How smart have weapons become?
Substantial elements of a real-time, theater-wide surveillance system capable of covering a region 1,000 kilometers (roughly 600 miles) across already existed in the mid-1980s. These elements would be supplemented by a robust theater-wide communications system. Surveillance would be carried out in part by forward observers on the ground and in part by small drone aircraft, equipped with global positioning system (GPS) navigation and with television cameras or other sensors that could obtain precise knowledge of the target position. Once a target was identified and located, attacking weapons were available that could be guided to the target by using a navigation grid common to the sensors and to the weapon.
As demonstrated in U.S. actions in Afghanistan in 2001 and in Iraq in 2003, this capability has been functionally achieved. The laser-guided bombs used during the Vietnam War have been augmented by the addition of highly accurate Joint Direct Attack Munitions (JDAMs). These devices are guided by GPS systems and do indeed “bomb by navigation” on coordinates provided by ground observers, aerial surveillance, or satellite observation. A typical JDAM is a 2,000-pound Mk 84 bomb. A much larger JDAM, a 21,000-pound device called Massive Ordnance Air Blast, or MOAB, was used in Iraq after its first test in 2003.
Despite the advances demonstrated by the U.S. Navy and Air Force, the Army has not yet seen the merit of largely replacing tube-fired artillery shells by GPS-guided rockets. Developing such weapons would be possible within the constraints of the Intermediate Range Nuclear Forces Treaty, which prohibits the United States and Russia from possessing ground-based ballistic or cruise missiles with a range between 500 and 5,500 kilometers. A ballistic missile with a range of 480 kilometers would give the Army the ability to mass accurate fire from secure areas onto targets across an entire theater. In contrast with a conventional howitzer, which has a range of only about 40 kilometers and might miss its target by as much as 150 meters, the probable error for GPS-guided rockets of any range is likely to be in the 5-meter range. The rockets also can be arranged for simultaneous arrival on target, with final approach from any desired angle.
The contribution of JDAMs has been realized in conjunction with an integrated targeting and communication system, including the possibility of changing the target coordinates in the individual weapons while the delivery aircraft is in flight. Similar in accuracy to laser-guided bombs, JDAMs offer the important capability of being able to work in cloud or smoke, and they can attack dozens of individual targets in a region tens of kilometers across from a single release of multiple bombs by a B-52 or other large aircraft.
Only extra care will prevent guided bombs from “accurately” destroying the wrong targets by mistake, as happened with the Chinese embassy in Belgrade. But it would be highly desirable in any case to add a feature to ensure that such weapons explode in the air rather than on the ground if their guidance system malfunctions or if surveillance shows a civilian bus approaching the target area.
The problem with missile defense
The Bush administration has placed great emphasis on National Missile Defense (NMD), focused on a possible North Korean attack on the United States using intercontinental ballistic missiles (ICBMs) bearing nuclear warheads. But as early as 1968, Hans Bethe and I warned that a missile defense that cannot deal with feasible countermeasures is worse than no defense at all. That, unfortunately, characterizes the midcourse interceptor system under development by the Pentagon. My colleagues and I have shown, for example, how balloons released by an ICBM could serve as credible decoys for a tumbling warhead, itself encased in a similar balloon, thus preventing intercept of a nuclear payload.
On the other hand, boost-phase intercept (BPI)-striking the missile before its rocket engine has driven it to full ICBM speed-has a real capability against the Taepo Dong 2 ICBM that North Korea has been expected to test since 1998. BPI would work against North Korea because the territory is small and almost surrounded by international waters. But progress has been slow in developing BPI, in large part because the administration has emphasized the ineffective midcourse system and to some extent because BPI would be more difficult to use against a missile launched from the much larger territory of Iran and, until the recent war, Iraq. Yet solving the most urgent problem first-North Korea-has some merit.