Restricted visibility at airports caused by fog significantly impacts commercial and military aviation by presenting a hazard to safe operations and by imposing economic burdens. At critical locations in the final approach, touchdown and rollout Phases of landings, clear and unobstructed visual contact provides the widest margin of safety. Sophisticated avionics have allowed the industry, to some extent, to adapt to visibility-reducing weather elements. Various techniques to eliminate the visibility restriction due to warm fog have been investigated, but none has proven technologically and economically viable. Recently, very successful, efficient laser dissipation of fog in a laboratory environment was carried out under SDIO sponsorship. The technique presents an innovative and practical approach for eliminating airport warm fog. A thorough study of transitioning the laboratory laser dissipation technique to airfield application will be made in Phase I. We will investigate the vacuous types of clearing lasers as well as the options for energy production to pump the lasers. Both radiation and advection fogs will be considered using several drop size distributions for each type. The effect of the laser energy within the effected volumes on temperature, relative humidity, total liquid water and drop size distributions as a function of time will be investigated. Considerable detail on the optical system architecture such as beam control, laser gas handling and reliability through redundancy will be addressed. An assessment will also be made of the potential environmental impacts and safety aspects. Laboratory experiments strongly indicate that an effective, practical laser fog clearing system is possible. Guided by Phase I research, a Directed Energy Fog Dissipation System (DEFDS) will be developed at the sub-scale prototype level during Phase II and at the full-scale level during Phase III. Expressions of financial support for both Phase II and Phase III effort have been received from Kaman Aerospace.
