Air and Space-Based Global Missile Defense
Current Systems and Future Architecture

Defense Support Program - (DSP)
    This is a constellation of satellites that detect missile launches, space launches and nuclear detonations. They are our primary early-warning capability. These satellites are equipped with infrared sensing technologies developed in the 1960s and early 1970s, but since their deployment, have provided uninterrupted coverage. They detected Iraqi Scud launches during the Gulf War, allowing US forces to evacuate civilians and deploy PAC-2 missiles against the Scuds, saving countless lives. The DSP satellites are operated by the 21st and 50th Space Wings, stationed at Peterson AFB in Colorado and Falcon AFB, also in Colorado.

Artist's rendering of a DSP satellite
Space-Based Infrared System - (SBIRS)
    The Space-Based Infrared System is divided into two components, SBIRS-High and SBIRS-Low. 
    SBIRS-High is analogous to, and indeed is slated to replace, the Defense Support Program satellites now serving in the early warning role. The SBIRS-High component will eventually consist of 4 satellites in geostationary orbit over the earth, along with 2 more in highly elliptical orbits. The lead contractor for SBIRS-High is Lockheed Martin. The first SBIRS-High satellite launch is scheduled for 2002.
    SBIRS-Low satellites will be deployed in low earth orbit to track missiles over their entire flight path from launch to re-entry, and provide relaible identification and classification of threats. It also provides the crucial midcourse tracking component, vital to any missile defense program. The entire program is slated to consist of 20 satellites, all in low earth orbit. The first SBIRS-Low satellites are scheduled to be launched in 2004. The lead contractor for SBIRS-Low is TRW.

Diagram of the SBIRS system in operation
Space-Based Laser (SBL)
   The Space-Based Laser program is still in the early stages of development, partially due to underfunding during the Clinton Administration. It has been funded at approximately 10-20% of its originally requested budget. The current stage of the program is the Integrated Flight Experiment (SBL-IFX). It is designed to culminate in a demonstration intercept in space of a boost-phase ballistic missile target. Due to the current funding constraints, this is not scheduled until 2013. The target number of satellites for the SBL in the current plan is 20, operating at a 40-degree inclination to the earth, ensuring maximum threat negation. Estimates of kill times per missile range from 1 to 15 seconds, depending on the range to the target. Retargeting for the SBL has been projected to be as short as half a second, dependent on the angle change required. Estimation of the effectiveness of a 12 satellite constellation against any missile threat from a source other than Russia is 94% in most threat scenarios, so the planned 20 should provide total threat termination, with a potential safety margin. The SBL program is being handled by a team of contractors, including Lockheed Martin, Boeing, and TRW.

Artist's conception of an SBL satellite (courtesy of TRW, Inc)
Airborne Laser (ABL)
   The Airborne Laser program is exactly what it sounds like: a high-energy laser mounted on an aircraft. It was initiated in 1992 to develop a new means of engaging short to medium range theater ballistic missiles such as the Scud, building on the experience of the Gulf War. The Air Force commissioned a study by Boeing to determine what might be the best platform for a high-energy laser and its control systems. The study concluded that the Boeing 747 with a turret mounted would be the best airborne platform. Boeing is the lead contractor for the ABL, and manufacturing is on track, pending approval and testing, to begin in 2003.
Kinetic Kill Vehicles???
   In 1992, the most mature SDI program in terms of technology and of near-term deployment feasibility, Brilliant Pebbles, was killed by then-Senate Armed Services Chairman Sam Nunn (D-GA). High Frontier Chairman Hank Cooper, then head of the Strategic Defense Initiative Organization, has expressed on numerous occassions that this program has been proven in testing, and represents the best option for an effective near-term defense for the United States against the ballistic missile threat. Recently, in hearings before the Senate Armed Services Committee, Assistant Secretary of Defense Paul Wolfowitz specifically mentioned a space-based kinetic kill program. The research, he said, "had been dormant for some time". Yet, the technology exists now, with a minimum of research needed to be ready for deployment. Will we see the resurrection of the Brilliant Pebbles program?

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