Boost Defense Segment (BDS)
The mission of the Boost Defense Segment (BDS) is to define and develop boost phase intercept (BPI) missile defense capabilities. The capabilities defined and developed in the BDS will progressively reduce the "safe havens" available to a hostile state. A "safe haven," is formed by geographic and time constraints associated with BPI. It is the region of a state from which it can launch a missile safely out of range of a potential boost phase intercept. To engage ballistic missiles in this phase, quick reaction times, high confidence decision-making, and multiple engagement capabilities are needed. The development of higher power lasers and faster interceptor capabilities are required to reduce the size of safe havens, whereas development of viable space-based systems could potentially eliminate them entirely. Thus, resources have been allocated to develop both kinetic and directed energy capabilities in an effort to provide options for multiple engagement opportunities and basing modes to address a variety of timing and geographic constraints.
There were initially four principal objectives for the BDS as of 2002. First, it will seek to demonstrate and make available the Airborne Laser (ABL). Second, it will define and evolve space-based and sea-based kinetic energy Boost Phase Intercept (BPI) concepts in the next two to four years, supporting a product line development decision in 2003-2005. This effort will include concept definition, risk reduction activities, and proof-of-concept demonstrations. For example, the sea-based boost program is considering a high-speed, high-acceleration booster coupled with a boost kill vehicle. This same booster will be evaluated (with a different kill vehicle) for sea-based midcourse roles. Third, the BDS will execute a proof-of-concept Space-Based Interceptor Experiment (SBX). Fourth, the BDS will also continue Space-Based Laser (SBL) risk reduction on a path to a proof-of-concept SBL Integrated Flight Experiment (SBL-IFX) in 2012. At appropriate times, MDA will insert mature system concepts and technologies into product line development and deployment.
By 2008 Program Element 0603883C, Boost Defense Segment (BDS), funded the Airborne Laser (ABL) element portions of the Ballistic Missile Defense System (BMDS). The ABL provides a capability to destroy ballistic missiles in the boost phase of their trajectory, the segment from post launch through propellant burnout. The boost phase typically includes the first 60-300 seconds of flight and concludes at altitudes between 20-450 kilometers. The ABL program is designing, building, and testing an airborne laser system with unique capabilities to provide boost-phase defense against ballistic missile threats by acquiring, tracking, and destroying ballistic missiles and to support the multi-tiered BMDS concept.
Successful BDS operational concepts could be fully integrated with midcourse and terminal elements in the overall BMD System. In accordance with the overall BMD acquisition strategy, BDS will employ multiple paths and acquisition methodologies to deliver initial capability blocks as soon as practical, and upgrade the initial capabilities over time.
Kinetic boost phase intercept is a challenge because the threat missile must be detected and confirmed within a few seconds of launch. It then becomes a race between an accelerating ballistic missile and the interceptor in which the threat missile has had a head start. Another technical challenge is designing a kill vehicle that can detect and track the target following missile-staging events and then impact the missile in the presence of a brilliant plume.
But boost-phase defense introduces significant challenges. First, the boost phase is relatively short. This means that sensors will have to detect a launch and relay accurate information about the missile very quickly. Second, an interceptor missile would have to be very close and/or extremely fast to intercept the accelerating missile. An effective boost-phase defense high-energy laser system could reduce or eliminate several of the complications associated with employing boost-phase interceptor missiles.
Decoy trajectories in the boost phase have major differences with respect to the mid-course or terminal phase counterparts. In the boost phase, the decoy begins to decelerate and separate from the real target following ejection. The decoy separation and deceleration are a big advantage from the defense system point of view. Since the decoy separates from the target, it may be possible to discriminate the decoy and the real target from each other in position. Since the decoy separates from the target smoothly, there is always a chance of transferring the sensor lock to the decoy. If the sensor is not able to reacquire the real target, the miss distance may be on the order of tens of kilometers depending on when the decoy is launched and which sensors are affected. Sensors may be able to reacquire the target. Even if the target is reacquired, there is always a chance of failure depending on when the decoy is launched and how long it takes for the sensors to reacquire the target.
Use of IR decoys is extremely ineffective due to the large amount of energy radiated by the missile plume upon launch. Designing LEO sensors with narrow instantaneous fields of views may increase the signal-to-clutter ratio greatly during intercept. IR sensors, being more resistant to the electronic attack, are the key sensors to keep the miss distance at acceptable levels.
Boost- phase interceptors orbiting in space were vulnerable to attack, technically challenging, and expensive to deploy, given the number needed for enough always to be on station.
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