With eyes in the sky and precision-guided public-health foot soldiers on the ground, Pennsylvania is in the midst of another summertime battle against the West Nile virus and the mosquitoes that bear it. Like other states, Pennsylvania uses rainfall data beamed from NASA satellites to guide mosquito control teams, but this season the Keystone State is taking its space-based surveillance efforts to a new level. In a new pilot program, NASA and state public-health authorities are using eight NASA earth science satellites to gather up-to-the-minute information not only on precipitation but on