Debate has focused on the nature and immediacy of foreign missile threats to the United States and its interests, the pace and adequacy of technological development, the foreign affairs and budgetary costs of pursuing missile defenses, and implications for deterrence and global stability. For most missile defense advocates the Airborne Laser (ABL) program represents the most promising near-term effort. Currently, the ABL program is the primary focus of the Missile Defense Agency's (MDA) Boost Defense program. Second, although the United States has primarily pursued kinetic energy kill mechanisms for missile defense some 25 years, many defense analysts believe that if the United States chooses to pursue increasingly effective missile defenses for the longer term future, then alternative concepts such as high-powered lasers may be the answer. This report tracks the current program and budget status of the Airborne Laser program. In addition, this report examines several related issues that have been of interest to Congress. This report does not provide a technical overview or detailed assessment of the ABL or Air-Based Boost Program. A number of subcontractors are also involved. The objective to acquire seven production aircraft likely remains. Until recently, Congress has largely supported the ABL program by appropriating the Defense Department's requests, which have totaled about $4.3 billion. For FY2007, the Bush Administration requested about $632 million for the ABL program, which Congress approved. For FY2008, the Bush Administration requested $548.8 billion for the ABL program. In the House version of the defense authorization bill ( H.R. First, the ABL continues to face technical challenges. Specific issues that may confront Congress include the severity and implications of the ABL programmatic and technological challenges, how the ABL might be employed if and when it is fielded, the potential for industrial base problems, the scheduled lethality test, and consideration of boost-phase alternatives to the ABL. There is some consensus on the ABL's current technical challenges. Lethality Test and Contingency Capability Issues

The lethality test now scheduled for August 2009 (some six years later than original plans) is seen as a critical next step in the ABL program's development. The objectives of this test include:
to demonstrate an actual shoot-down of a missile over the Pacific Ocean, possibly a Scud missile; to test the IRST (the Infrared Search & Track System), to see if the ABL can find, hold and track the intended target; and to demonstrate that the adaptive optics systems is able to compensate for atmospheric distortion. Some in the ABL program have suggested that the platform could be made available only as a airborne sensor and for battle management purposes. The ABL is DOD's most mature high power chemical laser program.
The United States has pursued a variety of ballistic missile defense concepts and programs over the past fifty years. Since the 1970s, some attention has focused on directed energy weapons, such as high-powered lasers for missile defense. Today, the Airborne Laser (ABL) program is the furthest advanced of these directed energy weapons in relative terms and remains the subject of some technical and program debate.
The Department of Defense (DOD) has remained a strong advocate for the ABL and its predecessor programs. The Defense Department and most missile defense advocates argue that the ABL, which is designed to shoot down attacking ballistic missiles within the first few minutes of their launch, is a necessary component of any broader U.S. ballistic missile defense system. Until recently, Congress has largely supported the Administration's ABL program.
Funding for the ABL began in FY1994, but the technologies supporting the ABL effort has evolved over 25 years of research and development concerning laser power concepts, pointing and tracking, and adaptive optics. Delayed now for many years, the ABL program plans to conduct a lethality test now scheduled for August 2009. Assuming a successful test, the Defense Department has said that this test platform could then be made available on an emergency basis for a future crisis. To date, about $4.3 billion has been spent on the ABL program, including $632 million for FY2007. For FY2008, the Administration requested $548.8 billion, which was cut substantially in the House and Senate defense authorization bills. Total ABL program costs are not available because the system architecture has not been defined.
Program skeptics continue to raise several issues. Their questions include the maturity of the technologies in use in the ABL program and whether current technical and integration challenges can be surmounted. If the ABL is proven successful, there have been questions about the number of platforms the United States should acquire. Seven aircraft have been mentioned previously, and apparently this number remains the program's objective, but is this number appropriate? What stresses might continued ABL program slippage or delays place on the supporting industrial base? How does the ABL compare to alternative concepts? To what degree should the United States invest in alternative missile defense technologies in the event that the ABL program may not prove successful?
This report examines the ABL program and budget status. It also examines some of the issues raised above. This report does not provide a detailed technical assessment of the ABL program (see CRS Report RL30185, The Airborne Laser Anti-Missile Program, by [author name scrubbed] and [author name scrubbed] (pdf)). This report is updated periodically as necessary.