A study on: Exploring U.S. Missile Defense Requirements in 2010: What Are the Policy and Technology Challenges?

Chapter 5

Assessing the U.S. Missile Defense Program


As outlined in the first four chapters, it is clear that both ballistic and cruise missiles are proliferating. It is also obvious that such capabilities as stealth technologies, missile and warhead maneuverability, decoys, and radar volume maskers will increasingly be incorporated into the world's offensive missile delivery platforms as nations, which have and are investing large sums of capital in missile technologies, seek ways of insuring that their missile forces can penetrate the expected defense environments.

Essentially, the whole issue of missile defenses represents but an opening gambit in the struggle for security against missile-delivered weapon systems that are expected to be in use during at least the first half of the next century as the revolution in military affairs changes the warfighting environment. Denial of the evolving challenge will not make that challenge disappear. At some point, the United States must address the full spectrum of the world's evolving offensive missile capabilities; it is merely a question of when. Of equal or greater long-term importance, however, is the challenge of insuring that the defenses the United States does develop are flexible enough to be adapted quickly to counter emerging offensive missile capabilities on a timely basis.

In this chapter, the technological issues associated with missile defenses will be reviewed, and the United States' program for dealing with these issues will be assessed. The assessment will include the organizational attributes necessary for dealing with future missile challenges.

Ballistic Missile Penetration Options

Missile Track

In planning offensive missile countermeasures to anticipated defenses, missile planners try to select the highest-payoff methods that can be packaged within the limits of the throwweight available for countermeasure devices. It is somewhat ironic that at the ICBM level agreements such as START II, which eliminate U.S. and Russian MIRVed warheads on land-based missiles, also mean that those missiles will, in the future, have a great deal of excess throwweight that could be used to carry penetration aids or extra fuel for warhead maneuvers to avoid interception by missile defenses.

Ballistic missiles with ranges longer than about 350 kms face two distinct environments: exoatmospheric and endoatmospheric. Each environment provides its own set of opportunities and challenges for evading missile defense systems. Many of the possible missile defense countermeasure options were outlined at the end of Chapter 1, but without much reference to the environments in which they operate. In this chapter, countermeasures tailored to the endo- and exo- atmospheric environments will be assessed separately.

Exoatmospheric. Exoatmospheric flight occurs in very cold temperatures while the missile's payload is flying through a vacuum. Objects traveling through a vacuum are neither slowed nor heated by air-molecule friction; however, these objects also lose the aerodynamic maneuverability and lift that is imparted by flight through an atmosphere. Thus, maneuvers in space require a high expenditure of fuel since the maneuvering thrusters do not have any air molecules to push against, and the resulting maneuvers are gradual and gentle in comparison to atmospheric flight.1 However, all objects that are part of the missile's payload of weapons and penetration aids, be they metallic-coated balloons, aluminum chaff, full-scale warhead decoys, or warheads themselves, will travel through this vacuum at the same velocity, thus making it difficult to identify and target a specific item within the cloud of objects that are released from the missile once it clears the earth's atmosphere at the end of the ascent phase of its flight.

Successfully targeting missile defenses against incoming missiles during the mid-course phase, while the offensive warheads are exoatmospheric, is one of the most difficult tasks inherent in the missile defense mission. This difficulty has several aspects.

First, the target must be specifically identified by one or more sensor systems. The current U.S. national missile defense program envisions the use of U.S. early warning satellites and radar systems to alert the U.S. Space Command (SPACECOM) of an incoming missile threat. SPACECOM would then orient the battle-management radar located near the launch site at Grand Forks, ND, to detect, discriminate, and identify the specific targets to be attacked. The battle-management radar is likely to be an advanced ground-based, frequency-hopping, x-band microwave radar system. For theater-wide systems, the same general type of radar will be used, one with only slightly over one-fourth of the number of transmit/receive modules as will be included in the NMD's Ground Based Radar (GBR). In addition, the land-based theater-wide missile defense system is not planned to include outside cuing from other radars or space-based sensors (an ABM Treaty consideration).

Although the envisioned x-band radar systems will be able to search large areas (with the NMD-related system having the capability to track up to 1000 objects simultaneously), their effectiveness might be degraded by the use of stealth technologies and other similar efforts designed to enhance the survival rate of the offensive warheads. To improve U.S. capabilities to handle the anticipated missile threat, the Space and Missile Tracking System (SMTS — formerly called Brilliant Eyes), will be developed as a space-based infrared suite of sensors that will augment the ground-based radars.

Second, the intercepting missile must be able to find the target identified by the ground- or space- based sensor. The target's location will be passed from the ground- or space- based tracking systems to the intercepting missile's seeker system, which will identify the target's infrared signature and determine the vector to the target. The relationship between IR and radar sensor technologies is very complex. One of the challenges in making the missile defense system work involves the refinement of the radar-infrared interface. In short, the challenge is how to develop a way of transmitting the three-dimensional (3-D) radar target object map (TOM) in a format that is recognizable to a two-dimensional (2-D) infrared seeker, a seeker that may not be able to detect the same objects as the radar system (due to differences in sensor capabilities and angle of view).

Third, there are many potential ways to try to deceive the radar/infrared targeting system in the exoatmospheric environment. As discussed earlier, Russia, China, the United Kingdom, France, the United States, and probably Israel and Ukraine have all researched this problem. In addition, it would not be surprising to learn that Iran, Iraq, North Korea, and several other states have also begun to address the issue. Exoatmospheric countermeasures that seem likely to be incorporated into missile systems against which the United States may have to defend include:


1.Exoatmospheric Penetration Aids. Penaids range from low-technology, low-cost countermeasures to sophisticated high-technology measures that either add many more signatures to the puzzle or act to mask the signatures of the re-entry vehicle(s).

Low-Technology Penaids. Aluminum chaff, metallic-coated balloons, and separation debris are low-cost means of greatly increasing the number of "signal returns" that the radar systems receive, essentially creating an electronic "shell game" to try to make the missile defense system guess which of the radar returns represent the actual re-entry vehicle(s). These types of penaids are within reach of even fledgling missile powers. For example, a country can use detonating cord to cut the upper stage of the missile body into pieces after burnout so as to increase the debris field in which the RV is located.

As these types of penaids begin re-entry, they will slow, become separated from the re-entry vehicle, and burn-up in the earth's upper atmosphere. (Balloons and chaff "strip-off" the RV at 90-100 kms altitude; objects with more mass or better aerodynamic characteristics may penetrate somewhat deeper before becoming separated from the RVs.)

High-Technology Penaids. These aids use active measures to assist RV penetration of defenses, including escort radar volume maskers, infrared decoys, and radar decoys. The latter two decoy systems will generate the radar or infrared signals normal for an actual warhead so as to provide the defensive battle manager with false targets. Some of these penaids are fairly inexpensive, but may be quite effective. For example, in 1996 a University of Pennsylvania professor built a radar volume masker using commercially available microwave technology. The masker mounted two spiraling microwave antennas mounted about 4 inches apart. The antennas were able to respond over the 2-18 gigahertz range without interfering with each other. With this equipment, one antenna received the microwave radar signal, the signal was amplified and elongated, then retransmitted back to its receiver as a stronger and longer signal, thus creating a void in the radar coverage behind the masker. Use of such maskers on the front of escort decoys could blind the radar to the objects trailing the volume maskers. Other countries could use similar techniques to try to jam or degrade the effectiveness of sophisticated frequency-hopping radars.2 2.

Signature-Masked RVs. The second way of avoiding interception during exoatmospheric flight is to alter or mask the radar and/or infrared signature of the re-entry vehicle itself. This technique could be especially effective if radar/infrared decoy(s) were included in the package so as to provide logical targets for missile defenses.

Radar. The shape of the RV can be structured to minimize the radar cross-section; it could also be coated with a radar-absorbing material (sold commercially) or put inside a shroud or otherwise camouflaged by adding materials to the outside of the RV such as strips of aluminum chaff or similar reflecting materials that will result in a non-standard signature being returned to the radar. (Materials attached to the skin of the RV would burn off during re-entry.) As for shrouding, something as simple as putting the RV inside of a metallic-coated balloon would make the warhead appear like a decoy, possibly rendering the RV unrecognizable as a target since radar cannot "see" through an electrical conductor. (The British Chevaline project reportedly incorporated this technique).3

Infrared (IR). During the ascent phase, the nose of the missile becomes extremely hot, which in turn increases the temperature of the already warm warhead payload. The payload gives off this heat as it is exposed to the frigid coldness of space, thereby providing a thermal signature for infrared sensors seeking exo-atmospheric targets. The IR sensor faces a challenging task. It must locate the correct IR signature against a background that includes many stars and suns that provide their own IR signals. Complicating the problem is the fact that the IR signature of the RV can be altered by using a special IR paint, thus changing the expected thermal characteristics of the target. The payload can also be insulated to reduce the amount of heat absorbed during the ascent, thus allowing the re-entry vehicle(s) to chill to near ambient temperature soon after burnout. In short, the parameters of the RV's IR signature can be changed so that the infrared sensors and seekers have difficulty recognizing the RV as a target.

3. Salvage Fusing. States may incorporate salvage fusing into their strategic nuclear warheads. Salvage fusing means that if an offensive nuclear warhead is struck while enroute to its target, a backup fuse will detonate the warhead. Since extremely fast fuse reaction speeds are required to detonate the nuclear device before an impact shockwave is able to destroy the integrity of the warhead, salvage fusing is unlikely to be incorporated into first-generation missile systems. However, more advanced systems may well include this capability. In cases where salvage fusing is encountered, the resulting nuclear detonation will be detrimental to U.S. missile defense efforts.

A nuclear warhead that explodes exoatmospherically creates a lot of thermal and radiation effects (without an atmosphere, blast effects are not an issue). In addition, the electro-magnetic pulse (EMP) generated by the explosion will fry the electronic circuits in all but the most hardened of the satellites and sensors within line-of-sight of the detonation. Radiation and thermal effects will also destroy or degrade selected hardware components for a considerable distance,4 and a significant portion of the surviving space sensor systems will experience increased electronic "noise," report false tracks, or be otherwise unable to perform their missions even if exposed only to the persistent radiation from enhanced electron belts and gamma-emitting debris collecting on the focal plane.5

As an aftereffect, a significant proportion of the world's satellite inventory in low earth orbit which was not destroyed by the initial explosion will fail prematurely as most are not hardened against higher levels of radiation. Studies by the Defense Special Weapons Agency (DSWA — formerly DNA) "show that the explosion of a single high-altitude low-yield nuclear weapon could destroy $14 billion worth of low-earth orbit satellites" (damage inflicted by the event and subsequent satellite transit through the enhanced radiation belts produced by that explosion).6 From the missile defense perspective, a nuclear explosion will also create "blooming" in infrared sensors as well as temporarily disrupt radar signals. Some space-based sensor systems will be damaged by the effects of the detonation allowing the follow-on offensive missiles to avoid early detection as they are likely to be shielded by the residual effects of the nuclear detonation. In short, salvage fusing is expected to provide some penetration assistance to those missiles that follow an intercepted warhead.

Endoatmospheric. Endoatmospheric flight will be characterized by extreme heating of objects re-entering the earth's atmosphere, the ability to use the atmosphere for maneuver, and the slowing of penetrating objects as drag reduces the speed of the objects. Many active signal transmitters, such as radar jammers, will suffer some degradation in their capacity to transmit during re-entry. As a result, the means of evading missile defenses in the atmosphere are more limited than they are exoatmospheric. However, due to the aerodynamic maneuverability that the atmosphere provides, maneuvering capabilities are enhanced during endoatmospheric flight.

Endoatmospheric countermeasures likely to be incorporated into missile systems against which the United States may have to defend include:


1. Endoatmospheric Maneuver. This is the primary means that most states will use to evade missile defenses in the atmosphere. There are three deliberate maneuver techniques that could be used, along with a couple of unplanned maneuvers.

Aerodynamic maneuvers. Essentially, this is the use of wings, fins, or thrusters to maneuver a warhead in the atmosphere. Russia's Project X and India's Agni warheads are examples of systems that incorporate aerodynamic maneuvering. In many ways, the technique used is very similar to that employed by air-to-air missile systems that use small wings and/or thrusters to maneuver to target. Warheads with this capability can be programmed to follow a series of complex maneuvers in the atmosphere. These types of warheads may include terminal position correction technology and be highly accurate.

Coning or Corkscrewing. Many re-entry vehicles, such as those used in MIRVed systems, are built as long, smooth, coned-shaped objects. If they are to fly smoothly, these cones must be balanced, much as the wheels on a car must be in balance, or they will wobble or "shimmy." If an RV is unbalanced, either through faulty design or deliberate engineering, the results can be a re-entry vehicle which engages in a corkscrewing maneuver during its endoatmospheric flight. This same motion can also be introduced by the use of fins or something called a "split-flap." The resulting maneuver resembles a corkscrewing motion around the axis of the RV's planned trajectory in a pattern that may be 30-40 meters in diameter, with turns of 10-15 G forces.

Acceleration/Deceleration. To an interceptor that is approaching a re-entry vehicle at a slant angle, the acceleration or deceleration of the target provides as much of a targeting challenge as does a lateral maneuver. As an RV penetrates the earth's atmosphere, the effects of drag will slow the vehicle. Unfortunately, the rate of slowing varies between different systems depending on their "beta" rating. For example, early-generation ICBM warheads re-enter the atmosphere at a velocity of around 6 or 7-kms per second, slow rapidly beginning at 25-55 kms altitude (depending on their beta), then impact at a velocity of less than l-km per second. However, the latest Russian and U.S. ICBM RVs are are very aerodynamic low-drag systems (high beta) that maintain most of their velocity until reaching about 12 kms altitude before slowing rapidly to perhaps 3.5 to 4 kms per second at impact.7 The different rates at which RVs decelerate must be compensated for by endoatmospheric interceptors.

Complicating the situation is the possibility that the RV could have a small acceleration booster incorporated into its system that would increase the velocity of the RV above the norm as it penetrated the atmosphere. This booster might be employed in cases where the RV was built as an earth penetrator (targeting underground facilities) or if the warhead designers decided to use boosted descent as a form of endoatmospheric maneuver, making the RV behave in an unexpected manner to missile defense interceptors.

Breakup or Tumbling. The warhead can also act in an unanticipated manner if it should breakup or tumble. This is, of course, what happened with the Iraqi Scud systems. The Scud does not have a detachable warhead. The warhead and missile body remain attached throughout the entire trajectory. During Desert Storm, it was found that the re-entry stresses sometimes caused the elongated missile models to breakup between 12-18 kms altitude. Unfortunately, U.S. radar systems were not programmed to identify the broken-up missiles as a threat to be reported for attack. (Since radar collects data on everything moving, to include birds, the software is programmed to ignore returns that fall outside the parameters determined to represent target characteristics — such as a Scud not following a ballistic trajectory.) In essence, the subsequent movement of the Scud after breakup represented an unintended maneuver.

2. Endoatmospheric Decoys. Ballistically matched decoys can accompany the RVs to increase the number of possible targets with which the missile defenses must cope. Some decoys can also be accelerated to match the velocity of the actual RVs.

3. Stealth. Efforts to reduce the radar cross section of the RVs help to degrade radar coverage in both the exoatmospheric and endoatmospheric phases of the trajectory. As seen in Chapters 1-4, most countries doing research on missile development are also working to decrease radar cross section profiles. This work is projected to bear fruit by 2010.

Assessing the Target Array

As was seen in the country reviews, Chapters 2-4, a number of states are working to develop tactical missile systems that can be employed against high value targets in the theater of operation (i.e., copying U.S. AirLand Battle Doctrine). Many of these countries also seem interested in the acquisition of strategic missile systems capable of deterring outside intervention into their region. It is likely that many of these states also seek the international prestige that is conferred on nuclear-armed nations, especially those that also have ICBM delivery systems.

Missile Track

Tactical Missile Defenses. The target array that missile defense systems must cope with differs somewhat between the tactical and the strategic levels. At the tactical level, shorter-ranged missile systems, such as China's DF-15/M-9 missile and India's Prithvi, will be equipped with a wide spectrum of warheads, warheads with both WMD and conventional capabilities: nuclear, chemical, biological, fuel-air explosives, explosive bomblets, smart independently targeted submunitions, electro-magnetic-pulse generators, scatterable mines, etc. Unfortunately, when the missile is launched, the defenders may not know what type of warhead is incoming. Consequently, the missile defense system must be able to intercept either unitary or submunition-filled warheads.

The requirement to defend against submunition-equipped warheads is becoming more acute. Countries are moving toward using bomblet technology to package conventional explosives, CW agents, and BW agents. It is the CW and BW options that have raised the most concern. As described by Israeli sources, bomblet technology could consist of a theater missile payload of 100 bomblets that each weigh 5 kgs for a total payload of 500 kgs of chemical or biological agents. According to reports, the missile would release its load of bomblets during the ascent phase of its trajectory at about 60 kms altitude. See Figure 5-4. They would fly in a cluster to the target area and descend in a 20-second-long volley.8 It seems clear from ongoing developments that bomblet packaging is likely to become common for ballistic missile-delivered CW or BW payloads.

In Chapter 2, the effects of BW and CW delivered by unitary warheads was compared to the blast effects of nuclear warheads, see Figure 2-6, page 2.18. Note the relative ineffectiveness of the unitary chemical warhead. However, when chemical and biological agents are packaged in bomblets, the agents are released over a wider area, making them considerably more effective. In the case of BW, bomblets also allow the delivery of a much higher payload of agent since increasing the amount of BW agent in a unitary warhead provides little increase in lethality as the additional concentration of agent is not likely to be distributed to many new victims. Figure 5-5 reflects the increased effects that can be achieved by packaging the agents in bomblets.9 Although the effects of CW agents are also increased by bomblet delivery, it is the anthrax BW strike that is most enhanced by this means of delivery. In essence, by increasing the amount of BW agent and releasing it at many separate points, the width of the pattern and the total area covered by the downwind effects are much greater than what could be achieved by a unitary warhead.

With the evolution of bomblet technology, it is clear that tactical missile defense systems must be developed to cope with submunitions. This requirement will be one of the major technological challenges for the future.

Strategic Missile Defenses. A majority of the missiles in the world that are currently capable of striking the United States are equipped with multiple independently targeted re-entry vehicles (MIRVs). As time moves toward 2010, MIRVs will still be a problem with which future missile defenses will have to deal. If the START II Treaty should ever be ratified and enter into force, MIRVed warheads will be eliminated from U.S. and Russian land-based missile forces. However, the nuclear submarine forces of both countries would still retain MIRVed missiles and, since START II does not apply to the United Kingdom or France, their MIRVed SLBMs (and their right to field land-based MIRVed missiles) will not be affected by the Treaty.

More importantly, MIRVed warheads are being developed in other countries that heretofore have not had MIRV technology. China is expected to MIRV its ICBMs within the next couple of years (and may have already begun the process); Iraq, as was discussed in Chapter 4, is also suspected of working on a multiple-warhead capability. (Many of these states are likely to introduce multiple re-entry vehicles — MRVs — to their inventories first and later introduce the independent targeting option. MRVs act like a shotgun, with all RVs following a trajectory to the same target area, but forming a dispersion pattern that increases the lethality of the strike.) As ballistic missile capabilities spread early in the next century, their related MRV or MIRV warhead packaging also seems likely to proliferate as technical knowledge spreads.


Through 2010, it seems probable that the vast majority of warheads on ICBM systems will remain nuclear. Chemical weapons lack the lethality necessary to provide an effective national deterrent. In comparison to the cost of an ICBM delivery system and the certain re-taliation from the United States that such an attack would provoke, a CW attack would not be sufficiently damaging to sway the United States from the pursuit of its key national interests.

On the other hand, BW bomblets could create havoc, not only from the initial lethality, but also from the potential that the contaminated area could remain unusable for decades to come.10 In a similar vein, radiological weapons (radioactive material dispersed by a conventional explosive) could be used to contaminate important economic or military sites.

However, there is a major shortcoming to using either CW and BW agents as a strategic weapon system delivered by ICBM. This shortcoming is the simple fact that the effectiveness of the strike is greatly influenced by weather conditions and wind direction. Thus, a warhead that delivers the agent at the edge of a target could result in most of the potential effects being wasted if local wind conditions were opposite that expected when the strike was planned. In addition, other weather conditions, such as high winds, could spread the agents too thinly to be effective. Likewise, a lack of wind in conjunction with temperatures and pressure conditions that encouraged surface air to rise can also dissipate the agents with minimal casualties. Consequently, CW and BW warheads do not make very predictable deterrent weapons as they can be employed effectively only under certain weather conditions and BW has an incubation period which delays its effects.

As a result, through the year 2010, the most common ballistic missile warhead types that will threaten the United States will be unitary or MIRVed nuclear devices, many of which will incorporate or be accompanied by penetration aids. Considering the delayed effects and uncertainty of results inherent in BW systems, the nuclear option remains the more likely weapon of choice for an ICBM warhead. The probable exceptions to this prediction might be those cases where a country of limited means obtains or develops more ICBMs than it has nuclear warheads to deliver. In that situation, it might develop BW or radiological warheads to make up the difference. On the other hand, at the theater level, U.S. missile defenses can expect to face a target array that includes a wide variety and number of conventional and WMD warheads and submunitions that will threaten high-value targets. However, in the longer term, the challenge that BW agents pose will grow as the biotechnology revolution evolves.

U.S. Missile Defense Program

The Patriot missile of Gulf War fame (the PAC-2) was essentially an anti-aircraft missile system composed of 1970s-era technology with a 1980s-era software upgrade to provide it with a limited anti-missile capability. The real importance of PAC-2's Desert Storm performance was not its record of hits and misses, but the demonstration of the fact that ballistic missiles could be intercepted. In context, its performance was the equivalent of the Wright brothers' first flight at Kitty Hawk. While that first flight was brief and far from perfect, it proved powered flight was possible.

With the realization that missile intercept was possible, coupled with the experience of trying to deal with offensive ballistic missile launches (i.e., Iraq's Scuds), the United States developed a program to field tactical missile defenses. Although there is general agreement regarding the need for tactical missile defenses, what is still hotly debated is whether or not the United States needs a national missile defense and, if judged necessary, should that defense be fielded within the limits prescribed by the ABM Treaty.

ABM Treaty Limiting Issue. If the country attempts to build a limited national missile defense within the constraints of the ABM Treaty, there are some restrictions that pose special difficulties. The first restriction is that no more than 100 interceptors can be fielded at only one site. The designated site for the United States is Grand Forks, ND. Prior to the addition of a protocol to the original ABM Treaty (added at U.S. insistence), each party was permitted to deploy its defensive missiles at two locations. A few defense strategists are now advocating that the U.S. negotiate a termination of the ABM Treaty's protocol, thus re-establishing the ABM Treaty's original provision which allowed two deployment sites. Others would either abrogate the ABM Treaty entirely or negotiate some major revisions to that agreement to allow for missile defenses at multiple sites.

The second restriction of note is that each ABM interceptor missile can only be equipped with a single warhead/kill vehicle. This provision makes it impossible to develop cost effective missile defenses, defenses that are not disproportionately more expensive than offensive forces. For example, a single Chinese missile with a 9-MIRV warhead would require a minimum of nine U.S. interceptor missiles to eliminate the threat. In reality, considering China's reported work on penetration aids and the probability that some number of U.S. interceptors would miss their targets, the number of actual interceptors required to prevent nuclear disaster would be considerably higher than nine.

The third difficulty is the limitations on ABM radars. Essentially, the ABM radar must be within 150 kms of the ABM site at Grand Forks, ND. Since the NMD radar is expected to have a range of about 4000 kms, this means that the potential for intercepting offensive missiles launched against Alaska or Hawaii will be very fragile. Although early warning radars are allowed to be deployed on the periphery of each country, the radar handling the intercept must be located within 150 kms of the ABM launch site.

The fourth difficulty is that it makes a number of potential theater missile defense systems legally questionable (e.g., airborne lasers and fast intercept missiles deployed on ships). Essentially, this fourth point revolves around the issue of what systems are subject to being counted against the Treaty's limits and which can be considered theater-level assets.


Planning Factors/Concepts. Missile defenses, like air de-fenses, usually are constructed by developing layers of defensive belts, with each belt thinning the number of incoming warheads. It is understood that some war-heads will get past the initial line of defense.

Ideally, the best place to destroy ballistic missiles is either prior to launch or while the missile is still in the ascent phase of its trajectory before its payload of munitions and penaids are deployed. Those missed in the ascent phase should be destroyed while in mid-course, and those that survive that effort, destroyed by endoatmospheric terminal defense systems.

One of the key issues has been trying to determine the demarcation line between a theater missile defense system and a national system that is subject to ABM restrictions. Although decision makers do not like to acknowledge the issue, the truth is that a theater defense missile, if properly placed, can engage missiles of greater ranges or speeds, to include ICBMs. The two key variables to the success of this effort are the speed of the intercepting missile (i.e., how fast it flies out) and the amount of time that can be provided to the interceptor for its flight to target. Of these two issues, the length of flight time is the more critical factor. For example, a slower missile that is cued early enough to fly a long distance to an intercept point can defend a considerable area. On the other hand, a very fast missile that only receives local targeting information will not be able to defend as large an area as the slower interceptor that is connected to a wide-area sensor network.

As a general rule, the intercepting missile should have at least half the speed of its target for a reasonable expectation of an interception. A slower missile might still make the interception, but the probability factor would be lower. Thus, the issue of velocity becomes a key planning factor.

For example, Figure 5-6 shows the penetration profiles for warheads of varying beta ratings (higher beta ratings reflect more streamlined warheads with lower drag effects in relationship to their respective weights). For example, if a primitive warhead were developed without much shielding, it could be designed as a bulky payload that "belly-flops" through re-entry with deceleration peaking at 40-50 kms altitude. Its flight profile might resemble that shown by the beta 10-20 lines in Figure 5-6. If the warhead is based on 1950s missile technology (systems like the Soviet SS-6 — similar to the Scud), the lines showing beta ratings of 100-200 reflect the re-entry profiles for that level of technology. It is likely that the first generation Chinese systems are also close to those profiles. On the other hand, the new Chinese systems, Russian warheads, and U.S. re-entry vehicles will have re-entry profiles similar to those reflected by the bottom two lines. In the chart shown, the missiles are hypothetically fired to a range of 9000 kms and re-enter the atmosphere at 6 kms per second. Notice that the modern warheads maintain the 6 kms per second velocity down to an altitude of about 18-20 kms before the higher atmospheric densities encountered at 21 kms begin to slow the warhead. Even so, the beta 2000 warhead is still travelling at 5.5 kms per second at 12 kms, with an impact velocity of about 3.7 kms per second. For ICBM flight ranges above 9000 kms, the re-entry velocity would be higher. Thus, the issue of TMD velocity limitations became an issue of debate with regard to the TMD demarcation negotiations with the Russians.

To resolve the issue of the demarcation line between theater missile defense (TMD) and national missile defense (NMD) systems, the U.S. administration reached a tentative agreement with Russia in June 1996 specifying some of the TMD systems that will not be considered national missile defense systems under the limits of the ABM Treaty.11 The agreement specified the limitations on the Theater High Altitude Area Defense (THAAD) system. The interceptor will be restricted to a speed of 3 kilometers per second or less; it also cannot be tested against targets traversing ranges greater than 3500 kilometers or at velocities in excess of 5 kilometers per second. Of perhaps greater significance, THAAD will not receive targeting data from satellites or adjunct radar systems, a restriction that could reduce the system's protective footprint by roughly half. Although the status of the Navy theater wide system and the Air Force's boost phase intercept systems have not yet been negotiated, and the U.S. administration reportedly opposes limitations on these systems, Russia is expected to try to have those two systems restricted as well. Russia is linking its continued participation in the START treaties to the ABM Treaty.

Area Defense Programs. The immediate priority in the post-Gulf War era was to add some near-term improvements to U.S. missile defense capabilities. This included deploying an updated version of the Patriot, the PAC-2 Guidance Enhanced Missile (GEM), which added a new seeker and a faster-acting warhead fuse to improve fragmentation coverage on the target. In addition, some improvements were also applied to the Marine Corps' Hawk missile system to add a missile defense capability, along with some improvements to the Air Force's early warning systems. The area defense programs that are underway for future improvements to U.S. missile defenses include:

Patriot Advanced Capability (PAC)-3. In 1999, the PAC-3 will begin to be fielded. The heart of the PAC-3 program is the incorporation of the new Extended Range Interceptor (ERINT), which will use a hit-to-kill principal rather than the current explosive fragmentation warhead. The PAC-3's sensors are also much improved over those of the PAC-2, with a refined ability to identify, detect, and track low-altitude threats among ground clutter, an especially important feature when defending against cruise missiles and depressed trajectory ballistic systems. The system will provide for local defenses and be effective against Scud and M-family types of missiles with ranges up to about 600 kms, providing coverage over roughly a 25 mile (42 kilometer) wide front. Its defensive footprint is about 10 times larger than that of the PAC-2. Six battalions will be fielded initially with another three battalions possible, depending on the outcome of the MEADS program.

Navy Area Defense (formerly known as Navy Lower-Tier). Essentially, this program will provide the Navy's Aegis systems with an area missile defense capability similar to that provided by the Army's PAC-3 program. To fill the Navy's requirements for the defense of ports, harbors, and amphibious operations, the Navy will modify Aegis sensor systems and the Standard Missile-2 Block IV-A (a version of the service's basic fleet defense missile) to detect, track, and engage ballistic missiles. The SM-2 Block IV-A uses a shaped-charge warhead to increase its destructive effects. Aegis ships are scheduled to begin being equipped with the modified missile by 2002.

Medium Extended Air Defense System (MEADS). The Patriot system has two major constraints. First, it is difficult to move. For example, the U.S. Army's VIIth Corps' deep assault during Operation Desert Storm could not be supported by the Patriot. Patriot units cannot be moved forward quickly enough to support that type of maneuver. Considering the agile mobile missile systems being developed around the globe (Chapters 2-4) and the speed with which cruise missiles are proliferating, this limitation will pose a major vulnerability to U.S. forces early in the next century. Second, the Patriot's radar systems only orient and search in one direction, limiting its potential contribution to futuristic cooperative engagement systems (such as the Navy is developing).

The solution to these limitations is MEADS, a multinational program, previously known by its U.S. program designation as Corps Surface-to-Air Missile (Corps SAM). The MEADS program is designed as a mobile anti-aircraft, anti-cruise missile, and anti-ballistic missile system capable of moving with maneuvering forces, offering all-azimuth protection. MEADS is planned to begin fielding in 2005, starting with the three Patriot battalions not upgraded to the PAC-3. MEADS will eventually supplant the Patriot as the U.S. Army's primary lower-tier air defense system. It possesses a slightly larger footprint than the PAC-3 and is capable of destroying targets at higher altitudes, up to 30 kms.

Theater Defense Programs. Theater missile defense systems are designed to protect areas hundreds of kilometers wide against ballistic missile attack. While the area defense systems described in the preceding section will be capable of defending against aircraft and cruise missile systems as well as ballistic missiles, the theater systems are specialized for employment against ballistic systems. The United States has two programs that are designed to provide theater-wide coverage. The more mature program is the Army's Theater High Altitude Area Defense (THAAD) system, while the Navy Theater Wide system (formerly called the Navy Upper-Tier) is the least mature of the TMD programs.

Theater High Altitude Area Defense (THAAD). The endo-exoatmospheric THAAD remains the centerpiece of the "core" TMD programs and should be fielded by 2004. It is designed to protect against the full spectrum of theater-class threats, including higher velocity ballistic missiles such as the North Korean Nodong and the Chinese CSS-2. Although it will be untested, THAAD should also have a limited capability against some ICBM-type targets. Like the PAC-3, the THAAD warhead is designed for hit-to-kill target engagement, but with a much higher ceiling, able to attack targets in both the endo- and exo- atmospheric environments. Essentially, THAAD has a robust exoatmospheric engagement capability that extends downward to low endoatmospheric altitudes. Being able to first engage the target exoatmospherically allows an increased number of shot opportunities when operating in a "shoot-look-shoot" mode. For example, the THAAD might fire an interceptor at an RV in the 120-150 kms altitude band, assess the results and, if necessary, fire a second missile to intercept the RV at 40 or 50 kms after many of the penaids, if present, are stripped off (an altitude that is above the "density wall" at 21 km which sometimes causes incoming missiles to breakup). The overall system is composed of a TMD Ground Based Radar (GBR); 2-2.5 km per second interceptors; launchers; and a ballistic missile command, control, and communication (BMC3) system.

The kill vehicle for THAAD uses an uncooled sapphire window through which it searches for IR signatures in the medium-wave infrared (MWIR) wavelengths. At launch, the kill vehicle is protected by a clam-shell shroud to prevent excessive heat build up on the seeker window during flight through the dense atmosphere of the lower altitudes.

figure 5-7

The TMD radar system is an x-band phased-array microwave system that uses 25,344 solid-state transmit/receive modules of the type that will be used in the NMD's GBR (which will incorporate over 80,000 mod-ules of 6-8 watts each). The TMD radar will have a range of about 2000 kms. More work is still needed to improve the efficiency of these transmit / receive modules.

Navy Theater Wide (NTW). The preliminary concept for an NTW system envisions deploying improved Standard missiles on Aegis platforms for exoatmospheric theater-wide missile defense. The NTW missile is anticipated to fly at a velocity of 4 to 4.5 kms per second, carry a kinetic hit-to-kill warhead, and be able to engage targets outside the atmosphere up to a reported altitude of perhaps 500 kms. Of the four kill vehicles under consideration, the most likely candidate is one derived from a BMDO technology demonstrator, the Hughes-Rockwell Lightweight Exoatmospheric Projectile (LEAP). The LEAP destroys its target by hovering in its path.12 As an exoatmospheric system, Navy Theater Wide would intercept ballistic missiles at ranges and altitudes greater than that of THAAD. The NTW may have some ability to intercept ballistic missiles while in boost or ascent phase, if the operational situation and the availability of water allows Aegis ships to position close enough to the launch site. The NTW system will leverage much of its technology requirements from the NMD R&D effort. It is expected to be operational by 2006.

Such capabilities, especially the missile's speed and its interface with a wide-area sensor network, have raised Russian concerns. They claim the system has a significant potential to intercept ICBMs and would violate the ABM Treaty. Like THAAD, any restrictions on external targeting information would substantially reduce NTW's effectiveness. Because these ship-launched missiles can greatly extend the range at which they can make an intercept (if cued by external sensors to begin their flight prior to the threat being visible on the Aegis radar system), an external sensor ban would reduce NTW's capabilities to a greater extent than the June 1996 agreement will do to THAAD. According to some analyses, restrictions on external targeting data supplied to NTW interceptors could reduce their probability of a successful kill by a factor of ten or more.13

The Airborne Laser (ABL) Boost-Phase Intercept (BPI) Concept. The BPI concept would mount a long-range, multi-megawatt chemical laser aboard a Boeing 747-400. The laser would be able to target boost-phase and possibly midcourse phase ballistic missiles from standoff ranges. Using either its own sensors, or cued from off-board sensors, the ABL would be capable of engaging missiles from any angle at ranges of 450 kms or more while flying above the clouds at 40,000 feet.14 It is envisioned to have an enhanced capability to defend against salvo-fired missiles, hopefully being able to engage three or more missiles that have been fired simultaneously.15 Possible additional roles for the ABL include anti-cruise missile, anti-aircraft, and perhaps anti-satellite.16 Although adverse weather limitations and beam propagation within the atmosphere have long been difficult obstacles for long-range lasers, some aspects (but not all) of these problems have been solved. An ABL test against a boosting ballistic missile is planned for 2002; the first three aircraft could achieve an initial operating capability by 2006, with the operation of a seven aircraft fleet possible by 2008.

BMC4I. Distributing relevant targeting information to the proper recipients has long been a difficulty challenge in military operations, but particularly so in missile defense operations. During Operation Desert Storm, despite the fact that sensors could detect Iraqi missile launches and build track files almost immediately, no existing communications infrastructure existed which could have provided the data to would-be interceptors. While systems such as the Army's Joint Tactical Ground Station (JTAGS) and the Air Force's Combat Integration Capability (CIC)17 do a great deal to bridge existing gaps, more seamless sensor-to-shooter links are required.

The NMD Deployment Readiness Program (NDRP). This program reflects the United States' NMD policy and is generally known as the "three plus three" plan. That is, in the initial three year period of the program's implementation (1997-2000), the Defense Department will develop technologies and options for a National Missile Defense system which could be deployed within another three year period if a sufficient threat to the United States exists. In the event the intelligence community determines that a requisite threat has not materialized, research and development of more advanced missile defense technologies will continue and threat reviews will be conducted annually. If a review determines a that there is a clear missile danger, deployment will commence to achieve an initial operating capability within three years, with 2003 representing the earliest possibility. A key advantage of the NDRP policy, according to its proponents, is that it will ensure that the United States deploys the most technologically advanced system available commensurate with existing adversary missile capabilities.

National Missile Defense (NMD) Elements. The main elements of the NMD program revolve around three projects. The first is to prepare a ground-based interceptor, sensors, and related BMC3 for deployment within three years of being directed to do so; second, to develop a space-based sensor system for early warning and cuing of missile defense assets; and third, eventually to develop a space-based laser system for defense against ballistic missile attack.

Ground-Based Interceptor (GBI) System. The Army proposes to emplace 20-100 commercial interceptors in the Safeguard Missile Defense site at Grand Forks (built in the mid-1970s). These interceptors would be tipped with an exoatmospheric kill vehicle (EKV) and would have a fly-out velocity of some 8.2 kms per second, allowing, for example, a missile launched from North Korea to be intercepted prior to its reaching Hawaii, a flight time of roughly 30 minutes. This system would be cued initially by the Defense Support Program (DSP), an existing geosynchronous-orbit satellite constellation capable of reporting the launch and direction of flight soon after the missile breaks through the clouds. The missile's flight would be tracked by upgraded U.S. early warning stations. The collection of exact targeting information and intercept data would be handled by the NMD's 4000-km range ground-based radar (GBR).

As an alternative to the Army's proposal, the Air Force has suggested using 20 Minuteman missiles as the NMD launch vehicles. There are also some other differences in the proposed sensor suites that must examined to determine which option or combination of the two options would best meet the nation's requirements. The alternative proposal also contains some START Treaty compliance/inspection considerations.

To determine which elements of these two programs provide the best choices for the United States' missile defense program, BMDO is contracting for a lead system integrator to determine which elements from these two proposals will be incorporated into the national program to provide the United States with an initial NMD capability.

Space and Missile Tracking System (SMTS). The Space and Missile Tracking System, formerly known as Brilliant Eyes, is the space-based infrared surveillance system designed to supplement and eventually supplant the existing geosynchronous-orbit Defense Support Program (DSP) constellation. There is also some speculation that a laser radar could be added to this satellite if it proves feasible.18 Along with improved resolution, in part due to its ability to have satellites in both low and high orbits, SMTS will have the capability to provide cuing data directly to interceptors (an ABM Treaty discussion issue). This is a feature not found in the DSP, which must first relay the information to a ground station.19 The SMTS will be hardened against the effects of radiation and is expected to achieve an initial operating capability by 2006.

Space Based Laser (SBL). BMDO has kept alive the SBL program with very limited funding. In briefings by BMDO personnel, the SBL is shown as a program, but few seem to believe that the system will ever be deployed. In any event, the SBL is a long-term NMD possibility, but could require another 15-30 years to prepare for deployment.

Future Missile Defense Program Requirements

As noted in Chapter 1, if the current U.S. missile defense program is fielded around 2003, it will deploy a system that is most capable of intercepting well-behaved missiles flying a standard ballistic trajectory.20 The standard ballistic trajectory aims the warhead during the ascent phase of the missile's flight, with the warhead then gliding on a "ballistic" trajectory (unguided) to its impact point. However, as was shown in the preceding chapters, many of the current and most of the future so-called ballistic missile systems are not truly ballistic systems since they either now or in the future will incorporate terminal endoatmospheric maneuver capabilities which, along with penetration aids, assist the RVs in evading interception by first-generation missile defense systems.

In assessing the U.S. missile defense program against the evolving situation, there appears to be four major areas that will require rapid upgrades as ballistic missile capabilities evolve.

New technologies need to be developed that will facilitate missile defense forces in identifying and engaging exoatmospheric warheads that incorporate advanced penetration aids.

A cost-effective means of defeating multiple re-entry vehicles or submunition payloads from a single missile must be developed, particularly for the TMD systems.

Future intercept missiles are likely to need a capability to determine range-to-target to improve their probability of hitting maneuvering re-entry vehicles.

The x-band radar needs to be miniaturized and made more power efficient, particularly with regard to the tactical systems (to improve system mobility, reduce power generation requirements, and improve ease with which the system could be airlifted).

Each of these concerns warrant a more detailed discussion.

Target Discrimination Technology Needs. There is agreement in the technical community that new technologies are needed to help solve the target discrimination problem. Microwave radar and IR sensors have some difficulty discriminating between closely spaced objects; some other technology may be needed to augment these systems. Moreover, the planned family of IR sensors, while extremely capable, will likely require augmentation and improvements as offensive missile defense penetration systems further evolve. The solutions to these challenges are believed to include such actions as the perfection of a laser radar system, development of multicolored IR sensors, the possible adoption of optical signal processing or similar technology, and the exploration of computer integration of multiple signals from small "slices" of each band of the electro-magnetic spectrum (hopefully providing insights not now obtainable).

Laser Radar. A laser radar has the capability to determine an object's size, shape, and activity to an accuracy of less than a centimeter. Essentially, this technology would improve the defense's capability to see inside of the debris and penetration aid clusters that are expected to be incorporated into most advanced ballistic missile warheads. Of the two types of laser radars commonly developed, the laser radar system sought by BMDO would include the capability of measuring angle, range, and range rate, with the latter feature enabling the system to track maneuvering RVs, to include those coning or tumbling. In cases where salvage fusing of offensive warheads result in exoatmospheric nuclear explosions, laser radars will be affected, but are believed to have more potential than their microwave counterparts for "seeing" through some of the disturbance. However, laser radar systems cannot be used to conduct general searches of large spaces looking for targets. By nature, a laser is a very focused beam that must be directed to a precise point. Clouds or smoke degrade, or defeat, laser systems.

Currently, the laser radar is still under development. Although technology demonstration laser radars have been built in the past, none have yet had the power to operate over the long distances required by the missile defense mission.

Multicolored IR Sensors. A number of advanced technology projects are aimed at developing two-color sensors for future missile seekers (will be discussed later). The problem is that the IR band used to identify targets against the coldness of space becomes overloaded if the sensor or seeker rotates so that the "hot" earth appears in the background of the search pattern. When this happens, the target is lost. The opposite also occurs. The IR band needed to track a target against the background heat of earth cannot find the target against the coldness of space. By developing two-color IR sensors, the seeker/sensor can track the target regardless of background. Further development of multicolored IR capabilities is expected to yield improved target tracking and discrimination advances.

Advanced Sensor Technology Program (ASTP). The ASTP is a BMDO-managed technology demonstrator designed to learn how to process and merge the information gained from microwave radars (Navy project), laser radars (Army project), and wide-area and narrow-search IR sensors (Air Force project). Sensor data from this project are collected and fused while in flight (introduces sensor movement). This program is a key component in developing U.S. missile defenses that are more capable of targeting stealthy missiles by improving discrimination capabilities between the accompanying penaids and the RVs. The program is based on the idea that although stealth can be achieved in a single frequency, it is impossible to achieve it across all frequencies. Displaced air-molecules, engine heat, etc. all leave a measurable signal. The key is to have a suite of integrated sensors that can read the signals that are broadcast. The "reading" is accomplished by a fusion processor that builds a composite picture based on multi-sensor inputs (BMDO-managed project). Currently, the components involved in ASTP have not yet been miniaturized, but eventually are expected to be used in ground-, air-, and space-based missile defense sensor suites.

Discrimination Interceptor Technology Program (DITP). DITP essentially is aimed at size reduction. This technology demonstrator is miniaturizing and integrating two of the systems being developed in ASTP (discussed above). The program will integrate a passive, narrow-field (1-2 degrees) infrared sensor and a laser radar, with both sensors sharing a common optical train (i.e., one 20 cm aperture). A key challenge is making the laser radar small enough to fit into an interceptor. If successful in this effort, combining the range and vector capabilities of these two sensors in a common seeker should increase the hit probability of defensive missiles trying to intercept maneuvering targets. The on-board processor will also improve the seekers' capabilities to discriminate between penaids and RVs.

Optical Signal Processor. One of the techniques (discussed earlier) for evading missile defenses was the use of radar jammers or volume maskers (illustrated by the example of the University of Pennsylvania professor elongating 2-18 gigahertz radar signals). These jammers and volume maskers work because radars have long used linear frequency modulation. One option that could be developed to defeat these types of active radar penetration aids would be to develop an optical signal processor that would generate arbitrary or random wave forms of radar signals which would be nearly impossible to jam or fool. (The technology is similar to that being used in experimental computer systems that use light to transmit data.) Adoption of this type of technology would eliminate one of the tools that missile designers may be considering adding to offensive missiles in order to aid their penetration of anticipated future missile defenses.

Spectral Band Processing. The technical community dealing with earth resource satellites discovered that splitting spectral bands provides new information for remote identification of objects. It is believed that band slices could be identified that, when combined into a composite picture using powerful processors, could overcome and defeat stealth efforts and better discriminate among penetration aids, decoys, and RVs. This potential solution to target discrimination for mid-course intercept is still futuristic and will require more research to identify which spectral bands hold the most promise for identifying the lethal RVs. Currently, the earth resources community at the U.S. Jet Propulsion Laboratory has been leading this effort. It is an area in which the missile defense community is likely to become increasingly involved.

On-Board Sensors and Processors. Missile defenses cannot be much more expensive than offensive missile capabilities or potential adversaries could engage in an arms race that would be lost by the defense. Thus, the missile-defense community is sensitive to the need to limit the per missile cost of the interceptor fleet. This need drives the question, how much of the information needed for a missile intercept should be transmitted to the missile's guidance system by high speed communication links to external sensor suites versus the preferred incorporation and use of on-board sensors and processors? The real question behind this issue is cost. Can a miniaturized multi-capable on-board sensor suite with integrated processor be developed at an acceptable price? This issue has not yet been fully resolved.

A key obstacle to the development of future missile defense sensor technologies is the challenge of developing the processing capabilities needed to integrate the outputs of several different kinds of sensors. For example, how does a processor receive several different images of an area, some in a 2-D format and others in 3-D, and determine how these different forms fit together, what information is key to the targeting problem, and what data should be ignored when resolving the differences between inputs? The software algorithms for this task have yet to be developed, and once developed, will undoubtedly prove to be an area that will need constant upgrades as new approaches to solving this complex problem are discovered.

Likewise, there still remains many unanswered questions regarding the interaction of the hardware with its environment. This area of research, called phenomenology, must be further developed if U.S. missile defenses are to be optimally programmed. In essence, phenomenology studies provide the critical measurements necessary to program missile defense sensor suites with the software decision matrices needed to guide the interceptor as the physical environment changes.

For example, if a missile is hit and creates a cloud of debris, what are the effects on the sensor suites and on the signatures of the follow-on missiles? In the same light, phenomenology research measures the precise signatures for various sensors so that a missile launch can be determined from space. It is also this type of investigation that discovers that debris from a broken-up missile provides a brighter infrared signature than does the RV. This type of data is critical if the interceptor's seeker is to discriminate correctly the valid targets from the clutter.

Weapon Technology Needs. The weapons technology should evolve in several directions. First, smarter kill vehicles will need to be deployed on future defensive missile systems as quickly as the technology can be matured. This technology may include integrating multiple sensors into the seeker unit, improving on-board processing, and increasing warhead agility. At the same time, a means must be developed to deal with submunition and bomblet technology. Yet, as the twenty-first century unfolds, it seems clear that directed energy weapons will eventually emerge that can play key roles in defense against missile-based attack. Inquiries need to continue into heretofore unheard of technologies that could provide the type of breakthrough needed to revolutionize missile defenses. As for now, the technologies that are being pursued or that show promise include:


Atmospheric Interceptor Technology (AIT) Program. The AIT program is designed as a demonstrator for the development of a common kill vehicle that could be mounted on all endoatmospheric missile defense interceptors. The kill vehicle (which has only been ground tested) is being built with sufficient flexibility to allow it to be used as a future test platform for technologies still to be developed, such as on-board laser radar. In its current version, the system will feature a strapdown two-color IR seeker, incorporate high density electronics packaging, use advanced algorithms for guidance and aimpoint selection, be built with lightweight materials, and feature a new technology for achieving a cooled window. See Figure 5-8.

The new cooled window feature is of particular interest. Lockheed Martin, the prime contractor for the AIT program, has developed a new silicon window for the IR sensor that includes etched channels that run through the thickness of the window, channels through which a coolant circulates to reduce the temperature of the aperture, while at the same time, wind tunnel experiments indicate that it seems to retain the strength necessary to withstand the tremendous shock and pressure inherent in rocket flight.

This breakthrough is significant in that it has the potential of nearly doubling the sensitivity of the atmospheric IR sensors on tactical missile defense interceptors. The tremendous heating that occurs as a missile races through the atmosphere baths the seeker's window in so much heat that it is difficult for the on-board infrared sensors to "see" through its own IR signal. This problem may have been diminished if flight tests prove the validity of this new cooled-window technology.


Swarm Interceptor Program. The Swarm program is designed to develop an effective kill vehicle for submunition payloads. Under the Swarm concept, some theater missile defense interceptors would be equipped with warheads filled with low cost Swarm kinetic-kill munitions (see Figure 5-9),


each of which would be autonomously guided using a seeker built on a single chip that processes information from a simple photo detector. The 4-inch wide Swarms would maneuver transversely to get in front of their submunition or bomblet targets through the use of a series of small explosive charge detonations. These charges are embedded around the outer ring of the munition (see divert module in Figure 5-10).21 Since the Swarm munition will close with its target at a velocity of about 5 kms per second, the energy generated from impact will destroy CW, BW or conventional submunitions. Although most of the current technology effort is aimed at exoatmospheric intercept, the Swarm could also be adapted for endoatmospheric use. However, due to ABM Treaty provisions Swarm munitions cannot be deployed on NMD interceptors.

Laser Weapon System Projects. Laser knowledge, as a field of research, is expanding rapidly as medical and other commercial uses for laser technology are discovered. Some of this commercial work, such as that involving beam focus and miniaturization, is feeding back into military research efforts. Nonetheless, some research for laser applications will never be conducted by the civil sector. Key among the areas of non-interest are laser weaponization programs. Although there are a number of laser-weapon projects being pursued, four are of note with regard to missile defense weaponization programs. Two of these programs, the Air Force's Airborne Laser and the BMDO's Space-Based Laser, have already been discussed and will not again be covered. The other two are weapons-related technology projects that warrant some attention.

figure 5-11

Mid Infrared Advanced Chemical Laser (MIRACL). This is the most powerful continuous wave laser in the Western Hemisphere. It is located at the U.S. Army's High Energy Laser Systems Test Facility near White Sands, New Mexico, a facility that is also used extensively in support of the Air Force's Airborne Laser and the BMDO's Space-Based Laser pro-grams. The MIRACL is a prototype system that is being worked to over-come obstacles to laser weaponization.

However, until such time as the technology matures to the point that will allow powerful lasers to be miniaturized and maintain a focused beam over great distances, systems such as MIRACL will remain too large to be put into orbit (see Figure 5-11).

As a related note, NASA has proposed a test that would use MIRACL to try to destroy space debris in low earth orbit below 300 kms altitude. If successful, this proposed FY98 test would open the prospects for using this system to clear space junk without the need of launching a system into orbit.22 Of course, the military potential for such a capability is also apparent.

Tactical High Energy Laser (THEL) Demonstrator (related to the Nautilus Program). Nautilus is a technology program designed to research tactical laser technology capable of providing short-range point defense against rockets, artillery projectiles, and missiles. On February 9, 1996, a successful intercept was made of a short-range rocket at White Sands, NM. See Figure 5-12. The February intercept was made using the MIRACL laser on a scaled-down power setting. As a result of the success of the Nautilus program, a new joint U.S.-Israeli effort was launched in July 1996 to further develop this potential capability. Under the agreement, the THEL program was chartered to design, fabricate, and test a demonstrator by about April 1998. The system will have a fairly limited range and require a few seconds of beam focus to detonate each target tracked. In the near-term, the system is seen as having the potential to defend limited-sized areas in northern Israel against sporadic rocket attacks; long-term, it may evolve into a weapon system that is useful under demanding combat conditions.

Microwave Directed Energy Weapons. Russia inherited the microwave anti-ballistic missile defense research program that was begun during the Soviet era. The reported aim of this effort was to develop a microwave "plasma" missile defense system capable of destroying incoming warheads at 50 kms altitude.23 Technologically, microwave weapons would work on a similar principle to the laser, directing high amounts of energy to a focused point. The major advantage that a microwave system might have over the laser is that microwaves, in selected frequency ranges, penetrate cloud cover — an obstacle that tends to defeat laser technology. It would seem that microwave weaponization technology should be investigated to determine its feasibility.

Cruise Missiles. Although not discussed in depth during the course of this study, cruise missiles are obviously becoming a major threat. To deal with the cruise missile threat as part of a unified program, BMDO was assigned the management responsibility for that program element in 1996. This assignment was a natural evolution. As was pointed out in Chapter 1, future military operation will require active defenses against the entire spectrum of air-delivered threats, be they cruise or ballistic missiles, aircraft, or advanced precision-guided munitions. Within these mission areas, there are obviously a number of areas in which the technology requirements will overlap. This is particularly true with regard to command and control and radar detection systems. At the same time, ballistic missile defense is heavily dependent on infrared technology, a technology that does not work well detecting a low-flying cruise missile, for example, in the middle of a rainstorm. Furthermore, cruise missiles flying low to the earth cannot be seen by radar systems unless the radar is positioned so as to look down on the flight path. This requirement spawned initiatives such as the aerostat program to provide platforms for anti-cruise missile radar systems.

The different requirements between portions of the programs raised concerns of defense planners working these issues. Their concern is that after the cruise missile defense portfolio passed to BMDO, administration and congressional budget analysts might remain focused on the previously established budget line for BMDO, without any real increase for the cruise missile element. Since cruise missile defense has heretofore been funded by the services, primarily the Navy, such an action could result in an overall decrease in the amount of funding available for ballistic missile defenses. Although there is a natural confluence among the various missile and air defense missions, the issue of funding requires careful attention.

Other Technology-Related Issues

Technical Challenges

The preceding descriptions and dis-cussions were not intended as an all-encompassing report on the current state of the missile defense program. Rather, the intent was to provide a flavor of the types of challenges and re-quirements that are still to be overcome.

Although many technology development program directors provide very "upbeat" assessments of their particular program areas, when pushed, many admit that in a number of critical areas only token amounts of research is ongoing due to limited funding. Consequently, some of the technology still needed to develop a missile defense capability beyond that of intercepting first generation ballistic missiles may not be ready for insertion in a timely manner. In this regard, it is interesting to review BMDO's list of unsolved challenges (see Figure 5-13).

There are several reasons for this state of affairs:

DoD-wide, Congressional authorization language usually allocates about 12 percent of the budget for advance technology research. BMDO has been allocating about 6 percent to advanced technology.

One explanation provided by a senior BMDO employee is that the organization is "gun-shy" about funding technology development. In the past, during the days of SDIO, all efforts were aimed at technology. BMDO does not want to be portrayed as a "technology only" organization. It may be over-reacting to that concern.

Another explanation offered by a ranking service official is that the missile defense community is afraid to program dollars against technology. When it does, Congress often rejects the request and pockets the cut as cost savings. Consequently, requesting funds for technology research simply "throws away" DoD's programming allocation to the organization.

The pressures on BMDO to be prepared to execute the "three plus three" NMD program (now approaching "two plus three") are also blamed. According to a couple of governmental sources, when additional research funding is obtained, it is usually targeted at the technology needed by the Program Managers to execute their programs. Consequently, much of the research funding is absorbed developing hardware needed "next year."

The resulting situation is an impasse. Under constrained funding levels, Congressional demands for accelerated system deployments are pulling most of the available funding into the procurement process. This trend is reinforced by a fear that Congress is most likely to reduce missile defense budget requests by cutting technology funding. Conversely, the administration is claiming that missile technology is not yet mature and that NMD deployment should be delayed until the technology does mature. Hence, on the one hand, are those who are reluctant to fund future technology requirements but want national missile defenses; on the other hand are those who advocate waiting to deploy national defenses until the underfunded technology program yields mature missile defense technologies.

Organizational Considerations

Historically, the relationship between technology developers and product production engineers (in government, program managers) has been adversarial. Technologists have long complained that applied engineers ignore cutting edge technology in favor of "tried and true" methods and that the production process is heavily infected with a "not invented here" (NIH) syndrome. Conversely, the applied engineering community has long scorned technology demonstrator products, claiming most of them are far from ready for production. They assert that technologists pass off products as "being ready for insertion" much too early in the development process. The applied engineers fear they will accept a new technology and discover later that it contains major problems or that it cannot be downsized or that the end product may be too expensive to manufacture.

In the commercial world, much progress has been made in breaking down the walls that have separated the advanced technology and the applied engineering/production communities. The programs involved in forcing their integration have been given many names. Concurrent engineering and integrated product production teams are but two of them. The other recent change is that companies are increasingly looking outside of their own organization for the new technologies required. In short, technology is becoming a commodity for purchase.

The Department of Defense is also taking steps to try to better integrate and improve its product development process. First, it is establishing registries of government-funded technology projects and expertise. One common complaint has been that it is too difficult to make prime system contractors aware of the work that has already been accomplished and of the technology that is already available. Second, DoD has implemented the use of Integrated Product Teams (IPTs) to manage program development. The team members represent the various governmental offices, agencies, and laboratories that have an interest in the products governed by that particular IPT. The establishment of the IPT process improves the probability that the government will act with one mind when it states its requirements to the contracting community.

Despite the government's efforts to improve its procurement process, it is hampered by its special circumstances. First, the procurement system is governed by hundreds of laws. Although the procurement reform act of 1994 addressed about one-fourth of the laws that the Department of Defense identified as requiring modification, much of the recommended reform was left undone. Second, the commercial enterprises are highly motivated by cost factors. They look outside of their organizations for technology because it makes financial sense to do so. On the other hand, most government contracts are cost plus contracts. As a result, the contractor does not have much incentive to look for technology outside of the corporation. The more work kept inside the company, the better the earnings statement.

Third, the inclusion of government laboratories and program managers (PM) adds a layer of complexity not found in commercial operations. The resulting relationships make it difficult to implement a workable concurrent engineering program. For example, there are several ways that technology can be inserted into a new product. The government usually provides to the prime contractor some components that are contracted directly. Usually these include such items as aircraft engines, black boxes that control classified projects, communications equipment, etc. The government can also specify the use of some technology, such as what kill vehicle will be used on a missile interceptor. However, there are a number of other practical reasons that make it difficult for the government to insert technology into a system that is under development. Understanding the role of the PM is key.

The Program Manager (PM). The PM is the person who drives the program to produce a product that is delivered in accordance with a specified production schedule at a specified cost and within specified performance standards. The careers of program managers rise or fall based on their ability to deliver products according to these criteria. For the PM, determining the needed elements of the program as early as possible allows that program to be stabilized and prepared for production. Once the program is frozen, its costs can be calculated and the production schedule arranged. Program change is a situation to be avoided. Consequently, insertion of new technology into a product that is being prepared for production is difficult:

Cost Factor. The PM has a budget based on the current program and its integral technologies. To insert advanced R&D usually means more dollars since there is usually a cost penalty for changing the configuration baseline of a product. Contractors call these types of changes "feeding the contract," since it is a factor that allows them to raise the price. Consequently, PMs are reluctant to accept a new technology that would require contract modification.

Funding Uncertainty. Advanced technology program funding is prone to disappear. If a PM commits to an advanced technology and the program is cut, the PM's program is also jeopardized. PMs, therefore, prefer to limit risks to their programs by managing their own technology initiatives.

Schedule Risk. Accepting a new technology can put the production schedule at risk. If the estimates on the technology's maturity prove overly optimistic (a common situation), the PM could produce the product late because of the new technology insertion.

Performance Risk. Advanced technologies usually provide enhanced performance characteristics, but at a risk. If the new technologies do not work as specified, the PM delivers a dud. PMs are usually reluctant to take that risk.

Previous Contractual Commitments. A new technology may cause the PM to have to cancel a previous commitment for the component that will be replaced by the new technology. This could entail a cost penalty. In addition, the prime contractor may be resistant to the new technology, particularly if it displaces an in-house technology. Often, the prime contractor bids proprietary technology that gives them a competitive edge, making it difficult to insert outside technology into the system. Perhaps worse is the possibility that the contractor could later deny responsibility for poor product performance based on claimed affects of inserted technology.

Performance-Based Contracting. In the new streamlined acquisition environment, PMs find it more difficult to direct the prime contractor's technology selection. It is akin to telling them how to build the system. On the other hand, the involvement of the government's new Integrated Product Teams (IPT) in the development process may provide more leverage in persuading prime contractors to look at other potential sources of technology for system needs.

The Technologist. Technologists often become frustrated with PMs because they think the PMs are always resisting better ways and new technologies for accomplishing the task at hand. To them, PMs do not want to use the best technologies, nor do they look beyond the task at hand.24 The technology community seems to believe that missile defenses must be managed differently if the country is to have a chance of fielding a system that stays effective against a rapidly evolving threat. Some of the ideas expressed include:

Do not "reach so far" for missile defense technologies. Technologists agree that missile defense systems should be modular so that they can be easily upgraded. A 4-5 year development cycle will just ensure that U.S. missile defense capabilities are always obsolete in terms of the threat. Offensive forces have the initiative to improve penetration technologies and techniques. Defensive systems must be designed for quick upgrades to meet the evolving challenge. Prime contractors must be required to design their systems to facilitate easy product improvement.

A concern with the current missile defense programs is that PMs are trying to freeze them in preparation for production. Several technologists interviewed expressed unhappiness with the idea that the missile defense systems the U.S. fields will contain technology that is 5-6 years old (since the PMs are now positioning themselves for system production).

Small and medium-sized companies produce the best technology, but the big companies are required to make the system work. The challenge is to get the large companies to use the innovative technology produced by smaller firms. This problem has no apparent solution and will not be easily solved.

Require PMs to first shop for technology already developed at government expense prior to contracting for outside development. Currently, PMs are not required to assess the in-house technology products prior to contracting for product development. A number of specialist in the field believe that if the PMs were required to first formally assess the technology already developed or under development (a system used by Ford Motor Company), that a higher rate of technology absorption would occur, benefiting the government in terms of both cost and possibly reduced development time.

To the extent possible, merge technologists and PM organizations. A general belief was expressed that artificial organizational splits that separate technologists and PMs cost the government in lost efficiency and, sometimes, in increased program costs to develop the same technologies twice. There was general agreement that the efforts of the program management operation and the technology development effort needed to be drawn closer together and operate with more unity of effort.


Many technologies are available that offensive missile designers can use to assist their missile systems to evade anticipated U.S. defenses. A number of countries are now including penetration devices or missile maneuvers as integral elements in their missile development programs. Consequently, U.S. missile defense systems will soon confront offensive systems that have enhanced capabilities to evade missile intercept. Since the need for missile defenses does not appear to be a requirement that is going to disappear, a key factor in the fielding of the United States' defenses is how easily can they be upgraded and are those upgrades now in train? Toward this end, the United States needs to ensure that its missile defense program is balanced for sustained operations and that the organizations supporting this effort work as a cohesive whole with a common unity of purpose.

The major focus of the United States' missile defense program should be the establishment of a well-balanced program, a program that is managed with a view that it will still be required 50 years from now. This means that the chain that feeds the technology, develops and applies the upgrades, and services the fielded systems must be maintained with a view towards long-term sustainment. Without that sort of vision, the United States may always be one-step from being able to mount an effective defense against hostile missile systems.

Tactical Missile Flight ProfilesFigure 5-1


1 Maneuver efforts in space result in turns of only 2-3 G forces and would require external instructions to initiate the maneuver at the correct moment necessary to avoid intercept. The maneuvers would have to be executed either as a very large change in direction after the interceptor's booster had burned out or as evasive maneuvers just prior to arrival at the calculated intercept point.

2 The volume masker experiment was related to the author during a telephone conversation with Dr. Ted Postal, Massachusetts Institute of Technology, June 20, 1996. The experiment was pending publication.

3 Norris, Burrows, and Fieldhouse, Nuclear Weapons Databook, Vol. V, op. cit., pp. 382-83.

4 R.C. Webb, Defense Special Weapons Agency, presentation to U.S. Army Space and Strategic Defense Command, "The Effects of Radiation on Space Systems," September 26, 1996.

5 Ibid.

6 R.C. Webb, Les Palkuti, Lew Cohn, Glenn Kweder, and Al Costantine, "The Commercial and Military Satellite Survivability Crisis," Defense Electronics, August 1995.

7 Endoatmospheric flight characteristics were discussed with a number of ballistic missile specialists on a nonattribution basis. Also see Paul Zarchan, Tactical and Strategic Missile Guidance (Washington, DC: American Institute of Aeronautics and Astronautics, December 1994), p. 365.

8 Re`uvaen Pedatzur, "New Missiles Seen Making Arrow Obsolete," Tel Aviv, Ha`aretz, translated in FBIS-NES-95-199, October 15, 1995.

9 Office of the Secretary of Defense, Proliferation: Threat and Response (Washington, DC: U.S. Government Printing Office, April 1996), p. A6.

10 Under normal conditions, anthrax spores (the most popular agent of choice for BW systems) can remain potent for up to 20 years in animal hides and soil. Under abnormal conditions, they can survive even longer. For example, the British dropped some experimental anthrax bombs on an island off the coast of Scotland during World War II. The bombs were inefficient and compacted the spores into the soil. The spores remained in the top 6-8 inches of the soil for over 40 years. U.S. Congress, Office of Technology Assessment, Technologies Underlying Weapons of Mass Destruction, OTA-BP-ISC-115 (Washington, DC: U.S. Government Printing Office, 1993), pp. 78-79.

11 The agreement reached in the Standing Consultative Commission (SCC) was the first of a two-part negotiation. The lower-tier area defense systems and the THAAD system were negotiated in phase one; the Navy Theater Wide (NTW), Airborne Laser (ABL), and the Space and Missile Tracking System (SMTS) are to be negotiated in phase two. The Russian's refused to sign the final phase one agreement until phase two is also negotiated and ready for signature.

12 LEAP is a small, highly maneuverable kill vehicle which is designed to hover in front of an incoming RV or missile, using the resulting kinetic energy of the impact to destroy its target. Some concerns have been raised, however, that the kill vehicle may be of insufficient mass to destroy or disable larger ballistic missile warheads, such as the SS-18 Mod 6 (although as a TMD system, it should not have to kill ICBM warheads).

13 "Limits on Cuing are Unnecessary, Former SDIO Chief Says," Defense Daily, September 27, 1996.

14 Mark Hewish, "Scudkillers: Tough Choices For Boost-Phase Intercept," Jane's International Defense Review, January 1996, p. 31.

15 General Ronald R. Fogleman, USAF, Air Force Chief of Staff, "Theater Ballistic Missile Defense," Joint Force Quarterly, Autumn 1995, pp. 75-79.

16 David A. Fulghum, "USAF Aims Laser at Antimissile Role," Aviation Week & Space Technology, August 14, 1995, pp. 24-25.

17 Frank Oliveri, "USAF Finds Low-Cost Key to Scud Fight," Defense News, November 27-December 3, 1995, pp. 1/29.

18 Phone conversation with George Lewis, Massachusetts Institute of Technology, June 20, 1996.

19 This, of course, presumes that the ABM Treaty will not proscribe such targeting information.

20 This point was confirmed by Lieutenant General Malcolm R. O'Neill, "Statement Before the Committee on Appropriations, Subcommittee on National Security, U.S. House of Representatives," April 17, 1996.

21 Of perhaps some human interest, the embedded explosive charges that maneuver Swarms are an improved derivative of a charge initially developed as a government-funded missile defense advanced technology demonstrator in the 1980s. The charges were later perfected by industry and are now used to deploy automotive air-bag safety restraints. The improved charge has now returned to the government for use as the divert mechanism for Swarm.

22 "Special Alert," Military Space, October 14, 1996, p. 1.

23 For example, see Mikhail Rebrov, "Russia: Discussion of Plasma ABM Weapon," Krasnaya Zvezda, translated in, FBIS-UMA-96-123-S, May 18, 1996; and "Russian Claim On Secret Weapons,' Intelligence Digest, March 29-April 5, 1996, pp. 2-3. The latter article claims that Russia is 6-7 years ahead of the United States in this field.

24 Personal interview with a senior government official on a non-attribution basis, February 23, 1996. The chapter contains information from interviews with 15 government officials or senior employees, four senior industrialists, and two academics. Almost all did not want to be quoted by name or organization.