targeting Israel. Additionally, Special Forces were inserted into Iraq to search for mobile launchers. Despite the extraordinary level of effort, only a handful of fixed sites were destroyed – no mobile launchers or missiles4.
In addition to kinetic offensive operations, the role of electronic attack in BMD is one that is experiencing greater investigation, in concert with similar efforts in ACMD. Electronic attack, whether it is via localized EMP, traditional jamming or computer network attacks (CNA) of supporting targeting and C4I infrastructure is gaining increasing prominence especially where mobile systems are concerned or traditional offensive action is either unavailable or deemed too escalatory.
Passive Defenses. Passive defenses include measures taken to reduce the probability of and to minimize the effects of damage caused by hostile action without the intention of taking the initiative. These measures include camouflage, concealment, deception, dispersion, reconstitution, redundancy, detection and warning systems, and the use of protective construction.5 Examples abound of passive defense, whether it is deeply buried and hardened command and control facilities, mobile launchers or the traditional strategic triad of manned bombers teamed with land- and sea-based ballistic missiles. More recently, the use of the Defense Satellite Program 6 constellation of early warning satellites for theater-ballistic missile warning and defense for Desert Storm and operations in Iraq and Afghanistan is another example. Finally, in this current age, counter-proliferation efforts and cyberspace protection and exploitation may also be construed to be included in passive defenses.
Active Defenses. When offensive operations and passive defenses fail to thwart ballistic missile attack, a third option, active defense, is now available. In the past, solution of the ballistic missile defense problem using active defenses has been an exceedingly complex and technologically challenging endeavor. To a large degree it is because most efforts have concentrated on the final phase of ballistic flight – the terminal phase , because kinetic solutions were usually upgrades of existing anti-aircraft or cruise missile systems. In the terminal phase, decoys and debris are stripped away by the atmosphere and the warhead is clearly visible to a range of sensors, simplifying the identification portion of the targeting solution. Complicating matters though are the very short period of time between initial reentry and impact or detonation (especially for high-altitude nuclear bursts) and cross range track angle and transient speeds which demand electronic vice mechanical steering of tracking and fire control sensors.
The boost phase of flight is the period of greatest vulnerability for a ballistic missile as it is still accelerating providing the best means for identification and localizing by orbital early warning assets. Additionally, because of airframe loading while in the atmosphere, any damage to the missile body is likely to cause subsequent catastrophic failure of the airframe and breakup. Unlike intercept in the terminal phase, intercept in the boost phase also ensures that any WMD material lands on the country of origin vice friendly territory negating the requirement for consequence management. Like the terminal phase7, the boost phase is short in duration are typically unannounced and launch areas tend to be deep in denied territory, significantly complicating the intercept problem technically as well as operationally.
The mid-course phase provides a number of opportunities and challenges for active defense. At once it provides the longest time for decision-makers and intercept, but it also presents some of the greatest obstacles to overcome. Among these obstacles are identification and discrimination of the warhead(s) within the target complex8 by tracking sensors and interceptors. Most sensors for the mid-course phase will be high-powered, ground-based radar whose characteristics permit the distinguishing of targets from clutter. Interceptors, on the other hand, will tend to rely on terminal IR seekers as they distinguish targets, updated by ground-based sensors, from clutter against the cold-backdrop of space. Given this challenge of developing a networked system of sensors and interceptors for this phase of flight it quickly becomes apparent why so few nations have undertaken this level of effort. Nevertheless, challenging as it may be there have been a number of attempts – some successful, others not so.
Today, there is a nascent global ballistic missile defense architecture being put into place by the US along with an underlayment of regional systems, land- and sea-based, being deployed by the US with a number of partners in joint endeavors. Up next: The Global BMDS and Regional Systems.
1 Joint Publication 3-01, Countering Air and Missile Threats (1 Feb 2007) defines “Offensive Counterair” as “Offensive operations to destroy, disrupt or neutralize enemy aircraft missiles, launch platforms, and their supporting structures and systems before and after launch, but as close to their source as possible. Offensive counterair operations range throughout enemy territory and are generally conducted at the initiative of friendly forces. These operations include attack operations, suppression of enemy air defenses, fighter escort, and fighter sweep. Also called OCA.” (p. GL-13)
2 POINTBLANK was the strategic bombing campaign directed at the German industrial heartland as agreed to at the Casablanca Conference in 1943.
3Adam L. Gruen, Preemptive Defense: Allied Airpower Versus Hitler’s V-Weapons, 1943-1945. Air Force History and Museums Program, 1998, p. 26.
4 Christopher Andrew, For the President’s Eyes Only, Harper Collins, 1996, p. 524.
5 Joint Publication 1-02, p.411 and Joint Publication 3-01, p. GL-14.
6 Existing Defense Support Program (DSP) satellites, now orbiting the earth in a geosynchronous orbit, provide global coverage for early warning, tracking and identification. Besides warning of a ballistic missile launch, satellite sensors can develop an early estimate of where the hostile missile is headed. Integration of DSP into the initial missile defense capability provides first, accurate warning and early tracking of a ballistic missile launch. Via Missile Defense Agency Link http://www.mda.mil/mdalink/html/sensors.html
7 Ballistic flight involving exoatmospheric flight consists of three distinct phases: boost, mid-course and terminal. The boost phase is the part of a missile flight path from launch until it stops accelerating under its own power. Typically the boost phase ends at altitudes of 300 miles or less, and within the first 3 to 5 minutes of flight. During this phase, the rocket is climbing against the Earth’s gravity. The midcourse phase is the point where the missile has stopped thrusting so it follows a more predictable glide path and could last up to 20 minutes for ICBMs. The terminal phase occurs when a missile (or its warhead) falls back into the atmosphere. This phase is typically the shortest and most challenging for intercepts, generally lasting from 30 seconds to one minute.
8 A target complex consists of the warhead(s), deployed countermeasures, upper stages and associated debris.