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Editor's Note: In order to place the APS boost-phase study in context, APS News asked James Riordon to find out what the current and projected plans of the Department of Defense are for boost-phase missile defense. His report follows.
The Boost Defense Segment (BDS) of the Ballistic Missile Defense System is intended to defeat missiles in the initial, 3 to 5 minute, powered phase of a launch. The ability to intercept a missile in the boost phase could potentially destroy a missile regardless of its range or intended target, and would provide missile defense for the US and its allies around the world. According to Department of Defense (DOD) documents, "When possible, for the global coverage and protection against more lethal payloads it can provide, a capability to intercept a missile near its launch point is always preferable to attempting to intercept that same missile closer to its target."
Missile Defense Agency (MDA) documents often define BDS capabilities in terms of reducing the "safe havens" of potentially threatening states. A safe haven is the region from which a nation could launch a missile that is outside the range of interception by a boost-phase defense system. According to DOD documents, a comprehensive, space-based BDS could theoretically eliminate safe havens entirely. Initial annual funding for the BDS stood at $600 million in fiscal year 2002 (compared to the total missile defense budget of more than $9 billion), and is planned to rise steadily to $2.275 billion in 2007. MDA plans call for a functioning BDS system to be in place by 2010.
Two types of BDS concepts are currently in development: kinetic energy interceptors, and directed energy systems. Boost phase kinetic energy interceptors are rocket-propelled kill vehicles that collide with ballistic missiles. After the launch of a threatening missile is confirmed (this can take about a minute) the interceptor must be fired within seconds. Moreover, the bright exhaust plume-several times larger than the target itself-can obscure the target as the interceptor approaches. The first realistic tests of kinetic energy BDS systems are scheduled for 2008-2009.
The BDS systems currently being studied consist of lasers mounted aboard aircraft or satellites. Lasers are only practical for missile defense during the initial phase of a missile trajectory because they are intended to compromise the integrity of the comparatively delicate booster while it is pressurized. Long range ballistic warheads are hardened to withstand reentry, so, ballistic missiles are typically not vulnerable to laser heating during later stages of their trajectories.
According to DOD officials, lasers have successfully destroyed missiles in a number of tests to date. In the early 1980's, the Airborne Laser Laboratory's carbon dioxide laser, mounted in a KC-135 military aircraft, shot down five AIM9-B Sidewinder air-to-air missiles during proof of concept flights. There was also a successful test in June 2000 using the Tactical High Energy Laser (THEL) to shoot down a Russian- made Katyusha rocket at White Sands Missile Range in New Mexico In August and September of 2000, the THEL shot down four more Katyushas.
The prototype Airborne Laser (ABL) is a high-energy, chemical oxygen iodine laser (COIL) system mounted in a highly modified Boeing 747 airplane. The ABL aircraft is designed to operate above the clouds where it can acquire and track ballistic missiles during boost phase flight. The first ABL aircraft completed its maiden flight over western Kansas on July 18, 2002. The ABL is scheduled to conduct a realistic lethality demonstration, by shooting down a ballistic missile, in 2005. Shortly thereafter, the ABL is anticipated to be available for deployment in emergency situations, although the final BDS will not be in place until 2010. A proof-of-concept Space Based Laser (SBL) experiment is planned for 2012.
BDS systems comprise a portion of the layered ballistic missile defense program, along with mid-course and terminal-course kinetic energy defense systems. According to DOD officials, the boost phase interceptor development is currently on track. Schedules for the three efforts are independent, say officials, and delays in mid-course or terminal programs are not expected to affect BDS development.
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