Previous Experiences with Ballistic Missile Attacks and Defenses
George N. Lewis In considering the threats posed by ballistic missile proliferation and possible responses, it is useful to begin by reviewing previous ballistic (and cruise) missile attacks. Here I will focus on the best documented cases: the German attacks on Britain and the Iraqi attacks on Israel.
The German V-1 and V-2 attacks on Britain
From June 1944 until March 1945, Germany fired about 1400 V-2 ballistic missiles and nearly 10,000 V-1 cruise missiles at Britain. An additional 2000 V-2s and 12,000 V-1s were fired at targets in continental Europe, primarily the port of Antwerp.
The V-2 was a ballistic missile with a range of about 275 km and a warhead containing about 750 kg of high explosive; these characteristics are very similar to those of the Scud-B that is widely deployed today. The V-1 was a cruise missile--essentially a small, pilotless airplane--with a range of about 230 km. It was launched either from a fixed catapult or from an airplane, carried an 850 kg warhead, and flew at speeds of about 550-650 km/hour at a typical altitude of 600-1000 meters.
Both missiles were so inaccurate that they were only suitable for attacking large urban targets, and London was the primary target. The two missiles did roughly equal damage per missile to structures. On average, each missile reaching London destroyed 10 houses and seriously damaged another 60.
Of the 1400 V-2 ballistic missiles fired at Britain, 1055 actually reached it. 518 landed in London, killing 2510 civilians (all V-1 and V-2 casualties cited here are for civilians only; if military personnel were included, the figure would be roughly 5-10% higher). 537 V-2s landed elsewhere in Britain, killing another 240 people. Of the nearly 10,000 V-1 cruise missiles fired at Britain, about 2420 hit London, killing 5370 people, and another 3200 hit elsewhere in Britain (many of these were shot down), killing another 470. Taken together, the V-1s and V-2s accounted for about 15% of all deaths due to bombing in Britain during World War II.
On average, each V-2 reaching London killed about 4.8 people while each V-1 killed about 2.2. The lower casualty rate for the V-1s was primarily due to the warning for the V-1 attacks--V-1s could be detected by radar and approaching V-1s could be heard, and often seen, from the ground. In contrast, there was no warning of V-2 attacks, since the supersonic V-2s could not be heard prior to impact. Although some V-2s were detected by radar, this detection capability was not sufficiently timely, reliable and accurate to warn to the public.
There were no effective defensive measures against the V-2, aside from the partial evacuation of London. It was not feasible to shoot them down in flight. On the other hand, using a combination of fighters, anti-aircraft guns, and barrage balloons, the British were able to destroy a significant fraction of the V-1 cruise missiles in flight. The shoot-down rate varied from about 30% early in the attacks to better than 70% towards the end of the attacks.
Britain, together with the U.S., devoted substantial resources to V-1 and V-2 defense, with relatively little success. During the 13-month peak of this effort, 14% of the bomber sorties and 17% of the tactical air forces missions from Britain were devoted to countering the V-weapons.
Well before the missile attacks began, the allies launched air attacks on the missile production, storage, and launch facilities. The V-2 development center at Peenemunde was bombed in August 1943 (and several times subsequently), but the development of the missile was nearly complete by then, and at most a few months delay was achieved. Several large, fixed V-2 launch facilities were bombed and destroyed. This had essentially no effect on the missile attacks, however, since V-2s were launched by mobile launchers at a rate essentially limited by supply. Once the V-2 attacks began, fighter and fighter-bomber sweeps of suspected launch areas were carried out, but also with little success.
Prior to the use of the V-1s, the allies attacked and largely destroyed the original network of launch sites the Germans were preparing. However, by the time the V-1s were ready to be launched, the Germans had developed a new network of more modest and better camouflaged launch sites. Although allied air attacks destroyed some of these sites, no effect on the V-1 launch rate was observed.
Bombing attacks on production facilities were also carried out. However, subcomponent production was dispersed and assembly was underground, and these attacks had little effect. The overall strategic bombing campaign probably indirectly affected production--the US Strategic Bombing Survey estimated a 20% reduction in total production. However, the V-1 and V-2 attacks continued until the allies occupied their launch areas with ground forces.
The V-1 and V-2 missile attacks failed to achieve their objectives (primarily that of persuading Britain to abandon the war) or to significantly affect the outcome of the war. Moreover, the V-weapons were a serious diversion of German resources. The U.S. Strategic Bombing Survey estimated that the resources devoted to V-weapon production were equivalent to that needed to produce 24,000 fighter aircraft.
The 1991 Gulf War
During the 1991 Gulf War, about 80 al-Hussein missiles fired by Iraq fell in or near Israel or Saudi Arabia. The Iraqi missiles--which were similar or identical to the missiles used against Tehran in the War of the Cities--were quite inaccurate, with a CEP of at least several kilometers.
I will focus on the attacks on Israel, because of the better quality of that data. Roughly 39 Scuds--the majority fired at Tel Aviv--landed in or near Israel, although about half fell in the Mediterranean or short of Israeli cities. These Scuds directly killed 2 people (11-12 other people died from heart attacks or improper use of gas masks) and caused 11 moderate to serious injuries and 221 light injuries. To put these figures in perspective, deaths from all causes in Israel during the period of the Gulf War were 4154--somewhat below average for that time of year.
It is immediately apparent that the consequences of the missile attacks--both overall and on a per missile basis--were very different in Israel and London. Based on the V-2 experience in London, after scaling for the higher population density of Tel Aviv and the smaller warhead of the Iraqi missiles, 3.3 deaths and 8.0 serious injuries would be expected per Scud falling in Israeli metropolitan areas. However, on average, each of the roughly 20 Scuds falling in Israeli metropolitan areas caused only 0.1 deaths and 0.6 serious injuries--a death rate lower by a factor of 30. What accounts for this difference?
Although the Patriot air defense system is often credited with reducing the casualty rate in Israel, it actually at best played a relatively minor role. At least 22-23 Scuds fell into areas defended by Patriot, with at least 6 of these falling before Patriot was operational. For the 16-17 Scuds that were engaged by Patriot, the U.S. Army claims a success rate of about 40%--or 7 Scuds successfully engaged. However, all independent reviews of the Army's still-classified data indicate that the Army's data is inadequate to back up its claims, the only independent analysis of Patriot's Gulf war performance concluded that its performance was much poorer than the Army is claiming, and the still-classified Israeli assessment concluded that there was at best circumstantial evidence for one successful engagement. Nevertheless, even if one accepts the Army's claim, it is clear that a roughly 7/22 = 32% reduction in Scuds striking Israeli cities could at best explain only a small part of the observed 3000% reduction in the per-missile death rate compared to the V-2 experience in London.
This conclusion is supported by the available damage and casualty data from before and after the Patriot deployment in Israel. Of the approximately 39 Scuds reaching Israel, 12 fell before Patriot was operational and 27 after. On a per missile basis (excluding the 8 Patriot missiles that dove into the ground in Israel), deaths, injuries, and light damage to apartments all increased after Patriot was operational, while heavy damage to apartments may (depending on how one counts the missiles) have decreased slightly. However, none of these increases or decreases are statistically significant--one can only conclude that any effect of Patriot on casualties is lost in the statistical noise.
What other factors can explain the relatively low casualties in the missile attacks on Israel? First, the Scuds were very inaccurate. Only six actually fell within Tel Aviv. In addition, several did not explode--including one that directly struck a multi-story building in downtown Tel Aviv.
Just as important, however, were several factors that worked synergistically to reduce the vulnerability of the Israeli population. Warning information from U.S. satellites enabled people to be in their sealed-room shelters rather than out in the streets when the missiles fell. As the V-1 versus V-2 casualty data from London indicates, even very brief warning can reduce casualties by at least a factor of two. In addition, air attacks on Iraqi missile launchers forced the Iraqis to launch almost all of their attacks at night, when people would be at home and only needed to step into their shelters.
Given that most Israelis were in their sealed room shelters during the missile attacks, the quality of these shelters becomes a crucial factor. The typical Israeli apartment building is constructed of reinforced concrete, and is thus collapse-resistant. In contrast, in London the typical dwelling was a row house with load-bearing walls, which readily collapsed due to nearby explosions. In London reinforced buildings had demolition areas eight times smaller than buildings with load-bearing walls. This has important implications for casualties, because even if a building's walls were blown in, injuries to the inhabitants were generally minor as long as it did not collapse.
Taken together, these factors could account for the relatively low casualties due to the Scud attacks. However, in any attack involving relatively small numbers of inaccurate, conventionally-armed missiles, luck will also inevitably play a crucial role. Changing the impact point of a single warhead by a few tens of meters could have completely changed the nature of the casualties due to the Scud attacks.
Aside from defensive countermeasures such as the deployment of Patriot, provision of warning, and civil defense measures, the Coalition launched a vigorous offensive countermeasure campaign. Of the roughly 42,000 strike sorties flown by coalition aircraft during the war, about 2500 were against Scud-related targets, including about 450 against Scud production and support facilities, 750 against fixed launchers or possible hiding places for mobile launchers (such as buildings or road overpasses), and 1200 searching for mobile Scud launchers. In addition, special forces teams were placed into Iraq to assist in the search for mobile Scud launchers.
However, while most or all of the fixed Scud launchers were quickly destroyed, few if any of the mobile Scud launchers--which were the ones actually used to launch the missiles--were destroyed. However, the rate of the missile attacks did fall off sharply after the first week (and the accuracy of the missiles also appeared to decrease, at least in Israel) which was perhaps at least in part due to the Coalition air attacks.
The U.S. also used ground-attack missiles. Unlike the missiles discussed previously, these were highly accurate ballistic and cruise missiles used against point industrial and military targets. 282 Tomahawk conventionally-armed land-attack cruise missiles, with ranges greater than 1000 km, were used against targets such as nuclear and chemical weapon facilities, surface-to-air sites, and command and control facilities, including many targets in Baghdad. On the first night of the war, an additional 35 conventionally-armed air-launched cruise missiles were used against targets such as communication facilities and electrical power sites in northern Iraq. These missiles, which were delivered by B-52s flying from the continental U.S., used information from Global Positioning System satellites for terminal guidance. The U.S. Army also fired about 20 to 30 Army Tactical Missile Systems ballistic missiles. These 100-km range missiles were used against targets such as surface-to-air missile sites, logistics sites, and howitzer and rocket batteries. These US missile attacks were generally successful.
Discussion
Ballistic (and cruise) missiles have been used for a variety of reasons: when bombers were not a viable option, to avoid risking pilots and airplanes, for psychological effects, or to retaliate or deter. In only one case do missile attacks appear to have possibly significantly affected the course of a war: the Iraqi missile attacks during the War of the Cities may have contributed to the Iranian decision to end the Iran-Iraq war. In the majority of the cases (Germany, Afghanistan, Iran, Iraq in 1991), the missile attacks failed to achieve their objectives. The U.S. missile attacks during the Gulf War may have achieved many of their objectives, but given the Coalition's overwhelming air superiority, were not crucial to the war's outcome.
At present, there is no direct theater ballistic missile threat to U.S. territory. The threat to U.S. allies and forces deployed overseas is almost exclusively in the form of inaccurate, conventionally-armed (or possibly chemically-armed) missiles such as the Scud and its derivatives. Such missiles are too inaccurate to pose a serious military threat, and are primarily of concern as a terror threat against cities.
The casualties to be expected due to such terror attacks will be highly dependent on the circumstances of the attacks, and moreover large statistical fluctuations in casualties would be expected for small-scale attacks by inaccurate missiles. As the Iraqi Gulf War missile attacks demonstrate, warning and proper sheltering can reduce casualties. However, it should not be assumed that the relatively light casualties inflicted by the Iraqi Scuds necessarily will be the case for future attacks. Iraqi Scuds were very inaccurate and had small warheads; plausible increases in accuracy coupled with larger warheads could increase the expected lethality by a factor of 10.
If chemical warheads are used in terror attacks on cities, casualties will again be highly dependent on circumstances, in particular on how well the chemicals are dispensed, the weather, and how well the population is prepared. If the chemicals are efficiently dispersed, even a well prepared and equipped population in favorable weather conditions could suffer casualties several times higher than for a conventional attack. If the weather conditions are unfavorable (for example, a calm, clear night) casualties are likely to be much higher.
The threat from theater missiles will change dramatically if GPS-guided missiles (in the near-term, more likely cruise rather than ballistic missiles) begin to proliferate. Such missiles could be accurate enough to pose real military threats in addition to being even more destructive as terror weapons. Missiles armed with nuclear (or possibly biological) warheads would of course represent an even greater threat.
Relatively straightforward defensive countermeasures, such as providing warning and shelters, or in the case of chemicals, adequate gas masks and training, can significantly reduce casualties from missile attacks. On the other hand, more expensive and technically-complex approaches, such as terminal defenses or attacks on missile launchers, have so far had relatively little success. The Patriot experience in the Gulf War highlighted the fundamental problem facing active missile defenses: how to deal with the countermeasures employed by an attacker. At present it is unclear what level of effectiveness missile defense systems can expect to achieve in the face of countermeasures.
The author is with the Defense and Arms Control Studies Program at M.I.T.