GAO presented an overview of the Department of Defense's (DOD) Space-Based Laser Program. Space lasers are one of several laser concepts that may some day serve as useful military weapons. Due to the early nature of the technology, a diversity of opinion exists in the scientific, industrial, and defense communities regarding whether current laser and related technologies can support a constellation of space-laser weapons that would be effective and affordable. GAO believes that several important technical uncertainties must be favorably resolved before the issues of effectiveness and affordability are addressed. A GAO review of the existing space laser program and management structure indicated that some measures need to be taken to ensure that the current program is structured to resolve uncertainties in an efficient manner. GAO recommended that the Secretary of Defense: (1) establish a DOD space-laser program plan containing clear and specific milestones and objectives which recognize the relative priority of space lasers within DOD, (2) commit the necessary funds to meet these objectives and to maintain stability of the program selected, and (3) establish a management structure to accomplish program objectives efficiently.